CivilEng, Volume 4, Issue 4 (December 2023) – 13 articles

Wooden utility poles are vulnerable to degradation and decay, which requires maintenance or replacement. The strengthening and retrofitting techniques for wooden poles are either prone to corrosion or encountering installation difficulties. However, the use of sprayed fiber-reinforced polymer (FRP) composites seems to be a viable solution as it has proven its efficiency and applicability for reinforced concrete members and connections. This study includes a comprehensive experimental program where the mechanical properties of the sprayed-glass FRP (GFRP) composite was evaluated in terms of tensile, compressive and shear strength, in addition to its bond strength to wood and confinement efficiency. Afterwards, the results of the material testing phase were implemented on full-scale old utility poles to evaluate their structural performance with varying composite thicknesses and sprayed zone lengths. The behavior of the retrofitted poles reflected remarkable effectiveness for the sprayed-GFRP composite and highlighted the need for a design model for the optimum length for the sprayed zone. Two simplified analytical models were introduced which predicted the failure loads and locations for the tested poles and estimated the required length for the retrofitted zone, which all agreed well with the experimental results of the tested poles. Full article

The need for openings in RC structures has increased, but their presence significantly affects the performance and strength of the structures. While small openings can be managed with additional reinforcement, dealing with large openings in reinforced or pre-stressed concrete members is challenging due to the lack of technical information and specific guidelines. This research provides an up-to-date overview of RC beam–column joints that incorporate web openings and evaluates appropriate strengthening methods. The research discusses the classification of openings in RC beams, considering factors such as size and shape. Additionally, it examines the failure modes of RC beams in relation to flexural and shear behavior when web openings are present. The research also provides a comprehensive review of various strengthening techniques, outlining their advantages and disadvantages. In conclusion, larger openings in beams result in reduced strength, while increasing loads lead to higher deflection, strain, and cracking until failure. Openings are classified as small or large based on their impact on beam behavior. Multiple smaller openings are preferred over a single large opening when size becomes excessive. Optimal placement is in the middle of the section to ensure adequate concrete coverage for the chords. Sufficient concrete and depth are essential for ultimate compression during bending and effective shear reinforcement. Full article

Bedload transport in a river is a deeply analyzed problem, with many methodologies available in the literature. However, most of the existing methods were developed for reaches of rivers rather than for confluences and are suitable for a particular type of material, which makes them very inaccurate in cases where the sediments are comprised of a mix of different types of soil. This study considers the effect of two different bed sediment sizes, gravel and sand, in relation to bed load transport in a confluence. Five well-known and validated equations (namely Meyer-Peter and Müller, Parker + Engelund and Hansen, Ackers and White, and Yang) are applied to the case study of the Tagus–Alberche rivers confluence (in Talavera de la Reina, Spain), where main and tributary rivers transport different materials (sand and gravel). Field works in the area of the confluence were conducted, and a set of alluvial samples were collected and analyzed. The previously mentioned methods were employed to analyze the geomorphology in the confluence area and downstream of it under different flooding scenarios, concluding different trends in terms of deposition/erosion in the area under historic flooding scenarios. When the trends show erosion, all methods are very consistent in terms of numerical predictions. However, the results present high disparity in the estimated values when the predictions suggest deposition, with Parker + Engelund and Hansen yielding the highest volumes and Meyer-Peter and Müller the lowest (the latter being around 1% of the former). Yang and Ackers and White predict deposits in the same range in all cases (around 15% of Parker and Engelund Hansen). Yang’s formula was found to be suitable for the confluences of rivers with different materials, allowing for the estimation of sediment transport for different grain sizes. The effect of different flow regimes has been analyzed with the application of Yang’s formula to the Tagus-Alberche confluence. Full article

