Seismic performance assessment of highway bridge networks considering post-disaster traffic demand of a transportation system in emergency conditions

Highway bridge networks (HBN) are one of the critical components of a transportation system that supports the operation of modern society. The traffic-carrying capacity of a transportation system is essential for emergency responses in a catastrophic seismic hazard. In this article, a methodology is proposed to assess the regional seismic performance of HBN considering the post-disaster traffic demand of a transportation system in emergency conditions. First, the framework of the methodology is introduced. Then, topological properties and vulnerability analyses are conducted to understand the connectivity of the HBN and the traffic-carrying capacity of the damaged bridge networks. In addition, traffic flow analysis is employed to consider the traffic situation in an emergency condition. Then, the entropy-right method is adopted to integrate these factors and to assess the importance of each bridge link in an emergency condition. Last, the seismic performance of HBN is also evaluated considering the decrease in the traffic-carrying capacity and the increase in traffic cost after earthquake events. The methodology is demonstrated using a HBN located in San Jose, California.     

Application of replaceable coupling beams to RC structures

An innovative structural component, replaceable coupling beam (RCB), was developed and used in reinforced concrete (RC) structures to enhance the structural performance. During strong earthquakes, damage may occur in replaceable devices to prevent severe damage in primary structural parts, and the damaged devices could be replaced after earthquake. This paper introduces the theory and design method as well as the application of RCBs to RC structures. First, a practical design procedure for RCBs was proposed. Then, cyclic static tests of the RC shear walls with and without RCBs were conducted. At last, a systematical RCB application to RC structure was introduced, and dynamic analysis for the entire structures was performed. The results indicate that RCB has good seismic performance by concentrating damage in the replaceable devices, while the global responses of the structures with and without RCBs changed slightly. Dynamic properties of the real structure were measured through the ambient vibration test, and the test results further validated the dynamic analysis to some extent. Copyright © 2016 John Wiley & Sons, Ltd.     

Experimental study on seismic performance of mega steel‐reinforced concrete columns subjected to cyclic loads

In recent years, mega steel‐reinforced concrete (SRC) columns have been applied in super tall buildings. The previous research on SRC columns mainly focuses on the components with simple arrangement of shaped steel, such as H‐shaped steel and cross‐shaped steel, with little attention paid to mega SRC columns, which always have complicated encased steel and large steel ratio. The cyclic loading tests were carried out on scaled mega SRC column models with different cross‐section type of encased steel and steel ratio. The principal damage states were investigated throughout the entire testing process. Based on the test results, the effects of steel ratio and the cross‐section type of encased steel on the damage characteristics, hysteretic behavior, ductility, secant stiffness degradation, energy dissipation capacity and maximum crack width were analyzed. The test results indicate that the steel ratio has significant effect on the seismic performance of mega SRC columns while the effect of cross‐section type of encased steel is not significant. Copyright © 2015 John Wiley & Sons, Ltd.     

钢框架-预制混凝土抗侧力墙结构抗震性能试验研究

为研究钢框架-装配式混凝土抗侧力墙结构体系(SPW体系)的抗震性能,对2榀足尺钢框架-预制钢筋混凝土抗侧力墙结构进行低周反复荷载作用下的试验,研究结构的破坏形态、滞回性能、延性及变形以及耗能性能等.试验结果表明:该结构体系为一种典型的双重抗侧力体系,加载过程呈现出明显的两阶段受力状态,抗侧力墙作为结构抗震的第一道防线,在加载前期承担主要的水平荷载,随着墙体退出工作,钢框架成为结构抗震的第二道防线;加载后期,由于抗侧力墙顶部连接发生破坏,钢框架承担所有的水平剪力和倾覆弯矩作用.     

