ABSTRACT This paper presents the architectural and structural analysis of the Templar Church of San Bevignate (Perugia, Italy), a monument renowned for its 13th-century frescoes and cultural significance. Preserved largely intact, the church has undergone structural interventions since the 1990s, aimed at mitigating seismic vulnerability while safeguarding its artistic heritage. The seismic behaviour was evaluated adopting a multi-level approach. Material properties were characterised at micro-scale through the Masonry Quality Index (MQI). Local collapse mechanisms were then investigated via kinematic analysis, while the global response under combined seismic actions was evaluated with nonlinear static analyses on an equivalent frame model. The study was supported by extensive on-site inspections, detailed geometric and structural surveys, and a review of previous interventions. Following the Italian Guidelines for the Evaluation and Mitigation of Seismic Risk to Cultural Heritage, the research highlights how standard assessment methodologies can yield results difficult to interpret without accurate historical reconstruction and diagnostic tests. By integrating multi-scale analyses with historical and technical evidence, the study identifies the mechanisms driving seismic vulnerability and underlines the main limitations and uncertainties of current procedures. The findings can help practitioners in critically approaching in-situ surveys, modelling, and data interpretation for preserving masonry and Templar architectural heritage.

Top-and-seat angle connections (TSACs) exhibit inherently asymmetric and nonlinear moment–rotation behavior, which can significantly influence the global response of steel frames subjected to combined gravity and lateral loading. In this study, a three-dimensional finite element model of an unstiffened TSAC is developed and validated against experimental moment–rotation data from the literature under monotonic loading conditions. The validated model is then used to investigate the influence of key geometric parameters, including top angle thickness, bolt diameter, and beam depth, on the connection’s moment–rotation response in both positive and negative bending directions. Subsequently, the monotonic connection behavior is incorporated into nonlinear static analyses of steel portal frames to examine the effects of asymmetric connection response and moment reversal on frame-level stiffness degradation and capacity. A practical SAP2000 modeling workflow is proposed in which the finite element-derived monotonic moment–rotation curves are implemented using zero-length rotational link elements, allowing combined consideration of material, geometric, and connection nonlinearities at the structural level. The comparisons between Abaqus and SAP2000 results demonstrate consistent frame-level responses when identical monotonic connection characteristics are employed, highlighting the ability of the proposed workflow to reproduce detailed finite element predictions at the structural analysis level. The results indicate that increasing top angle thickness, bolt diameter, and beam depth enhances the lateral stiffness and base shear resistance of steel frames. Positive and negative bending directions are defined consistently with the applied gravity-plus-lateral loading sequence.

Abstract Concentrically and eccentrically brace frames are two types of steel bracing used as a lateral load resisting system to improve the stiffness of the frame against earthquakes. The primary difference lies in how their members connect and how they dissipate energy during a seismic event. In this study, two types of bracing systems, eccentrically inverted V-brace frames (EBFs) and concentrically inverted V-brace frames (CBFs) for steel buildings are analyzed using the ETABS program. Nonlinear static (pushover) analysis (NSP) were performed then developing fragility curves in terms of spectral displacements. Fragility curves used to quantify how these two different bracing systems affect a model’s vulnerability. In addition, was investigated the story drift and forming of plastic hinges for the two systems. From the results, it can be noticed that the eccentrically inverted V- brace frames (EBFs) more ductile than concentrically inverted V-brace frames (CBFs) and could withstand in seismic action design. For instance the probability of the complete damage state 50%, the spectral displacement of the EBFs is higher about 63 % as compared with the CBFs.

