Mohamed E. El-Zoughiby

The choice of a structural system is an early design decision with implications for a building’s performance throughout its service life. For residential projects in Saudi Arabia, the selected system should balance structural safety and constructability with cost, energy consumption, occupant requirements, local supply conditions, and regulatory compliance. This study develops a survey-based, evidence-informed framework to support the evaluation of these competing requirements. A systematic literature review identified 152 records and retained a final set of 134 eligible studies, from which 29 sustainability-related decision indicators were organized into five literature-derived decision domains: four outcome-oriented sustainability domains and one digital/AI-enabled decision support domain. These indicators were assessed through a survey of relevant professionals and academics, yielding 267 valid responses. Data were analyzed using descriptive statistics, the Relative Importance Index, reliability and factorability testing, exploratory factor analysis, and hierarchical weighting. The questionnaire demonstrated strong internal consistency and factorability (Cronbach’s α = 0.960; KMO = 0.955; Bartlett’s test, p < 0.001). Although the responses supported three broader empirical factors explaining 61.09% of the total variance, the five a priori literature-derived decision domains were retained as formative decision categories for transparent hierarchical weighting rather than treated as five empirically confirmed latent constructs. Twenty-one indicators met the adopted critical-selection thresholds. Normalized domain weights ranged from 18.71% to 20.94%, providing limited numerical differentiation between domains within the surveyed sample. To demonstrate only the computational operation of the framework, a non-validated illustrative application was conducted using author-assigned performance scores rather than measured project data, structural simulations, or an independent expert assessment. Under these assumptions, the composite steel–concrete system produced the highest illustrative score, followed by the precast-concrete system. Within this hypothetical application, the two alternatives retained their respective positions in all 42 indicator-weight perturbation scenarios and in 146 of the 148 valid performance-score perturbation scenarios (98.65%). This sensitivity result demonstrates only internal stability under the tested assumptions and does not constitute external validation, empirical evidence of structural-system superiority, or a universally applicable design recommendation. The proposed framework provides a transparent basis for comparing structural-system alternatives during early design, subject to project-specific performance evidence and independent validation.

This study experimentally investigated the punching shear behavior of engineered cementitious composite flat-plate slabs incorporating cement kiln dust and crumb rubber. The considered criteria included replacing 50% of the rubber without treatment and treating the rubber at the same percentage; the flexural reinforcement ratio, whether in the bottom tensile reinforcement ratio or in the top compressive reinforcement; and the ECC cube compressive strength (f_cu). For this purpose, thirteen reinforced flat-plate slabs were cast and tested. All slabs had the same dimensions of 1100 × 1100 × 100 mm, with a central square column that had dimensions equal to 160 × 160 × 160 mm. The flexural RFT ratios in the tension and compression zones were 1.0, 1.2, and 1.6%. The tested slabs were cast with different values of f_cu of 50, 65, and 70 MPa. The study first presented and discussed the first cracking load, ultimate load, crack pattern, load–deflection response, stiffness, and RFT strain. The experimental results demonstrated that increasing the tensile reinforcement RFT ratio significantly improved punching shear capacity by up to 33%, while the concrete cube compressive strength only contributed an approximately 14.2% increase. Treated crumb rubber engineered cementitious composite slabs showed greater initial stiffness and reduced deflections under the same loads, along with higher post-cracking stiffness degradation compared to crumb rubber concrete engineered cementitious composite slabs. Increased tension reinforcement improved initial and post-cracking stiffness and reduced deflections, with more significant effects in crumb rubber concrete engineered cementitious composite slabs. The flexural tension had a more substantial impact on punching shear behavior than compression. Comparisons with building design codes (ECP 203-2020, ACI 318-25, and Eurocode 2) revealed that while these codes could estimate shear capacity, they were conservative, with Eurocode 2 providing the best predictions by considering flexural tension.

Functionally graded concrete (FGC) is an advanced building technique that allows structural components to satisfy diverse mechanical and durability specifications. In this study, hybrid geopolymer concrete (HGC) was used in constructing reinforced FGC beams to improve their flexural performance and sustainability. One HGC mix was used and compared with the corresponding control cement-based concrete mixture. The HGC mix was made of FA, slag, and dolomite powder (DP) binders. The structural performance of ten reinforced FGC beams, with different cross-sections and varying concrete layer configurations, was evaluated by four-point bending tests. The results indicated that beams utilizing HGC in the tensile zone showed improved ductility and load-carrying capacity relative to those constructed with the corresponding cement-based concrete. The functionally graded configuration, particularly when HGC is placed in the crucial tension zone, markedly enhanced both the ultimate deflection by 30% and ductility by 73%. These findings highlighted the advantages of using HGC in constructing FGC beams for sustainable, high-performance concrete structures, facilitating diminished cement usage, reduced carbon emissions, and enhanced structural resilience.

