Structures最新文献

{"title":"Study on size effects and failure precursor characteristics of concrete crack propagation behavior based on digital image correlation and acoustic emission technology","authors":"Xinxin Zhao ,&nbsp;Siwei Wang ,&nbsp;Shuyi Li ,&nbsp;Chao Xu","doi":"10.1016/j.istruc.2026.111357","DOIUrl":"10.1016/j.istruc.2026.111357","url":null,"abstract":"<div><div>This study investigated the effect of size on the deformation, damage, and failure modes of concrete through uniaxial compression tests combined with strain gauges, digital image correlation (DIC), and acoustic emission (AE) technologies. The results revealed that, under uniaxial compression, specimens of different sizes exhibit nonuniform deformation. The axial deformation of the 300- and 550-mm specimens was mainly concentrated at the top, whereas that of the 450-mm specimen was concentrated in the middle. Lateral deformation analysis was conducted to identify crack propagation zones. The critical stress threshold at the damage stage decreased as the specimen size increased and stabilized when L/D ≥ 2.0. Abrupt changes in the AE parameters characterize the crack damage stress threshold and can serve as a precursor indicator for specimen failure. The <em>Rise time/maximum amplitude (RA)–average frequency (AF)</em> distribution and <em>b</em>-value analysis revealed that small specimens tended to fail through tensile cracking, whereas large specimens exhibited shear failure. The combined use of DIC and AE enabled the capturing of the entire failure process of concrete, from microcrack initiation to macroscopic fracture. Small specimens exhibited high AE activity and substantial fragmentation, whereas large specimens exhibited a trend toward localized failure. The shear crack propagation height for the 550-mm specimen was 330 mm, consistent with the results obtained from layered strain measurements. As the specimen size increased, both the localized deformation initiation stress (<em>σ</em>_A) and peak stress (<em>σ</em>_f) decreased, and the <em>σ</em>_A/<em>σ</em>_f ratio also decreased, <em>σ</em>_A can serve as a precursor indicator for structural failure. The findings of this study provide theoretical support for concrete damage evaluation and early fracture warning.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111357"},"PeriodicalIF":4.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192125","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 fragility-based quantification of the efficiency of tuned mass damped technique with soil structure interaction effects","authors":"Davide Forcellini","doi":"10.1016/j.istruc.2026.111327","DOIUrl":"10.1016/j.istruc.2026.111327","url":null,"abstract":"<div><div>The benefits of applying Tuned Mass Damping (TMD) may be significantly reduced by soil structure interaction (SSI) effects. The paper proposes a parameter to quantify the efficiency of such technique when SSI effects are considered. Efficiency is based on the development of analytical fragility curves. A case study of a 20-floor structures subjected to 4 soil conditions was herein considered by modeling the SSI effects with Opensees. Unlike previous studies based on simplified soil representations, this work employs advanced nonlinear SSI simulations in OpenSees to capture amplitude-dependent soil behavior, plastic deformation accumulation, and permanent foundation movements. The proposed efficiency parameter provides a practical quantitative tool for assessing TMD applicability on deformable soils and has direct potential for integration into performance-based design frameworks and seismic design codes. The findings demonstrate that TMD efficiency depends on soil deformability as shown by performing 10 input motions selected to represent far and near field cases. In particular, the parameter efficiency was calculated as the ratio between the mean values of the fragility curves respectively calculated for the TMD and the original configuration. The ultimate scope of the paper is to implement the proposed formulation inside international codes to be used by practitioners and engineers to design TMD by quantifying the reduction of the efficiency due to the non-linear effects of SSI.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111327"},"PeriodicalIF":4.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192123","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":"Eccentric compression performance of a novel preplaced aggregate concrete-filled steel tube","authors":"Hongyuan Tang ,&nbsp;Yue Huang ,&nbsp;Jinjun Liu ,&nbsp;Jingxiang Huang ,&nbsp;Yang Wei","doi":"10.1016/j.istruc.2026.111290","DOIUrl":"10.1016/j.istruc.2026.111290","url":null,"abstract":"<div><div>This study presents a novel composite structure, Preplaced Aggregate Concrete-Filled Steel Tube (PACFST), designed to address the void defects between the core concrete and external steel tube in traditional Concrete-Filled Steel Tubes (CFST). Considering that structural components in practical engineering are typically not in pure axial compression, an orthogonal design approach was adopted. The experimental parameters, including the strength of preplaced aggregate concrete, the wall thickness of the external steel tube, the ratio of the inner to external tube diameters, and their eccentricity, were selected. Nine circular PACFST short columns were subjected to eccentric