This study proposes a field-calibrated, NDT-integrated BIM modeling framework to improve the reliability of post-earthquake assessment for reinforced concrete (RC) buildings. The approach combines destructive and nondestructive testing (NDT) data—including core drilling, Schmidt hammer, ultrasonic pulse velocity (UPV), and Windsor probe—through a site-specific WinSonReb regression model. The calibrated material properties (average compressive strength ≈ 18.6 MPa, CoV > 20%) were embedded into a Building Information Modeling (BIM) environment, producing an as-is, NDT-calibrated BIM model representing a Level-2 static digital twin of the structure. Nonlinear static pushover analyses performed in accordance with TBDY-2018 and ASCE 41-17 showed that the calibrated model exhibits a fundamental period of 0.85 s—approximately 18% longer than the uncalibrated BIM model. This elongation increased displacement demand and caused a shift in performance classification: while the uncalibrated model indicated Life Safety (LS), the calibrated model predicted behavior approaching Collapse Prevention (CP) in the Y direction. Furthermore, calibration reversed the predicted damage hierarchy, from ductile beam hinging to brittle column- and wall-controlled failure near elevator openings, consistent with post-event observations from the 2023 Kahramanmaraş earthquakes. These results demonstrate that integrating field-calibrated NDT data into BIM-based seismic models fundamentally alters both strength estimation and failure-mechanism prediction, reducing epistemic uncertainty and providing a more conservative basis for retrofit prioritization. Although demonstrated on a single case study, the proposed workflow offers a realistic and scalable pathway for NDT-supported seismic performance assessment of existing RC buildings.

Recently, rockfall accidents on railways in mountainous regions have been frequently reported. Rockfall-prevention facilities are needed to solve this problem. However, access to construction equipment along railways in mountainous areas is difficult. Therefore, a three-segment modular rock shed suitable for railway construction in mountainous regions is proposed. In this study, the rockfall resistance of the proposed rock shed was evaluated using finite element analysis. The analysis model was validated by comparison with test results, and rockfall resistance was assessed under different scenarios by varying the boundary and connection details. The results showed the foundation-column connection had an insignificant influence on rockfall resistance, whereas the number of slab-column connecting bars had a significant effect. The proposed modular rock shed is designed to withstand rockfall energies ranging from approximately 1,860 to 2,890 kJ.

Traffic light poles, which play a key role in urban traffic management, are increasingly being damaged by higher wind loads associated with climate change, increasing the likelihood of secondary accidents. In this study, the wind-resistance performance of single-direction traffic light poles was evaluated based on pole type and basic wind speed using nonlinear static pushover analysis. The influence of corrosion-induced local cross-sectional reduction on the yielding location and failure mode was also investigated. Field damage cases were collected and classified into representative failure modes. Comparison with the pushover analysis results enabled the identification of the governing failure modes and their associated vulnerability factors for each failure type.

Indonesia is located in a region with high seismic activity due to tectonic plate interactions and its position along the Pacific Ring of Fire. The update of the seismic design code from SNI 1726:2012 to SNI 1726:2019 has increased seismic demand, raising concerns regarding the safety of existing multi-storey buildings. This study aims to evaluate the seismic performance of a multi-storey building in Surabaya using a performance-based approach in accorandce with ASCE 41-17. Nonlinear static (pushover) analysis was conducted to identify beam elements exceeding the Collapse Prevention performance limit under BSE-2E earthquake demand. Subsequently, structural strengthening using Carbon Fiber Reinforced Polymer (CFRP) was implemented based on ACI 440.2R-17 provisions. The results indicate that CFRP strengthening effectively enhances beam capacity and overall structural performance, enabling the building to achieve the Life Safety performance level under the maximum design earthquake.

Tall buildings are crucial in the modern urban era, providing a solution to accommodating the rising population density and addressing the land scarcity problem. Despite mitigating population density, constructing tall buildings is complex, as their structural safety under seismic loading remains a significant challenge, particularly in a seismically active region such as Nepal. Performance-Based Design (PBD) is an advanced structural engineering approach that prioritises the design of buildings based on their expected performance under various seismic loading scenarios. This study focuses on the seismic-resistant design of a 16-storey Reinforced Concrete (RC) shear-wall-framed tall building using a Performance-Based Design approach. The structure was modelled and analysed using ETABS software, in accordance with NBC 105:2020. Linear static and response spectrum analyses were performed, followed by a non-linear static pushover analysis for performance evaluation using FEMA 440 equivalent linearization. The results confirmed that all structural components met strength and serviceability criteria. The pushover analysis revealed that plastic hinges formed primarily in beams, indicating a ductile failure mode. The capacity curve and performance point were obtained, indicating that the overall performance level met the Life Safety criteria for the Design Basis Earthquake. The study concludes that the PBD approach effectively ensures seismic resilience and recommends its expanded use for essential structures in high-risk zones.

