Pseudo Dynamic Performance and Analysis of A Full Scale CFT/BRB Composite Frame
Date Issued
2004
Date
2004
Author(s)
Hsiao, Po-Chien
DOI
zh-TW
Abstract
In recent years, a lot of researches concerning BRB(Buckling Restrained Braces) confirmed that BRBs are effective components resisting earthquakes. It’s because the BRBs won’t buckle with applied compression axial force, they can develop full hysteresis and dissipate lots of energy. BRBs have been used gradually in recent years including Taiwan, Japan and United States.
In past researches, the experiments of BRBs were always component tests by applying axial tension or compression force. The braced frame tests were insufficient. Furthermore, an one-story one-bay specimen is not enough to react the actual behavior of common structures. An 3-story specimen is needed to exactly present the behavior of real structures.
Therefore, the specimen of this research is a full-scale 3-story 3-bay composite structure, using concrete filled steel tube (CFT) columns in a buckling restrained braced (CFT/BRB) frame. The specimen was tested using pseudo dynamic test procedures and internet testing techniques. There are some topics in the thesis: 1) Finding the global response of the 3-stories frame, and discussing the error between experimental results and analytic responses(Prediction). The error analysis is helpful for modifying the analysis models(Simulation). 2) Discussing several items relating to BRBs behavior, including behavior of gusset, dissipated energy, CPD, end rotation, unbalanced load and ductility of BRBs. 3) By component testing, research a new type of unbonding material and how the thickness of unbonding material affect the behavior of BRBs. Help the discussions above is useful for the relative research in the future.
From experiment, we found the gussets buckle without stiffeners. After adding stiffeners at the edges of gusset, the buckling of gussets never occurred. In the analysis, abbreviating the distance between the end of BRBs and the surface of nearby beam or column is also helpful to avoid the gusset buckling. Besides, BRBs behave well in the frame. They take about 80% of story shear, and dissipate the most of imported earthquake energy. By discussing CPD of braces, it confirm that BRBs can take many large earthquakes without failure. The end rotation of BRBs is existent, and that can be estimate. In the research of the new unbonding material(asphalt), it’s proved that the thickness of unbonding material is the primary factor affecting the difference between tension and compression force. Asphalt can take the place of silicone rubber, it substantially reduce the cost of braced manufacture.
Subjects
誤差分析
位移設計法(DSD)
鋼管混凝土柱(CFT)
挫屈束制支撐(BRB)
Buckling Restrained Braces
Error Analysis
Type
thesis
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