Empirical study on reduction in input motions to improve the seismic performance based design of buildings

减少输入运动以改善基于建筑物抗震性能的设计的实证研究

基本信息

批准号：
15360298
负责人：
HAYASHI Yasuhiro
金额：
$ 9.6万
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：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

Nonlinear soil-structure interaction effects under strong ground motions are studied to consider in the seismic design.First, effectiveness of soil-structure interaction in earthquake response reduction of buildings is studied by earthquake response analyses using representative ground motion record of recent domestic or foreign big earthquakes. In the analyses, simple sway-rocking models are used and non-linearity of buildings is considered. It is assumed that buildings are supported by direct foundation on the elastic uniform soft soil. From the analyses, it is pointed out that the damage reduction effects by soil-structure interaction greatly depend on the ground motion characteristics, number of stories and seismic performance of buildings.Next, cyclic loading tests for pile foundation in dry sand are conducted to investigate the nonlinearity in the pile group effects in large pile-head-displacement region. The experimental parameters are the number of piles, loading rate, relative density of soil and alignment of pile group. The major findings obtained from tests are summarized as follows: 1) the soil around piles deformed significantly even at small amplitude, 2) shear force-displacement relationship, resultantly secant stiffness and equivalent damping factor, at pile head shows significant nonlinearity even in very small displacement range, 3) shear force at pile head hold almost constant value after the soil get failed, 4) variation in pile group efficiency with increase in pile-head displacement is not so large, 5) the ratio of the shear force at pile head to the total horizontal load is affected by the yield of piles and the failure of the soil as well as the number of piles, pile location, soil density, and loading direction.

研究强地震动作用下的非线性土-结构相互作用效应，以便在抗震设计中予以考虑。地震。在分析中，使用简单的摇摆模型并考虑建筑物的非线性。假设建筑物由弹性均匀软土上的直接基础支撑。分析指出，土-结构相互作用的减损效果很大程度上取决于地震动特性、建筑物的层数和抗震性能。接下来，对干砂桩基进行循环荷载试验进行研究。大桩头位移区域群桩效应的非线性。试验参数为桩数、加载速率、土体相对密度和群桩排列。试验获得的主要结果总结如下：1）桩周围的土体即使在小振幅下也会发生显着变形，2）剪力-位移关系、桩头处的割线刚度和等效阻尼系数即使在非常小的情况下也表现出显着的非线性位移范围，3）土体破坏后桩头剪力几乎保持恒定值，4）群桩效率随桩头位移增加的变化不大，5）桩头剪力比到总水平荷载受桩的屈服强度和土体破坏以及桩的数量、桩位置、土的密度和加载方向的影响。