The structural build-up of cementitious materials is the subject of more and more attention since it conditions several processes such as formwork pressure and multi-layer casting. However, this phenomenon originating from flocculation and chemical changes is complex and its reversibility is not clearly elucidated. The aim of this paper is to examine the effect of temperature on the reversibility of structural build-up. The results show that irreversible structural build-up remains negligible despite a rise in temperature. It represents between 0.5–7.3% of the total structural build-up. The addition of SCMs allows for a decrease in this irreversible structural build-up. Therefore, a large part of the chemical contribution is expected to be reversible. The effect of temperature can be explained by the increase in the dissolution rate leading to an increase in flocculation and to the bridging effect induced by early hydrates. Finally, the results suggest that the interparticle distance could be the key parameter governing the irreversibility of structural build-up. Full article

Earthen structures made of adobe bricks are complex systems that making the identification of their behavior difficult, especially when they have to sustain lateral forces such as seismic forces. This paper presents a numerical investigation for the assessment of the structural response of unreinforced adobe masonry structures and how the installation of wooden ring beams contributes to their overall resistance. In the framework of the numerical investigation, finite element models were created to simulate the response of an adobe building with and without the presence of wooden ring beams. The test building is located in Cyprus, in the South Eastern Mediterranean region which is a seismic area. The material properties used in this study were found in the literature and were based on experimental data for local materials. The models were subjected to earthquake loads, performing time history analyses for the calculation of pertinent displacements and stresses. The findings indicate that integrating wooden ring beams reduces the fundamental period by 6% and modifies the building’s seismic behavior. This modification is evident not just in the magnitude of the stresses but also in their distribution, leading to a stratified stress profile. Peak stresses are primarily concentrated around the ring beams. Full article

Steel storage tanks are widely used in different fields. Most of these tanks contain hazardous materials, which may lead to disasters and environmental damage for any design errors. There are many reasons which cause the failure of these tanks such as excessive base plate settlement, shear failure of soil, liquid sloshing, and buckling of the tank shell. In this study, five models of above-ground steel storage tanks resting over different types of clay soils (medium-stiff clay, stiff clay, and very stiff clay soils) are analyzed using the finite element program ADINA under the effect of static and dynamic loading. The soil underneath the tank is truly simulated using a 3D solid (porous media) element and the used material model is the Cam-clay soil model. The fluid in the tank is modeled depending on the Navier–Stokes fluid equation. Moreover, the earthquake record used in this analysis is the horizontal component of the Loma Prieta Earthquake. The analyzed tanks are circular steel tanks with the same height (10 m) and different diameters (ranging from 15 m to 40 m). The soil under the tanks has a noticeable effect on the dynamic behavior of the studied tanks. The tanks resting over the medium-stiff clay (the weakest soil) give a lower permanent settlement after the earthquake because of its low elastic modulus which leads to the absorption of the earthquake waves in comparison to the other types of soil. There are 29.6% and 35.6% increases in the peak dynamic stresses under the tanks in the cases of stiff clay and very stiff clay soils, respectively. The maximum values of the dynamic vertical stresses occur at a time around 13.02 s, which is close to the peak ground acceleration of the earthquake. Full article

The construction industry has witnessed a surge in heat-related accidents alongside rising summertime temperatures, exposing workers to potential injuries. The absence of specific heat stress standards by the Occupational Safety and Health Administration (OSHA) underscores the urgent need for more comprehensive and interactive educational materials to prevent such incidents in construction projects. This study proposes the adoption of an interactive Virtual Reality (VR) application to offer construction workers realistic and effective training, mitigating heat-related injuries. During the training sessions, VR headsets were utilized to immerse workers in two lifelike scenarios: (1) Addressing self-care during heat exhaustion; (2) Assisting a coworker experiencing heat exhaustion. A case study evaluated the effectiveness of the proposed VR training for 82 construction workers from two companies. Company A had traditional training, while Company B used VR training. Both groups took pre- and post-assessment surveys with six questions. The pre-assessment found no significant knowledge difference between the groups. After training, VR showed a significant reduction in incorrect answers compared to traditional training. Statistical tests confirmed the superiority of VR training (p-value = 0.00152 < 0.05), suggesting its effectiveness in preventing heat-related injuries in construction compared to traditional training methods. Full article

