CivilEng doi: 10.3390/civileng7030063

Authors: Zixian Zhou Yaqiang Yang Dongdong Zhao

A field-oriented, real-time implementation of the previously developed vision-based bridge weigh-in-motion (V-BWIM) framework is presented for vehicle-load monitoring under variable-speed and mixed-traffic conditions. Vehicle and wheel positions are obtained through YOLOv5-based object detection, binocular measurement, and coordinate transformation, whereas bridge responses are measured by strain gauges and synchronized with the vision-derived axle trajectories. A field-image dataset constructed from full-scale bridge experiments is used to compare object-detection performance, inference efficiency, and model complexity, and YOLOv5s is selected for field implementation. The calibrated bridge influence line is then combined with synchronized axle positions and structural responses for axle-load identification. Controlled field tests on a simply supported bridge quantitatively evaluate vehicle positioning and load identification under constant-speed, variable-speed, and two-vehicle car-following conditions. A further continuous-beam bridge experiment demonstrates vehicle-information estimation under random traffic. Because independent reference weights were unavailable for the randomly passing vehicles, the continuous-bridge results are interpreted as a field demonstration rather than an independent validation of load-identification accuracy.

CivilEng doi: 10.3390/civileng7030062

Authors: Liuyang Ji Shijie Soong Zhe Hong Zhilong Zhao Bo Nan

The compressive strength of 3D-printed concrete (3DPC) varies with the loading direction, and the lowest-strength direction is not fixed across printing groups. Testing in a limited number of directions may miss the governing direction and bias the acceptance decision toward false acceptance. This study used the RILEM TC 304-ADC interlaboratory database comprising 27 laboratories, 34 printing groups, and 907 directional compressive test specimens. Exact sampling-without-replacement enumeration and leave-one-laboratory-out (LOLO) cross-validation were used to evaluate the relationships among directional coverage, false acceptance, and specimen consumption. The observed governing directions of the 34 printing groups were distributed across the U, V, and W directions. At an operational threshold of 40 MPa, the observed false-acceptance rates of the single-direction V3 and two-direction VW6 strategies were 13.7% and 10.6%, respectively, compared with 4.9% for the complete-direction UVW9 baseline. The early-acceptance strategy reduced the expected specimen count from 9.00 to 4.97, a reduction of 44.8%, but the observed false-acceptance rate increased from 4.93% to 9.15%. The risk difference was 4.22 percentage points, exceeding the 2.5-percentage-point screening criterion. Under the restricted-direction strategy, partial-direction results could trigger only early rejection, and final acceptance required complete U, V, and W directional evidence; the strategy therefore produced no acceptance decisions beyond those of the UVW9 baseline. In the present evaluation set, the restricted-direction strategy yielded group-by-group decisions identical to those of the UVW9 baseline, with an expected specimen count of 6.49, a reduction of 27.9% (95% interval 16.8% to 39.9%). Adaptive direction ordering saved 0.47 specimens relative to the original fixed order, and a simple fixed order that tests the most frequently governing direction first achieved the same saving; the overall savings arose primarily from printing groups that did not meet the strength requirement. Overall, the results show that cross-directional historical information can optimize the testing order and identify nonconforming printing groups earlier, whereas final acceptance should continue to require complete directional evidence. In production settings where staged specimen preparation and testing are feasible, this procedure could reduce the cost of destructive testing and bring forward the review and process correction of anomalous printing groups.

CivilEng doi: 10.3390/civileng7030061

Authors: Geetika Mishra Irene Verdu Christopher M. Sales Yaghoob (Amir) Farnam

The effective delivery of bio-functional agents into cracked concrete remains a critical challenge for achieving reliable microbially induced calcium carbonate precipitation (MICCP)-based self-healing. This study investigates a hydrogel-assisted delivery approach using sodium alginate (SA) to facilitate the transport and distribution of Lysinibacillus sphaericus within subsurface cracks. An artificial crack (~0.2 mm width) was created in mortar specimens to provide a defined and localized pathway for hydrogel delivery. SA hydrogels at different concentrations (2%, 4%, and 6 wt%) and temperatures (20 °C, 40 °C, and 60 °C) were injected inside the crack in both types of samples with and without channels. The transport behavior was quantified through ImageJ analysis, while biological performance was evaluated using optical microscopy, thermogravimetric analysis (TGA), and X-ray computed tomography (X-CT). The results showed that 2% and 4 wt% SA hydrogels achieved >95% infiltration of the crack volume and with a minor influence of the drilled channel, indicating effective transport through the crack and pore network. Optical microscopy confirmed bacterial distribution throughout the crack depth. TGA showed about 18.23 mg and 8.14 mg higher CaCO3 precipitation in bacteria-treated specimens than in controls at 7 and 28 days, respectively, demonstrating MICCP activity. X-CT visualization further showed substantial crack filling in the bacteria-treated specimens, with an estimated 86.4% of the crack volume occupied by bio-products and a hydrogel matrix. These results demonstrate that an appropriately selected SA concentration and temperature can facilitate targeted bacterial delivery and MICCP-based crack filling.

CivilEng doi: 10.3390/civileng7030060

Authors: Yasuko Kawahata Noriaki Maeda Shunsuke Hatadani

Background and Objective: The deterioration process of infrastructure is increasingly modeled to include sudden extreme risks (jump phenomena) that lead to sudden collapses. Mathematically formulating these non-continuous transitions as partial integro-differential equations (PIDEs) introduces significant computational challenges due to the non-locality of the integral term, complicating analytical derivations for optimal inspection intervals. This study aims to construct a theoretical computational framework to evaluate the boundaries of existing analytical methods and explore AI-based dynamic maintenance strategies under assumed jump–diffusion scenarios. Approach and Methodology: To address these computational challenges, this study first evaluates continuous degradation limits using perturbation methods and Physics-Informed Neural Networks (PINNs) on synthetic datasets as a baseline. Subsequently, we propose an AI-based dynamic maintenance strategy utilizing a recurrent neural network (RNN) architecture designed to reconstruct the deterioration context from sparse sequential observation histories. To analyze the extreme risks driven by the assumed non-local jumps, we executed ultra-large-scale Monte Carlo simulations reaching N=109 iterations, numerically comparing the RNN approach with simple state-threshold rules (Markovian approaches) under idealized conditions. Conclusions and Social Significance: The computational experiments demonstrated that within the synthetic framework, the RNN-based strategy yielded a theoretical jump-miss error rate of 2.74%. However, because this outcome relies heavily on increased unconstrained inspection frequencies and the network’s ability to identify synthetic correlations rather than genuine physical precursors, it serves as an illustrative proxy rather than a fully controlled comparison. Furthermore, the jump intensity distributions and cost models lack empirical justification from field data. Despite these fundamental limitations, this research provides a conceptual numerical baseline for integrating deep learning with stochastic jump–diffusion models, highlighting the critical need for rigorous empirical benchmarks in future dynamic asset management studies.

CivilEng doi: 10.3390/civileng7030059

Authors: Gonzalo Martínez-Barrera Miguel Martínez-López Juan Enrique Martínez-Martínez

In the construction industry, there is a growing demand for materials with mechanical properties that surpass those of conventional options. Polymer concrete, composed of polymer resins and mineral aggregates, exhibits superior mechanical performance compared to traditional cement-based concrete. However, its relatively low ductility limits its application in load-bearing structures. To address this limitation, reinforcements such as polyester fibers can be incorporated to enhance ductility. Additionally, gamma radiation has been shown to effectively improve the toughness of polymer concrete. In this study, the effects of marble particle size (0.71, 1.4, and 2.36 mm), polyester fiber content (0.1, 0.3, and 0.5 wt%), and gamma radiation dose (50, 100, and 150 kGy) on the mechanical properties of polymer concrete were investigated. The results indicate increases in compressive strength, deformation capacity, modulus of elasticity, and dynamic modulus. These improvements are attributed to radiation-induced modifications in the morphology of the polyester resin, polyester fibers, and the overall polymer concrete matrix.

CivilEng doi: 10.3390/civileng7030058

Authors: Chan-Huy Mai Nhat-Nam Nguyen Khanh-Hoang Vu Nhat-Quang Nguyen Doan-Dang-Khoi Nguyen Duc-Duy Ho

This paper proposes a data-driven strategy leveraging the XGBoost (Extreme Gradient Boosting) algorithm to accurately predict the required reinforcement and the deflection of reinforced concrete (RC) slabs in real-world high-rise buildings. To achieve the objective, two distinct predictive models with tailored input parameters are developed. For estimating the required reinforcement ratio, the model incorporates the span direction, location, span length, slab thickness, beam height, and the design strengths of both concrete and steel. Meanwhile, for assessing the maximum deflection of the slab, the input parameters are streamlined to the span direction, span length, concrete strength grade, slab thickness, and the reinforcement area. The model evaluation results demonstrate robust predictive performance as a fast, finite element analysis-based surrogate tool, achieving a coefficient of determination (R2) of 0.971 for reinforcement ratio estimation and 0.974 for deflection prediction when validated against code-compliant finite element analysis data from a real-world high-rise building. Furthermore, the model’s cross-project transferability is successfully verified on an independent structural project within the same design-code domain. Overall, this paper demonstrates that the proposed dual-architecture XGBoost framework effectively approximates time-consuming finite element calculations, significantly accelerating preliminary design iterations while contributing to the advancement of data-driven civil engineering workflows.

CivilEng doi: 10.3390/civileng7030057

Authors: Jinhong Xie Tao Yang Gang He Haizhou Feng Tao Peng Hao Zheng

In Southwest China’s mountainous areas, subgrade slopes are prone to strain softening and progressive failure under rainfall conditions. To clarify the failure mechanism and evaluate slope stability, this study adopts the displacement-isosurface-based local slip point safety factor method incorporating element stress–strain relationships. Its applicability to strain-softening slopes is examined by comparing the calculated low-value zone of the local slip point safety factor with the observed slip surface of a weak-interlayer subgrade slope. Numerical analyses are conducted to investigate the progressive failure behavior of subgrade slopes, considering both global strain softening and weak-interlayer softening. The method is subsequently applied to a case study of a subgrade slope supported by anti-slide piles in Yunnan Province. The results indicate that for strain-softening subgrade slopes, progressive failure manifests as typical retrogressive sliding. Due to stress concentration at the slope toe, strength degradation initiates in this region and progressively extends upward, forming a potential slip zone. This eventually leads to the instability of the upper slope. Thinner weak interlayers and steeper dip angles accelerate the development of retrogressive failure, while multi-level bench configurations can delay its progression. Sensitivity analysis shows that, within the examined range, the plastic shear strain threshold mainly affects the degree and progression of strength degradation but has limited influence on the principal distribution of the local slip point safety factor. After replacing the weak interlayer, the risk of retrogressive failure is significantly reduced, and the local slip point safety factor meets engineering design requirements. By jointly examining the strength degradation coefficient and local slip point safety factor, this study characterizes the spatial evolution of retrogressive failure and supports reinforcement design for strain-softening subgrade slopes.

CivilEng doi: 10.3390/civileng7030056

Authors: Hao Cheng Jiashun Tang Jianghao Liu Yaolin Liu Xiangrong Guo

Continuous rigid-frame bridges with standardized spans are increasingly favored in high-speed railway networks owing to their stable structural mechanics and economical lifecycle maintenance. Despite their widespread adoption, comprehensive quantitative analyses detailing wind–vehicle–bridge coupled dynamic interactions remain notably sparse, particularly under the combined excitations of high-speed transit and overall track geometry deviations, which incorporate both stochastic irregularities and deterministic long-term deck creep. To bridge this knowledge gap, the present study investigates the dynamic stability and operational safety of a 4 × 40 m continuous rigid-frame bridge featuring a specialized parallel double-box cross-section. Initially, the tri-component aerodynamic force coefficients for this coupled system are extracted utilizing computational fluid dynamics (CFD) simulations. Subsequently, a three-dimensional wind–vehicle–bridge interaction model is formulated. This governing dynamic framework integrates turbulent wind pressures and track geometry deviations as external excitations. The mathematical derivation of this model is fundamentally based on d’Alembert’s principle. Utilizing this advanced model, the transient dynamic responses of traversing CRH6 trainsets are systematically evaluated across a comprehensive matrix of environmental lateral wind velocities, ranging from 0 to 30 m/s, and operational speeds varying between 120 and 200 km/h. The computational outcomes demonstrate that both the vehicular accelerations, in lateral and vertical directions, and the structural deflections strictly satisfy stringent statutory safety limits across all simulated environmental scenarios. This ensures satisfactory ride comfort and running stability for the high-speed trains. Ultimately, this research substantiates that the investigated bridge topology maintains an adequate dynamic safety margin even under severe crosswinds. It does not constitute a kinematic bottleneck for the maximum operational speed of the railway corridor under the modeled conditions. These insights establish a solid theoretical foundation for the aerodynamic design and safety evaluation of analogous high-capacity rail infrastructure.

CivilEng doi: 10.3390/civileng7030055

Authors: Jia Li Weikang Kong

To achieve proactive preventive maintenance of green and low-carbon infrastructure, this study systematically investigated the long-term durability and resistance degradation of prefabricated recycled aggregate concrete (RAC) bridge components. A 80-month multi-field coupled damage experiment under sustained flexural loading, natural atmospheric exposure, and chloride drying-wetting cycles was conducted, and an in-situ physical exposure and multi-source data-driven Support Vector Regression (SVR) dynamic surrogate model was established. Results indicate a prominent time-dependent ebb-and-flow mechanism of degradation drivers: environmental and stress boundaries dominate the early stage, whereas the material replacement rate (Rr) surges to become the absolute dominant driving variable (36.8%) in the ultra-long term (t=80 months), proving the cumulative dominance of recycled aggregates. Concurrently, the residual capacity exhibits a distinct two-stage decay characterized by a 10% critical reinforcement mass loss threshold, beyond which the degradation rate of RAC100 accelerates to 1.63 times that of conventional concrete. Driven by the multi-stage injection of in-situ experimental inspection data (surface crack profiling, 2D spatial chloride profiles, and rebar mass loss), the SVR network successfully achieves a collapse-like convergence of the remaining useful life (RUL) confidence interval, precisely locking the RUL of the RAC100 component at 34.5 years within a 1.4-year error margin. This framework provides critical algorithmic support for the life-cycle safety paradigm shift in low-carbon structures.

CivilEng doi: 10.3390/civileng7030054

Authors: Mohammadreza Kenarkoohi Munzer Hassan

This research evaluates the seismic resilience of lifeline bridge columns in Vancouver, British Columbia, by comparing traditional reinforced concrete (RC) columns with an equivalent circular concrete-encased steel (CES) system. Designed to meet the stringent performance-based requirements of CSA S6-25 and the BC Ministry of Transportation and Infrastructure (MoTI) Supplement, the structures were analyzed under a suite of ground motions representing the complex crustal, subcrustal, and subduction hazards of the Pacific Northwest. Nonlinear fiber-discretization modeling, validated against experimental data, was employed to assess damage progression and serviceability limits through comprehensive pushover, moment-rotation, and nonlinear time-history analyses. The results demonstrate that while both systems satisfy lifeline criteria, the CES configuration provides a superior safety margin due to the presence of the encased structural steel core. This internal steel member maintains vertical load capacity and extends the stable displacement plateau beyond the capacity of conventional RC, effectively reducing reinforcement strain and facilitating immediate post-seismic recovery. These findings highlight circular CES piers as a highly resilient alternative for critical transportation infrastructure in high-seismicity regions.

CivilEng doi: 10.3390/civileng7030053

Authors: Kai Cui Lichuan Wang Zheng Yang

Expansive mudstone tunnels often suffer long-term convergence and support damage because excavation-induced unloading is coupled with water-induced swelling. This study proposes a particle flow modeling framework for expansive mudstone tunnels by linking tunnel-wall displacement, swelling pressure, and the equivalent particle radius expansion coefficient. Constant-volume swelling pressure tests were first conducted to determine the representative swelling pressure of the mudstone. An independent confined particle model was then established to calibrate the relationship between macroscopic swelling pressure and microscopic particle expansion. The results show that a stable swelling pressure of 300 kPa corresponds to an equivalent particle radius expansion coefficient of 3.11%. Incorporating this calibrated swelling mechanism into the tunnel model indicates that swelling intensifies excavation-induced damage, increasing the final crack number from 1566 to 1852 and enlarging the equivalent damage-zone diameter from 21.6 m to 22.8 m. Under the original support scheme, the damage depth reaches 5.45 m, and the final crown settlement reaches 177.6 mm. After reinforcement, these values decrease to 3.40 m and 81.1 mm, respectively. Field monitoring confirms the predicted deformation-control trend. The proposed framework provides a practical approach for simulating swelling-induced damage evolution and optimizing support design in expansive mudstone tunnels.

