Bulletin of Earthquake Engineering最新文献

{"title":"Strengthening strategies for mitigating damage induced by high ground stories: field data and analytical findings from RC buildings in the kahramanmaraş earthquakes","authors":"Ercan Işık","doi":"10.1007/s10518-026-02569-8","DOIUrl":"10.1007/s10518-026-02569-8","url":null,"abstract":"<div><p>Reinforced concrete (RC) buildings with high ground stories are frequently constructed for commercial purposes, such as showrooms or retail spaces. However, this architectural requirement often results in significant stiffness and strength irregularities throughout the building height. The catastrophic earthquakes that struck Kahramanmaraş on February 6, 2023, provided extensive field data regarding the failure mechanisms of such buildings. In this study, a RC building model with a high ground story was created, and pushover analyses were performed, and damage mechanisms originating from the ground story were investigated in detail. Structural performance was evaluated under different strengthening scenarios; fibre reinforced polymer (FRP) strengthening and RC jacketing methods were analysed comparatively in terms of ground story-limited and multi-story applications. For this purpose, a 6-story RC structure was considered to represent mid-rise RC buildings. To create the effect of a high ground story, the ground story height was chosen as 4 m, while the height of each of the other stories was chosen as equal and 3 m. The study demonstrates that although strengthening the high ground story increases the lateral load-carrying capacity, it may inadvertently trigger shear damage in non-strengthened upper stories due to the redistribution of stiffness. The results suggest that multi-story strengthening strategies are essential for mid-rise RC buildings to maintain structural integrity and prevent brittle failure mechanisms observed in the field. In contrast, multi-story strengthening scenarios provided a more balanced structural response and eliminated shear capacity exceedances in the analysed columns. Furthermore, the RCJ-II model increased the base shear capacity from 1208.24 kN to 3015.40 kN while reducing the structural period from 0.81 s to 0.60 s. The study findings highlight that inter-story rigidity continuity is a critical design parameter in strengthening existing RC structures with high ground stories, and offer important engineering implications for post-earthquake performance improvement strategies.</p></div>","PeriodicalId":9364,"journal":{"name":"Bulletin of Earthquake Engineering","volume":"24 10","pages":"8687 - 8719"},"PeriodicalIF":4.2,"publicationDate":"2026-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149190006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of the bridge failure direction and the increased probability of collapse due to multi-hazard effects: scour and earthquakes","authors":"Bertha A. Olmos,&nbsp;Jose M. Jara,&nbsp;Alberto Gil,&nbsp;Juan I. López-Pérez,&nbsp;Guillermo Martínez,&nbsp;Alma R. Sánchez","doi":"10.1007/s10518-026-02562-1","DOIUrl":"10.1007/s10518-026-02562-1","url":null,"abstract":"<div><p>The southwestern region of Mexico is highly susceptible to the concurrent threats of river scour from frequent hurricanes and intense seismic activity. This study aims to evaluate the risks to simply supported reinforced concrete bridges from scour and earthquakes, incorporating the uncertainties of both natural hazards within a probabilistic framework. While multi-hazard risks to infrastructure are widely recognized, existing joint scour-earthquake frameworks typically use seismic records from transform faults. These cannot be reliably extrapolated to regions governed by interplate and intraplate subduction zones, which exhibit distinct frequency contents and energy radiation patterns. To bridge this gap, this study presents a probabilistic multi-hazard framework evaluating the system reliability of typical medium-span, simply supported reinforced concrete (RC) bridges along Mexico’s Pacific Coast. A Multi-Hazard Probabilistic Seismic Demand Model (MH-PSDM) was developed to generate component and system fragility surfaces based on curvature ductility demands under various scour depths. The findings reveal that combined hazards significantly modify the structural failure mechanism, driving a critical transition of damage from pier columns to the foundation piles as scour depth increases. The manuscript emphasizes that a bridge’s likelihood of collapsing is heavily influenced by the relationship between pier height and scour depth. Specifically, bridges with a low height of 4 m are particularly vulnerable to longitudinal collapse under extreme conditions. In contrast, taller bridges, measuring 12 m, are more prone to transverse collapse. Under maximum scour conditions, the reliability indices of the system decreased significantly across all scenarios, from a baseline range of 2.9 to 3.5 without scour to 1.9 to 3.1 with maximum scour depth. The study also shows that tall-pier bridges, unlike short-pier bridges, exhibit less pronounced reductions in the reliability index with increasing scour depth. The results show significant regional differences in vulnerability, with bridges in Oaxaca being the most critically affected. This indicates that macro-level seismic zonations need to be finely detailed to effectively address localized scour hazards. Ultimately, the quantified reliability indices provide a solid basis for adjusting multi-hazard load factors and prioritizing bridge maintenance programs across regions.