Experimental study on seismic performance of glued-laminated timber frame infilled with CLT shear wall

为研究胶合木框架及其填充正交胶合木（CLT）剪力墙板后结构的抗震性能，按照1∶1.5的缩尺比，设计并制作了1个单层单跨胶合木纯框架试件和4个具有不同设计参数的单层单跨胶合木框架-CLT剪力墙板试件，对其进行低周往复加载试验，得到了5个试件的破坏形态、荷载-位移滞回特性、刚度退化、耗能和变形能力等抗震性能指标，分析了胶合木框架与CLT剪力墙板的抗侧协同工作机理。结果表明：胶合木纯框架侧向变形较大，节点区出现明显的剪切裂缝，梁端节点破坏程度明显大于柱脚节点。填充CLT剪力墙板后胶合木框架的抗侧承载力得到较大幅度提高，框架节点的破坏程度得到显著改善,结构的耗能能力明显增强；CLT剪力墙板中开设的洞口类型及尺寸对其破坏方式和破坏程度产生影响。增设门洞、窗洞和无洞口CLT剪力墙板试件较纯框架试件的弹性抗侧刚度分别提高966%、1147%和1310%；随着CLT剪力墙板跨高比的增加，试件的承载能力和刚度均有一定的提升。填充CLT剪力墙板后胶合木框架的弹塑性层间位移角介于0.028~0.044；从加载开始至试件破坏，CLT剪力墙板承担的侧向荷载超过50%。     

Seismic performance analysis of Tibetan rubble stone walls based on irregular block geometry indexes

为量化不规则毛石墙体几何指标(块体形状、块体尺寸、水平和竖向接缝)对其抗震性能的影响，对3片1/2缩尺的传统藏式毛石墙体进行低周往复荷载试验，获得其典型破坏形态、滞回曲线、骨架曲线等抗震性能参数。基于藏式毛石墙体的不规则构造特征和块体形状，结合灰色理论建立不规则块体面积、周长等9个形状参数与墙体地震响应特征的关联度。研究结果表明：低周往复荷载下块材几何尺寸对墙体抗震性能的影响最大；大块石组砌的墙体抗剪刚度和承载力均较大，且墙体规则性和质量等级较好、抗震性能更优。确定了量化藏式毛石墙体抗震性能的几何指标的方法，可用于评价藏式毛石墙体的基本受力性能。     

基于Pushover方法的大跨度悬挑钢梁结构的弹塑性分析

本文以某实际工程为例,采用静力弹塑性分析方法,通过SAP2000进行Pushover分析,研究大跨度悬挑梁在地震作用下的结构抗震性能。通过在多遇和罕遇地震荷载作用下对结构的顶点位移、层间位移角以及塑性铰发展过程的研究,分析其抗震性能。同时研究不同悬挑长度对结构抗震性能的影响规律并提出相应的加固措施,可为今后类似结构的设计与抗震分析提供参考。     

某超高层框筒结构的抗震性能分析

本文以某超限框架-核心筒结构为例,通过对该结构在多遇地震下的弹性分析、设防烈度下的等效弹性计算以及罕遇地震下等效弹性分析和弹塑性分析,并对开洞楼层的楼板应力分析,检验其抗震性能。分析结果表明,通过加强措施后,能达到期望的性能目标,可供同类工程参考。     

受腐蚀钢筋混凝土墩柱抗震性能试验研究

为了研究腐蚀环境对钢筋混凝土桥墩抗震性能影响,试验制作8根相同几何尺寸和材料配比的钢筋混凝土墩柱模型。通过对试件进行实验室恒定电流加速腐蚀,得到不同腐蚀程度的墩柱,并在恒定轴压比下进行低周反复荷载试验。分别从极限承载力、延性、耗能能力等方面评估墩柱抗震性能。对试验得到的滞回曲线和相应的骨架曲线进行分析,得到钢筋混凝土墩柱的抗震性能随腐蚀率的变化规律。结果显示:在腐蚀率较小情况下,随着腐蚀率的增大,墩柱的延性、承载力、耗能均呈不同程度的下降趋势。