CivilEng doi: 10.3390/civileng7030052

Authors: Jianghao Liu Shipeng Wang Xinhang Zou Xiangrong Guo

Long-span road–rail steel truss bridges require support-level vibration mitigation without compromising bridge serviceability, train-running safety and comfort, or environmental vibration control. This entirely numerical study establishes coordinated vehicle–bridge interaction (VBI) and vehicle–bridge–soil models for the Wuchang-side 8×100 m continuous steel truss approach bridge of the Baishazhou road–rail Yangtze River Bridge. Ordinary steel bearing and anti-vibration spherical steel bearing (AVSSB) schemes are compared under the same track irregularity, train speeds, and one-to-four-line operating cases. Finite AVSSB vertical stiffness produces only limited modal shifts, reduces the impact coefficient by up to 4.4%, and reduces the selected pier lateral acceleration by up to 13.7%, without a discernible deterioration in the derailment coefficient, wheel-load reduction ratio, carbody acceleration, or Sperling comfort index at the reported precision. Frequency selectivity is important in engineering terms because reducing a narrow medium- or high-frequency component does not necessarily reduce the low-frequency-dominated overall ground vibration index. The practical contribution is therefore a system-level screening procedure; an AVSSB may be adopted as a dynamically compatible support modification when selective structural vibration reduction is required, but the speed and multi-line operating scenarios must still be checked independently for environmental vibration compliance.

CivilEng doi: 10.3390/civileng7030051

Authors: Areej Abbasi Malindu Sandanayake Guomin Zhang

Infrastructure systems play a critical role in shaping environmental performance, economic investment, and social well-being. Infrastructure systems are responsible for nearly 60% of global greenhouse gas (GHG) emissions. Pavement construction and maintenance alone consume over 350 million tons of asphalt annually and account for 30% of public infrastructure expenditure. While sustainability frameworks increasingly emphasize the integration of environmental, economic, and social dimensions commonly conceptualized as the Triple Bottom Line (TBL), their application in pavement engineering remains uneven. This study investigates the extent and nature of TBL integration in pavement sustainability research through a combined scientometric and qualitative content analysis of 529 peer-reviewed publications indexed in Scopus between 2015 and 2025. Using a PRISMA-guided review protocol, the study maps publication trends, geographic distribution, and thematic evolution, and systematically classifies each study according to its level of sustainability integration. The results reveal a pronounced imbalance across sustainability dimensions. Only 7.4% of studies achieve full TBL integration, while 45.2% address a single dimension and 29.1% remain primarily technical with limited sustainability framing. Environmental and economic dimensions are consistently operationalized through standardized methodologies such as Life Cycle Assessment (LCA) and Life Cycle Costing (LCC), whereas social sustainability appears in less than 10% of studies and is typically represented through simplified or proxy-based indicators. The findings suggest that this imbalance is not solely a result of data or awareness limitations but is associated with prevailing methodological preferences that favour quantifiable and optimization compatible indicators. These tendencies create systematic challenges for integrating context-dependent and participatory social considerations into engineering decision-making frameworks. By highlighting these structural patterns, the study contributes to ongoing discussions on sustainability governance and calls for more inclusive, methodological plural approaches to infrastructure assessment. The paper concludes by outlining pathways for advancing TBL integration through standardized social indicators, participatory assessment methods, and alignment with emerging ESG reporting requirements.

CivilEng doi: 10.3390/civileng7030050

Authors: Ahmed Hemida Magdy Abdelrahman Ahmed S. El-Ashwah

This study evaluates waste-derived used motor oil (UMO) as a softening and viscoelastic rebalancing agent for a sustainable asphalt binder incorporating guayule resin and crumb rubber modifier (CRM). ARG75(20):25 contained 75% asphalt rubber (20% CRM by asphalt weight) and 25% guayule resin, replacing 37.5% of asphalt (PG 64-22). CRM reinforced high-temperature performance, whereas the guayule-containing ARG system exhibited intermediate- and low-temperature stiffness, preventing PG 64-22 compliance. UMO at 1%, 3%, and 5% by total binder weight was evaluated using rotational viscosity, dynamic shear rheometer, bending beam rheometer, multiple stress creep and recovery (MSCR), black space analysis, and Fourier transform infrared (FTIR) spectroscopy under original, RTFO, and PAV aging. UMO reduced stiffness while maintaining Superpave rutting thresholds. MSCR showed lower Jnr,3.2 at 1% and 3% UMO, and higher R3.2 across dosages than base asphalt, despite increased stress sensitivity. Viscosity decreased, indicating improved flow. Continuous grades shifted from PG 73-16 to PG 70-19, PG 66-21.6, and PG 65-23 at 1%, 3%, and 5% UMO, respectively. FTIR showed attenuated PAV carbonyl development with 5% UMO; sulfoxide development remained comparable. The 3% dosage showed the best balance, whereas 5% UMO alone met standard PG 64-22 criteria, establishing binder-level feasibility for mixture- and pavement-level validation.

CivilEng doi: 10.3390/civileng7030049

Authors: Jiejia Guo Bin Shi Zhen Liu

Coplanar capacitance detection exhibits remarkable advantages in the detection of road texture in asphalt layers, including high sensitivity and minimal environmental constraints. However, the inherent performance contradiction between signal strength and penetration depth of traditional interdigitated coplanar capacitance sensors (ICCSs) has restricted their widespread application in road texture detection. To address this issue, a hybrid approach combining response surface methodology (RSM) and non-dominated sorting genetic algorithm II (NSGA-II) is developed to optimize the structural parameters that influence the signal strength and penetration depth of a novel ICCS. Initially, a central-composite design (CCD) based on RSM is employed to establish statistical models for the two key sensing performances of ICCSs, namely signal strength and penetration depth. Subsequently, Analysis of Variance (ANOVA) and three-dimensional (3D) response surface plots are utilized to investigate the significant effects of various structural parameters (electrode length, width, and inter-finger gap) on the two sensing performances. Furthermore, NSGA-II is applied to search for global optimal solutions using the established statistical models, thereby achieving multi-performance optimization of the ICCS. Finally, the fabricated ICCS is used to detect the surface texture of asphalt mixture specimens with different gradations, and the results are compared with those obtained by laser point cloud detection. The results indicate that both statistical models are highly significant, with the coefficient of determination (R-squared) exceeding 0.95. All individual structural parameters have a significant impact on the two sensing performances. Based on the optimization by the RSM-NSGA-II hybrid method, the predicted optimal parameters are verified, showing a relative error of less than 5% from the simulation results. Additionally, the detection results of the ICCS are consistent with the laser point-cloud data, demonstrating its feasibility for pavement texture detection.

CivilEng doi: 10.3390/civileng7030048

Authors: Nafise Einafshar Yassine El Mendili

The global construction industry is increasingly seeking sustainable alternatives to conventional structural materials to reduce environmental impacts and support circular economy goals. This review examines bio-based construction materials from a structural engineering perspective, focusing on the transition from intrinsic material properties to member-level behavior and system-scale applications. A combined bibliometric and “From Material to Member” framework is used to connect microstructural characteristics with structural performance across scales. The review covers microbial self-healing concretes, engineered bamboo, plant-aggregate concretes such as hempcrete and rice-husk composites, lignin-based polymers and resins, and mycelium composites, with emphasis on materials and systems relevant to structural and member-scale applications. Bio-based materials developed primarily for asphalt and pavement applications are outside the scope of this review. Mechanical, thermal, durability, and environmental performance are evaluated alongside emerging multi-scale modeling approaches and hybrid structural systems. The findings show that bio-concretes can provide autonomous crack repair, engineered bamboo offers high strength-to-weight efficiency, and lignin-based polymers enable renewable composite matrices with adaptable properties. However, challenges remain regarding connection design, moisture sensitivity, long-term durability, standardization, and the transfer of laboratory findings to structural-scale reliability. Life-cycle assessment studies indicate substantial embodied carbon reduction potential, although outcomes depend on processing methods, service-life assumptions, and end-of-life scenarios. Overall, performance-based design, durability assessment, standardized testing, and dynamic life-cycle approaches are essential for broader structural implementation.

CivilEng doi: 10.3390/civileng7030047

Authors: Mohammed Elhousseini Atef Eraky Ahmed Elbelbisi Shimaa Emad

Climate change has been associated with an increasing occurrence of extreme wind phenomena, including hurricanes, tornadoes, and downbursts, with noticeable rises in both their frequency and severity. These events have heightened concerns regarding their devastating impacts on structures, infrastructure, and economies. To provide a comprehensive and reliable review, a large number of previous studies and scientific references were collected and carefully screened. The selection process focused primarily on studies directly related to structural engineering applications, wind-induced structural responses, tornado and hurricane loading mechanisms, and simulation techniques used in wind engineering research. References unrelated to structural behavior, engineering analysis, or wind-resistant design were excluded to maintain the technical relevance and consistency of the review. This review explores parameters influencing wind loads, focusing on tornado flow field characteristics such as swirl ratio, ground roughness, translation speed, and topography. It also examines structural properties such as geometry, material, orientation, and proximity to the tornado path that govern a building’s ability to withstand wind-induced forces. The review evaluates experimental techniques, including wind tunnel tests, tornado simulators, and numerical simulations using Computational Fluid Dynamics (CFD) to improve understanding and resilience. These approaches are compared for effectiveness in replicating real-world scenarios and enhancing predictive accuracy. Furthermore, key engineering standards, such as ASCE 7-22 and FEMA guidelines, are highlighted, showing their role in improving structural design, identifying gaps in research, and advocating for future studies. It emphasizes integrating emerging computational technologies, including machine learning, to enhance structural design efficiency and disaster response performance. This review aims to guide researchers and engineers toward developing resilient structures capable of mitigating the impacts of extreme wind events.

CivilEng doi: 10.3390/civileng7030046

Authors: Hao Cheng Jiashun Tang Jianghao Liu Yaolin Liu Xiangrong Guo

Understanding the non-linear dynamic interaction between tracks and bridge structures is essential for maintaining the safety of continuous rigid-frame bridges. To accurately capture these beam–rail interactions, this study develops a detailed 3D finite element model based on the principle of stationary total potential energy. This framework fully integrates the track, main girders, and piers into a single system. Based on a 4 × 40 m continuous rigid-frame viaduct in an urban transit network, the numerical model accounts for the bilinear mechanical behavior of the rail fasteners. The study compares the transmission of longitudinal forces along the continuously welded rail (CWR) under two fastening layouts. The baseline case uses uniform constant-resistance fasteners across the entire bridge, while the optimized scheme places small-resistance fasteners at the final 20% of each structural segment. Analysis shows that placing low-resistance fasteners in the high-displacement areas near the girder ends creates an effective longitudinal “release zone.” This design effectively interrupts the buildup of longitudinal forces, resulting in a much smoother force distribution along the rails. Quantitative results indicate that this optimized fastener layout has only a minor effect on structural deflection and braking-induced rail stresses, keeping deviations below 11%. At the same time, it significantly reduces the peak expansion stress and broken-rail stress by 43.4% and 22.2%, respectively. By shifting the stress regulation philosophy from “rigid resistance” to dynamic “force channeling,” these findings demonstrate that local low-resistance fastener deployment improves the overall mechanical compatibility of the track–bridge infrastructure. Ultimately, this work offers a solid theoretical basis for the design and maintenance of CWR systems on long-span rigid-frame bridges.

CivilEng doi: 10.3390/civileng7030045

Authors: Michal Kloiber Miloš Drdácký Petr Münster Petr Dejdar Jaroslav Buzek

This article thoroughly documents the focus, long-term monitoring, and survey of the condition of a unique early Gothic wooden ceiling from the 13th century in Zvíkov Castle in the Czech Republic. Through long-term monitoring of climatic parameters, wood moisture, and the movement of ceiling beams, this paper described how wood constantly works, that is, swells and shrinks during a single annual cycle. At the interface of the ceiling beams and the masonry, the ambient temperature ranged from 2.75 °C to 31.75 °C, and the relative humidity of the air from 38 to 93%. The condition of the walled-in beam ends was assessed by resistance drilling and endoscopy. Out of a total of 16 beam ends, 7 ends are completely degraded by brown rot fungus. The condition of the ceiling structure is not good, even in the case of the boards covering the ceiling. Here, the sapwood parts are additionally damaged by the beetle Anobium punctatum which, in combination with rot, has broken down the wood into crumbling matter. High static load due to a massive embankment 35–50 cm thick, two layers of fired paving, and occasional loading causes the wood to deteriorate over time and requires urgent stabilization. The final section reflects on the approach to sustainably securing the uniquely preserved structure. Finding the optimal solution represents a challenging decision-making task between a conservation intervention of external support with minimal intervention in the existing structure and the structural restoration of individual elements, requiring disassembly and reassembly of the structure.

CivilEng doi: 10.3390/civileng7030044

Authors: Han Wang Zuohua Li Dan Han Jun Teng

The tuned mass damper (TMD) exhibits good performance in suppressing wind-induced vibrations of high-rise structures. However, a single TMD has a limited control bandwidth and poor robustness. The multiple-pendulum tuned mass damper (MPTMD) offers advantages, such as a wider control bandwidth, stronger robustness, and a simple structural configuration, while its working frequency can be easily adjusted by varying the pendulum lengths. With two optimization objectives, namely displacement and acceleration, this study derives the displacement and acceleration dynamic amplification factors of the primary structure equipped with the MPTMD under external excitation and examines the interrelationships among the optimal parameters and their underlying mechanisms. The accuracy of the proposed optimization method and the effectiveness of the MPTMD are validated by fitting the theoretically derived optimal parameter curves with results from numerical simulations. Finally, the control performance of MPTMD and TMD is compared through a numerical example subjected to realistic wind load excitations, verifying the control effectiveness of MPTMD. Nevertheless, several limitations should be acknowledged. The present optimization is based on a single-degree-of-freedom (SDOF) primary structure and targets only the first translational mode; the effects of higher modes and multi-degree-of-freedom (MDOF) coupling are not considered. Additionally, the wind load is represented by a synthetic time history with a fixed return period, and uncertainties in real wind fields are not fully addressed. Future work should extend the proposed method to multi-modal control, nonlinear behavior, and experimental validation.

CivilEng doi: 10.3390/civileng7030043

Authors: Yasuko Kawahata Durga Chavali Noriaki Maeda Shunsuke Hatadani

The aging of social infrastructure, intensively constructed during periods of rapid economic growth, is a pressing challenge facing modern society. Conventional infrastructure asset management has disproportionately emphasized a “managerial financial perspective,” aiming to maintain physical functions within limited budgets. However, the malfunction of road appurtenances such as tunnel lighting facilities induces severe traffic accidents and chronic congestion, resulting in public health risks for users (physical trauma, psychological stress, and the deterioration of Disability-Adjusted Life Years: DALYs) as well as massive socio-economic losses. The primary novelty of this study lies in bridging the gap between stochastic engineering deterioration models—specifically, discrete-time Markov chain models predicting physical degradation—and socio-economic stakeholder value chains. This study constructs a “Social Life Cycle Cost (LCC) Optimization Model” that directly incorporates these social losses and stakeholder risk disparities into the evaluation function, addressing the limitations of conventional financial-centric LCC models. By conducting robust uncertainty and global sensitivity analyses via large-scale Markov Chain Monte Carlo simulations (number of trials N=105), we reveal that a corrective maintenance strategy inheres a critical “fat-tail risk” of stochastically incurring catastrophic social losses. Conversely, preventive intervention at State C minimizes the expected total cost with statistical significance (p<0.001) and drastically decouples engineering costs from social risks. This research provides quantitative evidence that early infrastructure intervention functions as an indispensable “social investment” for mitigating public health risks under the specific parameters of the proposed model.

CivilEng doi: 10.3390/civileng7030042

Authors: Hamid Nikzad Shinta Yoshitomi

Outrigger systems incorporating buckling-restrained braces (BRBs) can improve the seismic performance and resilience of tall buildings by combining lateral stiffness enhancement with supplemental energy dissipation. However, determining the effective number, elevation, and stiffness distribution of outrigger–BRBs remains computationally demanding when many possible configurations are considered. This study proposes a computationally efficient power-based sequential optimization approach for identifying effective outrigger–BRB placement and stiffness allocation in tall building systems. A nine-zone finite element benchmark model, developed in MATLAB based on a previously tested structural configuration, is used to examine the proposed method through nonlinear time-history analysis under the 1940 El Centro ground motion. The optimization procedure incrementally allocates BRB stiffness to candidate outrigger locations and selects the configuration that minimizes the maximum inter-story drift ratio at each step. The results are compared with a complete combinational reference search within the selected candidate space to assess whether the proposed procedure can identify optimal or near-optimal configurations with fewer nonlinear analyses. The findings show that the proposed method can reproduce the main effective outrigger–BRB placement patterns while reducing the number of required analyses within the investigated benchmark problem. The results also indicate that BRB stiffness limits influence the distribution of stiffness along the building height and promote more gradual drift reduction. Although the numerical investigation is limited to a benchmark model and a single seismic input, the proposed framework provides a practical basis for preliminary design, rapid parametric assessment, and future extension to multi-record and multi-objective optimization of outrigger–BRB systems.

CivilEng doi: 10.3390/civileng7030041

Authors: Fan Feng Chuangsheng Cai Yu Wu Yongqiang An Penglin Li Weibin Wen

Microencapsulated phase change material (MPCM) can be used in place of sand in mortar to obtain phase change construction materials; however, this will degrade the mortar’s mechanical qualities. To address this challenge, a novel synergistic approach was proposed: phase change materials were used in mortar to enhance its thermal properties, while polyvinyl alcohol (PVA) fibers were uniquely incorporated to counteract the mechanical degradation caused by MPCM. Twenty different types of mortar were created and produced. Tests were conducted on the mortar’s micro properties, consistency, compressive strength, thermal conductivity, and specific heat capacity. The findings indicate that adding 0.4% PVA to the mortar optimally strengthened it, compensating for mechanical loss, while replacing sand with MPCM had a negative impact on consistency. The thermal conductivity of the PVA-MPCM mortar ranged from 0.75 to 1.2 W·m−1·K−1, decreasing by up to 34.45% when the MPCM substitution rate reached 4%. Furthermore, as the MPCM substitution rate rises to 4%, the peak value of specific heat capacity increased by 195.28% during the heating process, and replacing sand with MPCM had a negative impact on consistency. The thermal conductivity of the PVA-MPCM mortar ranged from 0.75 to 1.2 W·m−1·K−1, indicating that adding MPCM to the mortar had a significant impact on thermal conductivity. As the MPCM substitution rate rises, so does the peak value of specific heat capacity.

