Buildings

28 pages, 10168 KB

Open AccessArticle

A Framework for Rapid Vulnerability Assessment of Building Stock Utilizing Critical Seismic Wall Index Calculated via BIM Integrated into GIS for Prioritization of Seismic Risk to Avoid Demolition for Sustainable Cities

by Ahmet Çıtıpıtıoğlu and Can Balkaya

Buildings 2025, 15(18), 3292; https://doi.org/10.3390/buildings15183292 - 11 Sep 2025

Abstract

A framework for rapid seismic vulnerability assessment and disaster management of urban buildings was developed, incorporating structural information from Building Information Models (BIM) integrated into a Geographic Information System (GIS). The Critical Seismic Wall Index (CSWI) was evaluated for 252 undamaged and damaged [...] Read more.

A framework for rapid seismic vulnerability assessment and disaster management of urban buildings was developed, incorporating structural information from Building Information Models (BIM) integrated into a Geographic Information System (GIS). The Critical Seismic Wall Index (CSWI) was evaluated for 252 undamaged and damaged buildings and compared with their seismic performance analyses. The seismic vulnerability of these buildings was determined based on site-specific seismic hazard analysis and compared with each building’s CSWI. This study demonstrates the use of BIM within a GIS workflow to enable rapid wall index calculation. Building on previous research that identifies a Critical Seismic Wall Index (CSWI) of 0.0025 as an indicator of a building’s seismic vulnerability, it further proposes a CSWI threshold of 0.004 for buildings with structural irregularities, based on the analysis of the studied building. The implementation of the integrated BIM–GIS methodology could enable rapid risk and damage assessment, as demonstrated in the investigated case studies. This study is significant because it provides a model for quickly assessing the seismic vulnerability of buildings, supporting resilience planning and sustainability, particularly in earthquake-prone regions, by prioritizing seismic risk by identification of high-risk buildings for demolition and prioritization of retrofit. Full article

(This article belongs to the Section Building Structures)

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14 pages, 2723 KB

Open AccessArticle

Experimental Study on Engineering Properties of Guilin Red Clay Improved by PASS Composite LBG

by Yanshuo Cui, Kuiliang Han, Zhigao Xie, Haofeng Zhou and Bai Yang

Buildings 2025, 15(18), 3291; https://doi.org/10.3390/buildings15183291 - 11 Sep 2025

Abstract

To improve the engineering properties of red clay, sodium polyacrylate (PAAS) and locust bean gum (LBG) were used as modifiers, either singly or in combination. The modified soils were subjected to variable head permeability tests, triaxial compression tests, and scanning electron microscopy (SEM) [...] Read more.

To improve the engineering properties of red clay, sodium polyacrylate (PAAS) and locust bean gum (LBG) were used as modifiers, either singly or in combination. The modified soils were subjected to variable head permeability tests, triaxial compression tests, and scanning electron microscopy (SEM) tests to analyze the effects of different modifiers on the permeability and shear strength of the red clay and systematically explore the modification mechanism. The results showed that both PAAS and LBG significantly reduced the permeability of the red clay, with PAAS having a more pronounced effect. This mechanism is attributed to PAAS swelling upon water absorption, forming a hydrogel network that fills micropores and forms ionic bonds with clay particles. LBG, on the other hand, encapsulates the particles in a highly viscous colloid, enhancing their aggregation. Regarding shear strength, both PAAS and LBG improved soil cohesion, with PAAS exhibiting a superior combined improvement in cohesion and internal friction angle compared to LBG. The PAAS-LBG composite modification exhibits a significant synergistic effect: PAAS forms a continuous hydrogel network as the primary skeletal structure of the soil, while LBG supplements the pores and increases bonding, resulting in a denser soil structure. Microscopic analysis further confirms that the PAAS-LBG composite modification significantly reduces porosity and enhances interparticle interlocking, thereby simultaneously improving both the impermeability and shear strength of the red clay. This research can provide a reference for sustainable development and red clay modification in red clay regions. Full article

(This article belongs to the Special Issue Advances in Soil–Geosynthetic Composite Materials)

25 pages, 9423 KB

Open AccessArticle

Experimental Study on Local Bearing Capacity of Concrete Reinforced with Spiral Stirrups

by Hongbo Li, Ying Zhou, Shanshan Wang, Yongjian Ding, Deyu Jiang, Tianming Miao, Ruchen Qie, Xin Bao, Yongmei Qian and Bo Wang

Buildings 2025, 15(18), 3290; https://doi.org/10.3390/buildings15183290 - 11 Sep 2025

Abstract

To investigate the local compressive bearing capacity of concrete reinforced with spiral stirrups, a study was conducted on 40 specimens, focusing on the analysis of failure modes and strain variations. The study investigated the effects of concrete strength grade fcg, stirrup diameter [...] Read more.

To investigate the local compressive bearing capacity of concrete reinforced with spiral stirrups, a study was conducted on 40 specimens, focusing on the analysis of failure modes and strain variations. The study investigated the effects of concrete strength grade fcg, stirrup diameter d, volumetric ratio of the spiral stirrups ρv, and ratio of core area to load area Acor/Al on the local bearing capacity Fl. The experimental results indicated that the local bearing capacity Fl increased as the ratio of core area to load area Acor/Al decreased, with an observed increase of 23.0%. Furthermore, the local bearing capacity Fl increased with a reduction in stirrup spacing s, showing a 65.4% increase compared to the initial value. An increase in stirrup diameter d also would contribute to a higher Fl, with an improvement of 24.7%. Additionally, the local bearing capacity Fl exhibited a directly proportional relationship with the concrete strength grade fcg. Based on the theoretical analyses, the local bearing capacity of calculation equation Nu’ was established with the reinforcement term ρvfyAl and the concrete term fcAl. The experimental data on concrete reinforced with spiral stirrups were collected to verify the accuracy of calculation equation. The results show that there was a high calculation accuracy for the mechanical model and could provide a reference for local bearing capacity calculation. Full article

(This article belongs to the Section Building Structures)

54 pages, 5072 KB

Open AccessReview

Comparative Analysis of Autogenous and Microbial-Based Calcite Precipitation in Concrete: State-of-the-Art Review

by David O. Owolabi, Mehdi Shokouhian, Izhar Ahmad, Marshell Jenkins and Gabrielle Lynn McLemore

Buildings 2025, 15(18), 3289; https://doi.org/10.3390/buildings15183289 - 11 Sep 2025

Abstract

Cracks in concrete are a persistent issue that compromises structural durability, increases maintenance costs, and poses environmental challenges. Self-healing concrete has emerged as a promising innovation to address these concerns by autonomously sealing cracks and restoring integrity. This review focuses on two primary [...] Read more.

