Structures最新文献

{"title":"Experimental and numerical assessment of optimized hybrid strengthening techniques for unreinforced masonry columns under axial compression","authors":"Galal Elsamak ,&nbsp;Mohamed Ghalla ,&nbsp;Mohamed H. El-Naqeeb ,&nbsp;Ehab A. Mlybari ,&nbsp;Rabeea W. Bazuhair ,&nbsp;Mohamed Emara","doi":"10.1016/j.istruc.2025.110222","DOIUrl":"10.1016/j.istruc.2025.110222","url":null,"abstract":"<div><div>This study presents a comprehensive experimental and numerical investigation into the axial performance of unreinforced masonry (URM) columns strengthened with various hybrid retrofitting techniques. Thirteen full-scale brick masonry columns were tested under monotonic axial compression to evaluate the effects of strain-hardening cementitious composites (SHCC) jacketing, near-surface mounted (NSM) steel bars, and embedded steel/glass fiber reinforced polymer (GFRP) mesh. The experimental program examined load–displacement behavior, failure modes, ultimate capacity, ductility, and energy absorption. Results demonstrated that hybrid strengthening combining NSM bars and mesh-reinforced SHCC jacketing achieved up to 70 % increase in load capacity and double the energy absorption compared to the unstrengthened reference. A validated finite element model, developed in ABAQUS using cohesive damage and embedded interaction approaches, accurately replicated the experimental response, with an average experimental-to-numerical load ratio of 0.95 and displacement ratio of 0.90. Parametric studies showed that increasing longitudinal reinforcement ratio in hybrid systems enhanced axial capacity by up to 39 %, while increasing transverse mesh ratio improved strength by 25 % before plateauing. These findings highlight the synergistic role of axial and transverse reinforcement in improving strength and ductility and offer a reliable modeling framework for optimizing retrofit designs of URM columns in seismic and structural upgrade applications.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"81 ","pages":"Article 110222"},"PeriodicalIF":4.3,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145097410","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":"Study on temperature field distribution characteristics and fire resistance performance of pin-connected cable clamps in suspension bridges under fire conditions","authors":"Zhiheng Ma,&nbsp;Yongqi Chen,&nbsp;Xiuli Xu,&nbsp;Zhijun Li,&nbsp;Maofeng Chen,&nbsp;Xuehong Li","doi":"10.1016/j.istruc.2025.110196","DOIUrl":"10.1016/j.istruc.2025.110196","url":null,"abstract":"<div><div>This study focuses on pin-connected cable clamps and develops a numerical model of a tanker truck fire using the Fire Dynamics Simulator (FDS) to analyze the ambient temperature distribution around the cable clamp. A refined finite element model of the clamp is established, and a sequential thermal-mechanical coupling method is employed to systematically investigate the temperature field distribution, structural strength failure modes, and anti-slip performance evolution of the clamp under high-temperature fire conditions. The results indicate that under the combined effects of cable force and temperature, failure initially occurs at the pin hole of the lower clamp ear plate. When the clamp is installed at a height exceeding 16 m, no strength failure occurs within 60 min. For clamps at a height of 12 m, slip failure occurs under all horizontal thrust conditions due to the influence of high temperature and variable friction coefficients, with the fire resistance limit decreasing significantly as the horizontal thrust increases. Based on the analysis, calculation formulas for the anti-slip frictional resistance of the clamp under high-temperature conditions and corresponding fire protection measures are proposed.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"81 ","pages":"Article 110196"},"PeriodicalIF":4.3,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145097390","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 fragility assessment of base-isolated structures subjected to uneven settlement of foundation based on a synergistic multi-indicator damage model","authors":"Jiaoyan Du ,&nbsp;Chao Bao ,&nbsp;Weiping Xian ,&nbsp;Qi Fan ,&nbsp;Xiaotong Ma ,&nbsp;Kar Sing Lim","doi":"10.1016/j.istruc.2025.110213","DOIUrl":"10.1016/j.istruc.2025.110213","url":null,"abstract":"<div><div>The implementation of base isolation technology in high-intensity seismic areas underlain by collapsible loess is hindered by a critical challenge: the subsoil in these regions is susceptible to uneven settlement of foundations (USF), which can induce structural deformation, damage, and functional failure. To address this issue, a comprehensive numerical evaluation framework is proposed. The USF is introduced into a finite element model to examine the seismic response of a representative base-isolated structure. Based on these simulations, a synergistic multi-indicator damage model is developed by coupling inter-story drift ratio demand with cumulative energy dissipation. This model is subsequently employed to generate seismic fragility curves under combined earthquake-USF scenarios. The analysis indicate that USF markedly accelerates damage accumulation in both the isolation layer and the superstructure. The proposed model reliably captures the initial tilt induced by settlement and exposes incipient damage patterns at an early stage. Moreover, even settlements within code-prescribed tolerances are found to precipitate earlier damage onset and to some extent reduce the seismic performance of the system.