Seismic capacity assessment of postmainshock damaged containment structures using nonlinear incremental dynamic analysis

This paper investigates the structural performance and seismic capacity of the postmainshock damaged containment structure through the incremental dynamic analysis (IDA). To evaluate the seismic capacity with minimum uncertainty, the damage measure (DM) and intensity measure (IM) for IDA curves are selected in term of the coefficient of variation. The IDA using mainshock records is implemented to examine the seismic damage process of a containment structure and determine key damage states. The static cyclic loading analysis and aftershock IDA are also conducted on mainshock‐damaged containment structures to investigate the effect of initial damage states on the dynamic characteristics of structures. Finally, based on IDA results, limit states of a containment structure are defined using a generalized multidimensional limit‐state function that allows considering the dependence between the mainshock‐damaged level and residual seismic capacity. These proposed bidimensional limit‐state functions can be used in the fragility analysis and risk assessment of containment structures under mainshock–aftershock, which can improve the accuracy of seismic assessment.     

Cumulative seismic damage assessment of reinforced concrete columns through cyclic and pseudo‐dynamic tests

This paper presents the findings of a systematic experimental study conducted to investigate cumulative seismic damage in reinforced concrete columns. Fourteen identical large‐scale concrete columns were fabricated and tested to failure. Experimental tests were conducted in two phases. Phase I testing included benchmark tests to characterize the monotonic force‐deformation behavior and constant amplitude tests to determine the low‐cycle fatigue characteristics of typical flexural columns. Phase II involved testing of concrete columns under a series of earthquakes of varying duration and magnitude. Low‐cycle fatigue of the longitudinal reinforcing bars and confinement failure due to rupture of the confining hoops were the main failure modes in phase I. Phase II tests also demonstrated the potential for low‐cycle fatigue fracture of the main longitudinal steel when the specimen was subjected to relatively larger displacement amplitudes. A fatigue‐based damage model is proposed based on the data obtained from the constant amplitude tests of phase I. The damage prediction of the model is assessed by using the response of three specimens tested in phase II and the data from the cyclic tests of six reinforced concrete columns reported in the literature. Results show that the proposed fatigue‐based damage model offers a reliable means of assessing seismic structural performance. Copyright © 2016 John Wiley & Sons, Ltd.     

内嵌钢板钢筋混凝土框架抗震性能试验研究

为研究内嵌钢板钢筋混凝土框架结构的抗震性能,采用2层单跨1/3缩尺模型,设计1榀内嵌钢板钢筋混凝土框架试件和1榀钢筋混凝土框架对比试件。通过低周反复加载试验,研究内嵌钢板钢筋混凝土框架试件破坏机理、滞回性能、刚度退化规律、延性以及耗能能力,并与钢筋混凝土框架进行对比。试验结果表明:内嵌钢板钢筋混凝土框架的破坏机制更加合理,变形能力、抗侧刚度和承载力明显增高;在结构屈服前,梁柱无明显裂缝,钢板二层较一层变形发展充分,主应力沿对角线方向;ABAQUS有限元分析结果和试验结果吻合较好。     

在役钢筋混凝土受弯构件承载力评估方法

在分析钢筋锈蚀造成钢筋混凝土构件力学性能退化的基础上,根据钢筋混凝土构件碳化锈蚀规律及混凝土保护层锈胀裂缝宽度与钢筋锈蚀深度的关系,提出了保护层锈胀开裂前和锈胀开裂后钢筋混凝土受弯构件承载力评估方法,可为在役钢筋混凝土结构耐久性评估及修复决策提供理论依据。     

填充墙失效可控的结构整体抗震能力提升方法

结构失效模式对应结构整体抗震能力,结构失效时所对应的最小地震作用作为结构的整体抗震能力。通过推覆分析（Pushover）找到结构的失效模式,从而为布置失效填充墙提供信息,通过布置失效填充墙,可改变并消除原有结构的最弱失效模式,从而提高结构的整体抗震能力;通过增量动力时程分析,可最终确定失效填充墙的最佳布置方案及结构的整...     

锈蚀对承插式接头管道震害预测结果影响的分析

介绍了地下管道震害分析的方法、管道锈蚀作用的原因及危害,并从数值分析的角度出发,分析了震害预测中埋深、壁厚、水压力等参数变化对预测结果的影响。结果表明,管道的组合轴向变形与管长和水内压呈线性正相关,与管道埋深呈线性负相关;地下管道的锈蚀作用使管道壁厚变小,地震发生时更易遭到破坏,需要采取相应的措施减小管道锈蚀带来的震害影响。     

波形钢腹板PC组合箱梁疲劳损伤对抗弯承载能力的影响研究

制作两根体外预应力波形钢腹板简支PC组合箱梁,其中第一根梁进行静力全过程试验,另一根梁先进行疲劳试验直至波形钢腹板出现疲劳破坏后进行静力加载全过程试验;得到两根组合箱梁在弹塑性阶段的基本力学性能、典型疲劳损伤特征和疲劳前后的抗弯承载力。根据混凝土材料的S-N曲线和疲劳荷载的实际应力比,推导混凝土材料疲劳损伤后的强度退化规律、总结混凝土割线模量、极限应变的退化规律,据此得到混凝土材料疲劳损伤前、后的本构关系;基于截面M-N-Φ关系编制体外预应力简支组合箱梁抗弯承载力的非线性全过程分析程序,对两根试验梁进行全过程加载的模拟分析,理论与试验结果吻合良好;两者均表明波形钢腹板的疲劳损伤对组合箱梁抗弯承载力影响不大,但会大大降低结构的延性。     

The effect of design drift limit on the seismic performance of RC dual high‐rise buildings

Current building codes aim to ensure the acceptable performance of structures implicitly. Because these provisions are empirically developed for low‐ to medium‐rise buildings, their applicability to high‐rise building warrants further investigation. In this paper, the effect of design drift limit on the seismic performance of reinforced concrete dual high‐rise buildings is considered. Nine buildings are designed for 3 drift limits: the code limit (i.e., 2%), one that is lower than the code limit (i.e., 1.5%), and one that is higher than the code limit (i.e., 3%). For each drift limit, buildings of 3 heights (20, 25, and 30 stories) are designed. Finite element models are constructed in OpenSees, and incremental dynamic analysis is performed. The results are used to develop probabilistic seismic demand models, where model parameters are determined using maximum likelihood estimation to incorporate equality and censored data. Reliability analysis using probabilistic demand models is conducted to derive seismic fragility and demand hazard curves. In addition, the collapse performance of the drift limits is evaluated using the Federal Emergency Management Agency (FEMA) P695 procedure. The study results show that the design drift limit affects the building's seismic performance, and the effect depends on the performance level considered. Moreover, from a structural integrity perspective, a larger design drift limit does not induce a significantly higher risk and might yield a more cost‐effective design.