Limit States of Civil Engineering Structures under Combined Loads

由于近年来结构设计和施工技术的进步，在地震活跃区内设计和建造了许多新型和大型工程结构，如斜拉桥或悬索桥、高层建筑、工业和海洋结构等。在这些结构的设计中，对结构的组合荷载效应和结构构件的组合应力效应进行研究是至关重要的。寻找结构和构件在这些荷载和应力作用下的极限状态也很重要。本文首先提出了考虑轴向力动态变化的钢筋混凝土框架结构非弹性地震反应分析的应力应变概念。本试验研究采用新开发的基于子结构的混合加载系统对混凝土和钢材的应力-应变关系进行了检验和验证。本文提出的方法更适用于某塔式预应力混凝土斜拉桥的非弹性地震反应评价。通过试验研究了薄壁钢箱柱和豆柱节点在反复弯曲作用下的非弹性行为。其次，将地震能概念引入土木工程结构的新型抗震设计，并应用于基础隔震和动力阻尼结构。这些结构的地震能量分布为其可靠性评估提供了重要的信息。对具有前馈和反馈控制的结构进行了相位延迟主动控制的基础研究。第三，利用频域分析方法对海上结构在波浪和地震作用下的随机响应和可靠度进行了分析。第四，采用分析和试验相结合的方法，对震害结构的可靠度及其修复方法进行了研究。这项研究的细节见研究报告。少

Due to recent advances in structural design and construction technology, numerous new-type and large-size engineering structures such as cable-stayed or suspension bridges, high-rise buildings, industrial and offshore structures, and so on have been designed and constructed in seismically active regions. In design of these structures, it is critically important to examine the combined load-effects to structures and the combined stress-effects to structural members. It is also important to find the ultimate limit states of structures and members under these loads and stresses.Firstly in this study, stress-strain based concept is developed for inelastic earthquake response analysis of reinforced concrete frame structures taking into account dynamic variation of axial forces. The stress-strain relation of concrete and steel used in this study are examined and approved in this experimental studies using the newly developed substructure-based hybrid loading systems. The proposed methods are … More applied for inelastic earthquake response evaluation of a tower PC cable stayed bridge. Inelastic behaviors of thin wall steel box columns and bean-column joints under repetive bending are also investigated from the experiments.Secondly, earthquake energy concepts are introduced to new earthquake resistant design of civil engineering structures, and applied to the base-isolated and dynamically damped structures. The earthquake energy parioning in these structures is found to give significant information for their reliability assessment. Fundamental studies on phase-delayed active control of structures with feed forward and feed back controls are also conducted. Thirdly, random response and reliability analysis of offshore structure subjected to wave and earthquake motions is carried out using frequency domain analysis. Fourthly, reliability of earthquake damaged structures and their repair methods are investigated through analytical and experimental method. Details of this study are found in the research reports. Less