This study investigates the effectiveness of concrete jacketing in increasing the structural capacity of a multi-storey reinforced concrete building and estimates the associated retrofit cost. The existing structure was evaluated using static nonlinear pushover analysis based on ASCE 41-17 provisions to identify seismic deficiencies. Concrete jacketing was then applied to critical columns to enhance structural performance. Post-retrofit analysis shows a significant improvement in lateral load capacity and overall seismic behavior. Retrofit cost estimation was conducted based on retrofit work volumes and standard unit prices. The results indicate that concrete jacketing provides an effective and economically feasible solution for strengthening existing multi-storey buildings in seismic regions.

Abstract Past earthquakes have often caused brittle damage to buildings with short columns. Studies usually ignore the impact of short columns on a building's overall responses in contrast to focusing on the behavior of individual structural elements. Even while avoiding such short columns in buildings is preferred, building code standards typically recommend detailing for shear to prevent brittle failure. It is critical to confirm that the building code's requirements are sufficient. A set of 2 dimensional (2D) reinforced concrete (RC) moment frame buildings with short columns at the ground storey is examined by adjusting the following: (i) the height of the short columns (0.75–1.50 m); (ii) the buildings' height (3, 5, and 10 storeys); (iii) the removal of infill walls in bays 1, 2, 3, 4, and the entire ground storey; and (iv) the location of short columns without infill walls along the height. According to the results of nonlinear static and nonlinear time history analyses, buildings deformability is reduced (~1%) with decrease in short column height (1.5–0.75 m). The short columns (0.75 m) at the open‐ground storey is extremely vulnerable to shear failure, even with ductile detailing according to Indian Standard (IS) 13920; adding infill walls or raising the height of buildings may not prevent the brittle failure. Also, short columns located closer to the bottom three storeys experience shear failure or at the upper storeys causes more damage to the structural elements beneath those storeys. Hence, nowhere along the building's height should the short columns be positioned. It is validated with comparison between energy‐based assessments and the percentage of infill wall damage; always infill walls exhibit about 70% yielding and 50% ultimate failure. Consequently, flexural behavior is more common in short columns with 1.5 m high. Also, shear failure is indicated by a shear ratio ≤1.5 and shear bearing capacity ratio >2 may not be applicable to real buildings. Short column height and building height also affect the upper limit established by previous research that used just a few of specimens, which may not be suitable for buildings.

Reinforced concrete buildings with masonry-induced soft-storey irregularities exhibit extreme seismic vulnerability, a critical risk often underestimated by conventional code-based design. Standard equivalent static methods typically fail to capture the intense concentration of seismic demand at the flexible ground level, leading to unconservative designs that do not meet performance objectives. This research proposes a corrective linear–static methodology to address this deficiency. A new Equivalent Lateral Force profile (ELFi1) was developed, derived from modal analyses of 235 representative soft-storey archetypes to accurately account for stiffness heterogeneity. This profile was integrated with a realistic response modification coefficient (Ri1 = 5.04), determined to be 37% lower than the normative R-factor (R = 8) prescribed by code. Nonlinear static analyses confirmed that conventional design resulted in “irreparable” damage (mean Global Damage Index = 0.82). In contrast, redesigning the structure using the proposed ELFi1 and Ri1 methodology successfully mitigated damage concentration, upgrading structural performance to a “repairable” state (mean Global Damage Index = 0.52). Finally, Incremental Dynamic Analysis validated the approach; the redesigned structure satisfied FEMA P695 collapse prevention criteria, achieving an Adjusted Collapse Margin Ratio (ACMR) of 2.10. This study confirms the proposed method is a robust and practical design alternative for soft-storey mechanisms within a simplified linear framework.