CivilEng doi: 10.3390/civileng7030040

Authors: Lutz Auersch

The Federal Institute of Material Research and Testing has performed many impact tests, from very small laboratory tests to very big “free-field” tests with heavy containers on stiff foundations. The first measurements have been done on a big foundation where it should be guaranteed that the foundation is rigid and the container is tested properly. Later, a smaller drop-test facility has been built on the ground inside an existing building. It had to be controlled by prediction and measurements to ensure that the drop test will not damage the building. Tests from different heights on soft, medium, and stiff targets have been done to find out rules which allow to identify acceptable and unacceptable drop tests. Later, the biggest drop test facility has been built for masses up to 200 t. It was necessary for the design of the foundation to estimate the forces which occur during the drop tests. In addition, the acceptable tests should be selected and controlled by measurements where the impact duration is important. Different sensors, accelerometers, accelerometers with mechanical filters, geophones (velocity transducers), strain gauges, and pressure cells have been applied for these tasks. Signal transformations and model calculations have been used to check and understand the dynamic measurements. The simplest law is the conservation of the momentum which is a good approximation if the impact is short. If the soil under the foundation has an influence on the deceleration of the container, the maximum foundation velocity is lower than the simple estimation.

CivilEng doi: 10.3390/civileng7030039

Authors: Yulin Zou Shahab Hosseini Mohammad Afrazi Seyed Yaser Mousavi Siamakani Pijush Samui Danial Jahed Armaghani

The present study investigates the application of conventional and ensemble machine learning models for slope stability prediction, which is essential for landslide risk reduction and sustainable infrastructure management. A database containing 627 slope cases was used, including six input variables: unit weight, cohesion, friction angle, slope angle, slope height, and pore pressure ratio. Six machine learning models, namely Extreme Gradient Boosting (XGBoost), Support Vector Machine (SVM), Random Forest (RF), K-Nearest Neighbors (KNN), Classification and Regression Tree (CART), and Boosted Tree, were developed and evaluated. The models were assessed using ROC analysis, confusion-matrix-derived metrics, precision–recall analysis, feature importance assessment, and unseen testing cases. The results showed that ensemble-based models provided superior predictive performance compared with conventional machine learning models. Based on ROC analysis, RF achieved the highest ROC-AUC value of 0.93, followed by Boosted Tree and XGBoost with ROC-AUC values of 0.92 and 0.90, respectively. Based on confusion-matrix-derived metrics, Boosted Tree achieved the highest accuracy of 0.862 and F1-score of 0.874, while RF showed comparable performance with an accuracy of 0.857 and F1-score of 0.868. Feature importance analysis indicated that cohesion and unit weight were among the most influential variables affecting slope stability prediction. In addition, the unseen testing cases confirmed the practical generalization capability of the ensemble models, with Boosted Tree and RF achieving accuracies of 0.920 and 0.880, respectively. Overall, the findings demonstrate that ensemble learning models, particularly Boosted Tree and RF, can provide reliable and interpretable decision-support tools for preliminary slope stability assessment and landslide hazard management.

CivilEng doi: 10.3390/civileng7020038

Authors: Kálita Cristina Araújo Ana Carolina Fernandes Maciel Bruno Barzellay Ferreira da Costa

The decarbonization of the Architecture, Engineering, Construction, and Operation (AECO) sector has increased the need to incorporate carbon metrics into design decision-making. This article presents a Systematic Literature Review (SLR), based on the PRISMA protocol, to investigate whether the automation of CO2 emission calculation combined with artificial intelligence has been used to support lower-impact design decisions in BIM-based building design. Searches were conducted in the Scopus, Web of Science, and ScienceDirect databases, considering articles published between 2021 and 2025, resulting in 2567 records. After duplicate removal and successive screening stages, 85 studies composed the final sample, classified into Core studies (BIM + CO2 + AI) and Base studies (BIM + AI, BIM + CO2, BIM + AI + Sustainability, and AI + CO2). The results indicate the predominance of partial integrations and limited representation of Core studies. Although 60% of the studies quantify carbon, only 39% use this quantification to propose, compare, or optimize design alternatives. The findings suggest that BIM + CO2 + AI integration has potential to support low-carbon building design but still requires greater standardization, interoperability, validation, traceability, and operational integration.

CivilEng doi: 10.3390/civileng7020037

Authors: Lydia Konstantina Georgiou Zonara Panagiota S. Katsimpini

This study presents the nonlinear seismic analysis of a large-scale suspension bridge under multiple sequential earthquake records. A detailed 3D finite element model is developed in SAP2000, incorporating CFST pylons, a composite deck, and a main cable suspension system. The novelty of this work lies in the combined treatment of two critical and often independently studied factors: nonlinear pile foundation behavior and sequential seismic loading. A Winkler-based nonlinear pile foundation model is established through depth-dependent p-y, t-z, and Q-z nonlinear spring curves implemented as Multi-Linear Plastic Link elements, capturing the full nonlinear lateral and axial response of the 1.8 m diameter, 60 m long pile group. Simultaneously, the structural response is evaluated under real seismic sequences rather than single events, addressing the cumulative damage that conventional analyses systematically underestimate. The results demonstrate that the combination of foundation nonlinearity and repeated seismic loading significantly amplifies internal forces and deformation demands on critical structural components, highlighting the inadequacy of standard single-event, fixed-base design assumptions for long-span bridges.

CivilEng doi: 10.3390/civileng7020036

Authors: Quanyi Xie Xiaohan Li Jiabao Wang Yuan Gao Jian Liu

High rock temperature (HRT) and its associated thermal hazards, alongside secondary mechanical risks such as swelling pressures induced in clay layers, pose severe threats to the construction safety of deep-buried tunnels. This study aims to quantitatively reveal the evolution laws of the surrounding rock temperature field under varying heat source conditions. A combined approach of physical model testing and numerical analysis was adopted. Utilizing an independently developed test system with a 1:13 geometric similarity ratio, the coupled rock-heat-ventilation environment was simulated. A transient conduction-convection 3D numerical model was established in COMSOL and verified against experimental data under benchmark conditions. The research confirms that under the influence of localized block heat sources, the temperature field in the far-field region follows a significant linear attenuation law rather than the traditional exponential distribution, with a prototype-equivalent gradient of approximately 0.69 °C/m. Furthermore, the study quantitatively identifies 8 m3 as the critical volume for heat source geometric saturation, beyond which the incremental temperature rise efficiency decreases by 25%. It is further revealed that the effective cooling depth of conventional ventilation is only approximately 0.35 m, indicating a significant “ventilation shielding effect” within the deep surrounding rock.

CivilEng doi: 10.3390/civileng7020035

Authors: Yiming Li Bin Gan Peizhao Chen Shibin Tang Chun Zhu Shun Ding

Localized water infiltration in rock masses can significantly compromise the stability of foundations and underground structures. Conventional assessments often rely on average water content, while overlooking the spatial heterogeneity of water distribution. This study investigates the mechanical behavior and failure characteristics of black sandstone under partial water immersion through uniaxial compression tests at varying immersion depths and angles. The results indicate that partial immersion causes a sharp, nonlinear reduction in uniaxial compressive strength (UCS), with strength loss at 38.9% saturation reaching 88.5% of total failure, highlighting the vulnerability of partially wetted rock supporting building foundations. Wet–dry interfaces induce stiffness mismatch and stress concentration, shifting failure from global shear to localized lateral crushing, which may affect structural stability in underground or slope-adjacent buildings. Moreover, immersion angle governs a slight U-shaped evolution in strength, with the lowest strength at 45° and a limited recovery at 90°, suggesting orientation-dependent risks for inclined foundation beds. These findings demonstrate that spatial water distribution, rather than overall water content, is a primary factor in rock instability, providing a theoretical basis for risk assessment and design considerations in building and underground construction where localized wetting may occur.

CivilEng doi: 10.3390/civileng7020034

Authors: Tareq Salloum Ernest Forman

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CivilEng doi: 10.3390/civileng7020033

Authors: Wojciech Piątkiewicz

Hemp–lime composites are bio-based building materials with carbon sequestration potential, yet their properties exhibit significant variability depending on manufacturing variables, and standardized production guidelines remain lacking. This study investigates the influence of water-to-binder ratio (W/B = 1.75, 1.95, 2.15) and compaction degree (CD = 150%, 170%, 190%) on the thermal conductivity and compressive strength of hemp–lime composites using a full 3 × 3 factorial design at a binder-to-shiv ratio of B/S = 1:1. Results were synthesized with previously published investigations from a systematic research programme, enabling a comparative assessment of four technological variables across an extended dataset spanning densities from 227 to 518 kg/m3. The binder-to-shiv ratio was identified as the dominant factor governing both properties, primarily through its effect on bulk density and the mechanical character of the composite. Compaction degree was the most effective parameter for adjusting properties within a fixed mix design, with the strongest gains observed at the transition from CD = 150% to CD = 170%. The water-to-binder ratio exerted only marginal influence on bulk density and thermal conductivity, while its effect on compressive strength remained inconclusive at B/S = 1:1. Hemp shive particle size had a limited effect on thermal conductivity and no detectable influence on compressive strength. Both properties exhibited strong positive linear relationships with bulk density across the extended dataset. The findings support the standardization of hemp–lime composite production and the development of practical design guidelines.

CivilEng doi: 10.3390/civileng7020032

Authors: Yupeng Ou Pingan Liu Youlin Chen Tiehu Wang Xiang Liu Xun Zhang

Fault-crossing ground motions, characterized by velocity pulses, permanent fault dis-placement, and non-uniform support excitation associated with fault rupture, may significantly affect the seismic performance of siphon bridges crossing active faults. This study investigates a long-span siphon arch bridge subjected to pulse-type fault-crossing ground motions. A unified stochastic ground motion model is developed by integrating nonstationary high-frequency components based on the evolutionary power spectrum with low-frequency pulse components represented by an improved Gabor wavelet, capturing forward directivity effects, permanent displacement, and differential support input at the two sides of the fault. A three-dimensional nonlinear finite element model is established in OpenSees using fiber-based beam–column elements, with hydrodynamic effects incorporated through the added mass method. Parametric analyses consider pulse phase angle (0–90°), amplitude (Mw 6.0–7.5), and frequency (0–1 Hz). Results indicate that structural responses decrease with increasing phase angle, with 0° being most unfavorable, high-lighting the dominant influence of permanent displacement. Resonance amplification occurs when pulse frequencies approach the fundamental modes of the pier (0.345 Hz) and deck (0.51 Hz), while the arch is particularly sensitive near 0.439 Hz. Water added mass reduces natural frequencies by 8–14% and significantly amplifies internal forces. These findings provide guidance for seismic design of fault-crossing siphon bridges.

CivilEng doi: 10.3390/civileng7020031

Authors: Peter Ghoche Bernard Lavoie Maryam Kamali Nezhad Georges Abdul-Nour

Factors such as asset aging, climate change affecting hydrological events, and the growing demand in electricity are placing huge pressure on hydroelectric infrastructure—in particular, hydroelectric dams, whose most important and critical component is the spillway, which operates through a system of discharge gates. This research aims to present the technical, environmental, and functional parameters and issues affecting this system, highlighting the causes of their degradation and proposing solutions to improve their service life and their reliability. A literature review has been undertaken to identify the challenges related to the reliability and durability of the system. In addition, a case study based on real-world data was made to support and reveal the problems related to the spillway gates system. What sets this research apart is its integration of theoretical studies with a practical case study, supporting the proposed theories and uncovering potential hidden factors. Following the identification of key challenges, new updated and adaptable solutions explored world-widely are recommended to be developed in future research.

CivilEng doi: 10.3390/civileng7020030

Authors: Vassilios Aggelidis Costas A. Anagnostopoulos

The aim of this research was to evaluate the efficacy of water-soluble epoxy resin (ER) in regard to stabilising clay soils, specifically for the design of column-type reinforcement in soft ground. An extensive laboratory program was conducted to assess the mechanical enhancement of a silty clay soil via ER, both as a standalone stabiliser and in combination with cement, bentonite, and sodium polyacrylate (PA). In addition, the study investigated the impacts of thermal stabilisation and electro-osmotic dewatering on resin–soil specimens. Specimens stabilised solely with ER exhibited poor strength development due to the inhibition of polymerisation by water. The addition of bentonite at low concentrations resulted in low early strength development and a moderate increase in the final strength. The use of cement provided the most significant strength gains, which were further enhanced by optimising the dosage of PA, although an excessive PA content significantly reduced the strength properties. In terms of physical treatments, thermal stabilisation at an optimal temperature of 60 °C for 24 h substantially improved the performance of ER. Electro-osmotic treatment accelerated the development of early strength but failed to provide appreciable strength improvement, and resulted in brittle behaviour and reduced toughness in the later stages (90–180 days). These findings offer critical guidelines for optimising mix designs and treatment protocols for geotechnical ground improvement projects.

CivilEng doi: 10.3390/civileng7020029

Authors: Tianwen Dong Nobuaki Hanai Toshiyuki Kanakubo

In various countries, the shear-strength design formulas for reinforced concrete beam–column joints are primarily constructed based on concrete strength, and the influence of the main bars of the beam is not explicitly reflected in these expressions. To address this limitation, this study examines the shear behavior of the joint, focusing particularly on the amount and arrangement of the main bars of the beam passing through the joint. Four beam–column joint specimens were tested under cyclic loading. The main variables of the specimens were the amount and arrangement of the main bars of the beam. The detailed strain measurements were conducted to clarify the development of bond deterioration along the main bars and the associated internal force transfer mechanisms. The experimental observations revealed significant tension-shift phenomena and progressive bond deterioration in the compression-side main bars. Within the scope of the present test series, variations in the amount and arrangement of the main bars of the beam did not significantly affect the maximum applied load. However, the indirectly evaluated joint shear force was higher in specimens with two layers in the main beam bars. Force equilibrium using force components obtained by measured strain produced even larger values at greater drift angles, indicating that joint shear assessment depends strongly on the evaluation basis. A mechanics-based diagonal strut model incorporating the internal compression field provided improved agreement with experimental results, confirming its applicability for practical design.

CivilEng doi: 10.3390/civileng7020028

Authors: Maria Pomoni

Traditional road geometric design is based on assumptions regarding human perception and reaction, which directly influences Stopping Sight Distance (SSD) and the associated design parameters of vertical curves. Under a future scenario of full autonomous vehicle (AV) deployment, reduced perception–reaction times and modified sensing configurations may change visibility-controlled design requirements. This study presents a structured parametric assessment of SSD and vertical curve lengths under the assumption of full AV operation. Variations are considered in reaction time, sensor height, sensor inclination angle, longitudinal grade, and vehicle operating speed. Default parameter values derived from current design standards, together with ranges reported in the literature, are used to evaluate the geometric implications of full vehicle automation within a controlled analytical framework. The results indicate that reduced reaction times and increased sensor heights of AVs may decrease required SSD values and consequently shorten crest and sag vertical curve lengths compared to conventional human-driven vehicle assumptions. For sag curves in particular, headlight inclination angle is revealed as a significant geometric variable. Overall, the study proposes a framework for examining the interaction between AV sensing characteristics and vertical geometric design, thereby providing a basis for future evaluation of design standards without directly prescribing modifications to current practice.

CivilEng doi: 10.3390/civileng7020027

Authors: Ivelin Ivanov Dimitar Velchev

The methodology described in Eurocode 8, Part 4, for calculating seismic effects on vertical cylindrical rigid and fixed steel storage tanks is programmed in MATLAB®. The walls of the tanks are constructed of shell courses with varying thicknesses of sheet material. The strength conditions for the ultimate limit states of plasticity, elastic buckling, and elastoplastic buckling (“elephant foot”) are checked at many calculation points along the height of the storage tank. The thicknesses of the courses are determined to satisfy all strength conditions for different slenderness ratios of the tanks and for different volume capacities. Tanks with supported roofs and those with self-supporting roofs are considered, as well as open-top tanks. A mass per unit volume capacity is the criterion for optimization for different seismic loadings and steel grades. The criterion is not a smooth function because of the discrete thicknesses of the shell courses and their number. A smooth objective function is created for better parametric optimization analysis. The dependence of the optimal slenderness ratio on the volume capacity is determined, as well as the inverse dependence. The problem of the optimal number of storage tanks in a set of tanks with a given total volume capacity is also considered.