Cracks in concrete are a persistent issue that compromises structural durability, increases maintenance costs, and poses environmental challenges. Self-healing concrete has emerged as a promising innovation to address these concerns by autonomously sealing cracks and restoring integrity. This review focuses on two primary healing mechanisms: autogenous healing and microbial-induced calcite precipitation (MICP), the latter involving the biomineralization activity of bacteria, such as Bacillus subtilis and Sporosarcina pasteurii (formerly known as B. pasteurii). This review explores the selection, survivability, and activity of these microbes within the alkaline concrete environment. Additionally, the review highlights the role of fiber-reinforced cementitious composites (FRCCs), including high-performance fiber-reinforced cement composites (HPFRCCs) and engineered cement composites (ECCs), in enhancing crack control and enabling more effective microbial healing. The hybridization of natural and synthetic fibers contributes to both improved mechanical properties and crack width regulation, key factors in facilitating bacterial calcite precipitation. This review synthesizes current findings on self-healing efficiency, fiber compatibility, and the scalability of bacterial healing in concrete. It also evaluates critical parameters, such as healing agent integration, long-term performance, and testing methodologies, including both destructive and non-destructive techniques. By identifying existing knowledge gaps and performance barriers, this review offers insights for advancing sustainable, fiber-assisted microbial self-healing concrete for resilient infrastructure applications. Full article

(This article belongs to the Special Issue Mechanical Properties and Durability of Concrete Materials and Structures)

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48 pages, 1658 KB

Open AccessFeature PaperArticle

Obstacles to BIM Adoption in Construction Production: A Study of Swedish Construction Contractors’ Experiences

by Aina El Masry and Diana Chronéer

Buildings 2025, 15(18), 3288; https://doi.org/10.3390/buildings15183288 - 11 Sep 2025

Abstract

Digitalization in the construction industry has transformed efficiency and coordination, with Building Information Modeling (BIM) emerging as a central enabling technology. However, despite its potential, BIM usage during the implementation phase of Swedish construction projects remains limited. Using the Technology–Organization–Environment (TOE) framework, this [...] Read more.

Digitalization in the construction industry has transformed efficiency and coordination, with Building Information Modeling (BIM) emerging as a central enabling technology. However, despite its potential, BIM usage during the implementation phase of Swedish construction projects remains limited. Using the Technology–Organization–Environment (TOE) framework, this study combines a systematic literature review with a quantitative survey of 220 professionals. The data were analyzed using descriptive statistics, correlation analysis, factor analysis, and ordinal logistic regression. The results show that technological and organizational barriers are present to a moderate extent, but they manifest as distinct and separate dimensions. In contrast, the most significant barriers to actual BIM adoption lie within the environmental domain. Specifically, the absence of clear external requirements, policies, and incentives is strongly and negatively associated with BIM implementation. The study concludes that although contractors demonstrate internal technical readiness, external systemic support is crucial for scaling up BIM in practice. These insights carry important implications for industry stakeholders and policymakers aiming to accelerate the digital transformation of the construction industry. Full article

(This article belongs to the Section Construction Management, and Computers & Digitization)

33 pages, 5513 KB

Open AccessArticle

Modeling the Fire Response of Reactive Powder Concrete Columns with Due Consideration of Transient Thermal Strain

by Qin Rong, Zeyu Chang, Zhihao Lyu and Xiaomeng Hou

Buildings 2025, 15(18), 3287; https://doi.org/10.3390/buildings15183287 - 11 Sep 2025

Abstract

Transient thermal strain (TS) is a unique compressive strain that reactive powder concrete (RPC) experiences during temperature rise. RPC has a more rapid TS development than normal concrete (NC) during temperatures of 300 °C~800 °C, and under the same load level, the TS [...] Read more.

Transient thermal strain (TS) is a unique compressive strain that reactive powder concrete (RPC) experiences during temperature rise. RPC has a more rapid TS development than normal concrete (NC) during temperatures of 300 °C~800 °C, and under the same load level, the TS of RPC is 40% to 60% higher than that of NC. However, while TS is known to be significant in RPC, its quantitative influence on the structural fire response and ultimate fire resistance of RPC columns remains insufficiently understood and inadequately modeled, posing a potential risk to fire safety design. In this study, a method for modelling the fire response of RPC columns with due consideration to TS was developed using ABAQUS. The Drucker–Prager model was applied to assess the impact of TS on the fire resistance of RPC columns. The results indicate that ignoring the effect of TS could lead to unsafe fire resistance predictions for RPC columns. The influence of TS on the fire resistance performance of RPC columns increases with the increase in cross-sectional dimensions. When the cross-sectional dimension of RPC columns increases from 305 mm to 500 mm, the influence of TS on the fire resistance of RPC columns increases from 22% to 43%. Under the same load, the influence of TS on the fire resistance of RPC columns is 31.3%, which is greater than that on NC columns. When the hydrocarbon heating curve is used, if the influence of TS is not considered, the fire resistance will be overestimated by 18.2% and 37.7%. Under fire, the existence of TS will lead to a further increase in the compressive stress of the RPC element in the relatively low temperature region, resulting in a greater stress redistribution, and accelerating the RPC column to reach the fire resistance. Therefore, it is crucial to clearly consider TS for the accurate fire resistance prediction and safe fire protection design of RPC columns. Crucially, these findings have direct significance for the fire protection design of actual projects, such as liquefied petroleum stations. Full article

(This article belongs to the Special Issue Fire Science and Safety of Building Structure)

22 pages, 7467 KB

Open AccessArticle

Green Recycling and Long-Term Immobilization of Disposable Medical Masks for Enhanced Mechanical Performance of Self-Compacting Recycled Concrete

by Fubin Zhang, Zhenshuo Xu, Zhenyuan Lv, Dianchao Wang, Xiulian Li, Lingfeng Zhang, Bochao Sun and Chang Sun

Buildings 2025, 15(18), 3286; https://doi.org/10.3390/buildings15183286 - 11 Sep 2025

Abstract

The global outbreak and prolonged presence of Coronavirus Disease 2019 (COVID-19) have resulted in a substantial accumulation of discarded masks, posing serious environmental challenges. This study proposes an eco-friendly and low-carbon strategy to repurpose discarded DMFM fibers as a key component in fiber-reinforced [...] Read more.

The global outbreak and prolonged presence of Coronavirus Disease 2019 (COVID-19) have resulted in a substantial accumulation of discarded masks, posing serious environmental challenges. This study proposes an eco-friendly and low-carbon strategy to repurpose discarded DMFM fibers as a key component in fiber-reinforced self-compacting recycled aggregate concrete (FRSCRAC). The mechanical and environmental performance of FRSCRAC was systematically evaluated by investigating the effects of recycled coarse aggregate (RCA) replacement ratios (0%, 50%, 100%), discarded DMFM fiber material (DMFM) contents (0%, 0.1%, 0.2%, 0.3%), and fiber lengths (2 cm, 3 cm, 4 cm) on axial compression failure mode and stress–strain behavior. The results demonstrated that DMFM fibers significantly enhanced concrete ductility and peak stress via the fiber-bridging effect. Based on fiber influence, modified stress–strain and shrinkage models for SCRAC were established. To further understand the fiber fixation mechanism, X-ray computed tomography (X-CT) and scanning electron microscopy (SEM) analyses were conducted. The findings revealed a stable random distribution of fibers and strong interfacial bonding between fibers. These improvements contributed to enhanced mechanical performance and the effective immobilization of polypropylene microfibers, preventing further microplastics release into the air. This innovative approach provides a sustainable solution for recycling and effectively immobilizing discarded DMFM fibers in concrete over long curing periods, while also enhancing its properties. Full article

(This article belongs to the Special Issue Durability, Physical Properties and Mechanical Properties of Low-Carbon Concrete Materials)

15 pages, 5328 KB

Open AccessArticle

Mechanical Behavior and Failure Characteristics of Concrete–Fractured Rock Composites Under Confining Pressure

by Kai Cui and Zheng Yang

Buildings 2025, 15(18), 3285; https://doi.org/10.3390/buildings15183285 - 11 Sep 2025

Abstract

Concrete–fractured rock composites (CFRCs) are critical load-bearing systems in tunnels, dams, and other underground structures. Previous studies have not fully characterized how fracture geometry and confining pressure jointly influence crack propagation and failure modes. In this study, the particle flow discrete element method [...] Read more.