</p></div>","PeriodicalId":9364,"journal":{"name":"Bulletin of Earthquake Engineering","volume":"24 10","pages":"9297 - 9318"},"PeriodicalIF":4.2,"publicationDate":"2026-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149190034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seismic site categorization and H800 map for Lisbon: the first and second generations of Eurocode 8","authors":"Liliana Oliveira,&nbsp;Rui Carrilho Gomes,&nbsp;Paula Teves-Costa","doi":"10.1007/s10518-026-02552-3","DOIUrl":"10.1007/s10518-026-02552-3","url":null,"abstract":"<div><p>Worldwide, seismic code site categorization schemes have evolved in recent decades, to account for the strong correlation between seismic damage and site-specific conditions. While current schemes evaluate the time-averaged shear wave velocity of the top 30 m (<i>VS30</i>) jointly with qualitative descriptions of the stratigraphic profile, other factors, such as seismic bedrock depth, time-averaged shear wave velocity up to this depth, and the fundamental frequency of the site, also play an important role, especially for deep soft soil deposits. The second generation of Eurocode 8 exemplifies ongoing evolution; however, its practical implementation may be challenging in areas where site investigations do not reach seismic bedrock or vary laterally and have relatively scarce geophysical measurements, as is the case in Lisbon. This paper aims to support the application of the second generation of the Eurocode 8 site categorization scheme in Lisbon, where geology is complex and seismic bedrock is in many places unknown, as most site investigations are less than 15 m deep. Seismic bedrock mapping for Lisbon was based on the <i>H800</i> (depth at which the shear wave velocity, <i>V</i>_<i>S</i>, is greater than 800 m/s), considering (i) ambient vibration measurements combined with nearby boreholes and (ii) lithostratigraphic data combined with regression-based shear wave velocity curves derived from geophysical measurements. Results indicate that seismic bedrock depth is generally less than 30 m, except along the riverfront and in valleys. Applying both Eurocode 8 categorizations shows a heterogeneous site category distribution and significant lateral variability linked to surface geology. While the second-generation scheme is more sensitive to soil deposits with variable stiffness, leading to differences in categorization, a quantitative comparison of the site amplification factors reveals its significant practical impact. The continuous formulation given by the second generation of Eurocode 8 adjusts the seismic action, mitigating overly conservative blanket penalties for stiff and deep deposits, correcting prior underestimations in intermediate soils, and emphasizing the critical need for deep geotechnical characterization.</p></div>","PeriodicalId":9364,"journal":{"name":"Bulletin of Earthquake Engineering","volume":"24 10","pages":"7907 - 7942"},"PeriodicalIF":4.2,"publicationDate":"2026-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10518-026-02552-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shaking table study of seismic performance and retrofit effectiveness for rammed earth structures with precast concrete tie columns","authors":"Yukai Zhang,&nbsp;Xinlei Yang,&nbsp;Quanchang Ren","doi":"10.1007/s10518-026-02553-2","DOIUrl":"10.1007/s10518-026-02553-2","url":null,"abstract":"<div><p>This paper proposes a rammed earth (RE) structure with precast concrete tie columns. The structural system places tie columns at wall corners, together with horizontal tie bars and shear keys at compacted layer interfaces, forming a collaborative system to improve seismic performance. To investigate the seismic behavior of this RE structure, shaking table tests on a 1/2-scale model were conducted. Test results showed progressive damage development under strong seismic actions, with stable stiffness degradation observed throughout the loading process. The structure achieved the fortification objective of “no collapse under major earthquakes”, indicating satisfactory seismic performance of the structural system. Furthermore, this paper proposes a retrofit method using high-strength steel tie rods for earthquake-damaged structures. This approach achieves rapid strengthening by providing effective global confinement to damaged walls. Shaking table tests on the retrofitted structure showed that the retrofit components helped slow the stiffness degradation of the tested earthquake-damaged structure, while also contributing to restraining wall damage development and global deformation. Through two shaking table tests, this study verifies the seismic performance of the proposed RE structural system and the effectiveness of the rapid post-earthquake retrofit method. The findings provide a valuable reference for improving the seismic safety and post-earthquake resilience of traditional RE structures.