Development of Seismic Retrofitting Method and Proposal of Seismic Performance Evaluation Method for Steel Bridge Piers Corrected by Heating

加热校正钢桥墩抗震加固方法的发展及抗震性能评价方法的提出

基本信息

批准号：
16360231
负责人：
KIM You-chul
金额：
$ 9.6万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16360231/
关键词：
Repair Reinforcement Heating correction Residual imperfection Buckling strength Ultimate strength Buckling mode

项目摘要

In Hanshin-Awaji earthquake (1995), many members of large steel structures were damaged. After the earthquake, the local buckling deformations of many members were rapidly corrected by heating and pressing. However, correcting large deformation like buckling, the ultimate strength of the members is unknown. So it is necessary to confirm safety and reliability of members corrected by heating.A series of compressive tests was carried out for virgin cruciform column and one corrected by heating. According to the results, buckling deformation modes of projection panels corrected by heating were variously changed by the degree of residual imperfection. And deformations up to the ultimate situation of corrected projection panels became larger than those of virgin panels. However, the ultimate strength of projection panels corrected by heating was almost equal to those of virgin materials.To elucidate the reason why the compressive behavior of specimens corrected by heating differs from that … More of virgin specimens, elastic-plastic large deformation analysis was carried out. When considering only residual imperfection, the experimental phenomena could not be simulated. Then considering not only residual imperfection but also the rise of yield stress made by work hardening, the experimental phenomena could be simulated totally. From the analysis, it was elucidated that the reason why the buckling mode of specimens corrected by heating changed was both residual imperfection and the increase of yield stress made by work hardening.In order to verify the major factors affecting compressive behavior of box column corrected by heating, a series of experiment was carried out and it was simulated by elastic-plastic large deformation analysis. The results were same tendency as the case of cruciform column. It was elucidated that two factors as residual imperfection and increase of yield stress involved in large plastic deformation dominated the compressive behavior of the steel members corrected by heating.The alternative load test was carried out for the structural model of a bridge pier with considering the knowledge obtained from cruciform column and box column.According to the results, if heating temperature was made to be under A1 transformation temperature at heating correction, residual imperfection could be largely corrected by using water without spoiling the mechanical properties. Whether the ultimate strength was decreased or not was decided by the magnitude of the local deflection which was remained without completely corrected by heating. Therefore, although the restoration to the original state was desirable to be as complete as possible to the original state, if the complete restoration was difficult, heating correction to the opposite direction of buckling should be performed somewhat larger. Less

然而，在阪神淡路地震（1995年）中，大型钢结构的许多构件遭到破坏，地震后，许多构件的局部屈曲变形通过加热和加压得到了迅速纠正，纠正了屈曲等大变形，达到了极限强度。因此，有必要确认加热矫正构件的安全性和可靠性。对原始十字形柱进行了一系列的压缩试验，并根据结果进行了屈曲变形。通过加热校正的投影面板的模式根据残余缺陷的程度而发生不同的变化，并且校正的投影面板的最终变形比原始面板的变形更大，但是通过加热校正的投影面板的极限强度几乎相同。为了阐明经过加热校正的试样的压缩行为与原始试样不同的原因，进行了弹塑性大变形分析，当仅考虑残余缺陷时，实验现象无法被解释。然后不仅考虑了残余缺陷，而且考虑了加工硬化引起的屈服应力的上升，从而可以完全模拟实验现象，从分析中可以看出，加热校正的试件屈曲模式发生变化的原因是两方面的。为了验证影响加热修正箱形柱受压性能的主要因素，进行了一系列实验，并通过弹塑性大变形分析结果进行了模拟。与十字柱的情况具有相同的趋势，说明残余缺陷和大塑性变形中屈服应力的增加两个因素主导了加热校正钢构件的压缩行为。考虑十字形柱和箱形柱的知识，建立了桥墩的结构模型。根据结果，如果在加热校正时将加热温度设置在A1转变温度以下，则可以利用获得的水来很大程度上校正残余缺陷极限强度是否降低取决于未通过加热完全校正而残留的局部挠度的大小，因此，尽管希望尽可能完全地恢复到原始状态。原始状态下，若难以完全修复，则应向屈曲相反方向进行加热矫正，幅度要小一些。