Owing to the absence of robust analytical theoretical analysis methods, the elastic-plastic ultimate bearing capacity of angle steel section components in transmission tower is usually addressed by finite element simulation and experiments. In this work, the elastic stiffness matrix that accounts for the deformation of the element was derived using fifth-order interpolation function. The dual nonlinear static analysis method was proposed by combining the material nonlinear plastic stiffness matrix and geometrical nonlinear stiffness matrix. The material nonlinear plastic stiffness matrix of beam element with angle section was derived through the yield surface and the concentrated plastic hinge models, and the geometrical nonlinear stiffness matrix of angle section was derived by the rigid-body criterion. The accuracy and effectiveness of the analysis method proposed in this work were verified through various examples, and the research results can provide theoretical references for the analysis and calibration of the mechanical properties of transmission tower.

The Philippines, located along the Pacific Ring of Fire, is highly susceptible to significant seismic activity arising from the active convergence of major tectonic plates. These seismic events often induce ground shaking intense enough to trigger soil liquefaction, particularly in geologically sensitive regions such as Davao del Sur. This study presents a nonlinear static and dynamic analysis of a mat foundation for a proposed midrise building located within the liquefaction-prone zone of Padada, Davao del Sur. Geotechnical data were obtained through rotary drilling and Standard Penetration Tests (SPTs), which provided the basis for developing the numerical model. Liquefaction assessment was conducted using the PLAXIS Liquefaction Model (UBC3D-PLM), confirming that the site adjacent to the Padada–Mainit River exhibits a high liquefaction potential. Subsequently, finite element analyses were performed in PLAXIS 3D using ground motion records from the 2013 Bohol Earthquake, scaled to 1.0 g, and modeled under the Hardening Soil Model with Small-Strain Stiffness (HSsmall). Results showed excess pore pressure ratios approaching 1, and vertical displacements of the mat foundation exceed 100 mm. These results suggest severe degradation in soil strength, as well as reduced friction angles and mobilized pressure.

The interaction between soil and structure, which merges geotechnical and structural engineering, plays a crucial role in seismic regions. Traditional structural design often assumes that buildings are fixed at their foundations, neglecting the influence of local soil conditions. However, accounting for soil–structure interaction (SSI) indicates greater structural flexibility, modified dynamic behaviour, and variations in the intensity and distribution of earthquake forces. These influences are especially notable in soft or moderately stiff soils, where foundation flexibility may cause increases or decreases in seismic demand. To account for these influences, American pre-codes provide detailed guidelines for incorporating SSI into structural analyses. In this study, these guidelines were applied in both nonlinear static (push-over) and nonlinear dynamic (time-history) analyses of a six-storey reinforced concrete frame structure. The analyses considered two different soil types, B and C, which were classified according to Eurocode 8, to evaluate the effect of different soil rigidity on structural behaviour. The findings, with a focus on kinematic interaction, highlighted how foundation embedment influences seismic behaviour. The results showed notable deformations in storey displacements and inter-storey drifts, as well as the formation of plastic hinges, indicating nonlinear response mechanisms. Reduced capacity curves under lower seismic forces confirmed the influence of SSI. This study underscores the necessity of incorporating SSI effects to improve seismic design accuracy and enhance the prediction of structural behaviour during earthquakes.