CivilEng doi: 10.3390/civileng7020026

Authors: Mana Dastoum Yasmine Mahmoud Saad Abdelhamid Esraa Elareef Carmen Sánchez-Guevara Beatriz Arranz Reza Askarizad

Despite the growing use of tessellated and patterned façades in contemporary architecture, their thermal performance, particularly in cooling-dominated educational buildings, remains insufficiently quantified, with existing studies largely prioritizing daylighting or aesthetic outcomes over energy-driven thermal behavior. This study aims to systematically evaluate how different tessellated façade geometries and perforation ratios influence thermal performance and cooling demand in a Mediterranean climate, and to identify an optimal façade configuration that balances multiple thermal objectives. Three tessellation typologies—nature-inspired (Voronoi), Islamic geometric, and folded origami-based patterns—were parametrically generated and applied as external shading screens to an educational building. Annual thermal simulations were conducted using Climate Studio to assess four performance metrics: solar heat gain, energy use intensity, hours of overheating derived from operative temperature, and peak cooling demand. A post-simulation, data-driven, multi-objective, decision-support approach was applied using Compromise Programming to systematically evaluate and rank discrete façade alternatives based on multiple thermal performance criteria. Results indicate that all tessellated façades reduce solar heat gain and peak cooling demand relative to the unshaded baseline, with performance strongly dependent on both geometry and perforation ratio. Lower perforation ratios (20%) consistently outperform more open configurations, while Voronoi-based façades achieve the most balanced overall thermal performance across all evaluated criteria and emerging as the top-ranked solution. The study’s novelty lies in its comparative, cooling-focused evaluation of fundamentally different tessellation logics using transparent, decision-oriented optimization rather than subjective comfort indices or computationally intensive evolutionary algorithms. Beyond its specific findings, the research provides a transferable methodological framework for integrating geometry-informed façade design into early-stage decision-making, supporting climate-responsive and energy-efficient educational architecture in Mediterranean and similar climates.

CivilEng doi: 10.3390/civileng7020025

Authors: Zainab Al Qraiti Anmar Dulaimi Marisa Sofia Fernandes Dinis de Almeida Luís Filipe Almeida Bernardo

Comparing cold-recycled asphalt mixtures (CRAMs) to conventional hot-mix asphalt (HMA) shows that CRAMs offer several logistical, financial, and environmental advantages. However, such CRAMs, when using asphalt emulsion, still suffer from excessive water damage and poor early-age performance. The main aim of this study is to improve CRAMs by incorporating two biomass ashes and reclaimed asphalt pavement (RAP): palm leaf ash (PLA) and reed ash (RA) with different percentages of RAP. RAP was used in five percentage levels, 0%, 25%, 50%, 75%, and 100% by weight of mix, to develop the CRAMs. In addition, the improvement in CMA mechanical properties was assessed by incorporating PLA as filler replacement in five percentages, namely: 0%, 1.75%, 3.5%, 5.25%, and 7% by weight of aggregate. RA was used as an activator at 0.25%, 0.5, 1%, and 2% by weight of aggregate. The moisture susceptibility test, Indirect Tensile Strength Test (ITS), and Marshall test were used to assess the mechanical properties. The results obtained showed that the durability and mechanical properties of CMA are effectively enhanced with the addition of 1.5% PLA, 0.45% RA, and 5.5% Ordinary Portland Cement (OPC) as fillers. In addition, CRAMs with a higher percentage of RAP 75%, showed higher strength in terms of Marshall stability. These findings demonstrate that the studied CRAMs offer a reliable alternative for pavement applications, namely when sustainable and cost-effective materials are required.

CivilEng doi: 10.3390/civileng7020024

Authors: Kunal Mohinderu Sriram Aaleti Saahastaranshu R. Bhardwaj

Laminated bamboo (LB) has emerged as a promising sustainable structural material due to its rapid renewability, high strength-to-weight ratio, and favorable mechanical performance. Drawing on a comprehensive review of over 90 published experimental and analytical studies, this paper provides a critical synthesis of the structural behavior of LB, with emphasis on its compression, tension, flexure, shear, and creep responses. Reported mechanical properties exhibit variability, largely influenced by bamboo species, fiber orientation, processing methods, adhesives, lamination quality, and loading configuration. While LB demonstrates high tensile and flexural strengths comparable to or exceeding conventional timber products, pronounced anisotropy and brittle failure modes are consistently observed, particularly under shear and rolling shear loading. Recent studies on cross-laminated bamboo (CLB) highlight the significant role of interlaminar behavior and adhesive performance in controlling failure mechanisms, indicating that rolling shear capacities often govern the design of planar elements. Beyond mechanical behavior, this review synthesizes available research on thermal and fire performance. Emerging research on LB connections indicates that joint behavior often governs global structural performance, with strength and ductility strongly influenced by fastener type and embedment behavior. Key knowledge gaps are identified, underscoring the need for unified design frameworks to enable broader structural adoption of laminated bamboo systems.

CivilEng doi: 10.3390/civileng7020023

Authors: Hamid Nikzad Shinta Yoshitomi

This paper proposes a power-based optimization procedure to identify the optimal number and vertical placement of buckling restrained brace (BRB) outrigger systems for enhancing the seismic performance of core-wall-dominated benchmark model. The proposed method is validated using a nine-zone numerical model subjected to nonlinear time-history analysis implemented in MATLAB R2025.a (25.1.0.2943329). The optimization variables include the number and locations of outriggers as well as the stiffness of the BRBs, while the objective function is defined as the minimization of the maximum inter-story drift response. Outriggers are installed between zones 2 and 9, with each zone subdivided into five potential outrigger levels located 150 mm above the floor level, resulting in 40 potential outrigger placement scenarios. The total number of outriggers is constrained to range from one to eight, with at most one outrigger allowed per zone. Optimal outrigger–BRB configurations are identified by incrementally distributing BRB stiffness at the perimeter column-outrigger connection regions using a power-based allocation strategy. At each optimization step, the proposed framework evaluates only one candidate configuration per eligible story and outrigger level, resulting in several nonlinear time-history analysis grows linearly with the number of candidate locations. This contrasts with the combinatorial growth in computational demand typically associated with exhaustive or evolutionary optimization methods and leads to a significant reduction in overall computational efforts.

CivilEng doi: 10.3390/civileng7020022

Authors: Hui Yao Jiaran Han Dandan Cao Xuhao Cui Min Wang Yu Liu

The dynamic modulus of asphalt mixtures is a key design parameter in pavement design, which significantly impacts the mechanical properties of asphalt pavements. This study simulated dynamic modulus tests of asphalt mixtures using the three-dimensional (3D) discrete element method (DEM) to investigate mechanical behaviors such as the loading-bearing ratio of individual aggregates. Fine-grained AC-13 and medium-grained AC-20 asphalt mixture models were randomly constructed in the DEM program using user-defined methods. The dynamic modulus and phase angle values of the asphalt mixtures were predicted. By comparing laboratory experiments with DEM simulation results, the model was validated, and the effects of temperature and loading frequency on the dynamic modulus were explored. Further exploration was conducted on the loading-bearing ratio and mechanical interactions among aggregates of different sizes within the mixtures. The results show that the 3D DEM model can accurately predict the dynamic modulus and phase angle of asphalt mixtures. Temperature and frequency have an impact on these parameters, and the increase in gradation has an impact on the loading-bearing ratio, due to the proportion of coarse aggregates.

CivilEng doi: 10.3390/civileng7020021

Authors: Shuaiyuan Wang Jianzhong Chen Yong Lv Pengfei Song Mingqing Sun

Three-edge bearing (TEB) tests and a crack-width-dependent load-carrying model were used to assess the combined effects of recycled glass fiber-reinforced polymer (rGFRP) short fibers and glass fiber-reinforced polymer (GFRP) bars in concrete pipes. Using the force method, a circumferential statically indeterminate ring analysis was formulated to obtain internal forces at critical sections and the neutral-axis position. Fiber distribution was simulated by means of Monte Carlo sampling, and single-filament pull-out tests were fitted to relate embedded length to pull-out force, enabling calculation of the fiber-bridging contribution at cracked sections. Ten specimen types with different bar/fiber schemes were tested under external pressure to validate the model. Predicted cracking and ultimate loads agreed with measurements, with most errors within ±20%. Adding 1% (vol.) rGFRP fibers increased the cracking load by 11.81% and the ultimate load by 0.45%. Without fibers, replacing steel bars with equal-area GFRP bars increased the cracking load by 1.35% but reduced the ultimate load by 35.45%. For all specimens, the load–maximum crack-width relation was strongly linear (R2 > 0.93). The proposed approach and dataset support engineering use of recycled GFRP materials for crack control and load-carrying design of concrete pipes.

CivilEng doi: 10.3390/civileng7020020

Authors: Vincenzo Sepe Mariella Diaferio Francesco Potenza

Historic masonry towers are all around the world and play a significant role in shaping our built environment. Due to their slender shape, these towers are particularly vulnerable, as recent earthquakes have demonstrated. Many researchers have studied how these structures behave dynamically, with the aim of preserving their cultural value against the risks of damage or collapse. Lately, considerable attention has been paid to develop empirical formulas that estimate their fundamental frequency by considering geometric factors such as total height, reference base length, and effective height for constrained towers. These formulas are usually obtained using regression analysis on data from the technical literature, and so their reliability depends heavily on both the quantity and precision of available data. The variables chosen for calibrating these correlations are mainly determined by the information present in the literature; as a result, missing data can lead to underestimating the influence of some geometric aspects. To address this issue, the paper describes parametric analyses with a simplified model of masonry towers, i.e., the Euler–Bernoulli beam, aiming to show how sensitive the fundamental frequency is to different geometric and mechanical properties. These analyses show the importance of some parameters with respect to others and support the planning of experimental investigation needed for accurate predictions of a tower’s fundamental frequency.

CivilEng doi: 10.3390/civileng7010019

Authors: Zihao Wang Zeqi Zhu

Active support systems are being increasingly applied in the control of large deformation in soft rock tunnels, and exploring the bearing characteristics of prestressed anchor bolts is of great engineering value for improving the long-term stability of tunnel structures. To address the problems of insufficient quantitative characterization of the bearing performance of prestressed anchor bolt support in soft rock tunnels and the difficulty of small-scale model tests in revealing the synergistic bearing law of support and surrounding rock, this study took a 350 km/h double-line high-speed railway tunnel as the prototype and established a large-scale tunnel structure model test system to conduct comparative tests under three working conditions: unsupported, ordinary bolt support, and prestressed anchor bolt support. By monitoring the tunnel failure process and mechanical response of the support structure throughout the test, the failure modes, bearing capacity, deformation characteristics, and axial force distribution of anchor bolts of tunnels under different support forms were systematically analyzed to quantitatively reveal the active support mechanism and bearing strengthening effect of prestressed anchor bolts. The results show that the design bearing capacity of the tunnel model with prestressed anchor bolt support is increased by 127.3% and 31.6% compared with that of the unsupported and ordinary bolt support models, and the ultimate bearing capacity is increased by 120.0% and 43.5%, respectively. Its secant stiffness in the initial loading stage reaches 80.0 kPa/mm, which is five times that of the ordinary bolt support and can effectively restrain the early plastic deformation of the surrounding rock. When the design bearing capacity is reached, the tensile stress of prestressed anchor bolts accounts for 40.2~69.8% of the ultimate tensile strength, with a more uniform axial force distribution and a much higher utilization rate of material mechanical properties than ordinary anchor bolts, which can fully mobilize the bearing potential of deep rock mass and realize the synergistic bearing of support and surrounding rock. This study accurately quantifies the bearing strengthening law of prestressed anchor bolts on tunnel support systems and clarifies the core mechanism of their active support. The research results provide important experimental basis and theoretical reference for the optimal design and engineering application of prestressed anchor bolts in soft rock tunnel engineering.

CivilEng doi: 10.3390/civileng7010018

Authors: Deelaram Nangir Michaela Gkantou Ana Bras Georgios Nikitas Maria Ferentinou Mike Riley Paul Clark Simon Humphreys

The UK faces an urgent challenge to simultaneously accelerate housing delivery and reduce whole-life carbon emissions, yet robust empirical evidence on the carbon performance of modular steel housing remains limited. This study aims to quantify the carbon impacts of a modular light-gauge steel frame social housing dwelling in the UK and to benchmark its performance against contemporary low-carbon construction typologies. A cradle-to-grave life cycle assessment was conducted using primary project data from a real modular housing development, with embodied carbon modelled in One Click LCA and operational energy assessed through SAP 10.2-verified datasets. The results indicate a total whole-life carbon footprint of 91.3 tCO2e over a 50-year period, with embodied emissions (A1–A3) accounting for 38.2% and operational energy and water use contributing 48.1%. The normalised embodied carbon intensity of 366 kgCO2e/m2 (A1–A5) is comparable to recent high-performing cross-laminated timber buildings, demonstrating that optimised modular steel systems can allow for low-carbon outcomes typically associated with bio-based construction. Sensitivity analysis shows that low-carbon foundation concrete, bio-based insulation, and steel optimisation can reduce upfront emissions by approximately 8–10%. Dynamic energy simulations were also used to assess how different design choices influence operational carbon emissions. This study provides transparent, real-project evidence of the whole-life carbon performance of UK modular light-gauge steel frame housing and identifies practical design strategies for further decarbonisation. The findings support informed decision-making for policymakers, designers, and housing providers seeking scalable, low-carbon residential solutions.

CivilEng doi: 10.3390/civileng7010017

Authors: Meng Xiang Yanping Niu Leilei Liu Xicheng Zhang Maozhe Nie Yao Cui

To effectively enhance the seismic performance of traditional Chinese timber structures, this study proposes a reinforcement method utilizing friction dampers. Based on the working mechanism of friction dampers and the extended discrete element theory, an analytical model for timber structures equipped with these dampers was developed and validated through shake table tests. Subsequently, dynamic analyses were conducted to systematically evaluate the enhanced seismic energy dissipation capacity of the ancient timber structures by the reinforcement of friction dampers. The friction coefficient (μ), bolt pre-tension strain (ε), and action distance (l) were selected as key parameters. A multi-objective optimization function was constructed using the weighted sum method, enabling a multi-objective parameter optimization analysis for the friction dampers to identify the optimal parameter combination under specific conditions. The results indicate that the established extended discrete element model effectively simulates the dynamic characteristics of the structure. The installation of friction dampers significantly enhanced the structure’s energy dissipation capacity and substantially reduced the peak displacement. However, due to the initial stiffness introduced by the dampers, the lateral stiffness of the column frame increased markedly, leading to a significant amplification of the acceleration response, with a maximum increase in peak acceleration reaching 77%. The multi-objective optimization analysis revealed that with weighting coefficients λa = λb = 0.5, the optimal damper parameter combination is μ = 0.36, ε = 102 με, and l = 268 mm. Under these conditions, the structural displacement response decreased by 38.5%, while the acceleration response increased by 93.7%. It is noted that the derived optimal design solutions are pertinent to the specific structural typology and ground motions considered.

CivilEng doi: 10.3390/civileng7010016

Authors: Seunghyun Na Wenyang Zhang Woonggeol Lee Madoka Taniguchi

Alkali-activated materials can significantly reduce carbon dioxide emissions compared with cement. However, their durability remains insufficiently understood. This study investigated the effects of calcium hydroxide (Ca(OH)2, CH), an expansion agent (calcium sulfoaluminate, CSA), and a shrinkage-reducing agent (SRA) on the compressive strength and length change and determined the optimal content levels for each agent. Experiments were conducted to evaluate the compressive strength and length change of 17 mortar mixtures containing CH, CSA, and SRA. The substitution ratios of CH, CSA, and SRA were fixed at three predefined levels for each factor. The microstructural changes induced by the use of each agent were analyzed using pH measurements, porosity analysis, and X-ray diffraction. In addition, the water desorption behaviors associated with CSA and SRA were assessed. Experimental and statistical analyses demonstrated that the optimal contents of CH, CSA, and SRA for simultaneously improving the compressive strength and length change were 8.54, 10.0, and 0.76 wt.%, respectively. The use of CSA significantly enhanced the compressive strength development and dimensional stability of the mortar. This improvement was associated with a reduction in the porosity, which was attributed to ettringite formation. Furthermore, while the SRA slightly reduced the compressive strength, it significantly improved the dimensional stability.

CivilEng doi: 10.3390/civileng7010015

Authors: Bassel Bakleh George Wardeh Hala Hasan Ali Jahami Antonio Formisano

The long-term behavior of reinforced concrete (RC) structures under sustained loading is strongly affected by creep and cracking, particularly under service conditions where tension stiffening and curvature changes are significant. This study investigates the flexural response of cracked RC beams through combined numerical and experimental analyses. A new 1D finite element model is proposed, integrating nonlinear material behavior, damage mechanics, and time-dependent effects, including creep in both compression and tension. The model relies on a layered fiber section approach and uses a Newton–Raphson iterative procedure to solve equilibrium, allowing accurate prediction of strain, curvature, and internal force evolution over time. The model shows excellent agreement with experimental observations and ABAQUS simulations, accurately capturing deflection trends and crack development. Its performance is further validated using a database of 55 RC beams, including specimens with recycled aggregates and fiber reinforcement. Across this dataset, 84.5% of predicted deflections fall within ±1 mm of measured values, with an R2 of 0.960, demonstrating strong reliability. A Sobol-based sensitivity analysis identifies load ratio as the most influential parameter on long-term deflection, followed by concrete strength and humidity. Overall, the model offers an efficient and robust tool for long-term deflection prediction, bridging simplified design rules and complex 3D simulations.