</p></div>","PeriodicalId":9364,"journal":{"name":"Bulletin of Earthquake Engineering","volume":"24 10","pages":"9039 - 9066"},"PeriodicalIF":4.2,"publicationDate":"2026-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic characterization of masonry minarets using regression models","authors":"Mariam A. Sallam,&nbsp;Marco Fasan,&nbsp;Hany M. Hassan,&nbsp;Chiara Bedon,&nbsp;Giovanni Smiroldo,&nbsp;Hesham E. Abdel Hafiez","doi":"10.1007/s10518-026-02554-1","DOIUrl":"10.1007/s10518-026-02554-1","url":null,"abstract":"<div><p>The natural vibration period of a structure is an essential parameter for earthquake-resistant design, performance assessment, and structural health monitoring. However, it is challenging to quantify for existing structures and ancient construction typologies that are not properly covered by design standards. This paper investigates the natural vibration periods of historical masonry minarets through a database of 111 structures from Egypt, Turkey, Jordan, and Bosnia and Herzegovina, compiled from literature publications and local archives. The database includes minarets with different geometries, architectural styles, conservation states, ages, and dynamic information determined either from ambient vibration tests (AVTs) or finite element analyses (FEM), depending on data availability in the original sources. Empirical models are proposed to estimate the natural vibration period using simple geometric parameters: the total height <span>(H)</span> and a representative external plan dimension <span>(D_{rep})</span>, defined as the main body external diameter when available, or as the reported base dimension otherwise. The equations are developed through log-log regression and explicitly include the residual dispersion in logarithmic space, allowing the uncertainty of the estimates to be quantified. To avoid calibrating the empirical formulations on potentially uncertain numerical results, only AVT-derived records are used for the proposed regression models, while FEM-only records are analyzed separately as a comparison subset. Results show that height is a relevant predictor, while combining <span>(H)</span> with <span>(D_{rep})</span> significantly improves prediction accuracy. The resulting bivariate model, <span>(LL{rm{ - }}BIleft( {H,{D_{rep}}} right))</span>, provides lower dispersion and stronger statistical performance than the height-only formulation. A focused analysis of Cairo’s minarets further indicates that both slenderness and the bivariate formulation are informative within this more homogeneous subset. The proposed model provides a practical tool for preliminary period estimation and large-scale seismic risk screening of masonry minarets.</p></div>","PeriodicalId":9364,"journal":{"name":"Bulletin of Earthquake Engineering","volume":"24 10","pages":"8917 - 8943"},"PeriodicalIF":4.2,"publicationDate":"2026-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10518-026-02554-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of repair/reconstruction costs to existing reinforced concrete and masonry buildings following the 2023 Kahramanmaraş earthquakes","authors":"Hasan Huseyin Aydogdu,&nbsp;Alper Ilki","doi":"10.1007/s10518-026-02556-z","DOIUrl":"10.1007/s10518-026-02556-z","url":null,"abstract":"<div><p>The poor seismic performance of substandard building stock in Türkiye has consistently resulted in excessive seismic-induced losses after earthquakes. The catastrophic outcomes of past earthquakes underscore the urgent need to improve the seismic resilience of existing buildings. Most recently, the 2023 Kahramanmaraş earthquakes—among the most devastating seismic events in the history of Türkiye—once again exposed the structural deficiencies of the building stock. This earthquake sequence caused widespread severe damage across 11 provinces and led to an estimated post-earthquake economic loss exceeding 100 billion Euro. In the aftermath, the Turkish Catastrophe Insurance Pool (TCIP) assessed the damage and repair/reconstruction costs of more than 450,000 individual units and provided compensation totaling 33 billion Turkish Lira (approximately 1.6 billion EUR) for post-earthquake repairs and reconstruction. This study presents a detailed evaluation of the post-earthquake repair/reconstruction costs for reinforced concrete and masonry buildings estimated by TCIP experts, analyzing their relationship with several parameters, including soil conditions, distance to the ruptured fault line, peak ground acceleration demand, spectral acceleration demand, number of stories, and year of construction. Based on this analysis, a new empirical relationship for repair costs considering damage state, total floor area, structural system, and spectral acceleration demand of the building, proportional to the reconstruction cost, is proposed, rather than fixed cost ratios. Furthermore, fragility functions are derived for the probabilistic seismic loss estimation frameworks, allowing for the accounting of uncertainties in cost variability. Overall, this study provides scalable and data-driven tools for rapid and large-scale seismic loss estimation, offering a practical alternative to simplified cost ratio approaches.