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A Research on Steel Frames Having Large Elastic Deformation Capacity

大弹性变形能力钢框架的研究

基本信息

批准号：
07555643
负责人：
WADA Akira
金额：
$ 0.64万
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：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07555643/
关键词：
Steel Structures Seismic Design Structural Design Stress Strain Plastic Deformation

项目摘要

This paper is aimed to study the cyclic behavours of high strength steels with weld connection. Many fractures in or near the welds of bottom flange of beams connected to the columns had been observed in the investigations after Northridge Earthquake of USA (1994) and Hyogoken-Nanbu Earthquake of Japan (1995). Although in principle the high strength steels are assumed to be used below the yield point (within elastic range) in the damage tolerant structures, it is still necessary that the inelastic cyclic behaviors of high strength steels should be studied experimentally in case of extreme large earthquake. The most critical reason to result in the fracture at beam ends is the concentration of inelastic strain which is greatly influenced by the welding defective, heat affect and stress gradient. In this experimental study, a large number of test specimens with weld connection using 4 kinds of high strength steels and 2 kinds of plain strength steels had been manufactured. Tension and compression cyclic loading was carried out controlled by the measured displacement. It was found that the inelastic deformation capacity of high strength steels was dramatically reduced due to the influence of weld connection. Unfortunately, some of specimens were broken in brittle during the cyclic loading experiments. Although it is no problem for high strength steels with weld connection to be used in the elastic range, further detailed researches and advanced technologies should be necessary before the high strength steels could be put into the use of seismic structures if the plastic deformation of high strength steel is expected.

本文旨在研究焊接接头高强度钢的循环性能。在美国北岭地震(1994)和日本仙谷地震(1995)后的调查中，发现与柱连接的梁底翼缘的焊缝或附近有多处断裂。虽然在损伤容限结构中原则上假定高强度钢在屈服点以下(在弹性范围内)使用，但仍有必要对高强度钢在极大地震下的非弹性循环性能进行试验研究。导致梁端断裂的最关键原因是非弹性应变的集中，而非弹性应变的集中受焊接缺陷、热影响和应力梯度的影响很大。在本试验研究中，用4种高强度钢和2种普通强度钢制作了大量的焊接试件。利用测得的位移控制拉压循环加载。结果表明，由于焊接接头的影响，高强度钢的非弹性变形能力大大降低。不幸的是，在循环加载试验中，一些试件发生了脆性断裂。虽然在弹性范围内使用焊接连接的高强度钢是没有问题的，但如果希望高强度钢的塑性变形，则需要进一步的详细研究和先进的技术才能将高强度钢应用于抗震结构。