CivilEng doi: 10.3390/civileng7010014

Authors: Mona Rais Esmaili Anjan K. Bhowmick

Nonlinear seismic analysis procedures can accurately estimate structural responses but are computationally intensive, making them impractical for engineering design. This study provides the first comprehensive evaluation of N2 and modal pushover analysis for eccentrically braced frames (EBFs), revealing their strengths and limitations in predicting link rotations, shear demands, and drift distribution under Canadian seismic hazards. Analyzed were four-, eight-, and 14-storey chevron EBFs under real and artificial ground motions compatible with the response spectrum of Vancouver, Canada. The findings indicate that inelastic link rotations for all EBFs remain below the design limit of 0.08 rad, except for the upper two floors of the 14-storey EBFs. Seismic analysis reveals that maximum inelastic link shear forces often exceed design recommendations. It is also observed that both the N2 method and MPA procedure could reasonably predict the peak roof displacements for low-rise EBF buildings. In addition, while the MPA procedure provides better predictions of maximum inter-storey drifts over all storeys for medium-to-taller EBFs, inter-storey drifts are not predicted well in the N2 method. Additionally, the current code formula for estimating the fundamental period of EBFs predicts shorter periods than those obtained from analysis. An improved formula for estimating EBF periods is proposed.

CivilEng doi: 10.3390/civileng7010013

Authors: Lanying Xie Haifan Wang Ningbo Wang Cheng Zhang Xiangguo Li Yang Lv Bo Tian

Concrete, as a widely used construction material, suffers from performance degradation due to chloride penetration and sulfate attack in harsh environments. Conventional performance-enhancing methods are costly and emit high levels of carbon dioxide. This study modified graphene oxide (GO) with polycarboxylate superplasticizer (PCE) alone or PCE synergized with a rubber viscosity reducer, optimized dispersion (50 °C water bath for 1 h), and prepared C50 modified concrete (500 kg/m3 cementitious materials, w/b = 0.33). GO contents were 0%, 0.001%, 0.003%, 0.005%; a group with 8% reduced cementitious materials (460 kg/m3) was also tested. Results showed PCE-viscosity reducer synergy better dispersed GO, improving concrete workability. GO accelerated cement hydration via nucleation, refining C-S-H gel and reducing porosity. At 0.005% GO, 56 d drying shrinkage dropped by 29.3% vs. the blank, and 56 d chloride penetration electric flux was 586 C, meeting 100-year service life. Sulfate resistance also improved with higher GO content. Even with 8% less cementitious materials, modified concrete outperformed the blank. This provides support for GO’s application in cement-based materials.

CivilEng doi: 10.3390/civileng7010012

Authors: Baraa A. Alfasi Ata M. Khan

Avoiding highway infrastructure construction cost overruns and reducing associated claims and disputes continues to be a challenge in many countries. Research is needed in identifying notable project planning and management deficiencies that are likely to cause cost overruns. The literature suggests numerous potential causes of cost overrun but the clustering of cause variables and relative importance of clusters has not been researched. The research reported here addresses this knowledge gap using predictive models developed with data contributed by several agencies in participating countries and suggests mitigation measures. Following a review of methods and data sources, a methodological framework is advanced that encompasses statistical methods well suited for providing a scientific basis for identifying important clusters of cost overrun variables. Fifty-three completed questionnaires contributed by knowledge experts and experienced managers from Canada, the United States, the Middle East, and Australia met the sample requirements of statistical methods. Starting from 53 variables, the principal component-supported factor analysis method identified clusters of cost overrun variables and their relative importance was inferred with developed logistic regression models. Deeper insights into the causes of cost overruns obtained from this research suggest mitigation measures (e.g., improved qualification and experience of personnel, enhanced planning and design practices, risk analysis of inputs to cost estimation process) that are within reach of managers. The results can enhance infrastructure planning and management practice including a reduction in claims and disputes.

CivilEng doi: 10.3390/civileng7010011

Authors: Ajanta Kalita Nisha Kumari Singh Ghritartha Goswami Sudip Basack Moses Karakouzian

The demand for sustainable and environmentally friendly soil stabilization methods for subgrade improvement for pavements has led to exploring techniques that minimize ecological impact while optimizing engineering properties. Traditional stabilizers like cement and lime, though effective, have significant environmental drawbacks, including a high carbon footprint, disruption of vegetation, and health risks to workers. This study investigates the efficiency of biopolymers and eggshell powder as eco-friendly, sustainable soil stabilization agents. Parameters such as compaction characteristics, California Bearing Ratio (CBR), and micro-structural analysis were assessed. The research evaluates soil samples treated with varying concentrations of biopolymer (1%, 2%, and 3%) and eggshell powder (4%, 6%, and 8%). Results indicated that biopolymer addition slightly decreased the maximum dry density (MDD) and increased the optimum moisture content (OMC), while eggshell powder slightly increased MDD and decreased OMC. The optimal mix, soil + 1% xantham gum + 6% eggshell powder, enhanced CBR by 225.6% and 323.8% for soaked and unsoaked conditions, respectively. The scanning electron microscope revealed that treated soil samples transformed into a hard solid matrix, demonstrating improved stability. EDX analysis revealed the mineralogical composition of the mixes. Overall, the use of biopolymers and eggshell powder not only enhances soil strength but also promotes environmental sustainability.

CivilEng doi: 10.3390/civileng7010010

Authors: Shimaa Emad Alaa Elsisi Eman Sharaf Atef Eraky Abdallah Salama

The accurate estimation of the fundamental period is critical for seismic design using the Equivalent Lateral Force method. This study evaluates widely used empirical period formulae from international seismic codes and previous research by comparing them with detailed finite element method (FEM) analyses. A total of 93 reinforced concrete building models were assessed. The results show that most empirical formulae, notably the American Society of Civil Engineers Standard (ASCE 7-10), the Eurocode, the National Building Code of Canada (NBCC), and the Saudi Building Code (SBC 301), systematically underestimate the fundamental period in low- and mid-rise buildings often by more than 40% under cracked conditions, while discrepancies reduce under uncracked assumptions. Equations such as those proposed by the Building Standard Law of Japan (BSLJ) and Australian Standard (AS 11407.2) show comparatively closer agreements with FEM predictions, whereas formulae developed by Goel and Chopra and by Alguhane et al. have distinct differences, especially at greater heights. Statistical parameters, including the arithmetic mean difference and the standard deviation, were employed to enhance the comparison and assess the accuracy and dispersion of the estimated fundamental periods. The results indicate that empirical formulae, although beneficial in first-design stages, are likely to yield conservative results and suggest the use of advanced numerical computation or revised models and coefficients for RC high-rise and irregular buildings.

CivilEng doi: 10.3390/civileng7010009

Authors: P. D. P. O. Peramuna Srikanth Venkatesan N. G. P. B. Neluwala K. K. Wijesundara Saman De Silva

Cascade dams describe an arrangement of several dam structures built along a flow path. Failure of one upstream dam in the cascade system can trigger catastrophic consequences to the downstream dams, as evidenced recently in the Edenville Dam and Sanford Dam. Previous research has mainly focused on rainfall-induced dam failures, although recent failures have demonstrated a combination of floods and earthquakes. Moreover, limited studies have analyzed the sensitivity of dam breach parameters, such as dam breach height and width in dams arranged in a cascade system for seismic events. Most hydraulic simulations that model seismic-induced dam failures assume the complete collapse of dams to analyze the downstream consequences. Hence, this study presents a novel analysis in simulating earthquake-induced failures in a cascade dam system, considering the sensitivity of dam breach parameters. In addition, dam breach parameters have been derived from the structural analysis of dams employing Finite Element Models (FEMs) to a critical Peak Ground Acceleration (PGA) of 0.3 g. Two-dimensional hydrodynamic simulations, along with the full dynamic wave equations, are undertaken in the study to model the earthquake-induced cascade dam failures. The results further elaborate on the significance of modeling cascade dam failures in terms of the consecutive arrival of floods and total flow compared to individual dam failures. Sensitivity analysis of dam breach parameters shows that the breach height is more significant than the breach width and breach slope. However, its significance decreases as the dam breach flood flow path increases in distance. The study further confirms the novel utilization of structural analysis to derive dam breach parameters for seismic-induced dam failures of concrete arch dams and rockfill dams, which will guide the optimization of disaster mitigation strategies and the operational resilience of the dams.

CivilEng doi: 10.3390/civileng7010008

Authors: Tânia Feiri Til Lux Udo Wiens Marcus Ricker

Annex A of EN 1992-1-1:2023—recently revised and amended in the context of the Second Generation of Eurocodes—introduces a method to adjust partial safety factors for the resistance side alongside a set of factors for different conditions and design situations, both for new and existing structures. The method proposed in Annex A is complemented by a set of stochastic models for relevant basic variables and forms a rather simple and objective format to adjust the partial safety factors from the default values offered in EN 1990:2023. Yet, over the last few years, advanced reliability-based methods aligned with modern computational tools have proved to enable rather robust and efficient structural reliability assessments. A thorough comparative analysis is imperative to understand how distinct reliability-based methods can be applied to adjust partial safety factors in the design of new structural components composed of steel-reinforced concrete. This analysis sheds light on the use of different methods to derive partial safety factors for the resolution of common engineering problems and offers inferences regarding possible implications in terms of safety and economic efficiency of design solutions.

CivilEng doi: 10.3390/civileng7010007

Authors: Gaurav Chobe Ishaan Davariya Dheeraj Waghmare Shivam Sharma Akanshu Sharma Amit H. Varma Vilas G. Pol

Lithium-ion batteries (LIBs) are essential for electric vehicles, consumer electronics, and grid storage, but their rapidly increasing demand is paralleled by growing waste volumes. Current disposal methods remain costly, complex, energy-intensive, and environmentally unsustainable. This pilot study investigates a scalable, low-impact disposal method by incorporating LIB waste into concrete, evaluating both the structural and environmental effects of LIB waste on concrete performance. Several cement–mortar cube specimens were cast and tested under compression using the cement–mortar mix with varying battery waste components, such as black mass and varied metals. All mortar mixes maintained an identical water-to-cement ratio. The compressive strength of the cubes was measured at 3, 7, 14, 21, and 28 days after casting and compared. The mix containing black mass exhibited a 35% reduction in compressive strength on day 28, whereas the mix containing varied metals showed a 55% reduction relative to the control mix without LIB waste. A case study was conducted to evaluate the combined structural and environmental performance of a concrete specimen incorporating LIB waste by estimating the embodied carbon (EC) for each mix and comparing the strength-to-net EC ratio. Selective incorporation of LIB waste into concrete provides a practical, low-carbon upcycling pathway, reducing both embodied carbon and landfill burden while enabling greener, non-structural construction materials. This sustainable approach simultaneously mitigates battery waste and lowers cement-related CO2 emissions, delivering usable concrete for non-structural and low-strength structural applications.

CivilEng doi: 10.3390/civileng7010006

Authors: Navid Bohlooli Hadi Bahadori Hamid Alielahi Daniel Dias Mohammad Vasef

Construction on soft, highly compressible soils increasingly requires reliable ground improvement solutions. Among these, Rigid Inclusions (RIs) have emerged as one of the most efficient soil-reinforcement techniques. This paper synthesizes evidence from over 180 studies to provide a comprehensive state-of-the-art review of RI technology encompassing its governing mechanisms, design methodologies, and field performance. While the static behavior of RI systems has now been extensively studied and is supported by international design guidelines, the response under cyclic and seismic loading, particularly in liquefiable soils, remains less documented and subject to significant uncertainty. This review critically analyzes the degradation of key load-transfer mechanisms including soil arching, membrane tension, and interface shear transfer under repeated loading conditions. It further emphasizes the distinct role of RIs in liquefiable soils, where mitigation relies primarily on reinforcement and confinement rather than on drainage-driven mechanisms typical of granular columns. The evolution of design practice is traced from analytical formulations validated under static conditions toward advanced numerical and physical modeling frameworks suitable for dynamic loading. The lack of validated seismic design guidelines is high-lighted, and critical knowledge gaps are identified, underscoring the need for advanced numerical simulations and large-scale physical testing to support the future development of performance-based seismic design (PBSD) approaches for RI-improved ground.

CivilEng doi: 10.3390/civileng7010005

Authors: Tareq Salloum Ernest Forman

This paper presents a quantitative framework for assessing and managing public-safety risks around dams. The framework integrates a hazard–event–objective–control structure with the Analytic Hierarchy Process (AHP) to transform qualitative judgments into quantitative risk measures. Likelihoods, consequences, and overall risk are expressed on a ratio scale, allowing results to be aggregated, compared, and communicated in monetary terms. Probabilistic simulation accounts for uncertainty and generates outputs such as Value-at-Risk (VaR), loss-exceedance curves, and societal F–N charts, providing a clear picture of both expected and extreme outcomes. Optimization identifies control portfolios that achieve the greatest risk reduction for available budgets. A hypothetical dam case study demonstrates the framework’s application and highlights its ability to identify high-value safety investments. The framework offers dam owners and regulators a transparent, data-driven basis for prioritizing public-safety improvements and supports both facility-level (micro) and program-level (macro) decision-making consistent with international risk-tolerability and ALARP principles.

CivilEng doi: 10.3390/civileng7010004

Authors: Mohamed Algamati Abobakr Al-Sakkaf Ashutosh Bagchi

Base isolation is known as a useful and popular technique for seismic upgrading of reinforced concrete buildings. Predicting damage levels based on relative inter-story drift plays an important role for designing optimal base isolation systems. However, the existing codes usually rely on the acceleration spectrum for calculating the relative inter-story drift, and they do not provide an accurate estimation of the relative inter-story drift. Consequently, to cover the research gap, machine learning algorithms are being trained and used for identification of damage levels in retrofitted reinforced concrete buildings. More than 7000 datasets were derived by using nonlinear time-history and incremental dynamic analysis. A total of 48 reinforced concrete buildings with different stories and bay numbers were designed based on an older version of existing building codes, and then, base isolation systems were designed for the seismic retrofit. The machine learning algorithms used here were Decision Tree, Random Forest, Support Vector Machine, Extreme Gradient Boosting, and an Artificial Neural Network. Based on the results, four of the mentioned algorithms have the capability of predicting the damage level with an accuracy of more than 85%, with the best performance being reached by extreme gradient boosting with an accuracy of 89%. Finally, the most important parameters affecting the damage levels of retrofitted reinforced concrete buildings were derived.

CivilEng doi: 10.3390/civileng7010003

Authors: Hamed Abdul Baseer G. G. Md. Nawaz Ali

The construction industry significantly contributes to global sustainability challenges, producing 30–40 percent of global carbon dioxide emissions and consuming large amounts of natural resources. Pervious concrete has emerged as a sustainable alternative to conventional pavements due to its ability to promote stormwater infiltration and groundwater recharge. However, the absence of fine aggregates creates a highly porous structure that results in reduced compressive strength, limiting its broader structural use. Determining compressive strength traditionally requires destructive laboratory testing of concrete specimens, which demands considerable material, energy, and curing time, often up to 28 days—before results can be obtained. This makes iterative mix design and optimization both slow and resource intensive. To address this practical limitation, this study applies Machine Learning (ML) as a rapid, preliminary estimation tool capable of providing early predictions of compressive strength based on mix composition and curing parameters. Rather than replacing laboratory testing, the developed ML models serve as supportive decision-making tools, enabling engineers to assess potential strength outcomes before casting and curing physical specimens. This can reduce the number of trial batches produced, lower material consumption, and minimize the environmental footprint associated with repeated destructive testing. Multiple ML algorithms were trained and evaluated using data from existing literature and validated through laboratory testing. The results indicate that ML can provide reliable preliminary strength estimates, offering a faster and more resource-efficient approach to guiding mix design adjustments. By reducing the reliance on repeated 28-day test cycles, the integration of ML into previous concrete research supports more sustainable, cost-effective, and time-efficient material development practices.

CivilEng doi: 10.3390/civileng7010002

Authors: Cristian Georgeoi Ioan Petran Camelia Maria Negrutiu Pavel Ioan Sosa

This study examines the use of electronic waste (e-waste) as an alternative material in concrete for sustainability and natural resource conservation. Various e-wastes, such as Polyvinyl Chloride (PVC), Glass-Reinforced Plastic (GRP), Glass Fiber-Reinforced Polymer (GFRP), cross-linked polyethylene (XLPE), polyethylene (PE), electronic cable waste (ECW), Waste Electrical Cable Rubber (WECR), copper fiber (Cu Fib.), aluminum Fibers (Al fib.), steel fibers, basalt fibers, glass fibers, aramid−carbon fibers, Kevlar fibers, jute fibers, and optical fibers, were tested for influence on compressive, flexural, tensile strength, modulus of elasticity, and water absorption. Outcomes show that fine particle waste at low levels (0.2–1.5%) can improve mechanical performance, while higher levels of replacement or coarse particles generally reduce performance. Mechanical and physical properties are highly sensitive to material type, particle size, and dose. Life cycle assessment (LCA) and predictive modeling are recommended as validation for sustainability benefits.

CivilEng doi: 10.3390/civileng7010001

Authors: Ghazi Jalal Kashesh Hasan H. Joni Anmar Dulaimi Abbas Jalal Kaishesh Adnan Adhab K. Al-Saeedi Tiago Pinto Ribeiro Luís Filipe Almeida Bernardo

The growing demand for sustainable pavement materials has driven increased interest in asphalt mixtures incorporating recycled crumb rubber (CR). While CR modification enhances mechanical performance and durability, its often increases initial production costs and energy demand. This study develops an integrated framework that combines machine learning (ML) and economic analysis to identify the optimal balance between performance and cost in CR-modified asphalt overlay mixtures. An experimental dataset of conventional and CR-modified mixtures was used to train and validate multiple ML algorithms, including Random Forest (RF), Gradient Boosting (GB), Artificial Neural Networks (ANNs), and Support Vector Regression (SVR). The RF and ANN models exhibited superior predictive accuracy (R2 > 0.98) for key performance indicators such as Marshall stability, tensile strength ratio, rutting resistance, and resilient modulus. A Cost–Performance Index (CPI) integrating life-cycle cost analysis was developed to quantify trade-offs between performance and economic efficiency. Environmental life-cycle assessment indicated net greenhouse gas reductions of approximately 96 kg CO2-eq per ton of mixture despite higher production-phase emissions. Optimization results indicated that a CR content of approximately 15% and an asphalt binder content of 4.8–5.0% achieve the best performance–cost balance. The study demonstrates that ML-driven optimization provides a powerful, data-based approach for guiding sustainable pavement design and promoting the circular economy in road construction.