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"81 ","pages":"Article 110213"},"PeriodicalIF":4.3,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145097128","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":"Bolted steel plates for rigidly connecting decks to beams in precast concrete flooring systems","authors":"Abtin Baghdadi,&nbsp;Lukas Ledderose,&nbsp;Harald Kloft","doi":"10.1016/j.istruc.2025.110004","DOIUrl":"10.1016/j.istruc.2025.110004","url":null,"abstract":"<div><div>Given the pivotal role of connections in the advancement of the precast building industry, issues such as low adaptability, construction difficulties, chain collapse, and low robustness are critical considerations, demanding the design and study of new types of connections that meet the standards and can be practically used in the industry. The current study proposes and examines, experimentally and numerically, a connection method for rigidly combining two precast decks positioned on top of a beam. Two steel plates are positioned at the top middle of the two precast floors and the underside of the beam, with highly post-tensioned bolts, ensuring a rigid connection between all elements. This research includes 12 parametric experimental and corresponding numerical studies to analyze the performance of the connections under shear and bending, with parameters including floor height, bolt dimensions, and beam width. The initial calculation approach for the connection is described and compared to empirical findings. Various failure modes, including bending, shear, and rupture of the post-tensioning bolts, may occur depending on the selected geometric parameters. The proposed connections demonstrate a high capacity for carrying up to <span><math><mn>84</mn><mspace></mspace><mi>%</mi></math></span> of the load borne by monolithic elements.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"81 ","pages":"Article 110004"},"PeriodicalIF":4.3,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145097408","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":"Axial compressive behavior of multi-cavity square concrete-filled steel tube stub columns","authors":"Miao Li ,&nbsp;Wenkun Wang ,&nbsp;Yang Wen ,&nbsp;Boshuai Feng ,&nbsp;Chengjun Peng","doi":"10.1016/j.istruc.2025.110223","DOIUrl":"10.1016/j.istruc.2025.110223","url":null,"abstract":"<div><div>This study performed axial compression tests and used finite element method (FEM) to examine the effects of cavity number and wall thickness ratio of outer steel plates to inner cavity plates <em>β</em> on the compressive behavior of multi-cavity concrete-filled steel tube (CFST) stub columns. Experimental results demonstrate distinct failure mechanisms: single-cavity specimens exhibited catastrophic weld fractures triggered by continuous global buckling, while quadruple- and nonuple-cavity specimens developed localized half-wave buckling deformations owing to partition plate restraint. This mechanism significantly enhanced deformation uniformity and structural ductility, where specimens with <em>β</em>= 1.5 achieved the optimal ductility performance. Bearing capacity analysis quantified a 6.0 % higher ultimate load for quadruple-cavity specimens compared to single-cavity ones, whereas nonuple-cavity specimens demonstrated only a marginal 0.4 % improvement over quadruple-cavity ones. Bearing capacity of specimens with <em>β</em>= 1.5 exceeded those of specimens β= 1.0 and β= 2.5 by 28.0 % and 5.3 %, respectively. Evaluation of international design codes against experimental and FEM results proved the highest predictive accuracy of CECS 28:2012. Optimized design parameters include: <em>β</em>= 1.5, limiting number of cavities≤ 9, and core concrete strength restricted below C40 grade, based on rigorous validation of confinement effectiveness and material performance thresholds.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"81 ","pages":"Article 110223"},"PeriodicalIF":4.3,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145097162","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":"Gusset plate friction damper with double plate core buckling-restrained brace","authors":"Makoto Sakai ,&nbsp;Hiroshi Tagawa ,&nbsp;Xingchen Chen ,&nbsp;Makoto Uehara ,&nbsp;Makoto Nishimura","doi":"10.1016/j.istruc.2025.110243","DOIUrl":"10.1016/j.istruc.2025.110243","url":null,"abstract":"<div><div>Buckling-restrained braces (BRBs) are widely applied in building structures to control vibrations during major earthquakes. However, conventional BRBs do not yield or dissipate energy at low vibration amplitudes. To address this concern, this study proposes gusset plate friction dampers (GPFDs) with a double-plate core buckling-restrained brace (BRB). To delay the BRB action, gusset plates with multiple slot holes were used. Under a small vibration, a friction force is generated at the brace-end connection portions, whereas under a large vibration, the bolts contact the gusset plates, and the core plates of the BRB yield with a delay. Therefore, a BRB with GPFDs can provide a double-stage energy-dissipation mechanism for various earthquake intensities. Cyclic loading tests were performed for the test specimens of the BRB with GPFDs, and the results revealed a superior hysteretic performance, exhibiting double-stage energy dissipation. Furthermore, loading tests and finite element analyses were performed for connections with misaligned slot holes in the gusset plate to investigate the manufacturing accuracy requirements of slot holes for a safer design.