Abstract Castellated beams (CB), widely employed in modern construction, offer an improved strength-to-weight ratio and enhanced structural efficiency due to their increased depth and moment of inertia. However, the presence of web openings and discontinuous geometry significantly alters their lateral-torsional stiffness, making them more susceptible to lateral-torsional buckling (LTB), particularly. This study investigates the buckling and ultimate load behaviour of CB compared to solid I-sections through analytical (T-section method), numerical (IS 800, Handbook SP6-1-based), and finite element approaches. A steel I-section was castellated to form IC225 sections with hexagonal openings, maintaining a 50% increase in depth. Both parent and CB were analyzed for three spans: 2 m, 5 m, and 8 m under simply supported conditions and central point loading. Nonlinear static analysis and buckling analysis were conducted in ABAQUS (2024) using shell elements, incorporating initial geometric imperfections equal to depth/500. Results indicate that CB exhibit up to 24-42% higher ultimate load capacity and up to 37% lower deflection than solid beams due to increased depth and moment of inertia. However, their buckling resistance decreases by 8–31% due to a decrease in torsional rigidity, with LTB as the dominant failure mode in longer spans. In addition to these expected trends, the study highlights the post-buckling behaviour, for which the stress redistribution characteristics and modes of stability differed between the CB and parent beams. Nonlinear static analysis also showed that loads and deflection changes became almost constant for spans above 5 m, indicating span-dependent nonlinearity. Nonlinear FEM results closely matched numerical predictions, with an error of 7-11%, confirming model reliability. This study concludes that CB provides superior load performance and stiffness but requires careful design to mitigate LTB and localized Vierendeel failures around web openings. Results reveal a nonlinear response dependence on span, for which the loading and deflection become stabilized beyond 5 m. In comparison with previous works, this study provides new insights into the stress redistribution mechanisms and stability mode transitions of CBs, which contribute to the understanding of design guidelines for long-span steel structures.

Abstract This study proposes a comprehensive performance evaluation and intelligent decision support system for the maintenance and seismic retrofitting of aging transportation infrastructure, aimed at enhancing structural safety, extending service life, and optimizing life-cycle costs. The research focuses on reinforced concrete (RC) bridge columns commonly found in urban elevated railway systems in Japan, addressing key issues such as strength degradation, insufficient ductility, and inadequate seismic performance. Using static nonlinear analysis, the residual load-bearing capacity and damage state of the columns were evaluated, and a comprehensive performance index system was established. To enhance structural resilience while minimizing operational disruption, a space-efficient seismic reinforcement method characterized by high spatial adaptability was adopted, making it particularly suitable for dense urban environments. The decision-making process is underpinned by the Adaptive Integrated Digital Architecture Framework (AIDAF), which establishes a closed-loop system integrating data acquisition, performance assessment, parameter optimization, and feedback validation. By incorporating machine learning (ML), specifically the random forest (RF) algorithm, into the AIDAF framework, a data-driven retrofitting system was developed. Feature importance analysis identified key variables, including steel plate thickness, rebar diameter, and spacing. The ML-enhanced system reduces design iteration time and facilitates rapid evaluation of multiple reinforcement configurations. The predictive accuracy of the model was validated using an in-service railway viaduct, confirming its effectiveness. Furthermore, the study recommends integrating explainable AI techniques to improve transparency and regulatory acceptance. The findings demonstrate that the proposed ML-AIDAF framework is technically feasible, economically viable, and scalable for real-world infrastructure retrofitting projects.

India’s building stock remains highly vulnerable to seismic hazards, with conventional retrofitting strategies often limited in their applicability under varying earthquake intensities. This study investigates the effectiveness of the Yielding Brace System as a novel lateral load–resisting mechanism for improving the seismic resilience of mid-rise reinforced concrete buildings. A six-storey special moment-resisting frame was analysed in bare and Yielding Brace System (YBS)-integrated configurations using a comprehensive multi-analysis framework, including nonlinear static pushover analysis, nonlinear time history analysis, incremental dynamic analysis, and probabilistic fragility assessment. Results demonstrate that the incorporation of YBS significantly reduces inter-storey drift demands by 30–53% and increases normalized base shear capacity from 0.30 in the bare frame to 0.75 in the YBS frame. Ductility improved from 3.20 to 3.98, while residual drift ratios consistently remained below the FEMA P-58/ASCE 41 threshold of 0.5%. Fragility analysis revealed that the bare frame reached a 50% probability of collapse at 5.1 m/s², whereas the YBS-equipped frame required 15 m/s², highlighting a threefold enhancement in collapse safety margin. By reducing collapse probability and ensuring functional recovery after earthquakes, Yielding Brace System advances resilient infrastructure development and aligns with global sustainability objectives under UN SDG 9 (Infrastructure), SDG 11 (Sustainable Cities), and SDG 13 (Climate Action).