Concrete–fractured rock composites (CFRCs) are critical load-bearing systems in tunnels, dams, and other underground structures. Previous studies have not fully characterized how fracture geometry and confining pressure jointly influence crack propagation and failure modes. In this study, the particle flow discrete element method is employed to develop a heterogeneous concrete–fractured rock composite model in which the parallel bond model (PBM) is integrated with the smooth-joint model (SJM). The effects of fracture inclination (0–90°) and confining pressure (1–20 MPa) on the composite’s strength characteristics, crack propagation, and failure modes are systematically investigated. It is demonstrated that composite strength is markedly enhanced by confining pressure. Fracture inclination governs the evolution of the failure mode: as the inclination angle increases from 0° to 90°, overall composite strength increases. Confining pressure further modulates the failure path by altering the threshold for crack initiation. Specifically, under low confinement (<10 MPa), the shear-to-tensile crack ratio decreases with increasing dip angle, marking a transition from shear-dominated to tension-dominated mechanisms. At 20 MPa, the ratio remains relatively constant, with tensile failure being dominant. These findings establish a confining pressure–fracture geometry–failure framework for concrete–rock composites and suggest design strategies for deep tunnels, shallow structures, and inclination-specific reinforcement. Full article

(This article belongs to the Section Building Structures)

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25 pages, 9252 KB

Open AccessArticle

Mechanical Performance and Parameter Sensitivity Analysis of Small-Diameter Lead-Rubber Bearings

by Guorong Cao, Zhaoqun Chang, Guizhi Deng, Wenbo Ma and Boquan Liu

Buildings 2025, 15(18), 3284; https://doi.org/10.3390/buildings15183284 - 11 Sep 2025

Abstract

Small-diameter lead-rubber bearings (LRBs) are widely employed in shaking table tests of isolated structures, particularly reinforced concrete base-isolated structures. Accurately determining their mechanical properties and identifying their restoring force model parameters are essential for seismic response analysis and numerical simulation of scaled models. [...] Read more.

Small-diameter lead-rubber bearings (LRBs) are widely employed in shaking table tests of isolated structures, particularly reinforced concrete base-isolated structures. Accurately determining their mechanical properties and identifying their restoring force model parameters are essential for seismic response analysis and numerical simulation of scaled models. In this study, quasi-static tests and shaking table tests were conducted to obtain the compression–shear hysteresis curves of LRBs under various loading amplitudes and frequencies, as well as the hysteresis curves under seismic wave excitation. The variation patterns of mechanical performance indicators were systematically analyzed. A parameter identification method was developed to determine the restoring force model of small-diameter LRBs using a genetic algorithm, and the effects of pre-yield stiffness and yield force of the isolation layer on structural response were investigated based on an equivalent two-degree-of-freedom model. By incorporating appropriately identified restoring force model parameters, a damping modeling method for the reinforced concrete high-rise over-track structures with an inter-story isolation system was proposed. The results indicate that, when the maximum bearing deformation reached 150% shear strain, the post-yield stiffness and horizontal equivalent stiffness under seismic excitation increased by 11.97% and 19.40%, respectively, compared with the compression–shear test results, while the equivalent damping ratio increased by 18.18%. Directly adopting mechanical parameters obtained from quasi-static tests would lead to an overestimation of the isolation layer displacement response. The discrepancies in the mechanical indicators of the small-diameter LRB between the theoretical hysteresis curve, obtained using the identified Bouc–Wen model parameters, and the compression–shear test results are less than 10%. In OpenSees, the seismic response of the scaled model can be accurately simulated by combining a segmented damping model with an isolation-layer hysteresis model in which the pre-yield stiffness is amplified by a factor of 1.15. Full article

(This article belongs to the Special Issue Low Carbon and Green Materials in Construction—3rd Edition)

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25 pages, 7746 KB

Open AccessArticle

Integrating AI Generation and CFD Simulation in Coastal Hospital Landscape Design: A Case Study of Penghu, Taiwan

by Wen-Pei Sung, Chien-Shiun Huang, Po-Teng Wang and Ming-Yu Yang

Buildings 2025, 15(18), 3283; https://doi.org/10.3390/buildings15183283 - 11 Sep 2025

Abstract

This study aims to develop a climate-resilient landscape design framework for coastal healthcare facilities by integrating Artificial Intelligence (AI)-generated design prompts with Computational Fluid Dynamics (CFD) simulations and on-site validation. Focusing on a coastal hospital in Penghu, Taiwan—a region vulnerable to strong winds, [...] Read more.

This study aims to develop a climate-resilient landscape design framework for coastal healthcare facilities by integrating Artificial Intelligence (AI)-generated design prompts with Computational Fluid Dynamics (CFD) simulations and on-site validation. Focusing on a coastal hospital in Penghu, Taiwan—a region vulnerable to strong winds, salt spray, and extreme weather—the research proposes a climate-adaptive, microclimate-responsive, and resilient design framework. Key findings demonstrate that the optimized design reduced average winter wind speed from 12 m/s to 4.5 m/s (a 62.5% reduction) and increased the three-year survival rate of salt-tolerant plant species (e.g., Pittosporum tobira, Casuarina) to 92%, significantly outperforming conventional planting strategies. The combination of water features and evapotranspiration planting reduced summer temperatures by 2.3 °C and increased humidity to 75%, with the PMV comfort index improving from +1.5 to +0.5. The program also resulted in a 15% increase in biodiversity, a 20% reduction in soil erosion, and a 40% improvement in users’ perceived aesthetic value of outdoor spaces. Furthermore, AI-based analyses to determine foundational depth led to a reduction in structural failure rates—from 40% to 5%—substantially elevating the safety and long-term durability of outdoor infrastructures. This study demonstrates that integrating AI with CFD is both feasible and highly effective for addressing complex coastal climate challenges in landscape architecture. The developed framework is parametric, evidence-based, and tailored to site-specific requirements, enabling the formulation of intelligent, climate-responsive landscape solutions for future healthcare environments in vulnerable coastal areas. Full article

(This article belongs to the Special Issue New Technologies on Building Energy Saving and Housing Thermal Comfort)

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27 pages, 3530 KB

Open AccessArticle

Damage Identification and Safety Threshold During the Construction and Operation Phases of Cast-in-Place Continuous Rigid Frame Bridges

by Xuefeng Ye, Na Yang, Huina Chen, Manman Yang and Tingyao Wu

Buildings 2025, 15(18), 3282; https://doi.org/10.3390/buildings15183282 - 11 Sep 2025

Abstract

This paper presents an analysis of the mechanical characteristics of bridge structures during both construction and operation phases, with a focus on stress distribution patterns and the impact of vehicle loads on structural safety. The monitoring during the construction phase indicates that the [...] Read more.

