Development of Ductile Segmental External Prestressed Concrete and Its Design Method

延性节段体外预应力混凝土的研制及其设计方法

基本信息

批准号：
07555435
负责人：
MUTSUYOSHI Hiroshi
金额：
$ 0.64万
依托单位：
SAITAMA UNIVERSITY
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

项目摘要

The application of precast segmental structures with external prestressing is getting popular due to economical and time saving construction. However, since segmental externally prestressed concrete (SEPC) member shows brittle failure at the ultimate state, it has hardly been constructed in earthquake areas. When such a structure is applied to elevated bridge structures whose girders are fixed on top of the reinforced concrete bent and subjected to big earthquakes, some extent of ductility or deformation capacity of the girder will be required.In this study, the ductility improvement of SEPC beams has been developed, and analytical method to predict the load-deformation and design method for SEPC structures have also been established. An experimental investigation was conducted on a series of monolithic and precast segmental simply supported beams. The test variables were ; a) type of joint condition (dry or epoxy), b) provision of confinement reinforcements, c) method of prestressing (external or external together with internal bonded) and d) number of deviators (two or three). An analytical program that consists of an intensive iterative technique has been developed to predict the flexural behavior of the beams considering the material and structural non-linearities. The ultimate behavior of beams with dry or epoxy joints was nearly the same. There was a remarkable increase in the ultimate deflection for the beams with confinements. The experimental results were compared with the analytical predictions from the elastic range to the ultimate state. There was good agreement between them. From the above results it is concluded that the ductility could be improved by provision of confinements in precast SEPC beams and such structures can be erected in seismic areas. From many analytical results, design equations for flexural strength were proposed.

由于经济和节省时间的结构，将预先预应力的预制分段结构应用在外部预应力中越来越受欢迎。但是，由于节段性的外部预应力混凝土（SEPC）成员在最终状态下显示出脆弱的失败，因此在地震地区几乎没有建造它。当将这种结构应用于高架的桥结构上，其大梁的固定在钢筋混凝土弯曲并遭受大地震的顶部时，将需要一定程度的延性或变形能力。在这项研究中，已经开发了SEPC束的延展性改进，并分析了用于载荷形成和设计方法的分析方法。对一系列单片和预制节段简单地支撑的光束进行了实验研究。测试变量是； a）关节状况（干燥或环氧树脂），b）提供限制增援，c）预应力的方法（外部或外部与内部键合）和d）偏离者的数量（两个或三个）。已经开发了一个由密集的迭代技术组成的分析程序，以预测考虑物质和结构非线性的梁的弯曲行为。干或环氧关节的梁的最终行为几乎相同。横梁的最终挠度有显着增加。将实验结果与从弹性范围到最终状态的分析预测进行了比较。他们之间有很好的共识。从以上结果得出的结论是，可以通过在预制的SEPC梁中提供限制来改善延展性，并且可以在地震区域架设此类结构。从许多分析结果中，提出了弯曲强度的设计方程。