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"81 ","pages":"Article 110243"},"PeriodicalIF":4.3,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145097320","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":"Study on progressive collapse resistance of corroded RC continuous deep flexural members strengthened with BFRP sheets","authors":"Chao Bao ,&nbsp;Huan Long ,&nbsp;Luyuan Peng ,&nbsp;Huxiang Wang ,&nbsp;Xiaotong Ma ,&nbsp;Kar Sing Lim","doi":"10.1016/j.istruc.2025.110216","DOIUrl":"10.1016/j.istruc.2025.110216","url":null,"abstract":"<div><div>Durability degradation is a primary cause of failure in reinforced concrete (RC) structures. To mitigate this issue, externally bonded fiber-reinforced polymers (FRPs) have gained widespread attention due to their substantial impact on enhancing structural performance. This study investigates the effect of externally bonded FRP sheet on the anti-collapse performance of RC continuous deep flexural members under chloride ion erosion. Specifically, the study uses basalt fiber-reinforced polymer (BFRP) sheet, known for its excellent resistance to chloride ions, to reinforce corroded RC continuous deep flexural members. Quasi-static tests were conducted on four RC substructure specimens with a scale ratio of 1/3. The load-displacement curves, failure modes, and key beam deflection curves of both uncorroded specimens and corroded specimens—both without reinforcement and with different BFRP reinforcement methods—were compared. Additionally, the collapse performance of the structures was analyzed based on ductility and energy equivalence principles. The results show that corrosion and reinforcement did not alter the specimens' resistance mechanisms, which all exhibited beam, compressive arch, and catenary mechanisms. The use of BFRP reinforcement can significantly enhance the catenary action, but the effect of improving the compression arch action is very limited. At a 10 % corrosion rate, the ductility, energy dissipation, and safety reserve capacity of the specimens decreased by 14.0 %, 26.7 %, and 15.0 %, respectively. BFRP sheet reinforcement effectively restrains concrete expansion and enhances the shear capacity of the structure. The reinforcement schemes for specimens C-10-R1 and C-10-R2 increased the ductility, energy dissipation, and safety reserve capacity by 2.40 %, 1.19 %, and 13.43 %, and 29.20 %, 46.89 %, and 16.97 %, respectively. Compared with specimen C-10-R1, the reinforcement effect of specimen C-10-R2 was more pronounced. BFRP sheet plays a crucial role in improving the anti-collapse performance of corroded RC continuous deep flexural members and provides a valuable reference for the collapse resistance reinforcement of corroded RC deep flexural members.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"81 ","pages":"Article 110216"},"PeriodicalIF":4.3,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145097158","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":"Decisive effect of SSPT on post-fire mechanical properties of structural steel","authors":"Yue Yin ,&nbsp;Yunqi Zhang ,&nbsp;Yimei Gu ,&nbsp;Hongbo Liu ,&nbsp;Wenjia Qin","doi":"10.1016/j.istruc.2025.110185","DOIUrl":"10.1016/j.istruc.2025.110185","url":null,"abstract":"<div><div>The heating and cooling processes during a fire essentially constitute a simple heat treatment for structural steels, in which solid-state phase transformation (SSPT) often plays a decisive role in developing their mechanical properties. However, the post-fire mechanical properties of structural steels have rarely been studied following the general principles of heat treatment. The mechanical properties of Q355D steel after simulated fire exposure were investigated in this study. The steel was heated to target temperatures of 600°C, 700°C, 800°C, and 900°C in a furnace. Two cooling methods, cooled in air and cooled in water, were adopted respectively to investigate the influence of the cooling rate. Metallographic examination showed that the SSPT occurring in Q355D steel during the simulated fire exposure follows the general principles of heat treatment. Tension coupon tests were carried out for post-fire Q355D steels. It was found that the SSPT during the simulated fire exposure has a decisive effect on post-fire mechanical properties of Q355D steel. Post-fire Q355D steels significantly hardened only when the target temperature reached Ac1 and the steels were cooled rapidly in water. To verify the generality of these findings, results of fire tests on various steels in the literature were collected and analyzed. Variations in yield strength and tensile strength of all these steels after