CivilEng doi: 10.3390/civileng6040069

Authors: Onur Gurler Ozgur Ozcelik Sadik Can Girgin Atakan Aksoy Cagri Cetik

Energy-dissipating braces are novel structural components as they not only accommodate the seismic energy demand but also enhance both the flexibility and overall earthquake resistance of the structure, preventing brittle or non-ductile behavior. The novel brace proposed in this study was developed to achieve two primary objectives: first, to restrict relative displacements at its ends by dissipating energy through U-shaped flexural plates (UFPs), and second, to provide a self-centering mechanism through the use of post-tension (PT) to ensure structural re-centering after cyclic loading. The novelty of this research lies in the experimental findings showing that post-tensioned (PT) braces exhibit a flag-shaped self-centering hysteretic response, improved initial stiffness, and reduced residual displacements by 72%, while non-PT braces behave as conventional metallic dissipators with larger residual displacements. Increasing UFP thickness from 6 to 8 mm enhances strength by 22%. Stainless steel UFPs offer superior plastic recovery, whereas regular steel UFPs dissipate ~%10 more energy through greater plasticity. Energy dissipation of the brace increases with increasing PT forces and displacement due to the PT force pulling the force–displacement curve towards high force levels. This study highlights the importance of PT force and UFP parameters in a brace configuration with self-centering and metallic dissipators such as U-shaped flexural plates.

CivilEng doi: 10.3390/civileng6040068

Authors: Mohamed Gindy Moutaman M. Abbas Radu Muntean Silviu Butnariu

The cement industry significantly contributes to global CO2 emissions, making material efficiency in concrete structures a crucial sustainability goal. This study addresses the challenge of excessive cement usage in traditional concrete design by optimizing a cast-in-place concrete bench. A density-based topology optimization framework was implemented in ANSYS Mechanical and enhanced with a deep-learning surrogate model to accelerate computational performance. The optimization aimed to minimize the structural mass while satisfying serviceability and strength constraints, including limits on displacement and compressive stress under realistic public-use loading conditions. The topology optimization converged after 62 iterations, achieving a 46% reduction in mass (from 258.3 kg to 139.4 kg) while maintaining a maximum deflection below 2 mm and a maximum compressive stress of 15.5 MPa, within the allowable limit for C20/25 concrete. The deep-learning surrogate model achieved strong predictive accuracy (IoU = 0.75, Dice = 0.73) and reduced computation time by over 105× compared to the full finite element optimization. The optimized geometry was reconstructed and rendered using Blender for visualization. These results highlight the potential of combining topology optimization and machine learning to reduce material use, enhance structural efficiency, and support sustainable practices in concrete construction.

CivilEng doi: 10.3390/civileng6040067

Authors: Mohammad Amin Oyarhossein Gabriel Sugiyama Fernanda Rodrigues Hugo Rodrigues

This article presented a method for grading and visualising corrosion in steel pedestrian bridges using Building Information Modelling (BIM). Traditional inspection methods are often manual and subjective, which reduces their reliability and repeatability. To enhance the recording and reporting of inspection results, a five-level corrosion severity grading system was developed using matched photographic data from two inspection campaigns conducted in February 2024 and April 2025. The grades were assigned based on visual signs, including surface rust, coating damage, and flaking. A Dynamo script was used to link each grade to the corresponding elements in a Revit model using colour overrides. The proposed approach enables corrosion data to be integrated into the BIM environment in a clear, structured manner. This helps engineers assess the structure’s condition, monitor changes over time, and make informed maintenance decisions. The workflow was demonstrated using case studies from a steel pedestrian bridge in Aveiro, Portugal. The method is adaptable for future digital twin applications and supports the development of BIM-based tools for bridge asset management. The workflow was applied to over 2600 elements, with 75 visually degraded cases identified and classified into five grades, demonstrating the method’s feasibility for systematic corrosion tracking. The proposed workflow was tested on a coastal steel bridge and could be generalised to other bridges with similar environmental conditions.

CivilEng doi: 10.3390/civileng6040066

Authors: Fahmidah Ummul Ashraf William H. Pennock Ashish D. Borgaonkar

Given the apparent gap between scientific research and engineering practice, this paper tracks the dominating perspectives that have shaped the growth of hydrological research. Based on five eras, dominated with specific paradigms and/or ideologies, this paper highlights the punctuated growth of flood frequency analysis comparative to the enormous progress made in hydrological modeling can be claimed by the 20th century. The historical narrative underpinning this inquiry indicates that progress in hydrological understanding can be characterized by two contrasting claims: modeling breakthroughs and inconclusive results. Contradicting statistical assumptions, complex modeling structures, the standardization of specific techniques, and the absence of any unified physical meaning of the research results brought an apparent conflict between the scope of hydrologic research and the scope of end users, i.e., civil engineers. Some hydrologists argue that the debates associated with hydrologic progress, i.e., the evolution of statistical methods, dating back to the 1960s remain unaddressed, with each era introducing additional uncertainty, questions, and concerns. Progress, for it to happen, needs synthesis among scientists, engineers, and stakeholders. This paper concludes that, in a similar way to how physicists acknowledge the conflicts between quantum and Newtonian physics, hydrology too can benefit from acknowledging divergent principles emerging from engineering practice. While many advanced analytical tools—though varied in form—are grounded in the assumption that past data can predict future conditions, the contrasting view that past data cannot always do so represents a key philosophical foundation for resilience-based civil engineering design. Acknowledging contrasting philosophies describing the nature of reality can help illuminate the conundrum in the scope of hydrological research and can enable synthesis activities aimed at ‘putting the puzzle together’.

CivilEng doi: 10.3390/civileng6040064

Authors: Aaron Gutierrez-Lopez Dante Tolentino Federico Valenzuela-Beltran J. Martin Leal-Graciano Juan Bojorquez J. Ramon Gaxiola-Camacho

The structural performance of mid-rise buildings with a soft first story is a critical issue in earthquake-prone regions. This paper presents a detailed assessment of both the seismic performance and the structural reliability of a confined masonry mid-rise building with a soft reinforced-concrete first-story irregularity located in Mexico. This structure was designed according to outdated building codes to reflect construction practices that remain common in some parts of the country. Nonlinear dynamic analyses were conducted using ETABS v21. To simulate various seismic scenarios, ground motion records associated with return periods of 72, 475, and 975 years, respectively, were implemented. The results demonstrated that maximum inter-story drift is predominantly concentrated at the first story, exceeding the performance thresholds for immediate occupancy, life safety, and collapse prevention. Furthermore, a probabilistic performance assessment was developed considering the randomness of inter-story drift responses. Then, reliability index (β) was calculated for each seismic scenario. In all cases, β values remained consistently below the minimum recommended limit. These findings confirm the formation of a soft-story mechanism at the first level and are relevant for buildings designed under construction provisions like those used in the present case study.

CivilEng doi: 10.3390/civileng6040065

Authors: Muhammad Usama Aslam Tariq Umar Musaab Suliman Muhammad Usman Siddiq Hamid Rajabnejad Ambar Farooq

The increasing integration of Chinese-engineered infrastructure in Pakistan under the China–Pakistan Economic Corridor (CPEC) necessitates a comparative evaluation of seismic resilience between the Chinese and Pakistani building codes. This study focused on the seismic performance of reinforced concrete (RC) frames designed according to these two codes. Fragility curves were generated for 4-story, 8-story, and 12-story buildings subjected to varying seismic intensities using Incremental Dynamic Analysis (IDA). The results indicate that structures designed under the Chinese code exhibit up to 12% lower fragility values, suggesting enhanced seismic resilience, particularly at higher seismic intensities. Additionally, the study investigates the effectiveness of Lead Rubber Bearings (LRBs) for seismic isolation, demonstrating that their integration improves the seismic performance of RC frames by enhancing energy dissipation and reducing the likelihood of exceeding various damage states by up to 25%. These findings underscore the importance of adopting stringent seismic design provisions, such as those found in the Chinese code, to enhance the resilience and safety of infrastructure, especially in seismic-prone regions.

CivilEng doi: 10.3390/civileng6040063

Authors: Cheng Peng Yang Wang Bo Deng Dongxing Wang

This study presents an environmentally friendly alternative to conventional energy-intensive methods for soil improvement by investigating an enzyme-induced active magnesium oxide carbonation (EIMC) technique for the stabilization of gravelly soil. The solidification efficacy and strengthening mechanism of EIMC-treated soil were systematically investigated through a combination of mechanical property tests and microstructural analyses. Results indicate that key mechanical properties—including compressive strength, shear strength, and elastic modulus—were directly proportional to the magnesium oxide (MgO) content. Notably, an 8% MgO content resulted in a 113-fold increase in unconfined compressive strength (UCS) compared to the untreated soil. The strength development stabilized after a five-day curing period. While higher MgO content yielded greater absolute strength, the efficiency of strength gain per unit of MgO peaked at a 4% dosage. Consequently, considering both performance and efficiency, an MgO content of 4% and a curing period of 5 days are recommended as the optimal parameters. The EIMC treatment substantially improved the soil’s mechanical properties, inducing a transition in the failure mode from plastic to brittle, with this brittleness becoming more pronounced at higher MgO concentrations. Furthermore, the treatment enhanced the soil’s water stability. Microstructural analysis revealed that the formation of hydrated magnesium carbonates filled voids, cemented particles, and created a dense structural matrix. This densification of the internal structure underpinned the observed mechanical improvements. These findings validate EIMC as a feasible and effective eco-friendly technique for gravelly soil stabilization.

CivilEng doi: 10.3390/civileng6040062

Authors: Sakdirat Kaewunruen Charalampos Baniotopoulos Patrick Teuffel Hamza Driou Otso Valta Jan Pešta Diana Bajare

It is undeniable that digital technology enables, e.g., building information modelling, digital twins, extended reality (i.e., virtual reality, augmented reality, mixed reality), and automation, have recently played a significant role in the construction and engineering industry. The traditional applications of digital technologies include design and construction management, waste management, and, to a limited extent, asset management. Despite some applications of digital technologies, the technology users are often isolated and siloed. In reality, the cross-functional applications, roles, and co-benefits have not been thoroughly understood or well demonstrated. This is evident by a very limited usage of such technology across either the whole lifecycle or the value chain of built environment sectors. On this ground, this study is the first to tackle the challenges by conducting expert and stakeholder interviews using open-ended questionnaires both online and offline (n = 42) to identify synergic roles and influences, as well as co-benefits of digital technology enablers. Industry participants are dominant in our study and, unsurprisingly, siloed practice can undermine cross-collaboration among value chain stakeholders. Clearly, co-benefits may hypothetically occur, but they can be only unlocked by genuine, participative stakeholder engagement. This study is unprecedented, and our new findings also reveal technical and societal capabilities of digital technologies, which can inclusively enable participative decision-making, engagement, and integration of stakeholders for implementing buildings’ circularity through viable business and management models. New insights clearly exhibit that digital technology enablers must be co-created by main stakeholders in order to yield co-benefits and harvest synergic value for circular management models in the built environment.

CivilEng doi: 10.3390/civileng6040061

Authors: Felix Weber

This paper analyzes the physics of the TMD-Inerter for harmonic vibrations. The basic TMD-Inerter layout is assumed, where the inerter is installed between the TMD mass and the structural mass. For harmonic vibrations, the inerter force can be formulated as a function of terminal displacements. This formulation demonstrates that the inerter force is, in fact, a negative stiffness force with frequency-dependent negative stiffness coefficient. Based on this finding, the optimal stiffness tuning of the TMD-Inerter is derived. As this stiffness tuning can only be realized by a controlled actuator, the tuning of the spring of the TMD-Inerter is presented. As this spring is a passive element, its optimum tuning must be made at a selected frequency of vibration. It is shown that the average of the TMD natural frequency and structural eigenfrequency leads to a close to optimal spring tuning. This approach needs to be combined with increased damping of the TMD-Inerter to minimize the structural displacement response. Despite the close to optimal tunings of stiffness and damping, the resulting primary structure displacement response is approximately 41.6% greater than that due to the classical TMD. The reason for this lies in the fact that the passive spring of the TMD-Inerter cannot compensate for the frequency-dependent negative stiffness of the inerter within the entire frequency range.

CivilEng doi: 10.3390/civileng6040060

Authors: Andreas Ratka Wolfgang Ernst Matthias Wörlein

Within the scope of this article is the presentation of a modelling and measurement approach for the effects of roof greenings and the application of the approach to evaluate the influence of roof greenings upon the thermal conditions inside a typical residential building. It is shown that overheating in summer can be reduced, and thermal comfort for inhabitants can be increased. The cooling is caused by the transpiration of plants and by the evaporation of water from the substrate. Other relevant physical effects are the shading of plants and the increase in the heat capacity of the building. In state-of-the-art buildings, a layer with a high insulating effect is incorporated into the envelope. This leads to the effect that a huge fraction of the cooling power is taken from the outside of the building and only a smaller part is taken from the inside. In order to mitigate this decoupling, a hydraulic connection between the greening and the interior of the building is introduced. To evaluate the effect of the inside cooling, the difference in the number of yearly hours with overheating in residential buildings is estimated. In addition, the reduction in energy demand for the climatisation of a typical residential building is calculated. The used methods are as follows: (1) Performance of laboratory and free field measurements. (2) Simulation of a typical residential building, using a validated approach. In summary, it can be said that green roofs, in particular with hydraulic connections, can significantly increase the interior thermal comfort and potentially reduce the energy required for air conditioning.

CivilEng doi: 10.3390/civileng6040059

Authors: Maximilian Gehring Jascha Brötzmann Uwe Rüppel

Traditional construction logistics rely on manual processes and fragmented tools, leading to inefficient planning, poor communication, and disorganized supply chains. Despite advances in digitalization, there is a lack of integrated, data-driven approaches tailored to construction logistics. To address this gap, this paper adopts a design-science approach to develop and evaluate a modular Digital Twin (DT) framework, the ConLogTwin. The framework integrates planning data with real-time site data through a robust data storage layer and digital services for automated planning and analytics. A prototype demonstrates the technical feasibility of mirroring both physical and organizational setups of projects, enabling more efficient and adaptive logistics management. The work contributes a modular reference architecture that integrates established open-source tools into a coherent, adaptable framework for construction logistics, enhancing practical applicability and lowering implementation barriers. A limitation is that the framework has not yet been validated in a full-scale field study, leaving its effectiveness in practice to be tested in a future study.

CivilEng doi: 10.3390/civileng6040058

Authors: Mu’tasim Abdel-Jaber Rawand Al-Nsour Ahmed Ashteyat

The incorporation of Basalt Fiber-Reinforced Polymer (BFRP) materials marks a significant advancement in the adoption of sustainable and high-performance technologies in structural engineering. This study investigates the flexural behavior of four-meter, two-span continuous reinforced concrete (RC) beams of low and medium compressive strengths (20 MPa and 32 MPa) strengthened or rehabilitated using near-surface mounted (NSM) BFRP ropes. Six RC beam specimens were tested, of which two were strengthened before loading and two were rehabilitated after being preloaded to 70% of their ultimate capacity. The experimental program was complemented by Finite Element Modeling (FEM) and analytical evaluations per ACI 440.2R-08 guidelines. The results demonstrated that NSM-BFRP rope application led to a flexural strength increase ranging from 18% to 44% ductility by approximately 9–11% in strengthened beams and 13–20% in rehabilitated beams, relative to the control specimens. Load-deflection responses showed close alignment between experimental and FEM results, with prediction errors ranging from 0.125% to 7.3%. This study uniquely contributes to the literature by evaluating both strengthening and post-damage rehabilitation of continuous RC beams using NSM-BFRP ropes, a novel and eco-efficient retrofitting technique with proven performance in enhancing structural capacity and serviceability.

CivilEng doi: 10.3390/civileng6040057

Authors: Raid S. Alrashidi Megan S. Voss Ali Alsubeai Emad Alshammari Kyle A. Riding

UHPC has been found to have excellent freeze–thaw durability in cold regions. Previous UHPC testing performed has mostly focused on concrete with compressive strength above 21 ksi (145 MPa). In this study, testing was conducted to determine at what strength level concrete transitions to provide excellent freeze–thaw (F–T) performance. Non-proprietary concrete samples were made for freeze–thaw durability from four different concrete mixture designs: 12–15 ksi, 15–18 ksi, 18–21 ksi, and 21+ ksi (83–145+ MPa), and these were tested according to ASTM C666, using 1.5% steel fibers. The samples were made for three different curing regimens: limewater curing in a fog room, simulated precast curing, and steam curing. Low-temperature differential scanning calorimetry (DSC) and mercury intrusion porosimetry (MIP) tests were carried out to reveal the freeze–thaw mechanism of the concrete samples. All mixtures with compressive strength above 15 ksi (103 MPa) performed excellent in freeze–thaw testing with no damage seen. Steam curing was found to negatively affect the freeze–thaw performance at the lowest strength level tested.