This paper presents an analysis of the mechanical characteristics of bridge structures during both construction and operation phases, with a focus on stress distribution patterns and the impact of vehicle loads on structural safety. The monitoring during the construction phase indicates that the compressive stress of the main beam segments is mainly controlled by prestress, and the maximum compressive stress meets the specification requirements; the maximum tensile stress of the main beam occurs in the stage when the tension reinforcement of the top pier is under stress, and the tensile stress value is within the allowable range of the specification. Under the negative bending moment of the pier top, the tensile stress at the upper edge reaches the peak simultaneously with the pre-pressurization stress. In contrast, the tensile stress at the mid-span joint transfers to the lower edge, and the corresponding bending moment significantly decreases. Based on the maximum tensile stress theory, when the stress of the structure caused by the earthquake wave reaches the ultimate tensile strength of the concrete, it is prone to cause structural damage. Therefore, it is necessary to limit the vehicle weight and driving speed to reduce the vibration impact. According to the “Regulations on the Management of Over-limit Transport Vehicles on Highways” issued by the Ministry of Transport (the total designed load shall not exceed 55 tons), after calculation, it is known that the maximum allowable driving speed of a 60-ton vehicle is 81.4 km per hour, which exceeds the safety limit of the specification. The research shows that in actual operation, the driving speed needs to be dynamically controlled according to the vehicle weight to ensure the long-term safety and durability of the bridge structure. Full article

(This article belongs to the Section Building Structures)

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24 pages, 5968 KB

Open AccessArticle

An Experiment on the Impact of Evacuation Signage Position on Wayfinding Efficiency in Subway Stations Based on VR Technology

by Shuxiang Wei, Jingze Wu, Dayu Xu, Tong Nie and Qi Shen

Buildings 2025, 15(18), 3281; https://doi.org/10.3390/buildings15183281 - 11 Sep 2025

Abstract

Subway stations are complex spaces with high passenger density and mobility, making evacuation efficiency particularly important. The position of evacuation signage is a key factor affecting the efficiency of passenger wayfinding. This study constructed a virtual subway station scenario by virtual reality technology [...] Read more.

Subway stations are complex spaces with high passenger density and mobility, making evacuation efficiency particularly important. The position of evacuation signage is a key factor affecting the efficiency of passenger wayfinding. This study constructed a virtual subway station scenario by virtual reality technology (VR), recording and analyzing the evacuation time and exit selection of 60 participants. The results showed that hanging evacuation signage, with their superior visual advantages, can greatly improve passenger wayfinding efficiency, followed by signage affixed to walls and columns, and finally signage on the ground. This study has provided a theoretical basis for the scientific layout and optimization of evacuation signage positions in subway stations, thereby enhancing passenger safety and evacuation efficiency. Full article

(This article belongs to the Section Construction Management, and Computers & Digitization)

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22 pages, 19211 KB

Open AccessArticle

The Impact of Earth-Based Building in Residential Environments on Human Emotional Relief Using EEG + VR + LEC Method

by Junjie Li, Ziyi Liu, Xuewen Zhang, Yujie Chen and Shuai Lu

Buildings 2025, 15(18), 3280; https://doi.org/10.3390/buildings15183280 - 11 Sep 2025

Abstract

Urbanization exacerbates mental health challenges, prompting the exploration of biophilic design solutions. This study examined the therapeutic potential of raw earth through its thermal interactions in architecture. First, energy consumption simulations established distinct indoor temperature ranges for raw earth, concrete, and steel under [...] Read more.

Urbanization exacerbates mental health challenges, prompting the exploration of biophilic design solutions. This study examined the therapeutic potential of raw earth through its thermal interactions in architecture. First, energy consumption simulations established distinct indoor temperature ranges for raw earth, concrete, and steel under identical energy constraints: low (22.8 ± 0.32 °C), medium (26.5 ± 0.39 °C), and high (30.1 ± 0.84 °C). The study then quantified the differences in physical and psychological perceptions across material-dominated spaces under controlled temperatures above. Nine scenes were constructed for emotional healing evaluation, incorporating the olfactory dimension into the Electroencephalogram (EEG) + Virtual reality (VR) + Laboratory environmental control (LEC) approach. The results indicated that raw earth materials were most effective in promoting emotional recovery under thermal stress conditions (low/high temperatures), as evidenced by a significant enhancement of α EEG rhythms. However, under moderate conditions, concrete environments produced the greatest relaxation effects, while steel environments were most conducive to enhancing focus. The core conclusion of this study is that the therapeutic effects of building materials are not static but are intricately linked to the surrounding thermal environment. This provides a new perspective for evidence-based healthy building design and underscores the importance of optimizing material selection based on specific environmental conditions and needs. Full article

(This article belongs to the Section Building Energy, Physics, Environment, and Systems)

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15 pages, 2086 KB

Open AccessArticle

New Insight into the Phenomenon of Buckling in Compressed Beams with Firm Support

by Mikel Goñi, Faustino N. Gimena and José-Vicente Valdenebro

Buildings 2025, 15(18), 3279; https://doi.org/10.3390/buildings15183279 - 11 Sep 2025

Abstract

This work presents a new insight into the buckling phenomenon to approach the calculation of the compressed bar with the following firm supports: bi-pinned, bi-fixed, and fixed-pinned. Buckling is redefined as the result of second-order deformations in the real bar by gradually applying [...] Read more.

This work presents a new insight into the buckling phenomenon to approach the calculation of the compressed bar with the following firm supports: bi-pinned, bi-fixed, and fixed-pinned. Buckling is redefined as the result of second-order deformations in the real bar by gradually applying the compression load, thus dismissing Euler’s critical load. The analytical results are obtained from the differential equation of the directrix beam with sinusoidal deformation associated with each type of support. The bending moment is generated only by the compression load acting on the initial geometric imperfection. These analytical solutions are associated with first-order effects, applying the entire compressive load, and with second-order effects, applying the load gradually. The analytical solutions are continuous functions. In this paper, the Finite Transfer Method was applied to obtain numerical results. The bending moments, transverse displacements, and normal stresses are presented as the results. Beams with different initial imperfections in the directrix are studied: with sinusoidal deformation, with deformation produced by a specific transverse load, and with deformation produced by a uniform transverse load. The results obtained through the analytical expressions derived from the gradual application of the load are compared with those results obtained numerically when calculating the beam under second-order conditions. It is concluded that in structural practice, they are equivalent. Full article

(This article belongs to the Section Building Structures)

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17 pages, 6085 KB

Open AccessArticle

Experimental and Finite Element Investigation of Bond Strength of Earthen Mortar–Brick Interfaces in Historic Masonry Structures

by Tian Zhang, Jianyang Xue, Chenwei Wu, Yan Sui and Yuanshen Feng

Buildings 2025, 15(18), 3278; https://doi.org/10.3390/buildings15183278 - 11 Sep 2025

Abstract

This study aims to investigate the bond behavior at earthen mortar–brick interfaces in historic masonry structures. To that end, a series of combined compression–shear tests were conducted to systematically assess the influence of varying water–soil ratios and applied lateral compression on interfacial bond [...] Read more.

This study aims to investigate the bond behavior at earthen mortar–brick interfaces in historic masonry structures. To that end, a series of combined compression–shear tests were conducted to systematically assess the influence of varying water–soil ratios and applied lateral compression on interfacial bond behavior. A fully decoupled microscopic finite element (FE) framework employing cohesive elements was developed to simulate the bond strength of earthen mortar–brick interfaces and validated using Spearman correlation analysis. The results indicate that increasing lateral compression markedly enhances both the peak displacement and shear strength, although it also reduces inter-specimen correlation by 18%. Notably, even under high lateral compression, the finite element predictions maintained a strong correlation with experimental data (R = 0.86), with a maximum deviation of less than 5%, demonstrating the model’s capability to accurately simulate the bond behavior of loess earthen mortar in masonry. These findings provide essential data and a robust computational framework for the preventive conservation of historic masonry structures. Full article

(This article belongs to the Special Issue Structural Assessment and Strengthening of Masonry Structures)

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13 pages, 8209 KB

Open AccessArticle

Influence of Mixing Conditions on the Strength and Microstructure of Cement Paste

by Yufan Wan, Hongbo Cao, Guangqiao Zhang, Xue Lu, Yanru Gao, Jintao Niu, Chuang He and Xiaolei Lu

Buildings 2025, 15(18), 3277; https://doi.org/10.3390/buildings15183277 - 11 Sep 2025

Abstract

The conventional “one-pot” mixing method employed in concrete production restricts both efficiency and quality optimization. This study systematically investigates the effects of mixing duration and rotational speed on the compressive strength and microstructure of cement paste by varying these parameters. Results indicate that [...] Read more.