Engineered cementitious composite (ECC) is an advanced material known for its superior flexibility, high durability, and crack resistance, making it ideal for a variety of structural applications. However, it uses cement at a rate of 2–3 times more than conventional concrete which raises environmental concerns. This study focused on the production of eco-friendly ECC by incorporating various waste materials as partial cement and sand substitutes. Cement kiln dust (CKD), ceramic powder waste (CPW), and eggshell waste (ESW) were used as partial substitutes for cement in doses of 10% and 20%. Crumb rubber (CR) was used as a partial substitute for sand in doses of 25, 50, 75, and 100%. Chemical treatments using sodium hydroxide, sodium silicate, and a mix of both of them were carried out for the CR in the production of the proposed ECC. Physical treatment using the same cement substitute materials (CKD, CP and ESP) was also carried out for the CR. The effect of fiber type—such as basalt fibers (BF), polypropylene fibers (PPF), and steel fibers (S_tF)—on the performance of ECC was also investigated. Slump, compressive strength, uniaxial tensile strength, flexural strength, and sorptivity were the measured properties for the proposed ECC. Microstructure analyses were also conducted on some selected ECC mixtures. Among the tested mixtures, the results showed that replacing 10% of the cement with CKD improved the compressive strength by up to 22.6% and the tensile strength by up to 18.3%. Using 50% untreated CR reduced compressive and tensile strength by 32.8% and 28.1%, respectively, compared to the control ECC. The physical treatment of CR using CKD improved the compressive strength by up to 12.7% and the tensile strength by up to 3.2% compared to untreated CR. The microstructure analyses revealed an improvement in fiber-matrix bonding and a reduction in crack width in the mixtures, especially in the BF and PPF blends.

This study presents a comprehensive experimental and numerical investigation into the flexural behavior of sustainable self-compacting geopolymer concrete ( SCGC ) beams incorporating granite waste and slag powder. While the environmental benefits of geopolymer concrete are widely studied, its structural performance, particularly when utilizing industrial wastes, remains underexplored. To address this gap, six reinforced concrete beams (100 × 150 × 1500 mm), including five SCGC beams and one Portland cement concrete ( PCC ) control beam, were tested under four-point bending. The investigation systematically evaluated the influence of key parameters: the longitudinal reinforcement ratio (0.85%, 1.34% and 2.0%) and the shear span-to-depth ratio (4.27, 4.48 and 4.7). Experimental results demonstrate that the cracking load, yield load, and ultimate flexural capacity of the SCGC beams increased with a higher reinforcement ratio and a lower shear span-to-depth ratio. Notably, the SCGC beams exhibited a higher moment capacity compared to the conventional PCC beam. A nonlinear finite element model, validated against the experimental data, provided accurate predictions of the load–deflection response and ultimate strength. The findings confirm that SCGC incorporating granite waste is a structurally viable and superior alternative to conventional concrete, with the developed model serving as a reliable tool for future design and analysis.

This research investigates the shear performance of sustainable self-compacting reinforced geopolymer concrete (GPC) beams incorporating granite waste powder (GWP) and ground granulated blast-furnace slag (GGBFS) as eco-friendly binding agents through experimental and numerical analyses. Five geopolymer reinforced concrete beam specimens (100 mm × 150 mm × 1500 mm) were tested under two-point loading conditions to evaluate the influence of longitudinal reinforcement ratio (0.85% to 2.0%) and shear span-to-effective depth ratio on the structural shear performance. The experimental investigation revealed that geopolymer reinforced concrete beams exhibit shear behavior characteristics similar to conventional Portland cement concrete beams, with the 2.0% reinforcement ratio achieving 18.3% higher shear strength compared to the 0.85% reinforcement ratio, while shear capacity increased proportionally with increasing shear span-to-depth ratio. Experimental data, including load–displacement response, shear strength measurements, strain distributions, failure modes, and crack patterns, were studied. Finite element nonlinear analysis was conducted by modifying the concrete modulus and stress–strain relationships to reflect the properties of geopolymer concrete using ABAQUS software integrated with the concrete damaged plasticity model. The results demonstrated that for the tested geopolymer reinforced concrete beams, first cracking load, steel yielding load, and ultimate load capacity increased systematically with increasing tension steel reinforcement ratio and proportionally with higher shear span-to-depth ratios.

Being a critical component of reinforced concrete (RC) structures, retrofitting beam-to-column joints (BCJs) has been extensively investigated, particularly for substandard designs. These investigations attempted to avoid possible shear failure in the joint region; however, careful consideration of the most effective and potentially practical solution was limited. Therefore, this study systematically evaluates three retrofitting techniques that are assumed to be both effective and replicable in real applications. The three techniques were carbon-fiber-reinforced polymers (CFRP), steel angles with pretension bolts, and U-shaped steel bars. First, finite element (FE) models were validated against experimental data to confirm the accuracy of the proposed numerical model. Then, a parametric study was conducted to explore the effect on the joint performance. The considered parameters for CFRP: bond shear stress and the ply count; for steel angles with pretension bolts: angle’s leg size, component thickness, and bolt diameter; for U-shaped bar technique: diameter and length of the bar. Based on the parametric analysis, a comparison between the three techniques was performed to achieve the most robust designs possible. Results indicated that the overall joint strength in terms of ultimate load was enhanced using the CFRP and U-shaped techniques compared to the control joint by 103.93% and 43.55%, respectively. Steel angles with pretension bolts exhibited the highest performance, with a 148.50% increase in ultimate load, and was the most effective in relocating the failure to the beam.

We extend our heartfelt gratitude to our diligent and meticulous reviewers of Mansoura Engineering Journal for their unwavering commitment and invaluable contributions throughout the year 2024. Their dedication to maintaining the highest standards of academic excellence has been instrumental in shaping the scholarly discourse within the engineering community. The editorial and review process is the cornerstone of academic publishing, ensuring the integrity, relevance and rigor of the research disseminated to the global scientific community. The tireless efforts of the editors in overseeing the publication process with precision and efficiency, coupled with the meticulous scrutiny of