compression tests to explore their failure process, failure modes, and working mechanisms. Finally, based on the superposition principle and reduction factor method, a predictive formula for the eccentric compression bearing capacity of circular PACFST short columns was developed. The results show that under eccentric loading, the failure mode primarily involves bending near the center height of the specimen, along with localized bulging at the middle and ends. The load-displacement curve under eccentric loading can be roughly divided into three stages: elastic, elastoplastic, and plastic. The steel tube's confining effect on PAC is observed to occur earlier than in axially loaded specimens. Increasing eccentricity, external steel tube wall thickness, and the inner-to-external diameter ratio can mitigate the post-peak decline to some extent. The predicted values obtained from the proposed formula are in good agreement with the experimental results. The average ratio of <em>N</em>_u/<em>N</em>_cal is 0.97 and a standard deviation of 0.089. The average ratio of <em>N</em>_ue/<em>N</em>_ue,cal is 1.018, with a standard deviation of 0.007.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111290"},"PeriodicalIF":4.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192120","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 response of foam-filled multi-tube beams subjected to transverse low-velocity impact: Theoretical and numerical studies","authors":"Junhua Shao ,&nbsp;Bingxue Dai ,&nbsp;Wei Zhang ,&nbsp;Chunping Xiang","doi":"10.1016/j.istruc.2026.111269","DOIUrl":"10.1016/j.istruc.2026.111269","url":null,"abstract":"<div><div>The large-deflection behavior of foam-filled multi-tube beams subjected to transverse low-velocity impact is investigated using theoretical analysis and numerical simulations. A yield criterion for large-deflection plastic deformation is proposed, and analytical models based on upper-bound, lower-bound, and membrane theories are developed to predict the impact response while accounting for the coupling between bending and axial forces. The theoretical predictions are validated through finite element simulations, with numerical results consistently lying within the theoretical bounds. The numerical results demonstrate that, under the same impact conditions, the foam-filled multi-tube configuration exhibits superior deformation resistance and enhanced energy absorption capacity compared with foam-filled single-tube and hollow tube beams. Parametric studies based on the theoretical model further indicate that, under conditions of constant mass per unit length, increasing the yield strength ratio of the foam and the tube or reducing the thickness of the inner and the outer tubes effectively reduces plastic deformation and improves load-bearing and energy absorption capacity, whereas an excessive aspect ratio of beam or a low inner-to-outer tube thickness ratio degrades impact resistance. These findings provide valuable theoretical insights and practical guidance for the design and optimization of foam-filled multi-tube configurations for energy absorption and impact protection applications.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111269"},"PeriodicalIF":4.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192117","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":"Reliability-based minimum earthquake load factors for evaluation of existing buildings","authors":"Reza Fathi-Fazl,&nbsp;Zoubir Lounis,&nbsp;Zhen Cai,&nbsp;Farrokh Fazileh","doi":"10.1016/j.istruc.2026.111362","DOIUrl":"10.1016/j.istruc.2026.111362","url":null,"abstract":"<div><div>This paper presents a practical and reliability-based method for determining the minimum earthquake load factors to be used with the force-based approach for the evaluation of the safety of existing buildings. This method derives the target reliability indices based on three key contributory factors affecting the seismic risk to life safety, namely: (i) consequence class; (ii) redundancy degree; and (iii) inspection quality. These derived reliability indices range from 1.30 to 2.55 and correspond to earthquake load factor values, ranging from 0.35 to 1.0, respectively. Furthermore, the method considers the impact of building practice quality, a crucial element in evaluating the seismic risk of existing buildings. The main objective of the proposed method is to improve consistency in seismic risk assessment and management of existing buildings. Building owners may choose to adopt higher reliability indices and earthquake load factors for their evaluations. To demonstrate this method, a numerical example is provided, illustrating the determination of the earthquake load factor for assessing an existing office building in Ottawa, Ontario, Canada.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111362"},"PeriodicalIF":4.