Amirkabir University of TechnologyAUT Journal of Civil Engineering2588-289910120260201Moment Capacity Assessment of Hybrid GFRP-Steel Reinforced Concrete Beams314597210.22060/ajce.2026.24542.5936ENVui VanCaoFaculty of Civil Engineering, Ho Chi Minh City University of Technology (HCMUT), 268 Ly Thuong Kiet Street, Dien Hong Ward, Ho Chi Minh City, Vietnam.Vietnam National University Ho Chi Minh City (VNU-HCM), Linh Xuan Ward, Ho Chi Minh City, Vietnam0000-0003-2575-1540Khanh BaLeFaculty of Civil Engineering, Ho Chi Minh City University of Technology (HCMUT), 268 Ly Thuong Kiet Street, Dien Hong Ward, Ho Chi Minh City, VietnamVietnam National University Ho Chi Minh City (VNU-HCM), Linh Xuan Ward, Ho Chi Minh City, VietnamDet VanDoanFaculty of Civil Engineering, Ho Chi Minh City University of Technology (HCMUT), 268 Ly Thuong Kiet Street, Dien Hong Ward, Ho Chi Minh City, VietnamVietnam National University Ho Chi Minh City (VNU-HCM), Linh Xuan Ward, Ho Chi Minh City, VietnamJournal Article20250811Combinations of fiber-reinforced polymer (FRP) bars and steel bars to reinforce concrete structures appear to be an advanced solution, as it combines the advantages of both materials. Research effort has been devoted to steel-reinforced concrete (RC) and FRP RC structures, while it has been limited to hybrid FRP-steel RC structures. This study thus aims at assessing the moment–curvature behavior and ultimate moment of hybrid glass FRP (GFRP)-steel RC beam sections. To achieve this aim, fiber models were developed to model beam sections reinforced with different GFRP-steel combinations. These combinations are expressed by the ratio of the GFRP area to the total area of GFRP and steel, namely <em>r</em><em><sub>f/fs</sub></em>, which varies from 0 to 1. The fiber models were verified by comparing with the experimental results, with satisfactory agreement. The verified models were then used for parametric investigations considering the effect of concrete strength, steel strength, FRP strength, and<em> </em><em>r</em><em><sub>f/fs</sub></em> on the behavior and ultimate moment capacity of hybrid GFRP-steel beam sections. When <em>r<sub>f/fs</sub></em> increases from 0 to 1, the bilinear response transitions to a linear response, and the ultimate moment increases. The pivot point is a phenomenon of the moment–curvature curves when <em>r<sub>f/fs</sub></em> varies from 0 to 1. Concrete with higher compressive strength, which delays the compression failure, more effectively exploits the tensile strength of GFRP bars. GFRP bars effectively replace low-strength steel bars, resulting in a higher ultimate moment. Multivariate regression analysis was performed, and the established model indicates that the considered parameters exhibit positive effects on the ultimate moment.https://ajce.aut.ac.ir/article_5972_d8a3a3c3234392b0add43c5f9c05a246.pdfAmirkabir University of TechnologyAUT Journal of Civil Engineering2588-289910120260201Performance of Eco-Friendly Self-Compacting Concrete Incorporating Waste Glass Powder as Fine Aggregate Replacement1524596110.22060/ajce.2026.24449.5933ENHajir AAl-HussainyDepartment of Civil Engineering, College of Engineering, University of Kerbala, Karbala, Iraq.0009-0006-8812-8050Journal Article20250726This study examines the influence of waste glass powder (WGP) as a partial replacement for fine aggregate on the fresh, mechanical, and absorption properties of self-compacting concrete (SCC). Replacement levels of 0 %, 5 %, and 10 % were investigated in accordance with ASTM and EFNARC standards. The incorporation of WGP enhanced workability, increasing slump flow from 650 mm in the control mix to 750 mm at 10 % replacement. Mechanical performance improved significantly, with compressive strength rising from 26.3 MPa to 49,2 MPa at 28 days, and splitting tensile strength increased from 1.9 MPa to 3,4 MPa. These improvements are attributed to the micro-filling capability of fine glass particles and the pozzolanic reaction of amorphous silica, which contribute to matrix densification. Nevertheless, there was a 60% and 58% increase in absorption for cubic and cylindrical specimens (5.5% to 8.78% and 2.15% to 3.39%, respectively), thereby indicating that additional durability tests are necessary and freeze-thaw. In general, the results have shown that waste glass powder can be effectively used as a partial replacement of fine aggregate to enhance the mechanical properties and workability of SCC as well as encourage the sustainability of the environment and recycling