The conventional “one-pot” mixing method employed in concrete production restricts both efficiency and quality optimization. This study systematically investigates the effects of mixing duration and rotational speed on the compressive strength and microstructure of cement paste by varying these parameters. Results indicate that appropriately extending mixing duration and increasing rotational speed enhances the strength of cementitious paste. However, excessive duration or overly high speeds adversely affect strength. When the rotational speed is 250 r/min and the mixing time is 100 s, the compressive strength of the hardened cementitious pastes at all curing ages is good, with strengths of 50.1 MPa, 61.1 MPa, and 77.0 MPa at 3 days, 7 days, and 28 days, respectively. Microstructural analysis further reveals that this mixing condition produced lower porosity, denser morphology, and increased hydration product formation, collectively explaining the superior mechanical properties. Full article

(This article belongs to the Special Issue Advanced Cementitious Materials: Integrating Nanotechnology, Sustainability, and Intelligent Design)

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27 pages, 5306 KB

Open AccessArticle

Interfacial Shear Strength of Sand–Recycled Rubber Mixtures Against Steel: Ring-Shear Testing and Machine Learning Prediction

by Rayed Almasoudi, Hossam Abuel-Naga and Abolfazl Baghbani

Buildings 2025, 15(18), 3276; https://doi.org/10.3390/buildings15183276 - 10 Sep 2025

Abstract

Soil–structure contacts often govern deformation and stability in foundations and buried infrastructure. Rubber waste is used in soil mixtures to enhance geotechnical performance and promote environmental sustainability. This study investigates the peak and residual shear strength of sand–steel interfaces, where the sand is [...] Read more.

Soil–structure contacts often govern deformation and stability in foundations and buried infrastructure. Rubber waste is used in soil mixtures to enhance geotechnical performance and promote environmental sustainability. This study investigates the peak and residual shear strength of sand–steel interfaces, where the sand is mixed with recycled rubber. It also develops predictive machine learning (ML) models based on the experimental data. Two silica sands, medium and coarse, were mixed with two rubber gradations; however, Rubber B was included only in limited comparative tests at a fixed content. Ring-shear tests were performed against smooth and rough steel plates under normal stresses of 25 to 200 kPa to capture the full τ–δ response. Nine input variables were considered: median particle size (D₅₀), regularity index (RI), porosity (n), coefficients of uniformity (C_u) and curvature (C_c), rubber content (RC), applied normal stress (σ_n), normalised roughness (R_n), and surface hardness (HD). These variables were used to train multiple linear regression (MLR) and random forest regression (RFR) models. The models were trained and validated on 96 experimental data points derived from ring-shear tests across varied material and loading conditions. The machine learning models facilitated the exploration of complex, non-linear relationships between the input variables and both peak and residual interfacial shear strength. Experimental findings demonstrated that particle size compatibility, rubber content, and surface roughness significantly influence interface behaviour, with optimal conditions varying depending on the surface type. Moderate inclusion of rubber was found to enhance strength under certain conditions, while excessive content could lead to performance reduction. The MLR model demonstrated superior generalisation in predicting peak strength, whereas the RFR model yielded higher accuracy for residual strength. Feature importance analyses from both models identified the most influential parameters governing the shear response at the sand–steel interface. Full article

(This article belongs to the Special Issue Innovative Trends and Future Prospects of Sustainable Green Building Materials)

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21 pages, 14313 KB

Open AccessArticle

Experimental Study and Practical Application of Existing Crack Repair in Concrete Dam Tunnels Using MICP and EICP

by Xu Zhang, Yu Zhang, Huiheng Luo, Bo Peng, Yongzhi Zhang, Jiahui Yao and Mateusz Jan Jedrzejko

Buildings 2025, 15(18), 3275; https://doi.org/10.3390/buildings15183275 - 10 Sep 2025

Abstract

Cracks in concrete dam tunnels compromise structural safety, watertightness, and durability, while conventional repair materials such as epoxy and cement impose environmental burdens. This study investigates biomineralization methods, namely Microbially Induced Calcium Carbonate Precipitation (MICP) and Enzyme-Induced Carbonate Precipitation (EICP), for repairing fine [...] Read more.

Cracks in concrete dam tunnels compromise structural safety, watertightness, and durability, while conventional repair materials such as epoxy and cement impose environmental burdens. This study investigates biomineralization methods, namely Microbially Induced Calcium Carbonate Precipitation (MICP) and Enzyme-Induced Carbonate Precipitation (EICP), for repairing fine cracks in a large hydropower dam tunnel. Laboratory tests and field applications were conducted by injecting urea–calcium solutions with Sporosarcina pasteurii for MICP and soybean-derived urease for EICP, applied twice daily over three days. Both techniques achieved effective sealing, with precipitation efficiencies of 93.75% for MICP and 84.17% for EICP. XRD analysis revealed that MICP produced a mixture of vaterite and calcite, reflecting biologically influenced crystallization, whereas EICP yielded predominantly calcite, the thermodynamically stable phase. SEM confirmed that MICP generated irregular layered clusters shaped by microbial activity, while EICP formed smoother spherical and more uniform deposits under enzyme-driven conditions. The results demonstrate that MICP provides higher efficiency and localized nucleation control, while EICP offers faster kinetics and more uniform deposition. Both methods present eco-friendly and field-applicable alternatives to conventional repair, combining technical performance with environmental sustainability for hydraulic infrastructure maintenance. Full article

(This article belongs to the Special Issue Sustainable Concrete: Innovations in Eco-Friendly Materials and Construction Methods)

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28 pages, 7503 KB

Open AccessArticle

Cognitive Differences Between Residents and Merchants in Ciqikou Mountainous Historic Districts Oriented by the Living Development–Authenticity Preservation Framework

by Cong Gong, Ruihan Ran and Changjuan Hu

Buildings 2025, 15(18), 3274; https://doi.org/10.3390/buildings15183274 - 10 Sep 2025

Abstract

As urban-living heritage sites, mountainous historic districts face the dual challenges of authenticity preservation and living development and the diverse and complex needs of different user groups. To address these challenges, this study systematically examines the cognitive differences between residents and merchants in [...] Read more.