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192041","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":"Incorporating the effects of liquid displacement exceedance and associated air entrainment in passive tuned liquid column damper design","authors":"Hao Ding ,&nbsp;Jian Zhang ,&nbsp;Jin-Ting Wang","doi":"10.1016/j.istruc.2026.111310","DOIUrl":"10.1016/j.istruc.2026.111310","url":null,"abstract":"<div><div>Traditionally, the optimization of tuned liquid column dampers (TLCDs) has favored larger length ratios (the ratio of the horizontal liquid column length to the total liquid column length), assuming they always yield better performance. However, this conventional approach often overlooks the vulnerability of TLCDs with large length ratios to strong vibrations, which can lead to air being drawn into the horizontal pipe and reducing damping efficiency. To address this, a novel two-phase design framework that treats the excitation intensity as a critical design parameter is proposed. This framework optimizes three key parameters: length ratio, area blocking ratio of the orifice (related to flow resistance), and frequency tuning ratio (the liquid-to-structure frequency ratio), while explicitly considering the negative impact of air entering the horizontal pipe on TLCD performance. The process begins with the use of closed-form solutions and numerical search methods, based on the classical TLCD model, to determine the optimized frequency tuning ratio in the frequency domain. Subsequently, a newly developed generalized TLCD model, which accounts for the effects of air entering the horizontal pipe, is employed to perform time-domain analyses across a wide range of excitation amplitudes and parameter combinations. The results identify the optimized length and blocking ratios that balance efficiency and robustness, revealing specific conditions under which conventional designs underperform. These findings provide a more realistic design philosophy for TLCDs, ensuring reliable vibration control performance under design excitation amplitudes, especially during high-intensity events.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111310"},"PeriodicalIF":4.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192196","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 novel balloon-framed rocking CLT shear wall system: Kinetics and proof of concept","authors":"Chenhui Qian ,&nbsp;Orhan Sahutoglu ,&nbsp;Fei Tong ,&nbsp;Leo Panian ,&nbsp;Thomas Tannert","doi":"10.1016/j.istruc.2026.111291","DOIUrl":"10.1016/j.istruc.2026.111291","url":null,"abstract":"<div><div>As seismic force-resisting systems (SFRS), the balloon-framed cross-laminated timber (CLT) configuration offers several advantages, but current code provisions and design guidelines in North America are limited to platform-framed construction. Due to their inherent limitations, platform-framed systems are challenging to implement for taller buildings in seismically active regions, thereby posing barriers to the broader applications of CLT. To address this challenge, an innovative balloon-framed CLT shear wall system is proposed in this paper. This system leverages rocking and pivoting actions to minimize damage to CLT shear wall panels and incorporates distributed hysteretic dampers to achieve the desired kinematics and energy dissipation. The basic concept, configuration, and kinetics of the system are introduced as proof of concept. An analytical model of a two-story assembly is developed, establishing the relationships between global structural behavior and the geometric and mechanical properties of the kinematic components and supplemental damping devices. To verify the analytically derived behavior, nonlinear numerical models are developed for two-, six-, and twelve-story archetype buildings. Monotonic pushover analyses are conducted to investigate system behavior, focusing on characteristic response states and their transitions. Based on the presented analyses, mechanical behaviors are discussed for key components in the proposed system, paving the way for further investigations through dynamic numerical analyses and large-scale experimental tests.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111291"},"PeriodicalIF":4.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192352","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":"Experimental investigation on retrofit effectiveness of CFRP strips for a transverse circular opening in an RC beam under cyclic loading","authors":"Chien-Kuo Chiu ,&nbsp;Hsin-Fang Sung ,&nbsp;I.-Ting Shen","doi":"10.1016/j.istruc.2026.111315","DOIUrl":"10.1016/j.istruc.2026.111315","url":null,"abstract":"<div><div>A web opening of a reinforced concrete (RC) beam can take various forms, including circular, rectangular, and square, based on architectural and service-routing requirements. While web openings may vary in shape, the present study is limited to circular openings, which are widely used. Previous studies have proposed internal retrofit methods for transverse circular openings in RC beams, applicable to both plastic and non-plastic hinge regions. In addition to internal solutions, external retrofit techniques—such as the application of carbon fiber-reinforced polymer (CFRP) strips—have demonstrated potential for delaying shear failure around openings and enhancing beam ductility. Owing to their lightweight, high tensile strength, corrosion resistance, and ease of installation, CFRP strips are widely employed in civil engineering practice. However, the effectiveness of CFRP strips in retrofitting RC beams with transverse circular openings has yet to be thoroughly investigated. This work aims to improve the ductility and energy dissipation capacity of RC beams with transverse circular openings through the use of externally bonded CFRP strips. To this end, four cantilever RC beam specimens with circular openings are tested under cyclic loading. The key parameters investigated include the tensile strength of the CFRP strips and the configuration of steel anchor plates around the openings. The experimental results are analyzed to evaluate the retrofit performance of the CFRP strips. Based on these findings and comparisons with prior research, this work proposes design recommendations for retrofitting regions near transverse circular openings using CFRP strips. Furthermore, equations for estimating the shear strength of CFRP-retrofitted regions are presented to support the retrofit design process.