| Summary: | 碩士 === 臺灣大學 === 土木工程學研究所 === 98 === The present study of this thesis is focus on the seismic performance of a gusset plate subjected to frame action in Buckling-Restrained Braced Frames (BRBF). In order to test the stress concentration effects on gusset palte edges induced by frame action, an equivalent sturt model was proposed to estimate the frame action forces on a gusset plate, and a new design criteria by considering frame action and brace action simultanesly was proposed.
In order to interpret the difference of each design methods, i.e. the AISC design method, or the design method by considering frame action presented in this thesis, a totally five full-scale, one story BRBF was tested to investigate the seismic performace of gusset plates under frame action. Single gusset plates was used in Specimen 1 and 2, dual gusset plates was used in Specimen 3 to 5, and edge stiffeners was applied on the gusset plate edges in specimen 1 and 3, so as to identify the contribution of edge stiffeners on gusset plate edges. One of gusset plates in five specimens was buckled after test, which was designed using AISC method, and the others gusset plates, which was designed using the theoretical formula presented from this study, was all fine. From the test observation, the edge of gusset plates will suffer large stains by frame action, but the applying of edge stiffeners can reduce the maginitude of normal strains effectively on the edge of gusset plates, and it seems true that single gusset plates will suffer larger frame action compared with dual gussets.
Besides the test results, nonlinear FEM program ABAQUS was used to simulate the responses of specimen. This study describes the detailed analytical model and the modeling techniques, such as material model, boundary conditions, initial imperfections. The cyclic base shear versus the story drift relationships obtained from the test and FEM analytical results are quite agreeable. The analytical result confirm that the magnitude of frame action forces on a gusset plate can be accurately simulated. And baed on the theortical formula presented in this thesis, the edge stresses can also be accurately predicted when compared with FEM analytical results, so as to confirm the proposed design method in this thesis.
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