CivilEng doi: 10.3390/civileng6040056

Authors: Yanuar Haryanto Gathot Heri Sudibyo Hsuan-Teh Hu Fu-Pei Hsiao Laurencius Nugroho Dani Nugroho Saputro Habib Raihan Suryanto Abel Earnesta Christopher Haryanto

This study presented a comprehensive finite element (FE) investigation into the flexural behavior of RC T-beams strengthened in the negative moment region using near-surface mounted (NSM) carbon-fiber-reinforced polymers (CFRP) rods. A three-dimensional nonlinear FE model was developed and validated against experimental data, achieving close agreement with normalized mean square error values as low as 0.006 and experimental-to-numerical ratios ranging from 0.95 to 1.04. The validated model was then employed to conduct a systematic parametric analysis considering CFRP rod diameter, concrete compressive strength, longitudinal reinforcement ratio, and FRP material type. The results showed that increasing CFRP diameter from 6 to 10 mm enhanced ultimate load by up to 47.51% and improved stiffness by 1.48 times. Higher concrete compressive strength contributed to stiffness gains exceeding 50.00%, although this improvement was accompanied by reductions in ductility. Beams with reinforcement ratios up to 2.90% achieved peak loads of 309.61 kN, but ductility declined. Comparison among FRP materials indicated that CFRP and AFRP offered superior strength and stiffness, whereas BFRP provided a more balanced combination of strength and deformation capacity.

CivilEng doi: 10.3390/civileng6040055

Authors: Nguyen Quoc Bang Dinh Van Duy Tran Van Ty Cu Ngoc Thang Nigel K. Downes Hitoshi Tanaka

Riverbank erosion in the Vietnamese Mekong Delta (VMD) poses a serious threat to agricultural lands, infrastructure, and local communities. Conventional protective measures, such as synthetic geotextiles and concrete revetments, are often costly and environmentally disruptive. This study investigates the potential of Eichhornia crassipes, a widely available invasive species, commonly known as water hyacinth (WH), to produce biodegradable geotextiles as a low-cost, nature-based solution (NbS) for small-scale riverbank protection. It is the first to test minimally processed WH mats under simulated tidal conditions in the VMD. Laboratory experiments were conducted to evaluate the geotextile’s (1) sediment retention capacity, (2) wave energy reduction, and (3) mechanical durability under wet–dry cycles. Results show that the WH geotextile effectively reduced sediment resuspension, decreasing turbidity levels from 800 FTU (unprotected scenario) to below 50 FTU. The geotextile also attenuated wave energy, reducing significant wave heights by approximately 35–40%. Mechanical testing revealed that the fish bone weaving pattern with adhesive coating achieved the highest tensile strength (8.36 kN/m after 12 wet–dry cycles), while uncoated samples demonstrated higher elongation (up to 61.67%), providing greater flexibility. These demonstrate the feasibility of WH geotextiles as a scalable nature-based solution for erosion-prone tropical deltas. Future studies should focus on field-scale validation, biodegradation rates, and performance optimization for long-term applications.

CivilEng doi: 10.3390/civileng6040054

Authors: Peng Gao Yongjin Cheng Bin Wang Zhenqiang Jiang Ben He Weijiang Chu Gen Xiong Ruilong Shi Xiangming Ge Jingfang Zhang Qingxiang Meng

This study presents the design and performance assessment of suction anchor foundations for an integrated offshore wind–solar–aquaculture system located in Jiangsu Sheyang, China. The project represents one of the first practical demonstrations of coupling renewable energy production with large-scale marine aquaculture on a shared floating platform. Using three-dimensional numerical simulations in FLAC3D and ABAQUS, the study evaluates the anchors’ bearing capacity, structural safety, and fatigue performance under ultimate (ULS), accidental (ALS), and fatigue (FLS) limit states. The analysis incorporates site-specific geotechnical conditions, seabed scour, and installation deviations, providing a realistic framework for foundation design in layered coastal sediments. Results confirm that the suction anchor system meets international safety requirements (DNV, CCS) and maintains robust performance throughout its service life. The findings demonstrate that scour depth and installation accuracy are critical factors governing anchor reliability and offer practical insights for updating offshore foundation design standards in future multifunctional renewable–aquaculture developments.

CivilEng doi: 10.3390/civileng6040053

Authors: Lu Liu Zhouhong Zong Yulin Shan Yao Yao Chenglin Li Yihao Cheng

Explosions, including those from war weapons, terrorist attacks, etc., can lead to damage and overall collapse of bridges. However, there are no clear guidelines for anti-blast design and protective measures for bridges under blast loading in current bridge design specifications. With advancements in intelligent construction, precast segmental bridge piers have become a major trend in social development. There is a lack of full understanding of the anti-blast performance of precast segmental bridge piers. To study the engineering calculation method for blast load acting on a typical precast segmental reinforced concrete (RC) pier in near-field explosions, an air explosion test of the precast segmental RC pier is firstly carried out, then a fluid–structure coupling numerical model of the precast segmental RC pier is established and the interaction between the explosion shock wave and the precast segmental RC pier is discussed. A numerical simulation of the precast segmental RC pier in a near-field explosion is conducted based on a reliable numerical model, and the distribution of the blast load acting on the precast segmental RC pier in the near-field explosion is analyzed. The results show that the reflected overpressure on the pier and the incident overpressure in the free field are reliable. The simulation results are basically consistent with the experimental results (with a relative error of less than 8%), and the fluid–structure coupling model is reasonable and reliable. The explosion shock wave has effects of reflection and circulation on the precast segmental RC pier. In the near-field explosion, the back and side blast loads acting on the precast segmental RC bridge pier can be ignored in the blast-resistant design. The front blast loads can be simplified and equalized, and a blast-resistant design load coefficient (1, 0.2, 0.03, 0.02, and 0.01) and a calculation formula of maximum equivalent overpressure peak value (applicable scaled distance [0.175 m/kg1/3, 0.378 m/kg1/3]) are proposed, which can be used as a reference for the blast-resistant design of precast segmental RC piers.

CivilEng doi: 10.3390/civileng6030052

Authors: Shuhan Wang Long Li Xianfei Yin Ziwei Yi Shu Shi Meiqi Wan

The complexities of megaprojects, particularly major transportation infrastructure projects (MTIs), require technological innovation that advances economic, social, and ecological objectives. Traditional engineering innovation emphasizes economic gains while neglecting sustainability. Therefore, implementing green innovation (GI) in MTIs is essential. This research examines key factors and correlations influencing MTI-GI to strengthen theoretical understanding and guide effective implementation. First, literature and interviews are used to identify MTI-GI influencing factors through the technology–organization–environment (TOE) framework. Second, an intuitive fuzzy number approach reduces subjectivity in expert scoring and, combined with the DEMATEL method, constructs a fuzzy DEMATEL model to quantify factor importance and identify critical drivers. Critical factors are then analyzed to formulate GI promotion strategies. Results reveal that MTI-GI influencing factors span technology, organization, and environment dimensions. Prioritizing green technological innovation and feedback mechanisms, optimizing organizational structures, and aligning with regional environmental characteristics are crucial for successful MTI-GI implementation. These findings support GI expansion in MTIs and offer targeted strategies for managing complex systems.

CivilEng doi: 10.3390/civileng6030051

Authors: Mortada Sabeh Whwah Mushtaq Sadiq Radhi Anmar Dulaimi Luís Filipe Almeida Bernardo Tiago Pinto Ribeiro

This research investigates the influence of incorporating perlite aggregate and silica fume on the properties of cement mortar, with a focus on compressive strength, flexural strength, density, water absorption, and thermal conductivity. The results show that increasing the percentage of perlite (Pe) in the mixes causes a marked reduction in the compressive strength, reflecting the lightweight nature and low density of perlite. For mixes with Pe-20% through Pe-100%, the compressive strength decreased by up to 78% compared to the reference mix. However, the addition of silica fume (SF) in mixes with SF-20% to SF-100% partially offset this effect, limiting the strength losses to 18–71%, which indicates that silica fume contributes to strength enhancement over time. The flexural strength followed a similar trend, decreasing with a higher perlite content: reductions of up to 40% were observed for Pe mixtures, while SF mixes showed slightly smaller decreases, reaching 36%. The density also declined consistently with increasing perlite replacement, with a maximum reduction of 57% in mix Pe-100% due to the inherent porosity of perlite. The water absorption increased substantially in the same mix (Pe-100%), by 327% compared to the reference one, whereas the addition of silica fume (SF-100%) limited the increase to 181%, confirming its role in refining the pore structure. The thermal conductivity decreased with a higher perlite content, attributed to the formation of voids in the matrix. The lowest value was observed for Pe-100%, with an 82% reduction, while silica fume mixes also showed reductions of 37–81% relative to the reference mix. Based on a comprehensive evaluation of strength, density, water absorption, and thermal performance, mix SF-60% was identified as the optimal mixture, offering a balanced profile with a compressive strength of 4.4 MPa, thermal conductivity of 0.28 W/(m·K), and density of 1089 kg/m3. These performance levels make the developed mortars particularly suitable for non-load-bearing masonry units, lightweight blocks, and insulation panels, where reduced weight and enhanced thermal efficiency are essential. The study therefore provides practical guidance for the design of sustainable, lightweight mortars for energy-efficient construction applications.

CivilEng doi: 10.3390/civileng6030050

Authors: Jhabindra Poudel Prashidha Khatiwada Subash Adhikari

Earthquakes remain among the most destructive natural hazards, causing severe loss of life and property in seismically active regions such as Nepal. Major events such as the 1934 Nepal–Bihar earthquake (Mw 8.2), the 2015 Gorkha earthquake (Mw 7.8), and the 2023 Jajarkot earthquake (ML 6.4) have repeatedly exposed the vulnerability of Nepal’s built environment. In response, the Ready-to-Use Detailing (RUD) guideline (NBC 205:2024) was introduced to provide standardized structural detailing for low-rise reinforced concrete buildings without masonry infill, particularly for use in areas where access to professional engineering services is limited. This study was motivated by the need to critically assess the structural performance of buildings designed according to such rule-of-thumb detailing, which is widely applied through owner–builder practices. Nonlinear pushover analyses were carried out using finite element modelling for typical configurations on soil types C and D, under peak ground accelerations of 0.25 g, 0.30 g, 0.35 g, and 0.40 g. The response spectrum from NBC 105:2020 was adopted to determine performance points. The analysis focused on global response, capacity curves, storey drift, and hinge formation to evaluate structural resilience. The maximum story drift for the linear static analysis is found to be 0.56% and 0.86% for peak ground acceleration of 0.40 g, for both three and four-storied buildings. Also, from non-linear static analysis, it is found that almost all hinges formed in the beams and columns are in the Immediate Occupancy (IO) level. The findings suggest that the RUD guidelines are capable of providing adequate seismic performance for low-rise reinforced concrete buildings, given that the recommended material quality and construction standards are satisfied.

CivilEng doi: 10.3390/civileng6030049

Authors: Yannik Schwarz David Sanio Peter Mark

Conventional strengthening measures for existing structures are usually not effective for the self-weight, which accounts for around 70% of the total load in reinforced concrete structures. Therefore, their effect on the overall load-bearing capacity is low. A self-weight-effective alternative for flexural strengthening is the thermal prestressing of additional reinforcement installed on the structure. In this method, reinforcing bars are slotted into the tensile zone, embedded in filler material, and tempered from the outside. They are thermally stretched, and once cooling starts, the bond with the hardened filler prevents re-deformation. The induced prestressing force counteracts dead loads and relieves the tensile zone, making the additional bars effective for the self-weight. In this paper, the effectiveness of the strengthening method is experimentally investigated in the serviceability and the ultimate limit states. Experiments involve strengthening a reinforced concrete beam under load by a thermally prestressed additional bar. Moreover, two reference tests are made to evaluate the method. An unstrengthened beam characterizes the lower capacity limit. Another beam with the same reinforcement amount as the strengthened one, but completely installed at casting, serves as the upper benchmark. All beams are loaded until bending failure. The strengthening method is assessed by means of the load-bearing behavior, deflection, crack development, and the strains in the initial as well as the added reinforcement. The results demonstrate the effectiveness of the strengthening method. The thermally prestressed bar achieves an effective pre-strain of approximately. 0.4‰ by heating at about 70 °C. The induced prestressing force and associated compression reduce tensile cracks by approx. 45% and increase stiffness. The strengthened beam reaches the maximum load of the upper benchmark, but with about 33% less deflection. The filler, which also expands thermally, generates an additional prestressing force that is effective up to about 20% of the load capacity. Beyond this, the filler begins to crack and its effect decreases, but the pre-strain in the reinforcing bar remains until maximum load.

CivilEng doi: 10.3390/civileng6030048

Authors: Gregor Trtnik Jakob Šušteršič Tomaž Hozjan

This study presents the outcomes of a comprehensive experimental investigation focused on the bond behavior between reinforcing steel bars and tremie concrete, assessed through standardized pull-out tests. The objective was to evaluate the influence of some key parameters: reinforcement bar diameter, concrete age (and associated compressive strength), steel fiber content, and a bentonite coating on rebar surfaces. Experiments were conducted under laboratory conditions according to relevant standards. Slip between the reinforcement and tremie concrete was measured using a sophisticated high-precision optical laser device, enabling accurate assessment of bond characteristics. A large, i.e., a statistically sufficient, number of specimens was tested, allowing the results to be analyzed using the ANOVA technique to determine the statistical significance of each parameter. The results show that, under most test conditions, the influence of the bentonite suspension coating on the bond strength was not statistically significant. Similarly, variations in the bar diameter and fiber content showed no statistically significant impact within the tested ranges. In contrast, concrete age (compressive strength) exhibited a statistically significant influence, confirming that concrete maturity is a dominant factor in bond development. The results contribute to a better understanding of the bond mechanisms in reinforced concrete and can assist in optimizing design strategies where bond performance is critical.

CivilEng doi: 10.3390/civileng6030047

Authors: Moein Mousavi Prasad Rangaraju

The growing application of 3D concrete printing (3DCP) in construction has raised important questions regarding its long-term durability under freeze–thaw (F–T) exposure, particularly in cold climates. This review paper presents a comprehensive examination of recent research focused on the F–T performance of 3D-printed concrete (3DPC). Key material and process parameters influencing durability, such as print orientation, admixtures, and layer bonding, are critically evaluated. Experimental findings from mechanical, microstructural, and imaging studies are discussed, highlighting anisotropic vulnerabilities and the potential of advanced additives like nanofillers and air-entraining agents. Notably, air-entraining agents (AEA) reduced the compressive strength loss by 1.4–5.3% after exposure to F–T cycles compared to control samples. Additionally, horizontally cored specimens with AEA incorporated into their mixture design showed a 15% higher dynamic modulus after up to 300 F–T cycles. Furthermore, optimized printing parameters, such as reduced nozzle standoff distance and minimized printing time gap, reduced surface scaling by over 50%. The addition of a nanofiller such as nano zinc oxide in 3DPC can result in compressive strength retention rates exceeding 95% even after aggressive F–T cycling. The lack of standard testing protocols and the geometry dependence of degradation are emphasized as key research gaps. This review provides insights into optimizing mix designs and printing strategies to improve the F–T resistance of 3DPC, aiming to support its reliable implementation in cold-region infrastructure.

CivilEng doi: 10.3390/civileng6030046

Authors: Anmar Dulaimi Yasir N. Kadhim Qassim Ali Al Quraishy Hayder Al Hawesah Tiago Pinto Ribeiro Luís Filipe Almeida Bernardo

The use of hot mix asphalt (HMA) has several drawbacks, such as the emission of harmful gases into the atmosphere, difficulties in maintaining temperature over long distances, and the requirement for high energy consumption during preparation and installation. In order to solve these issues, this research aimed to produce High-Performance Cold Mix Asphalt (HP-CMA), in which Ordinary Portland Cement (OPC) is used as a filler to replace limestone filler at 0%, 1.5%, 3%, 4.5%, and 6% of the aggregate weight. Indirect Tensile Stiffness Modulus (ITSM), moisture susceptibility, temperature susceptibility, and microstructural analysis tests were carried out. The results showed that the ITSM was considerably enhanced when OPC was utilized. When comparing HP-CMA with 3% OPC to the control HMA (100–150 pen), the ITSM increased by approximately 80% after three days. In contrast, HP-CMA with 4.5% OPC achieved the same ITSM as the control HMA (40–60 pen) after seven days. Moreover, the ITSM of the HMA 40–60 pen decreased by 91.93% when the temperature rose from 20 °C to 45 °C, whereas the ITSM of the HP-CMA with 6% OPC decreased by 42.47% over the same temperature range. This suggests that HP-CMA is more stable than the HMA 40–60 pen at elevated temperatures. The superior performance of the HP-CMA can be attributed to two essential factors: the improved binding effect due to the demulsification of the asphalt emulsion used as a binder, and the formation of hydration products from the added cement.