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111315"},"PeriodicalIF":4.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192348","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 novel encased dovetail profiled steel-concrete composite T-beam: Flexural performance","authors":"Junlong Zhou ,&nbsp;Zhihua Wang ,&nbsp;Shuangshuang Jin","doi":"10.1016/j.istruc.2026.111323","DOIUrl":"10.1016/j.istruc.2026.111323","url":null,"abstract":"<div><div>To overcome local buckling and interfacial slip in conventional composite beams, this study proposes a novel encased dovetail profiled steel-concrete composite (EDPSC) T-beam. Its interfacial bond and flexural performance were investigated through push-out tests, four-point bending tests, finite element modeling, and theoretical analysis. Push-out tests demonstrated that the closed ribs provide effective shear connection via transverse doweling action and longitudinal mechanical interlock. Four-point bending tests confirmed high ductility, with a displacement ductility coefficient <em>μ</em> of 4.2 and a plastic development coefficient <em>γ</em>_p of 1.55, surpassing conventional RC members. External welding a 3.0 mm thick U-shaped steel sheeting increased the flexural capacity by 93 % while maintaining ductility (<em>μ</em> of 5.2 and <em>γ</em>_p of 1.51). Parametric analysis revealed that increasing the web width, beam depth, or bottom reinforcement ratio enhances flexural stiffness and capacity, whereas high-strength concrete (e.g., C50) is not fully utilized. Increasing steel sheeting thickness significantly boosts capacity by improving compressive concrete utilization. The flexural capacity decreases with an increasing shear span-to-depth ratio, and a span-to-depth ratio of at least 1/14 is recommended to ensure material utilization and serviceability. Simplified theoretical models are proposed to predict flexural stiffness and capacity, providing a design basis for small and medium-span bridges.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111323"},"PeriodicalIF":4.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192347","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":"Non-uniform thickness design for steel bridge deck and steel bridge deck pavement: Feasibility and stress analysis","authors":"Yitong Min ,&nbsp;Yongchao Xue ,&nbsp;Zijian Xu ,&nbsp;Zhendong Qian","doi":"10.1016/j.istruc.2026.111268","DOIUrl":"10.1016/j.istruc.2026.111268","url":null,"abstract":"<div><div>To address recurring distresses in steel bridge deck pavement (SBDP), this study proposes a non‑uniform thickness design that locally thickens the steel bridge deck (SBD) while thinning the SBDP at critical regions to mitigate stress concentrations. Three representative SBDP combinations were examined: GA+SMA (flexible), EA+EA (rigid), and EA+SMA (rigid–flexible), where GA, EA, and SMA denote guss asphalt mixture, epoxy asphalt mixture, and stone mastic asphalt, respectively. First, the principles and implementation methods of the proposed non-uniform thickness design were defined based on the mechanical characteristics of the SBDP, with the key design parameters including the baseline thickness of the SBD, the thickness increment and the thickening range. Then, according to design standards and the transformed section method, the deflection and equivalent flexural stiffness of the SBD–SBDP composite structure were calculated. The effects of the parameters for non‑uniform thickness design on the composite structure were analyzed. Finite element models were developed to evaluate the resulting stress responses in the SBDP. Finally, a newly constructed steel box girder bridge was used as an engineering case to validate the feasibility of the proposed design. The results show that applying the non‑uniform thickness design at the mid‑span region significantly reduces the deflection of the composite structure. Compared with the uniform‑thickness reference group, all non‑uniform groups achieved deflection reductions greater than 35 %, with the maximum reduction reaching 90.4 %. The non‑uniform groups also exhibited significant increases in stiffness, particularly when the baseline SBD thickness was 12 mm. Finite element analysis further demonstrated that the non‑uniform thickness design markedly reduced the transverse tensile stress (<em>S</em>11) and longitudinal tensile stress (<em>S</em>33) in the SBDP, with maximum stress reductions up to 48.1 %. Stress reductions were observed for all three SBDP combinations, with the flexible GA+SMA showing the most pronounced reduction in stress concentration.</div></div>","PeriodicalId":48642,"journal":{"name":"Structures","volume":"86 ","pages":"Article 111268"},"PeriodicalIF":4.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192354","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}