A squat is a type of fatigue defect caused by short-wavelength rotational contact; if squats are detected early, the maintenance cost of the track can be effectively reduced. In this paper, a method for the early detection of squats is presented based on ABA (axle box acceleration) and frequency signal processing techniques. To increase the measurement sensitivity for the squat, ABA was used to measure the longitudinal vibration. Compared to vertical ABA, longitudinal ABA does not include vibrations from rail fasteners and sleepers, so it is possible to effectively measure the vibration signal in relation to the impact of the rail. In this paper, vibration data were measured and analyzed by installing a 3-axis accelerometer on the wheel axle of the KTX; squat signals were more effectively extracted using the longitudinal vibration measurement presented above. The algorithm to detect the position of squats was developed based on wavelet spectrum analysis. This study was verified for the section of a domestic high-speed line, and as a result of conducting field verification for this section, squats were detected with a hit rate of about 88.2%. The main locations where the squats occurred were the rail welds and the joint section, and it was confirmed that unsupported sleepers occurred at locations where the squats occurred in some sections. Full article

One common theme in the international construction sector is project variation, which influences project outcomes. This study argued that variation could occur during the lifecycle of a construction project that might affect the contracted project success criteria (PSC), including cost, time, quality, or scope parameters. These variations can originate from the owner, consultant, contractor, or external factors. The construction industry is a critical partner in operationalizing and implementing the long-term sustainability objectives of Vision 2030 in the Kingdom of Saudi Arabia (KSA). The present study identified 18 factors that can cause variation orders by the owners of construction projects and evaluated them using statistical and fuzzy-based methods. To estimate the influence of variation orders on PSC in Saudi Arabia, over 70 experienced professionals, including project managers (58%), engineers (26%), and strategic management officers (16%) working in the construction industry evaluated the identified factors through a questionnaire survey. A 1–4 Likert scale, no impact (1) to high impact (4) on PSC, was used to rank identified factors. Analysis of variance and Tukey tests found no statistically significant difference between the respondents’ opinions. Out of the four PSC, cost and time with 14 out of 18 factors obtaining scores higher than “3” superseded quality with seven and scope with six factors. The Fuzzy Synthetic Evaluation identified inadequate planning, managerial corruption, the method of lowest bidding procurement, the inadequate experience of owner’s staff, additional work added by the owners, delayed starts, mode of financing and payments, and public works contract rigidity as the most critical factors affecting PSC of the construction projects in the view of participated stakeholders. Conversely, shortening the project period, long intervals between design and project initiation, and restrictions against foreign companies were identified as the least important factors. The study helps stakeholders achieve long-term sustainability by focusing on the top-ranked factors in KSA’s construction industry and the Gulf Region with similar working environments, rules, and regulations. Full article

This study provides a comprehensive review of the engineering challenges of formwork in concrete construction. The paper investigates different formwork systems, their design based on form pressure, and the difficulties of form stripping. Alternative binders are gaining more and more interest by opening new opportunities for sustainable concrete materials and their impact on form pressure and concrete setting is also investigated in this paper. The discussion involves several engineering challenges such as sustainability, safety, and economy, while it also explores previous case studies, and discusses future trends in formwork design. The findings pinpoint that choosing an appropriate formwork system depends significantly on project-specific constraints and that the development of innovative materials and technologies presents significant benefits but also new challenges, including the need for training and regulation. Current trends in formwork design and use show promising possibilities for the integration of digital technologies and the development of sustainable and ‘smart’ formwork systems. Continued research within the field has the possibility to explore new formwork materials and technologies, which will contribute to the implementation of more effective and sustainable practices in concrete construction. Full article

