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Study of dynamic fracture of structure and anti-earthquake design under near-source earthquake

近源地震下结构动力断裂及抗震设计研究

基本信息

批准号：
10355022
负责人：
TANIMURA Shinji
金额：
$ 11.46万
依托单位：
Osaka Prefecture University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10355022/
关键词：
Near-source earthquake Structure Fracture Dynamic response Analysis Impact Solid model Vibration 鉄骨構造

项目摘要

Initial transient behavior of a tall-building-model due to a strong near-source earthquake has been numerically studied using the code MSC/DYTRAN.It is found that stresses greater than the yield stress of the column material, for an elastic/plastic building-model, and stresses greater than the tensile strength of the column material, for an elastic building-model, are achieved in many columns of the building-models, in the initial transient stage.One of unexpected fractures of structures due to the great Hanshin-Awaji earthquake is the fracture of a bridge bearing part of the Nielsen bridge type. The obtained numerical results show that a high stress sufficient to lead to a fracture appears in the upper part of the bridge bearing, when an impact of velocity higher than 5 m/s occurs between the upper and the lower parts of the bridge bearing.It is also illustrated that the maximum stress values occurred in the transient stage are strongly dependent on the size of the structure and the acceleration profile of the earthquake motion.In order to secure the inelastic energy absorptions capacity of structural members, the possibility of brittle fracture must be eliminated.Based on the full scale shaking table test, the ultimate energy absorption capacity of H-section beams influenced by the brittle fracture was minutely observed.A simple procedure to secure the ultimate energy absorption capacity is summarized as follows.1.Brittle fracture can be eliminated by detecting FTP condition through Charpy impact test of used materials.When2.FTP condition is satisfied, the ultimate energy absorption capacity can be estimated on the basis of tensile strength of materials.3.Since the inelastic deformation capacity of a member is proportional to the stress increase at the end of member, the efficiency in transmitting member's strength at the end of member (joint efficiency) must be adequately evaluated.

本文用MSC/DYTRAN程序对一高层建筑模型在近源强震作用下的初始瞬态行为进行了数值研究，发现在弹塑性模型中，许多柱的应力大于柱材料的屈服应力，在弹性模型中，许多柱的应力大于柱材料的抗拉强度，坂神淡路大地震引起的结构物意外断裂之一是Nielsen桥型的桥梁支承部分断裂。计算结果表明，在桥梁支座的上部出现了足以导致断裂的高应力，当撞击速度大于5 m/s时，结果表明，结构在地震作用下的最大应力值与结构尺寸和地震加速度分布有很大关系为了保证结构构件的非弹性耗能能力，必须消除构件发生脆性断裂的可能性，根据足尺振动台试验，H的极限能量吸收能力本文详细分析了脆性断裂对截面梁的影响，提出了一种保证截面梁极限吸能能力的简单方法：1.采用通过对所用材料的夏比冲击试验检测FTP条件，当满足FTP条件时，可以根据材料的抗拉强度估算极限吸能能力; 3.由于构件的非弹性变形能力与构件端部应力的增加成正比，必须充分评估在构件端部传递构件强度的效率（接头效率）。