As urban-living heritage sites, mountainous historic districts face the dual challenges of authenticity preservation and living development and the diverse and complex needs of different user groups. To address these challenges, this study systematically examines the cognitive differences between residents and merchants in mountainous historic districts and their implications for sustainable heritage management, using the Ciqikou Historic District in Chongqing as a case study. Through grounded theory methodology, we investigate residents and merchants via questionnaires and semi-structured interviews. Using coding analysis, the study reveals the cognitive similarities and differences of different users toward mountainous historic districts and explores their formation mechanisms, focusing on the spatial differentiation of cognition influenced by topographical and locational factors. Results indicate that both user groups share common cognitive concerns regarding building safety, transportation, policies, and infrastructure. Residents prioritise aspects related to daily convenience, whereas merchants focus more on economic benefits, leading to differences in their cognitive classifications and evaluations. Location plays a significant role in shaping user cognition, with notable cognitive differences observed between residents and merchants across different locations, and intra-group variation exists within the same user group at different locations. Based on a living–authenticity theoretical framework, this study constructs a living development–authentic preservation strategic framework and a multidimensional synergistic implementation framework encompassing integrity–locality–user, providing effective pathways for the preservation and sustainable development of mountainous historic districts. Full article

(This article belongs to the Section Architectural Design, Urban Science, and Real Estate)

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20 pages, 4917 KB

Open AccessArticle

Innovative Seismic Strengthening of Reinforced Concrete Frames with U-Shaped Precast Concrete Wall Panels: Experimental Performance Assessment

by Sookyoung Ha

Buildings 2025, 15(18), 3273; https://doi.org/10.3390/buildings15183273 - 10 Sep 2025

Abstract

Many existing reinforced concrete (RC) frames with brick infill walls are vulnerable to earthquake damage, particularly when the walls contain window openings that reduce the lateral resistance. This study aims to examine the seismic performance of RC frames strengthened with U-shaped precast concrete [...] Read more.

Many existing reinforced concrete (RC) frames with brick infill walls are vulnerable to earthquake damage, particularly when the walls contain window openings that reduce the lateral resistance. This study aims to examine the seismic performance of RC frames strengthened with U-shaped precast concrete (PC) wall panels. In the proposed method, the window-containing brick infill walls within the RC frames are replaced with factory-fabricated U-shaped PC wall panels, thereby converting the infill into a strong and rigid structural element while preserving the openings. The panels are anchored to the RC frame using post-installed anchors inserted through predrilled holes, allowing for rapid and secure installation with minimal on-site work. To validate the method, five full-scale, one-bay, one-story RC frames were constructed and tested under reversed cyclic lateral loading. Three frames were strengthened with U-shaped PC wall panels of varying thicknesses and large openings. Displacement-controlled cycles following ACI 374.1-05 (R7.0) were applied, with three cycles at each drift ratio stage, and no axial load was applied to the columns. Compared with the reference specimen with a U-shaped brick wall, the strengthened frames exhibited up to 3.29 times higher lateral strength, 4.39 times higher initial stiffness, and 4.33 times greater energy dissipation capacity. These findings demonstrate that the proposed strengthening technique significantly enhances seismic resistance while maintaining the architectural openings, offering a practical and efficient solution for upgrading low-rise RC buildings. Full article

(This article belongs to the Section Building Structures)

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16 pages, 2911 KB

Open AccessArticle

Experimental Study on a UHPC Precast Pier with External Energy Dissipation Device for Seismic Resilience

by Chao Li, Yaowei Peng, Pengyu Yang and Kang Xiao

Buildings 2025, 15(18), 3272; https://doi.org/10.3390/buildings15183272 - 10 Sep 2025

Abstract

This study proposes a precast concrete bridge pier system designed to enhance seismic resilience and post-earthquake reparability. The structural configuration integrates ultra-high-performance concrete (UHPC), externally replaceable steel-angle energy-dissipating components, and unbonded post-tensioned tendons. The seismic performance of the system was evaluated through quasi-static [...] Read more.

This study proposes a precast concrete bridge pier system designed to enhance seismic resilience and post-earthquake reparability. The structural configuration integrates ultra-high-performance concrete (UHPC), externally replaceable steel-angle energy-dissipating components, and unbonded post-tensioned tendons. The seismic performance of the system was evaluated through quasi-static tests under cyclic loading. Experimental results demonstrated that the proposed pier exhibited stable hysteretic behavior and minimal residual displacement, effectively concentrating damage within the intended plastic hinge region. The superior strength of UHPC further contributed to improved load-bearing capacity and less localized concrete compressive damage at the rocking interface. The external steel angles improved the energy dissipation capacity of the precast column significantly, and its external arrangement made the post-earthquake replacement much easier as compared to internal energy dissipation bars. The feasibility of the proposed seismic-resilient pier system was successfully validated, offering a promising solution for bridge design in high-seismic-intensity regions. Full article

(This article belongs to the Special Issue Seismic Performance of Seismic-Resilient Structures)

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19 pages, 7452 KB

Open AccessArticle

Analysis of the Application of Protective Blocks and Structural Systems for Ultra-Fast Fire Response Accompanied by Overpressure

by Won-Woo Kim, Gyeong-Cheol Choe, Heung-Youl Kim, Seung-Wook Kim and Jae-Heum Moon

Buildings 2025, 15(18), 3271; https://doi.org/10.3390/buildings15183271 - 10 Sep 2025

Abstract

Ultra-fast fire, characterized by rapid heat release and associated overpressure, poses serious challenges to structural safety in industrial facilities. This study presents the design and evaluation of a protective block capable of resisting both the thermal and mechanical effects of ultra-fast fires. The [...] Read more.

Ultra-fast fire, characterized by rapid heat release and associated overpressure, poses serious challenges to structural safety in industrial facilities. This study presents the design and evaluation of a protective block capable of resisting both the thermal and mechanical effects of ultra-fast fires. The study combined material- and component-level fire tests with structural simulations. The fire scenario was defined as reaching 1 MW within 60 s with a peak overpressure of 5 bar, comparable to dust fire conditions. Fire resistance was achieved with a layered system comprising a 1 mm perforated steel plate to prevent coating detachment, a 5 mm fire-resistant coating, a 2 mm front steel plate, 25 mm glass wool, and a 2 mm back steel plate. Structural analysis confirmed that a frame system with 200 mm × 200 mm H-beams (vertical) and 150 mm steel plates (horizontal) limited deflection to about 50 mm under 5 bar overpressure. These results demonstrate the feasibility of integrating material-level fire resistance with structural optimization, providing a practical basis for protective block design in ultra-fast fire scenarios. Full article

(This article belongs to the Special Issue Building Structures Under Fire, Structural Dynamics and Material Degradation)

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16 pages, 5693 KB

Open AccessArticle

Influence of Structural Stiffness Representation in Settlement Calculations and Practical Advice

by Christian Wallner, Sabrina Stummer and Dirk Schlicke

Buildings 2025, 15(18), 3270; https://doi.org/10.3390/buildings15183270 - 10 Sep 2025

Abstract

State-of-the-art geotechnical and structural analyses commonly rely on finite-element analysis, treating soil and structure models separately. Incorporating the overall stiffness of the structure into the geotechnical model enables more realistic settlement predictions and assessments of founding force distribution, ensuring optimized and cost-effective designs. [...] Read more.

State-of-the-art geotechnical and structural analyses commonly rely on finite-element analysis, treating soil and structure models separately. Incorporating the overall stiffness of the structure into the geotechnical model enables more realistic settlement predictions and assessments of founding force distribution, ensuring optimized and cost-effective designs. Although stiffness increases with building height, the effective contribution to settlement control is limited to a finite number of floors, making the internal stiffness distribution more relevant than the construction method itself. Reliable predictions require modeling approaches that realistically represent structural stiffness. This study evaluates various equivalent-model techniques in PLAXIS 3D and SOFiSTiK for their practicability and accuracy and explains their application. While simplified methods can adequately capture total stiffness under uniform distribution, constructing a full 3D model may be faster or more practical than elaborate simplifications requiring extensive setup and post-processing. Moreover, the construction sequence and evolving stiffness during the build, as well as time-dependent effects like creep and limit-state-dependent stiffness changes within structural elements, significantly influence settlements. A 3D structural model allows these factors to be accounted for comprehensively. Therefore, whenever feasible, geotechnical settlement analyses should employ full 3D structural models. Full article

(This article belongs to the Section Building Structures)

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19 pages, 2550 KB

Open AccessArticle

Evaluation of the Use of Waste Almond Shell Ash in Concrete: Mechanical and Environmental Properties

by Tuba Demir

Buildings 2025, 15(18), 3269; https://doi.org/10.3390/buildings15183269 - 10 Sep 2025

Abstract

This study focuses on the use of almond shell ash (ASA) obtained from agricultural waste through the pyrolysis process in concrete production while, at the same time, presenting an environmentally sustainable design. For this purpose, ASA was obtained from the biomass energy facilities [...] Read more.