The joint configurations of prefabricated segmental cap beams exhibit considerable diversity in engineering applications. In recent years, combined shear key corbel connections have been increasingly adopted due to their advantages in prefabrication efficiency, rapid assembly, and favorable mechanical performance. Nevertheless, research on their ultimate shear capacity remains limited. To systematically assess the effects of joint configuration on shear performance, two types of cap beam models were developed reflecting engineering loading characteristics dominated by positive shear with secondary negative shear effects: a shear key model (SK1) and two keyed corbel models (SK2 and SK3), subjected to positive and negative loading, respectively. A full nonlinear static analysis with progressive loading to failure was conducted to obtain cracking load, ultimate capacity, stress distribution, deflection, and damage evolution. The results reveal that (1) all beams exhibited damage localization near adhesive joints, with shear–compression as the governing failure mode; (2) SK1 and SK2 achieved comparable shear capacities, whereas SK3 reached less than 30% of their ultimate strength; (3) SK2 attained the highest ultimate capacity, 1.07 times that of SK1; and (4) SK2 reached a maximum deflection of 3.24 mm, exceeding the other two by more than 29%. Overall, the keyed corbel configuration (SK2) demonstrated the most favorable comprehensive shear performance.

ABSTRACT Seismic retrofitting greatly improves the safety and effectiveness of reinforced concrete (R.C.) buildings in earthquake-prone areas, and this study examines this phenomenon in the G+9 multiple-story concrete buildings. It examines the seismic response and the effects of two common retrofitting techniques — RCC (Reinforced Cement Concrete) Jacketing and Steel Wrapping. Using ETABS software, we carried out digital modeling and analyses, including both nonlinear static and dynamic (time history) analyses with reference to the El-Centro and Uttarkashi earthquake data. For both retrofitted and non-retrofitted scenarios, important features of the buildings, including the natural and derived (shear and axial) frequencies, lateral slip and uneven shifting (drift) of the floors and base, overall mass, and stress distribution, were assessed. The data indicated improved stiffness, overall mass, and load-carrying-ability of all retrofitted structures, and showed noticeable differences in the RCC Jacketing and Steel Wrapping techniques. For the overall retrofitting of buildings, RCC Jacketing was more effective in stiffness improvement and overall mass than Steel Wrapping. Improved strength and drift minimization were achieved, and practical applications retrofitting-system-selection of high-rise concrete structures gained based on steel wrapping development. Keywords: Seismic Retrofitting, RCC Jacketing, Steel Wrapping, ETABS, Time-History Analysis, Inter-Storey Drift, Lateral Displacement, Base Shear, Structural Stability, Earthquake-Resistant Design.

Chloride-induced corrosion represents a critical deterioration mechanism for reinforced concrete (RC) structures, yet its time-dependent impact on structural reliability remains insufficiently investigated. This study integrates a corrosion progression model with finite element analysis and the First-Order Reliability Method (FORM) to evaluate the seismic performance and serviceability of a single-bay, single-story RC frame throughout a 60-year service life. Nonlinear dynamic, static, and modal analyses were conducted using OpenSees and MATLAB to quantify failure probabilities for both drift-based seismic damage states and serviceability criteria (deflection and vibration). The results demonstrate that corrosion significantly amplifies failure risk: for slight, moderate, and extensive seismic damage states, failure probability increases by approximately 46–56%, 52–55%, and 34–47%, respectively, compared to an uncorroded frame. Serviceability reliability similarly deteriorates, with corrosion raising the probability of deflection and floor vibration failure by approximately 30–37% over the 60-year period. A sensitivity analysis identified the corrosion initiation time, chloride diffusion coefficient, and rebar diameter as governing uncertainties affecting the reliability index. Notably, the influence of corrosion-model parameters (such as time to initiation) on reliability is pronounced during early years but diminishes at later stages of the service life. These findings highlight the significant long-term vulnerability of RC frames in chloride-rich environments and underscore the value of probabilistic approaches for assessing structural resilience under progressive corrosive deterioration.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-24197-z.