simulated fire exposure can be well explained by general principles of heat treatment of hypoeutectoid steels. When no SSPT occurs during simulated fire exposure, the post-fire tensile strength of these steels varies within 15 %. For mild and cast steels, the SSPT induces significant hardening of the post-fire steels, typically increasing the post-fire tensile strength by over 20 %. For high-strength and ultra-high-strength steels, the SSPT may lead to varying degrees of post-fire hardening or softening, depending on the peak temperature, cooling rate, and the fractions of different phases in both the original and post-fire steels. The decisive effect of SSPT caused by the heating and cooling processes during simulated fire exposure on post-fire mechanical properties of structural steels was confirmed.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"81 ","pages":"Article 110185"},"PeriodicalIF":4.3,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145097161","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":"Performance optimization of inter-storey isolation systems with negative stiffness devices for super high-rise buildings","authors":"Sitong Fang","doi":"10.1016/j.istruc.2025.110177","DOIUrl":"10.1016/j.istruc.2025.110177","url":null,"abstract":"<div><div>To enhance the seismic isolation performance of inter-storey isolation systems in super high-rise buildings, this study proposes an improved inter-storey isolation system integrated with negative stiffness devices (IIS-NSD). The system parameters are optimized using fixed-point theory combined with H₂ optimal control methods. A two-degree-of-freedom dynamic model is established, introducing correction factors to improve optimization accuracy. Nonlinear time-history analyses under near-fault and far-field ground motions are conducted to systematically evaluate the response control capabilities of the IIS-NSD system under various conditions. Results indicate that the IIS-NSD system significantly improves isolation performance under strong nonlinear seismic scenarios. The optimized IIS-NSD system substantially reduces structural acceleration and inter-storey displacement, with maximum displacement reductions exceeding 40 % and peak acceleration decreases averaging over 30 %. Meanwhile, the system effectively suppresses excessive structural deformation during nonlinear phases and enhances overall energy dissipation capacity. Notably, under strong near-fault earthquakes, the system demonstrates more stable control effects and exhibits good robustness against uncertainties in seismic input.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"81 ","pages":"Article 110177"},"PeriodicalIF":4.3,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145097157","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 performance assessment of steel braced frames with segmentally controlled steel braces","authors":"Qianqian Cheng ,&nbsp;Yan Guo ,&nbsp;Yuguang Yin ,&nbsp;Ming Lian","doi":"10.1016/j.istruc.2025.110212","DOIUrl":"10.1016/j.istruc.2025.110212","url":null,"abstract":"<div><div>A novel segmentally controlled steel brace (SCSB) featuring a simplified configuration analogous to conventional steel braces was proposed to enhance energy dissipation capacity primarily through repeated axial yielding in both tension and compression. The SCSB can be directly incorporated into traditional concentrically braced frames (CBFs), thereby forming a steel braced frame with segmentally controlled steel braces (SBF-SCSB). Seismic energy is predominantly dissipated via inelastic deformation of the link segments located at both ends of the SCSB. The detailing and design of the SCSB were presented, and a simplified finite element model was developed and validated against experimental results. Furthermore, three global structural models representing a steel moment frame (SMF), a CBF, and a proposed SBF-SCSB were established using OpenSEES. Time history analyses under various seismic intensities and incremental dynamic analyses were performed to comprehensively investigate the seismic response and fragility. Results indicate that the SBF-SCSB demonstrates significantly improved seismic performance compared to both the SMF and CBF. Under service level earthquakes, both conventional braces and SCSBs effectively increase lateral stiffness and reduce inter-story drift ratios. When subjected to severe earthquakes, the SCSBs develop stable and full hysteretic loops, enabling efficient energy dissipation and reducing base shear demands, thereby mitigating damage to primary structural members. Moreover, the residual inter-story drift ratios of the SBF-SCSB are substantially lower relative to those of the SMF and CBF. Additionally, the average peak ground accelerations corresponding to various performance limit states are consistently higher for the SBF-SCSB than for the SMF and CBF, highlighting its superior capacity for seismic damage control. Overall, the SBF-SCSB serves as an optimized and practical alternative to traditional steel braced frames.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"81 ","pages":"Article 110212"},"PeriodicalIF":4.3,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145097159","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}