This study focuses on the use of almond shell ash (ASA) obtained from agricultural waste through the pyrolysis process in concrete production while, at the same time, presenting an environmentally sustainable design. For this purpose, ASA was obtained from the biomass energy facilities (BEF) for use in concrete mixes. A total of 25 concrete series were prepared, including 1 control series. In these series, 5%, 10%, 15% silica fume (SF), 5%, 10% metakaolin (MK), and 1%, 3%, 5%, and 7% ratios of ASA were chosen to be substituted by volume with cement. Fresh and hardened concrete tests were performed on the specimens. Experiments have shown that the use of ASA in concrete production improves concrete performance up to a certain extent. With the data obtained from the test results, performance evaluation was performed in the artificial neural network. Because of this evaluation, a mathematical model able to predict the concrete compressive strength with high accuracy was developed. To evaluate the effectiveness of the developed model, it was tested again on control specimens to confirm its accuracy and applicability. A life cycle assessment (LCA) was also performed. The aim is to make a new contribution to the literature and practical application with the method to be developed because of the study and to pioneer future studies in this field. Full article

(This article belongs to the Section Building Structures)

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21 pages, 9743 KB

Open AccessArticle

Aseismic Experimental Research on Safety-Belt System of a Low-Gravity-Center Cable-Stayed Bridge

by Qing Li, Xiangtao Lu, Zhen Wang and Rong Fang

Buildings 2025, 15(18), 3268; https://doi.org/10.3390/buildings15183268 - 10 Sep 2025

Abstract

The seismic performance of low-gravity-center cable-stayed bridges is influenced by their structural system. This paper introduces a novel anti-seismic structural system designed to enhance the earthquake resistance of low-gravity-center cable-stayed bridges while reducing secondary internal forces during operation. A total of 47 groups [...] Read more.

The seismic performance of low-gravity-center cable-stayed bridges is influenced by their structural system. This paper introduces a novel anti-seismic structural system designed to enhance the earthquake resistance of low-gravity-center cable-stayed bridges while reducing secondary internal forces during operation. A total of 47 groups of shaking table tests were conducted, considering four types of seismic waves and acceleration levels. In the shaking table tests, a safety-belt device was constructed and integrated into a scale model of a low-gravity-center cable-stayed bridge. The anti-seismic performance of the safety-belt system was validated by comparing the shaking table test results of the asymmetric restraint system and floating system reported in previous studies. The experimental findings revealed that the strain response at the tower bottom and the displacement response at the tower top were lower in the safety-belt system model. The safety-belt system shows potential for application in low-gravity-center cable-stayed bridges to reduce earthquake impacts. Furthermore, this study elucidates the damage mechanism of low-gravity-center cable-stayed bridges equipped with the safety-belt system under seismic loading, providing references for optimizing the anti-seismic design of such bridges. Full article

(This article belongs to the Special Issue Advances and Applications in Structural Vibration Control)

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22 pages, 4193 KB

Open AccessArticle

Hospital Ventilation Optimization: Balancing Thermal Comfort and Energy Efficiency in Nonlinear Building Dynamics

by Fengchang Jiang, Haiyan Xie, Quanbin Shi and Houzhuo Gai

Buildings 2025, 15(18), 3267; https://doi.org/10.3390/buildings15183267 - 10 Sep 2025

Abstract

Despite growing interest in AI-driven Heating, Ventilation, and Air Conditioning (HVAC) systems, existing approaches often rely on static control strategies or offline simulations that fail to adapt to real-time environmental changes, especially in high-risk healthcare settings. There remains a critical gap in integrating [...] Read more.

Despite growing interest in AI-driven Heating, Ventilation, and Air Conditioning (HVAC) systems, existing approaches often rely on static control strategies or offline simulations that fail to adapt to real-time environmental changes, especially in high-risk healthcare settings. There remains a critical gap in integrating dynamic, physics-informed control with human-centric design to simultaneously address infection control, energy efficiency, and occupant comfort in hospital environments. This study presents an AI-driven ventilation system integrating BIM, adaptive control, and computational fluid dynamics (CFD) to optimize hospital environments dynamically. The framework features (1) HVAC control using real-time sensor datasets; (2) CFD-validated architectural interventions (1.8 m partitions and the pressure range at a return vent); and (3) patient flow prediction for spatial efficiency. The system reduces airborne pathogen exposure by 61.96% (159 s vs. 418 s residence time) and achieves 51.85% energy savings (0.19 m/s airflow) while maintaining thermal comfort. Key innovations include adaptive energy management, pandemic-resilient design, and human-centric spatial planning. This work establishes a scalable model for sustainable hospitals that manages infection risk, energy use, and occupant comfort. Future directions include waste heat recovery and lifecycle analysis to further enhance dynamic system performance. Full article

(This article belongs to the Section Building Energy, Physics, Environment, and Systems)

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25 pages, 7703 KB

Open AccessArticle

Research on Optimization of Intelligent Recognition Model for Bridge Cracks Based on Dual-Parameter Error Evaluation Indexes

by Keke Peng and Wenlang Wei

Buildings 2025, 15(18), 3266; https://doi.org/10.3390/buildings15183266 - 10 Sep 2025

Abstract

The optimization model of intelligent identification for bridge cracks based on dual-parameter error indexes’ feedback mechanism is studied here. An interdisciplinary evaluation system of geometric morphology and fracture mechanics is proposed and established. The weighted average of two parameters is proposed as the [...] Read more.

The optimization model of intelligent identification for bridge cracks based on dual-parameter error indexes’ feedback mechanism is studied here. An interdisciplinary evaluation system of geometric morphology and fracture mechanics is proposed and established. The weighted average of two parameters is proposed as the index to evaluate the crack information model. The two parameters are as follows: (1) effective crack width index (ECWI), which reflects the geometric error of crack information vector graphics; (2) the tip curvature radius error (TCRE), which reflects the stress concentration degree of structural cracks. The aforementioned dual-parameter error evaluation indexes are processed by weighted averaging with reference to current specifications, and the recognition errors of cracks identified by the lightweight semantic segmentation model MobileNetV2-DeepLabv3+ are comprehensively evaluated. The above errors are fed back to the model training code, and parameters such as crack training hyperparameters and data augmentation parameters are adjusted for retraining. After iterative optimization from Version 1 to Version 5, the model’s prediction accuracy is improved: the Dice coefficient is increased by 3.5~32.4%, IoU by 5.3~56.5%, and PA by 0.42~1.33%, finally iterating to an optimized crack recognition model. This combined evaluation system of geometric morphology and fracture mechanics can optimize the information model through error feedback. Meanwhile, by virtue of this method, the disease photos from bridge inspections during the maintenance phase can be identified and converted into an information model of bridge diseases, which holds significant theoretical significance and engineering value for promoting digital maintenance. Full article

(This article belongs to the Special Issue Sustainable Geopolymers and Low-Carbon Cementitious Materials for High-Performance Concrete)

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27 pages, 9269 KB

Open AccessArticle

Physicochemical Properties of Alkali-Activated Ground-Granulated Blast Furnace Slag (GGBS)/High-Calcium Fly Ash (HCFA) Cementitious Composites

by Yi Si, Hong Wu, Runtao La, Bo Yang, Ting Liu, Yong Huang, Ming Zhou and Meng Li

Buildings 2025, 15(18), 3265; https://doi.org/10.3390/buildings15183265 - 10 Sep 2025

Abstract

This study advances alkali-activated cementitious materials (AACMs) by developing a ground-granulated blast furnace slag/high-calcium fly ash (GGBS/HCFA) composite that incorporates Tuokexun desert sand and by establishing a clear linkage between activator chemistry, mix proportions, curing regimen, and microstructural mechanisms. The innovation lies in [...] Read more.