CivilEng doi: 10.3390/civileng6030045

Authors: Saman Hedjazi Macy Spears Ehsanul Kabir Hossein Taheri

Ground penetrating radar (GPR) is a non-destructive testing (NDT) method increasingly used for evaluating concrete structures by identifying internal flaws and embedded objects. This study presents a structured image-based methodology for interpreting GPR B-scan data using a practical flowchart designed to aid in distinguishing common subsurface anomalies. The methodology was validated through a laboratory experiment involving four concrete slabs embedded with simulated defects, including corroded rebar, hollow pipes, polystyrene sheets (to represent delamination), and hollow containers (to represent voids). Scans were performed using a commercially available device, and the resulting radargrams were analyzed based on signal reflection patterns. The proposed approach successfully identified rebar positions, spacing, and depths, as well as low-dielectric anomalies such as voids and polystyrene inclusions. Some limitations were noted in detecting non-metallic materials with weak dielectric contrast, such as hollow pipes. Overall, the findings demonstrate the reliability and adaptability of the proposed method in improving the interpretation of GPR data for structural diagnostics. The proposed methodology achieved a detection accuracy of approximately 90% across all embedded features, which demonstrates improved interpretability compared to traditional manual GPR assessments, typically ranging between 70 and 80% in similar laboratory conditions.

CivilEng doi: 10.3390/civileng6030044

Authors: Jaime R. Ramírez-Vargas Sergio A. Zamora-Castro Agustín L. Herrera-May Rafael Melo-Santiago Luis Carlos Sandoval Herazo Domingo Pérez-Madrigal

Recycled asphalt pavement (RAP) can support traffic loads comparable to those of roads constructed with conventional materials. The structural evaluation of RAP is performed through the deflection generated by vehicles via recoverable deflection in the pavement layers. The deflection record is translated into a curve that geometrically interprets the behavior of the layers that make up the pavement. In this study, a falling weight deflectometer (FWD) was used to emulate transit loads and measure deflection in two models. Both contained 30% RAP, and one of them had fiberglass geogrid in the center of the asphalt layer. Through normalized maximum deflection (limit value based on constant stress), the structural index (SI), and the dynamic stiffness modulus (DSM), the structural behavior of the models under different load levels was evaluated. The pavement structure exhibited similarities in strength for both models subjected to impact. The presence of the geogrid reinforcement (Z1) showed structural index values ranging between 0.17 and 0.54, while the layer without geogrid (Z2) presented structural index values in a range of 0.23 to 0.78. In addition, the dynamic stiffness modulus presented a difference of 10 kN/mm between the maximums of the models in favor of reinforcement with glass fiber geogrid. Therefore, low structural index values are associated with the interaction between RAP and geogrid, highlighting this combination as an innovative and functional system for road surfaces, while the dynamic stiffness modulus indicates the stability and structural integrity of sustainable pavement, which has the potential to extend its lifespan.

CivilEng doi: 10.3390/civileng6030043

Authors: Ghasan Fahim Huseien Mohammad Hajmohammadian Baghban Iman Faridmehr Kaijun Dong

In the construction sector, cement and concrete are among the most widely utilized manufactured materials, yet their environmental impact remains a significant concern. The concrete industry is a major contributor to carbon dioxide emissions, accounting for over 8% of global greenhouse gas emissions annually. Several reports have estimated that between 1930 and 2013, a total of 4.5 gigatons of carbon was sequestered through the carbonation of cement-based materials. This process offset approximately 43% of the carbon dioxide (CO2) emissions resulting from cement production during the same period, excluding emissions related to fossil fuel consumption in the manufacturing process. It is well established that producing one ton of cement results in approximately 0.60–0.98 tons of CO2 emissions, coupled with substantial energy consumption. To mitigate these environmental effects, developing low-carbon or cement-free binders has become crucial. Alkali-activated binders (AABs), derived from industrial by-products or agricultural waste materials and activated with a low-molarity or one-part activator, are increasingly recommended as sustainable alternatives to reduce greenhouse gas emissions in the cement industry and minimize the consumption of natural resources. The production of alkali-activated concrete (AAC) involves several critical factors that significantly influence its mix design, fresh properties, and compressive strength (CS) performance. This study aims to provide a comprehensive review of the key factors affecting AAC’s mix design, workability, and CS characteristics. Firstly, the study discusses various methods employed for AAC mix design and the factors influencing these designs. Secondly, it examines the impact of binder type, source, chemical, mineralogical, and physical properties, as well as alkaline activator solutions, water content, and fillers on AAC’s workability, setting times, and strength development. Additionally, the study explores the correlation matrix and predictive performance models for fresh and strength properties. Lastly, the relationship between workability and CS is extensively analyzed. The review concludes by highlighting the existing challenges and prospects of AACs as sustainable construction materials to replace traditional cement and reduce carbon emissions.

CivilEng doi: 10.3390/civileng6030042

Authors: Pingan Liu Yupeng Ou Tiehu Wang Fei Yue Yingming Zhen Xun Zhang

This study presents a comprehensive analysis of hydration heat-induced temperature and stress fields in a U-shaped aqueduct during the casting phase, integrating field measurements and numerical simulations. The key findings are as follows: (1) Thermal Evolution Characteristics: Both experimental and numerical results demonstrated consistent thermal behavior, characterized by a rapid temperature rise, subsequent rapid cooling, and eventual stabilization near ambient conditions. The peak temperature is observed at the centroid of the bearing section’s base slab, reaching 83.8 °C in field tests and 87.0 °C in simulations. (2) Stress Field Analysis: Numerical modeling reveals critical stress conditions in the outer concrete layers within high-temperature zones. The maximum tensile stress reaches 6.37 MPa, exceeding the allowable value of the tensile strength of the current concrete (1.85 MPa) by 244%, indicating a significant risk of thermal cracking. (3) Temperature Gradient and Cooling Rate Anomalies: Both methodologies identify non-compliance with critical control criteria. Internal-to-surface temperature differentials exceed the 25 °C threshold. Daily cooling rates at monitored locations surpass 2.0 °C/d during the initial 5–6 days of the cooling phase, elevating cracking risks associated with excessive thermal gradients. (4) Mitigation Strategy Proposal: Implementation of a hydration heat control system is recommended; compared to single-layer systems, the proposed mid-depth double-layer steel pipe cooling system (1.2 m/s flow) reduced peak temperature by 23.8 °C and improved cooling efficiency by 28.7%. The optimized water circulation maintained thermal balance between concrete and cooling water, achieving water savings and cost reduction while ensuring structural quality. (5) The cooling system proposed in this paper has certain limitations in terms of applicable environment and construction difficulty. Future research can combine with a BIM system to dynamically control the tube cooling system in real time.

CivilEng doi: 10.3390/civileng6030041

Authors: Zahraa Ahmed al-Mammori Israa Mohsin Kadhim Al-Janabi Ghadeer H. Abbas Doaa Hazim Aziz Fatin H. Alaaraji Elaf Salam Abbas Beshaer M. AL-shimmery Tameem Mohammed Hashim Ghanim Q. Al-Jameel Ali Shubbar Mohammed Salah Nasr

With rising global temperatures and increasing sustainability demands, the need for advanced pavement solutions has never been greater. This study breaks new ground by integrating phase change materials (PCMs), including paraffin-based wax (Rubitherm RT55), hydrated salt (Climator Salt S10), and fatty acid (lauric acid), as binder modifiers within warm mix asphalt (WMA) mixtures. Moving beyond the traditional focus on binder-only modifications, this research utilizes recycled cigarette filters (CFs) as a dual-purpose fiber additive, directly reinforcing the asphalt mixture while simultaneously transforming a major urban waste stream into valuable infrastructure. The performance of the developed WMA mixture has been evaluated in terms of stiffness behavior using an Indirect Tensile Strength Modulus (ITSM) test, permanent deformation using a static creep strain test, and rutting resistance using the Hamburg wheel-track test. Laboratory tests demonstrated that the incorporation of PCMs and recycled CFs into WMA mixtures led to remarkable improvements in stiffness, deformation resistance, and rutting performance. Modified mixes consistently outperformed the control, achieving up to 15% higher stiffness after 7 days of curing, 36% lower creep strain after 4000 s, and 64% reduction in rut depth at 20,000 passes. Cost–benefit analysis and service life prediction show that, despite costing USD 0.71 more per square meter with 5 cm thickness, the modified WMA mixture delivers much greater durability and rutting resistance, extending service life to 19–29 years compared to 10–15 years for the control. This highlights the value of these modifications for durable, sustainable pavements.

CivilEng doi: 10.3390/civileng6030040

Authors: Xiaohua Wang Chonghao Sun Junjie Dong Xiangbo Du Yuan Lu Qianqing Zhang Kang Sun

In this study, to solidify the silt in an expressway, a stabilizing agent composed of industrial wastes, such as ordinary Portland cement (OPC), calcium based alkaline activator (CAA), silicate solid waste material (SISWM) and sulfate solid waste material (SUSWM) was developed. Orthogonal experiments and comparative experiments were carried out to analyze the strength and water stability of the stabilized silt, and get the optimal proportion of each component in the stabilizing agent. A series of laboratory tests, including unconfined compressive strength (UCS), water stability (WS), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analyses, were conducted on solidified silt samples treated with the stabilizing agent at optimal mixing ratios of OPC, CAA, SISWM, and SUSWM to elucidate the evolution of mineral composition and microstructure.

CivilEng doi: 10.3390/civileng6030039

Authors: Marike Bornholdt Martin Herbrand Kay Smarsly Gerhard Zehetmaier

Earthen flood protection structures are planned and constructed with an expected service life of several decades while being exposed to environmental impacts that may lead to structural or hydraulic failure. Current maintenance procedures involve only repairing external damage, leaving internal processes contributing to structural damage often undetected. Through structural health monitoring (SHM), structural deficits can be detected before visible damage occurs. To improve maintenance workflows and support predictive maintenance of dikes, this paper reports on the integration of digital twin concepts with SHM strategies, referred to as “digital-twin-based SHM”. A digital twin concept, including a standard-compliant building information model, is proposed and implemented in terms of a digital twin environment. For integrating monitoring and sensor data into the digital twin environment, a customized webform is designed. A communication protocol links preprocessed sensor data stored on a server with the digital twin environment, enabling model-based visualization and contextualization of the sensor data. As will be shown in this paper, a digital twin environment is set up and managed in the context of SHM in compliance with technical standards and using well-established software tools. In conclusion, digital-twin-based SHM, as proposed in this paper, has proven to advance predictive maintenance of dikes, contributing to the resilience of critical infrastructure against environmental impacts.

CivilEng doi: 10.3390/civileng6030038

Authors: Teuku Ferdiansyah Romaynoor Ismy Shaban Shahzad Waqas Rafiq Kashif Nadeem

Concrete resistivity is a critical parameter for assessing durability and monitoring the structural health of reinforced concrete. This study systematically evaluates the effects of the water-to-cement (w/c) ratio, saturation ratio (SR), and temperature on concrete resistivity using three different predictive models: linear regression, cubic Support Vector Machine (SVM), and Gaussian Process Regression (GPR). Each model was independently trained and tested to assess its ability to capture the nonlinear relationships between these key parameters. Experimental results show that resistivity decreases significantly under increasing load due to geometrical effects. For a w/c ratio of 0.4, resistivity decreases by −12.48% at 100% SR and by −6.68% at 60% SR under 20% loading. Higher w/c ratios (0.5 and 0.6) exhibit more pronounced resistivity reductions due to increased porosity and ion mobility, with a maximum decrease of −13.68% for w/c = 0.6. Among the developed predictive models, the Matern 5/2 Gaussian process regression (GPR) model demonstrated the highest accuracy, achieving an RMSE of 5.21, R2 of 0.99, MSE of 27.19, and MAE of 3.40, significantly outperforming the other approaches. Additionally, a permutation importance analysis revealed that the saturation ratio (SR) is the most critical variable influencing resistivity, followed by the water–cement ratio, while temperature has the least impact. These findings provide valuable insights into the durability assessment and corrosion prevention of reinforced concrete, offering practical implications for the optimization of material design and structural health monitoring in civil engineering.

CivilEng doi: 10.3390/civileng6030037

Authors: Nicola De Fazio Luca Placidi Francesco Fabbrocino Raimondo Luciano

In this study, we aim to analyze the dispersion of ultrasonic waves due to second-gradient contributions and attenuation within the framework of continuum mechanics. To investigate dispersive behavior and attenuation effects, we consider the influence of both higher-order gradient terms (second gradients) and Rayleigh-type viscoelastic contributions. To this end, we employ the extended Rayleigh–Hamilton principle to derive the governing equations of the problem. Using a wave-form solution, we establish the relationship between the phase velocity and the material’s constitutive parameters, including those related to the stiffness of both standard (first-gradient) and second-gradient types, as well as viscosity. To validate the model, we use data available in the literature to identify all the material parameters. Based on this identification, we observe that our model provides a good approximation of the experimentally measured trends of both phase velocity and attenuation versus frequency. In conclusion, this result not only confirms that our model can accurately describe both wave dispersion and attenuation in a material, as observed experimentally, but also highlights the necessity of simultaneously considering both second-gradient and viscosity parameters for a proper mechanical characterization of materials.

CivilEng doi: 10.3390/civileng6030036

Authors: Xian Gao Xilong Chen Kun Lu Xueyuan Deng

Although prefabricated buildings offer environmental advantages, their construction process inevitably generates environmental impacts. However, current research on prefabricated buildings focuses on the environmental impact level, and there is a lack of intelligent tools for analyzing their spatial and temporal dimensions. Therefore, this study develops a framework using 5D building information modeling (BIM) to monetize environmental impacts into environmental costs for prefabricated building construction. This framework includes defining boundaries and indicators, obtaining a resource inventory using the 5D BIM coding system, calculating environmental impact results, and converting environmental impacts into environmental costs. Taking a prefabricated substation as a case study, its environmental costs are 172.81 CNY/m2, with these costs caused by climate change accounting for the largest proportion (91.2%). This study unifies different environmental impacts into a single monetary form, providing stakeholders with intuitive indicators. It also expands 5D BIM applications from conventional costs to environmental costs, which can display their spatiotemporal changes.

CivilEng doi: 10.3390/civileng6030035

Authors: Haining Wang Yuhe Zhang Yang Wang Weizhe Feng Jie Li Kaixing Zhang Yu Rong Zhanyong Yao Kai Yao

The Deep Cement Mixing Integrated Drilling, Mixing, and Jetting (DMJ) technique was innovatively developed by incorporating high-pressure jetting apertures into the mixing blades to enhance the bearing capacity of deep cement-mixed piles. In this study, the bearing characteristics of DMJ pile composite foundations under embankment loading are investigated using numerical simulation. Through comparative simulations involving various pile configurations, the results demonstrate that DMJ pile composite foundations exhibit significantly enhanced settlement control compared to conventional deep mixing piles. Notably, under identical area replacement ratios, the use of DMJ piles reduces total foundation settlement by approximately 30%. Furthermore, the findings indicate that larger pile diameters and smaller spacing are particularly effective in minimizing settlement. In terms of load transfer efficiency, DMJ piles are capable of transmitting embankment loads to depths of up to 15 m, surpassing the 10 m transfer depth observed in conventional pile systems. An analysis of excess pore water pressure further reveals that DMJ piles promote more effective dissipation, highlighting their superior performance in maintaining foundation stability under embankment loading.

CivilEng doi: 10.3390/civileng6030034

Authors: Konstantinos I. Christidis

The present research aims to the evaluation of the deformation capacity of existing reinforced concrete shear walls designed with past non-conforming seismic regulations. A refined analytical model (referred to as the Proposed Model) is presented for generating Load–displacement (P-d) curves for RC shear walls. The model is applicable to medium-rise walls designed with or without modern seismic provisions and incorporates shear effects in both deformation and strength capacity. The application of the Proposed Model is assessed through comparison with numerical models implemented in the widely accepted OpenSees platform. Specifically, two types of elements are examined: the widely used flexural element Force-Based Beam-Column Element (FBE) and the Flexure-Shear Interaction Displacement-Based Beam-Column Element (FSI), which accounts for the interaction between flexure and shear. The results of both analytical and numerical approaches are compared with experimental data from four RC shear wall specimens reported in previous studies.

CivilEng doi: 10.3390/civileng6030033

Authors: M. A. Karim Youngguk Seo Ibrahim Alamayreh Stuart Suttle

This study is a preliminary investigation of the independent utilization of two types of fly ash (FA)–FA Type C and FA Type F-as partial replacement of fine aggregate (sand) and cement in Portland cement concrete (PCC) mixes. The main objective was to determine an optimum substitution range for each type of FA that would offer well-performing concrete in terms of workability, compressive strength, and durability. To this end, multiple concrete batches were prepared, incorporating each type of FA at four different levels: 5%, 10%, 15%, and 20% by weight of fine aggregate replacement and 10%, 20%, 30%, and 40% by weight for cement replacement. Then, concrete samples (100 mm diameter × 200 mm tall cylinders) were cast from each batch and were moisture-cured for 7, 14, and 28 days prior to testing. The addition of FA contributed positively to the strength development at specific replacement levels: all percentages for both FA Type C and Type F for fine aggregate replacement and up to 30% FA content for both Type C and F for cement replacement, 10% for both FA Type C and Type F provided the higher strength for aggregate replacement, and 10–20% for both types of FA provided the higher strength for cement replacement. Furthermore, these additions of FA exhibited comparable workability and durability except for FA Type F, which did not exhibit comparable workability for aggregate replacement. FA Type C can be recommended for both early and long-term strength for fine aggregate replacement, whereas FA Type C is suggested to be used for early strength and Type F provides for long-term strength for cement replacement. Type C provides better durability and Type F provides better workability for cement replacement.