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Development of Menshin(Repair-Free)Bridge Piers

免修桥墩的开发

基本信息

批准号：
11650478
负责人：
KAWASHIMA Kazuhiko
金额：
$ 2.3万
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 (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650478/
关键词：
Seismic Design Bridge Bridge Pier Smart Material Ductility High Damping Rubber Lateral Confinement New Construction 塑性ヒンジ長実験新技術地震

项目摘要

This research was conducted for aiming to develop a new reinforced concrete bridge pier that is free from damage under the near-field ground motions. Current practice to enhance the ductility capacity of a reinforced concrete bridge pier consists of providing larger amount of ties for lateral confinement of concrete at the plastic hinge region. The lateral confinement enhances the ultimate strain of concrete, which in turn increase the ductility capacity. However no matter how the lateral confinement is provided, once plastic deformation occurs at the plastic hinge region, it may be required to be repaired after an earthquake.The basic ideal of this research is to replace the concrete at the plastic hinge region with a material that is stable under large cyclic load excursion in the plastic range. The material should be sustainable for long-term use, and stable for natural environmental condition. In the current research, we developed a new reinforced concrete piers that satisfies the following two requirements ;(1)high ductility with drift of 4%, and(2)repair-free after cyclic excursion with displacement up to 4% driftWe used the high damping rubber for such a purpose. After clarifying the conditions required for the rubber layer, its effectiveness was verified by a series of cyclic loading test. Eight 1.35m high reinforced concrete piers with a 40cm x 40cm cross section were constructed, and rubber layers with various parameters such as the anchor to the concrete, steel plates on and bottom of the rubber layer, and shear key, were provided for the replacement of concrete in the plastic hinge region. An analysis using the fiber element was conducted to clarify the test results.It was found from the investigation that the damage-free pier based on the above concept is feasible. The use of rubber layer anchored to concrete with shear key is proposed for implementation.

这项研究的目的是开发一种在近场地震动下不会损坏的新型钢筋混凝土桥墩。当前增强钢筋混凝土桥墩延展能力的做法包括在塑性铰区域提供大量拉杆以横向限制混凝土。横向限制增强了混凝土的极限应变，从而提高了延展性。然而，无论如何提供侧向约束，一旦塑性铰区发生塑性变形，震后可能需要进行修复。本研究的基本理想是用在塑性范围内大循环荷载偏移下稳定的材料代替塑性铰区的混凝土。该材料应可持续长期使用，并且对自然环境条件稳定。在目前的研究中，我们开发了一种新型钢筋混凝土桥墩，它满足以下两个要求：（1）高延性，漂移量为4%，（2）循环偏移后无需修复，位移量漂移量高达4%。我们为此使用了高阻尼橡胶。在明确了橡胶层所需的条件后，通过一系列循环加载试验验证了其有效性。施工8个1.35m高、断面40cm×40cm的钢筋混凝土桥墩，并设置混凝土锚栓、橡胶层上下钢板、剪力键等各种参数的橡胶层，用于更换塑性铰区混凝土。利用纤维单元进行分析，阐明了试验结果。调查发现，基于上述理念的无损桥墩是可行的。建议采用橡胶层与剪力键锚固混凝土的方式实施。