Plastic Deformation and its Variation Demanded of Structures and Structural Members in Steel Building

钢结构建筑结构及构件的塑性变形及其变化要求

基本信息

批准号：
07455223
负责人：
NAKASHIMA Masayoshi
金额：
$ 3.65万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07455223/
关键词：
Reliability-Based Design Steel Building Frame Plastic Deformation Demand Variation Monte-Carolo Simulation

项目摘要

In seismic design, plastic deformations of structures and structural members play an important role, but the quantities are known to vary very significantly. In this course, seismic design incorporated with the reliability concept is of serious consideration. The objective of this project is (1) to develop a simple, systematic method to estimate the degree of variation of plastic deformations demanded of steel building structures and their elements and (2) to provide a guideline as to the variation to be considered in seismic design. A analytic procedure consisting of the following steps was developed ; (1) to select likely collapse mechanisms by use of the Symplex method, (2) to estimate plastic hinge rotations by solving the stiffness matrix corresponding to the instant of a collapse mechanism, and (3) to estimate the variation of the obtained plastic hinge rotations by the application of the FOSM method. Several steel building frames were analyzed for the variation of their plastic hinge rotations, where the proposed method and Monte-Carlo simulation were employed. It was found that, for an coefficient of variation of 0.1 assigned for the member plastic moment capacities, the coefficient of variation of the ultimate load was about 0.03, whereas the coefficient of variation of the member plastic rotations ranged from 0.3 to as much as 0.7. The finding indicates that the member plastic deformation can vary very significantly even for a moderate variation of member strength and that a large margin of safety has to be introduced if seismic design is formed to consider the plastic deformation, in terms of both the demand and capacity, in an explicit manner.

在抗震设计中，结构和结构构件的塑性变形起着重要作用，但众所周知，其数量变化很大。在这个过程中，结合可靠性概念的抗震设计是需要认真考虑的。该项目的目标是（1）开发一种简单、系统的方法来估计钢建筑结构及其构件所需的塑性变形的变化程度，以及（2）为地震中要考虑的变化提供指南设计。开发了由以下步骤组成的分析程序； (1) 使用 Symplex 方法选择可能的塌陷机制，(2) 通过求解对应于塌陷机制瞬间的刚度矩阵来估计塑性铰旋转，以及 (3) 估计所获得的塑性铰的变化通过应用 FOSM 方法进行旋转。采用所提出的方法和蒙特卡罗模拟，分析了几种钢建筑框架的塑性铰旋转的变化。结果发现，当构件塑性力矩能力的变异系数为 0.1 时，极限载荷的变异系数约为 0.03，而构件塑性旋转的变异系数范围为 0.3 至 0.7。。研究结果表明，即使构件强度适度变化，构件塑性变形也可能变化很大，如果抗震设计考虑塑性变形，则在需求和能力方面都必须引入很大的安全裕度，以明确的方式。