Stiffness modulus represents one of the most important parameters for the mechanical characterization of asphalt mixtures (AMs). At the same time, it is a crucial input parameter in the process of designing flexible pavements. In the present study, two selected mixtures were thoroughly investigated in an experimental trial carried out by means of a four-point bending test (4PBT) apparatus. The mixtures were prepared using spilite aggregate, a conventional 50/70 penetration grade bitumen, and limestone filler. Their stiffness moduli (SM) were determined while samples were exposed to 11 loading frequencies (from 0.1 to 50 Hz) and 4 testing temperatures (from 0 to 30 °C). The SM values ranged from 1222 to 24,133 MPa. Observations were recorded and used to develop a machine learning (ML) model. The main scope was the prediction of the stiffness moduli based on the volumetric properties and testing conditions of the corresponding mixtures, which would provide the advantage of reducing the laboratory efforts required to determine them. Two of the main soft computing techniques were investigated to accomplish this task, namely decision trees with the Categorical Boosting algorithm and artificial neural networks. The outcomes suggest that both ML methodologies achieved very good results, with Categorical Boosting showing better performance (MAPE = 3.41% and R² = 0.9968) and resulting in more accurate and reliable predictions in terms of the six goodness-of-fit metrics that were implemented. Full article

India is confronted with the substantial issue of plastic debris due to the absence of an efficient waste management infrastructure. Recycled plastic has the potential to enhance various construction materials, such as roofing tiles, paving blocks, and insulation. The aforementioned materials possess notable attributes such as high strength, low weight, and exceptional resistance to extreme temperatures and humidity. The objective of this study is to ascertain feasible alternatives for manufacturing road paver blocks utilizing plastic waste (Polyethene terephthalate (PET)), and M-sand (stone dust). Three variations of a discarded plastic cube measuring 150 mm × 150 mm × 150 mm were prepared for the experiment. The experimental findings indicated that a ratio of 1:4 was determined to be the most effective in achieving the desired level of compressive strength. I-section road and brick paver blocks were produced as an alternative to the traditional concrete ones. Compressive strength tests were performed on I-sections and brick paver blocks, revealing that the 1:4 mix ratio exhibited the highest average compressive strength for both materials. The findings indicated that including plastic waste positively impacted the compressive strength of the I-sections and brick paver blocks. Additionally, the quality grading of these materials was evaluated using an ultrasonic pulse velocity test. The ultrasonic pulse velocity test results demonstrated a high-quality grading for the I-sections and brick paver blocks. Scanning electron microscopy (SEM) tests assessed the microstructural behavior and performance. The results of this study demonstrate that incorporating plastic waste in combination with M-sand can effectively improve the mechanical characteristics of composite materials, rendering them viable for use in construction-related purposes. Full article

Saline soils belong to the category of problematic soils with high compressibility and weak shear strength when exposed to water. Water dissolves the salts in soils which are the primary cementing agents. Therefore, stabilization methods that provide sustainable cementing substances are employed in this study using deep soil mixing techniques to enhance the properties of saline soil. In this regard, a laboratory-scaled deep soil mixing procedure was developed to treat the soil in a way similar to the field methods. A binder, consisting of marble powder and cement, was employed to treat the soil. This study aimed to select the most efficient binder mix design in terms of optimum marble powder/cement ratio and optimum water/binder ratio. Unconfined compressive strength, durability, density measurements and ultrasonic velocity pulse tests were conducted on the treated soil. To determine the treatment efficacy, microstructure analysis of the treated samples was conducted. The 80C20MP and 70C30MP samples exhibit a dense soil structure with minimal voids, and their microstructure is denser than the other treated specimens. Additionally, the EDX analysis shows increased calcium percentages with up to 30% MP replacement, aligning well with the microstructure analysis and the UCS values. The results indicate that the economical and eco-friendly binder mix consisted of (70% to 80%) cement and (20% to 30%) marble powder with water/binder ratio in the range of 1.1 to 1.3. This mix contributed greatly to the improvement in soil strength and integrated columns. Full article