of waste in the construction industry.https://ajce.aut.ac.ir/article_5961_094366eaa7a4b5d7f9ed227f212b3649.pdfAmirkabir University of TechnologyAUT Journal of Civil Engineering2588-289910120260201Seismic Behavior of Dry Sandy Soils Improved with Block-Type Deep Soil Mixing in Near-Fault Regions2548592710.22060/ajce.2025.24157.5923ENAliYaghfooriSchool of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran.0009-0009-0542-8712IradjMahmoudzadeh KaniSchool of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran0000-0003-0124-7868HassanYousefiSchool of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran.Journal Article20250515Block-Type Deep Soil Mixing (BDSM) method is widely recommended for enhancing soil in sensitive geotechnical projects. Nevertheless, previous studies have predominantly focused on alternative DSM techniques, particularly grid-type methods, with emphasis on liquefaction mitigation, while the dynamic and seismic performance of BDSM—especially under high-frequency and near-fault excitations—has received limited attention. Considering the high-frequency content of nuclear power plant structures and the stiffness enhancement introduced by BDSM, a precise seismic evaluation is essential. This study investigates the seismic response of dry Nevada sand treated with BDSM under Ricker waves and near-fault earthquake records, including scenarios with and without pulse effects. Plane-strain modeling of the sand layer was conducted in GID, and numerical analyses were performed in OpenSees using the PDMY02 constitutive model. Lateral and bottom boundaries were modeled with semi-infinite free-field columns and viscous dampers. Results indicate that BDSM effectively reduces horizontal accelerations at higher frequencies; however, increasing its thickness can amplify vertical accelerations due to rocking. A thickness equivalent to one-fifth of the shear wavelength is recommended as an initial design criterion. While increasing the DSM width has minimal effect on horizontal accelerations, it can moderate vertical rocking-induced responses. The relative density of sand increases horizontal accelerations, whereas its impact on vertical response depends on input frequency and the dynamic properties of both the soil and BDSM. These findings underscore the critical importance of project-specific design and performance evaluation of BDSM, particularly for sensitive, high-frequency structures such as nuclear facilities, to optimize seismic performance and mitigate dynamic effects.https://ajce.aut.ac.ir/article_5927_c8afe805c097dab1f1e5bdd57f8d2931.pdfAmirkabir University of TechnologyAUT Journal of Civil Engineering2588-289910120260201Impacts of Different Deterioration Processes on Structural Time-Dependent Reliability via Dynamic Bayesian Networks4964593510.22060/ajce.2025.23682.5895ENPouyanZargarDepartment of Civil Engineering, University of Kurdistan, Sanandaj, IranAzadYazdaniDepartment of Civil Engineering, University of Kurdistan, Sanandaj, IranMohammad-RashidSalimiDepartment of Civil Engineering, University of Kurdistan, Sanandaj, IranMohammad-SadeghShahidzadehDepartment of Engineering, Behbahan Khatam Alanbia University of Technology, Behbahan, IranJournal Article20241117Engineering structures are typically subjected to time-dependent deterioration processes, such as corrosion, fatigue, and carbonation, which gradually reduce their service life and reliability. This study investigates the time-dependent reliability of structures under different deterioration mechanisms using Dynamic Bayesian Networks (DBNs). This analysis has the potential to significantly influence future decisions about the structure's usage. Three deterioration models: deterministic, stochastic, and Gamma process, are implemented to represent distinct degradation behaviors. The methodology involves discretizing the resistance variable in DBN and comparing reliability indices obtained from DBN and Monte Carlo simulation (MCS) to validate the approach. The DBN results are validated against Monte-Carlo simulations, showing a maximum discrepancy of 3%, as well as providing standard deviation (0.0211) and root-mean-square error (0.023) of differences that demonstrate the DBN approach's validity and precision. This paper calculates the time-dependent reliability of a portal frame structure experiencing resistance deterioration, influenced by various deterioration models. Finally, it presents a comparison of the results from time-dependent reliability analysis utilizing various deterioration