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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.

利用E-Defense软件对某全尺寸桥柱进行了振动台试验，发现在极端激励下，破碎的核心混凝土从钢笼中溢出。这种破坏模型首先是基于全模型柱激励确定的。预计这种破坏模式会加速柱破坏的退化。由于以往受大型实验设施的限制，对这种尺度效应的研究不够充分，因此本研究对塑性铰处的尺度效应破坏机制进行了研究。设计并构建的4个尽量接近全尺寸模型的5/36几何比例模型，根据相似律对模型进行缩尺后，得到了相同的响应位移和变化的轴向载荷。研究发现，对具有不同直径和表面变形形状的变形杆的截面面积进行评估和对最大骨料粒径进行评估是识别尺度效应的重要依据。结果表明，全尺寸模型的损伤进展速度比比例模型快，但比例模型能较好地预测其抗弯能力。由于E-Defense对全尺寸柱的激励水平不足以极端到发生破坏，研究发现，在极强的激励下，比例模型对全尺寸柱破坏机理的预测有较大的局限性。