</p></div>","PeriodicalId":9364,"journal":{"name":"Bulletin of Earthquake Engineering","volume":"24 10","pages":"8645 - 8685"},"PeriodicalIF":4.2,"publicationDate":"2026-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10518-026-02556-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seismic performance of reinforced concrete structural systems under mainshock–aftershock sequences: insights from the 2023 Türkiye–Syria earthquakes","authors":"Valid Aljobrani,&nbsp;Aydin Demir,&nbsp;Omar Abdulaziz Hassan","doi":"10.1007/s10518-026-02557-y","DOIUrl":"10.1007/s10518-026-02557-y","url":null,"abstract":"<div><p>This study investigates the seismic performance of reinforced concrete buildings subjected to realistic mainshock–aftershock earthquake sequences using strong-motion records from the 2023 Türkiye–Syria earthquakes, addressing the limitation of conventional seismic design approaches that primarily consider single-event loading and may not capture cumulative damage effects. Six mid-rise prototype buildings representing moment-resisting frame and dual system were designed in accordance with three generations of Turkish Earthquake Code (TEC-1975, TEC-1998/2007, and TEC-2018). Nonlinear time-history analyses were performed by sequentially applying recorded ground motions while preserving cumulative damage and residual structural states, thus enabling explicit simulation of damage accumulation across successive events. Structural performance was evaluated in terms of global stability, element-level damage, residual displacements, inter-story drifts, the reduction of the system stiffness and standard performance limits. The results show that although code evolution improves overall seismic behavior, modern code compliance does not consistently ensure satisfactory performance under mainshock–aftershock loading. All models maintained global stability; however, several exceeded Collapse prevention (CP) limits, particularly under aftershock-dominant sequences. Residual displacements remained relatively limited under mainshock-dominant loading (generally below approximately 100 mm for MF systems and about 10–12 mm for DS systems), but increased significantly under aftershock-dominant scenarios, reaching approximately 150–260 mm in MF systems and remaining below approximately 30 mm in DS systems. In addition, stiffness degradation exceeded approximately 40–60% in several cases, indicating substantial cumulative structural deformation. Dual systems reduced damage concentration and residual displacements under mainshock-dominant excitation, but their relative advantage diminished when stronger aftershocks followed prior inelastic damage, in some cases resulting in less favorable performance than moment-resisting frames. Significant residual displacements were observed even in TEC-2018-compliant buildings, indicating limitations of current design provisions in controlling post-earthquake functionality. The findings highlight the need for sequence-aware, performance-based seismic design approaches that explicitly account for cumulative damage and residual deformation demands.</p></div>","PeriodicalId":9364,"journal":{"name":"Bulletin of Earthquake Engineering","volume":"24 10","pages":"8605 - 8644"},"PeriodicalIF":4.2,"publicationDate":"2026-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ductility and lateral load performance of substandard RC columns retrofitted with CFRP over plastered Surface","authors":"Ali Gurkan Genc,&nbsp;Medine Ispir,&nbsp;Alper Ilki","doi":"10.1007/s10518-026-02540-7","DOIUrl":"10.1007/s10518-026-02540-7","url":null,"abstract":"<div><p>Seismic strengthening of existing reinforced concrete (RC) columns often involves applying carbon fiber-reinforced polymer (CFRP) jackets, which typically requires the removal of existing plaster layers to ensure direct bonding. While this practice is widely adopted, it increases construction costs, prolongs retrofit duration, generates considerable plaster waste, and may damage already low-strength concrete substrates. Previous experimental research has mainly focused on CFRP jackets applied directly to bare concrete, demonstrating their effectiveness in improving load-carrying capacity and ductility. However, the combined effects of plaster thickness, plaster strength, and CFRP jacket configuration on the seismic performance of square-section columns with retained plaster layers remain insufficiently explored. This study experimentally investigates the seismic performance of eight full-scale substandard RC columns (300 × 300 × 1350 mm) constructed with low-strength concrete (~10 MPa) and widely spaced transverse reinforcement, tested under reversed cyclic lateral loading while maintaining constant high axial load ratio of 60%. The experimental variables include three plaster thicknesses (12.5, 25, and 37.5 mm), two plaster compressive strengths (~3.5 and ~8.5 MPa), and single- or double-layer CFRP jackets. Test results demonstrate that retaining the plaster layer does not prevent significant ductility enhancement; in several cases, plastered CFRP-jacketed specimens achieved drift capacities comparable to or exceeding those of unplastered counterparts. These findings provide new experimental insights into the feasibility and effectiveness of CFRP jacketing over plastered concrete surfaces, highlighting a practical retrofitting approach that minimizes construction time, and environmental impact while maintaining structural performance.