This study advances alkali-activated cementitious materials (AACMs) by developing a ground-granulated blast furnace slag/high-calcium fly ash (GGBS/HCFA) composite that incorporates Tuokexun desert sand and by establishing a clear linkage between activator chemistry, mix proportions, curing regimen, and microstructural mechanisms. The innovation lies in valorizing industrial by-products and desert sand while systematically optimizing the aqueous glass modulus, alkali equivalent, HCFA dosage, and curing temperature/time, and coupling mechanical testing with XRD/FTIR/SEM to reveal performance–structure relationships under thermal and chemical attacks. The optimized binder (aqueous glass modulus 1.2, alkali equivalent 6%, and HCFA 20%) achieved 28-day compressive and flexural strengths of 52.8 MPa and 9.5 MPa, respectively; increasing HCFA beyond 20% reduced compressive strength, while flexural strength peaked at 20%. The preferred curing condition was 70 °C for 12 h. Characterization showed C-(A)-S-H as the dominant gel; elevated temperature led to its decomposition, acid exposure produced abundant CaSO₄, and NaOH exposure formed N-A-S-H, each correlating with strength loss. Quantitatively, acid resistance was weaker than alkali resistance and both deteriorated with concentration: in H₂SO₄, 28-day mass loss rose from 1.22% to 4.16%, with compressive/flexural strength retention dropping to 75.2%, 71.2%, 63.4%, and 57.4% and 65.3%, 61.6%, 58.9%, and 49.5%, respectively; in NaOH (0.2/0.5/0.8/1.0 mol/L), 28-day mass change was +0.74%, +0.88%, −1.85%, and −2.06%, compressive strength declined in all cases (smallest drop 7.77% at 0.2 mol/L), and flexural strength increased at lower alkalinity, consistent with a pore-filling micro-densification effect before gel dissolution/cracking dominates. Practically, the recommended mix and curing window deliver structural-grade performance while improving high-temperature and acid/alkali resistance relative to non-optimized formulations, offering a scalable, lower-carbon route to utilize regional desert sand and industrial wastes in durable cementitious applications. Full article

(This article belongs to the Collection Sustainable and Green Construction Materials)

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31 pages, 4077 KB

Open AccessArticle

Intelligent Generation of Construction Technology Disclosure Plans for Deep Foundation Pit Engineering Based on Multimodal Knowledge Graphs

by Ninghui Yang, Na Xu, Dongqing Zhong and Jin Guo

Buildings 2025, 15(18), 3264; https://doi.org/10.3390/buildings15183264 - 10 Sep 2025

Abstract

To address the challenges in multimodal information integration and the inefficiency of knowledge transfer in the construction technology disclosure of deep foundation pit projects, an intelligent generation method based on graph rule reasoning and template mapping was proposed. First, a multi-level domain knowledge [...] Read more.

To address the challenges in multimodal information integration and the inefficiency of knowledge transfer in the construction technology disclosure of deep foundation pit projects, an intelligent generation method based on graph rule reasoning and template mapping was proposed. First, a multi-level domain knowledge structure model was constructed by designing domain concepts and relationship types using the Work Breakdown Structure (WBS). Second, entity and attribute extraction was performed using regular expressions and the BERT-BiLSTM-CRF model, while relationship extraction was conducted based on text structure combined with the BERT-CNN model. For image and video data, cross-modal data chains were built by adding keyword tags and generating URLs, utilizing semantic association rules to form a multimodal knowledge graph of the domain. Finally, based on graph reasoning and template mapping technology, the intelligent generation of construction disclosure schemes was realized. The case verification results showed that the proposed method significantly improved the structural integrity, procedural logical consistency, parameter traceability, knowledge reuse rate, environmental compliance, and parameter compliance of the schemes. This method not only promoted the standardization and efficiency of construction technology disclosure activities for deep foundation pit projects but also enhanced the visualization and intelligence level of the schemes. Full article

(This article belongs to the Section Construction Management, and Computers & Digitization)

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29 pages, 5344 KB

Open AccessArticle

Structural Behavior Analysis for Existing Pile Foundations Considering the Effects of Shield Tunnel Construction

by Cong He, Jun Wei, Huan Liang, Zhongzhang Chen, Wenqi Ding and Bin Li

Buildings 2025, 15(18), 3263; https://doi.org/10.3390/buildings15183263 - 10 Sep 2025

Abstract

The development of underground space, as a critical strategy for enhancing urban land use efficiency, requires careful consideration of the effects that new construction may have on existing foundations and structures to prevent safety hazards such as foundation damage. This paper investigates the [...] Read more.

The development of underground space, as a critical strategy for enhancing urban land use efficiency, requires careful consideration of the effects that new construction may have on existing foundations and structures to prevent safety hazards such as foundation damage. This paper investigates the influence of shield tunnel construction on the pile foundations of adjacent bridges. Based on the shield tunnel project intersecting the Haiqin Bridge pile foundations along a segment of the Guangzhou–Zhuhai Intercity Railway as a case study, a finite element (FE) model was developed. The validity of the numerical method was confirmed through comparison with existing model test results. Building on this foundation, this paper analyzed the impact patterns of shield tunnel construction on existing bridge pile foundations. Additionally, the model was employed to assess how variables such as the relative spatial positioning between the pile foundations and the tunnel, as well as the stiffness coefficient of the pile foundations, affect the structural response of the piles. The findings reveal that shield tunnel construction crossing adjacent bridge pile foundations induces bending deformation of the piles toward the tunnel side. The maximum horizontal displacement and internal forces occur near the tunnel axis, whereas the peak vertical displacement is observed at the pile head. The zone most affected by tunnel excavation extends approximately one tunnel diameter (1D) before and after the pile foundation location. The vertical relative position between the tunnel and pile foundation governs the relative displacement behavior between the pile and surrounding soil during excavation. Specifically, when the pile toe moves downward relative to the tunnel, the excavation’s influence on the pile foundation shifts from being dominated by negative skin friction and settlement to positive skin friction and rebound, leading to substantial changes in the force distribution and displacement patterns within the pile. As the horizontal clearance between the tunnel and pile foundation increases, the internal forces and displacements within the pile foundation progressively diminish and eventually stabilize. Furthermore, an increase in pile stiffness coefficient decreases the maximum pile displacement and increases internal forces in the pile shaft. Pile diameter has a greater influence than Young’s modulus, which exhibits a relatively minor effect. Full article

(This article belongs to the Special Issue Advances in Building Foundation Engineering and Underground Structures)

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