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Development of Ductile Bridge Columns with Enhanced Flexural and Shear Incore Zone

具有增强的弯曲和剪切核心区的延性桥梁柱的开发

基本信息

批准号：
21360212
负责人：
KAWASHIMA Kazuhiko
金额：
$ 11.32万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2009
资助国家：
日本
起止时间：
2009 至 2011
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-21360212/
关键词：
防災構造工学・地震工学耐震減災自然災害

项目摘要

Based on a series of shake table experiments for a full-size bridge column using E-Defense, it was found that crushed core concrete spilled out from steel cage under extreme excitations. Such a failure model was first identified based on a full-model column excitation. It is anticipated that this failure modes accelerate degradation of column failure. Since such a scale-effect has not been sufficiently studied in the past due to limitation of large experimental facilities, the scale effect on the failure mechanism at the plastic hinge was investigated in this study. Four 5/36 geometrical scale models which were design and constructed as close to the full-size model as possible were exposed to the same response displacement and varying axial load after they were scaled-down based on the similarity law. It was found that both 1) an evaluation of sectional areas of deformed bars which have difference diameters and shape of surface deformation and 2) the maximum aggregate size were important for identifying the scale effect. It was found that progress of damage was faster in the full-size model that the scaled models though the flexural capacity can be well predicted by the scaled-model. Since the level of excitation to the full-size column by E-Defense was not extreme enough to develop collapse, it was found based on the study that under extremely strong excitation, the scaled models have a large limitation for predicting the failure mechanism of full-size columns.

基于E-Defense对一个实尺寸桥梁立柱进行的振动台试验，发现在极端激励下，钢筋笼内的核心混凝土会发生破碎溢出现象。首先根据全模型柱激励确定了这种失效模型。预计这种失效模式会加速柱失效的恶化。由于大型实验设备的限制，这种尺度效应在过去没有得到充分的研究，在这项研究中，塑性铰的破坏机制的尺度效应进行了研究。根据相似律，将4个5/36几何比例模型按比例缩小后，使其在相同的响应位移和不同的轴向载荷作用下，尽可能接近于全尺寸模型。结果发现，1）具有不同直径和表面变形形状的变形钢筋的截面积的评估和2）最大骨料尺寸对于识别尺度效应是重要的。结果表明，尽管缩尺模型能较好地预测试件的抗弯承载力，但足尺模型的损伤发展比缩尺模型快。由于E-Defense对全尺寸柱的激励水平不足以产生倒塌，因此研究发现，在极强激励下，缩尺模型对全尺寸柱的破坏机理预测有很大的局限性。