processes. Among the models, the Gamma process yields the highest reliability index over a 40-year period, while deterministic and stochastic models exhibit slightly lower reliability. Estimates derived from measurements are more realistic than those based on design values. The findings demonstrate the capability of DBN to incorporate measurement evidence, providing a robust basis for lifetime reliability assessment and maintenance planning of deteriorating structures also DBN effectively captures deterioration effects and probabilistic uncertainty over time, offering a computationally and time-efficient alternative to Monte-Carlo simulations.https://ajce.aut.ac.ir/article_5935_234dd9e577ac5892481bc60663ffa405.pdfAmirkabir University of TechnologyAUT Journal of Civil Engineering2588-289910120260201Innovative SMA-Based Retrofitting Techniques for Concrete Columns6590593610.22060/ajce.2025.23997.5910ENMahdiehSabbaghianDepartment of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran0000-0003-4386-4565Mohammad ZamanKabirDepartment of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran0000-0002-8318-4583Journal Article20250310Shape Memory Alloys (SMAs) are advanced metallic materials that exhibit two distinct behaviors: the Shape Memory Effect (SME), which enables the recovery of pre-stress through heating in the martensitic phase, and the Superelasticity (SE), which allows for reversible strain recovery upon unloading in the austenitic phase. The main families of SMAs include Cu-based, Fe-based, and Ni-Ti alloys. However, the high cost of Ni-Ti limits its widespread use in civil engineering applications. This review paper synthesizes and compares previous experimental and numerical studies on the use of SMAs as longitudinal or transverse reinforcements in reinforced concrete (RC) columns and cylinders. This paper is divided into two main sections that introduce the research using the SE (enhancing self-centring behavior) and SME (in pre-stressing application) features of SMA in the last decades. The results showed that using SMAs in the plastic hinge region of the column was an excellent idea for reducing residual deformation and increasing the ductility of the column under seismic loading. The results related to utilizing SME features in the column enhanced its stiffness and lateral strength. In contrast, in SE cases, the existence of SMA showed reverse consequences, causing a decrease in the column's stiffness, although its strength occasionally declined. It underscores the need for further research toward cost-effective alloys, improved bonding, and the development of design guidelines for SMA-reinforced RC structures.https://ajce.aut.ac.ir/article_5936_60131a2a3f223dc8f4753bcc5771660c.pdfAmirkabir University of TechnologyAUT Journal of Civil Engineering2588-289910120260201The Appropriate Statistical Distribution for Residuals in Seismic Attenuation Relationships9198594210.22060/ajce.2026.24671.5942ENShahinBorzooDepartment of Civil Engineering, Technical University of Buein Zahra, Buein Zahra, Qazvin, 3451745346, Iran.Journal Article20250903The developed ground motion models are mainly based on the assumption of normality of the residuals. The extreme value distribution is a statistical distribution used in modeling rare events and extreme scenarios. In large earthquakes with a long return period, the recorded peak ground accelerations (PGAs) are large and rare, so the assumption of extreme distributions is not unexpected for these accelerations. The extreme value distribution has two conventional forms: generalized extreme value (GEV) for maximum values of blocks with the same time duration and generalized Pareto distribution (GPD) for values above a determined threshold. Due to the lower recorded numbers of PGAs, using the GPD distribution in examining the extreme values of the PGAs is more appropriate. If the GPD distribution assumption for PGA data be accepted, it is suggested to develop a seismic acceleration attenuation relationship for large or extreme data based on the GPD distribution, and the common assumption of lognormal distribution is discarded. This article reviews the statistical distributions used in ground motion models. The results suggest that in the development of ground motion relationships, the normal distribution for residual should be abandoned with a fundamental revision, and the next generation of these models should be developed based on the GPD distribution.https://ajce.aut.ac.ir/article_5942_b0dd033cbe58aa5ea27747271bfd84e3.pdf