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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.

本研究旨在开发一种在近场地震动作用下不受损伤的新型钢筋混凝土桥墩。目前提高钢筋混凝土桥墩延性能力的做法包括在塑性铰区域为混凝土横向约束提供更大数量的纽带。侧向约束提高了混凝土的极限应变，进而提高了延性能力。然而，无论如何设置侧向约束，一旦塑性铰区域发生塑性变形，可能需要在地震后进行修复，本研究的基本思想是用一种在塑性范围内的大循环荷载漂移下稳定的材料来替换塑性铰区域的混凝土。材料应长期可持续使用，并对自然环境条件稳定。在目前的研究中，我们开发了一种新的钢筋混凝土桥墩，它满足以下两个要求：(1)高延性，漂移4%；(2)循环漂移后免修复，位移高达4%。在明确橡胶层所需条件的基础上，通过一系列循环加载试验验证了橡胶层的有效性。建造了8个高1.35m、横截面为40 cm×40 cm的钢筋混凝土桥墩，并设置了不同参数的橡胶层，如混凝土锚杆、橡胶层上和橡胶层底部的钢板以及剪力键，用于更换塑性铰区的混凝土。利用纤维单元对试验结果进行了分析，结果表明，基于上述概念的无损伤桥墩是可行的。建议采用橡胶层加剪力键锚固混凝土。