挫屈束制消能支撐構架梁柱效應對接合板耐震行為研究

Abstract

本研究主要為探討消能支撐構架中梁柱效應對接合板耐震行為，測試在構架效應下，接合板在受梁、柱之開合效應下端部應力集中之影響，提出一等效支撐概念，設計接合板在構架運動之受力及斜撐軸力下所需之尺寸。並為瞭解與AISC-LRFD(2005)接合板設計方法之差異，設計五組接合板試體，分別使用於五組實尺寸一層樓之消能支撐構架試驗。其中試體一及二為利用單接合板將消能支撐與構架接合，試體三至五採用雙接合板將消能支撐與構架接合，並且為了測試接合板端部側邊加勁板對接合板端部的影響，於試體一及三之接合板試體端部加入側邊加勁板。五組試體中，除了其中一組為依照AISC-LRFD(2005)設計方式而得之單接合板在試驗時發生挫屈外，其餘四組試體於試驗後其行為良好，並由試驗觀察出，構架梁柱之開合效應，對接合板端部會因應力集中造成可觀的應變量，但加了側邊加勁板後，應變量即可降低，而單接合板與雙接合板在接合板與梁、柱界面比較上，單接合板之應變較雙接合板來得高。本研究並利用非線性有限元素分析程式ABAQUS(2005)，針對五組試驗構架進行模擬與分析，可預測五組試驗構架之整體行為。而經由實驗與有限元素分析之結果，可知本研究所提出之等效支撐模型確實可以準確預測接合板在構架梁柱效應下之受力，進而驗證本研究所提出之接合板設計方法。

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.