</p></div>","PeriodicalId":9364,"journal":{"name":"Bulletin of Earthquake Engineering","volume":"24 10","pages":"8489 - 8520"},"PeriodicalIF":4.2,"publicationDate":"2026-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10518-026-02540-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seismic resilience assessment of high-rise RC frame office buildings considering mechanical performance of infill walls","authors":"Han Zhao,&nbsp;Shihao Guo,&nbsp;Juan Liu,&nbsp;Jian Zuo,&nbsp;Zuozhou Zhao","doi":"10.1007/s10518-026-02532-7","DOIUrl":"10.1007/s10518-026-02532-7","url":null,"abstract":"<div><p>Current research on seismic resilience of buildings often overlooks the mechanical performance of non-structural components, particularly the contribution of infill walls. This study conducts a seismic resilience assessment of a high-rise reinforced concrete frame office building designed for a 7-degree (0.1 g) seismic fortification level, following the Standard for Seismic Resilience Assessment of Buildings (GB/T 38591—2020). By introducing and refining an equivalent diagonal strut constitutive model for autoclaved aerated concrete infill walls, the study quantitatively evaluates the impact of infill wall mechanics on the seismic resilience of high-rise frame structures. The findings reveal that considering the mechanical contributions of infill walls can substantially mitigate the inter-story drift angles within the structural system, thereby significantly enhancing the seismic resilience of the building. This approach can markedly reduce the repair costs and downtime associated with structural components and displacement-sensitive non-structural elements. However, it may also lead to an increase in the repair expenses for acceleration-sensitive non-structural components. These results highlight the importance of accounting for the mechanical contribution of infill walls in resilience evaluations of high-rise frame structures, offering valuable insights for enhancing seismic resilience design.</p></div>","PeriodicalId":9364,"journal":{"name":"Bulletin of Earthquake Engineering","volume":"24 10","pages":"8463 - 8487"},"PeriodicalIF":4.2,"publicationDate":"2026-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new proposal for the estimation of the equivalent viscous damping ratio of RC framed structures","authors":"Andrea Floridia,&nbsp;Melina Bosco,&nbsp;Dario Panarelli,&nbsp;Pier Paolo Rossi","doi":"10.1007/s10518-026-02491-z","DOIUrl":"10.1007/s10518-026-02491-z","url":null,"abstract":"<div><p>The prediction of the maximum response of an inelastic structure by means of a linear single degree of freedom system with proper lateral stiffness and viscous damping ratio is at the basis of displacement-based design procedures or assessment procedures based on non-linear-static analyses. Several closed-form expressions of the viscous damping ratio were proposed in the past, all depending on the ductility demand of the considered hysteretic systems. The use of these expressions in the case of existing buildings is not straightforward since the evaluation of the global ductility demand is required. Thus, a proper idealization criterion of the capacity curve has to be selected. Finally, the choice of the most appropriate expression of the equivalent viscous damping ratio for the structural type under examination introduces an additional element of discretion. This paper proposes a ductility-independent expression of the equivalent viscous damping ratio suitable for existing reinforced concrete framed structures. The proposed expression depends on the ratio between the elastic and the secant period of vibration of the structure and the chord rotation demand of beams and columns. These response parameters can be easily determined by non-linear static analysis without need of idealization of the capacity curve. A procedure for the application of the proposed expression to multi-storey framed RC buildings is also illustrated and applied to six case studies. The effectiveness of the proposed expression is assessed through non-linear dynamic analysis.</p></div>","PeriodicalId":9364,"journal":{"name":"Bulletin of Earthquake Engineering","volume":"24 10","pages":"8335 - 8361"},"PeriodicalIF":4.2,"publicationDate":"2026-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10518-026-02491-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}