STUDY ON DEVELOPMENT OF NEW COMPOSITE HIGH PIER COLUMNS AMING AT REDUCTION OF TIME AND LABORS FOR ON-SITE CONSTRUCTION

本研究的目的是开发一种新的组合高墩体系，能够简化现场施工，并具有良好的抗震性能。在1996 ~ 1998年的科研资助期间，对拟建的高墩体系进行了动力、静力分析和荷载试验，获得了一些有益的抗震性能的认识。（1）动力和静力分析结果表明，钢管混凝土柱组合桥墩是一种具有良好结构性能和抗震性能的结构形式。(2)在连接主柱的加劲杆布置合理的情况下，钢管混凝土柱多柱组合桥墩可以表现出较高的强度和延性。(3)对于主墩与加劲杆连接部位的设计，按现行规范进行设计已不能满足安全要求。(4)考虑钢管的约束效应，提出了能准确评价钢管混凝土柱受弯性能的混凝土和钢材的应力-应变关系。通过使用建议的应力-应变模型，钢管混凝土柱的弯曲性能，包括轴压水平可以正确估计。

The objective of this study is to develop a new composite high pier system that is able to simplify the field construction and has good seismic performance. During the term (1996-1 998) of the grant-in-aid for scientific research, dynamic and static analysis and loading test have been fulfilled to obtain some useful knowledge of the seismic properties on proposed high pier system. Results of this study are shown as follow :(1) As results of dynamic and static analysis, multi-column composite pier using concrete filled steel tubular columns (CFT columns) is good structural form for constructive and seismic performance.(2) If the stiffening struts connected the main columns is arranged properly, multi-column composite pier using CFT columns could show high strength and ductility.(3) About the design of the connecting part between main pier and stiffening strut, it is impossible to design them safely by applying past design code.(4) Each stress-strain relationship of concrete and steel that can estimate flexural behavior of CFT columns exactly is proposed by considering the confining effect of steel tube. By using a proposed stress-strain model, flexural properties of CFT columns including axial load level can be estimate correctly.