削切蓋板鋼骨梁柱接頭之耐震行為研究

Abstract

本研究設計四組全尺寸削切蓋板梁柱接頭試體，以強度設計法決定削切蓋板尺寸。研究的重點著重於此種削切蓋板梁柱接頭的塑鉸位置、彈性勁度、強度、韌性行為及能量消釋能力，並藉由削切蓋板與柱、梁翼板間之各種接合設計來探討其差異性。此種新型式的接頭與傳統蓋板梁柱接頭最大的不同點在於蓋板經由削切，削減蓋板強度與勁度，迫使所有的能量消釋皆發生在此削切蓋板而非梁上，在歷經地震作用下削切蓋板達到非彈性變形階段後，鋼梁仍保持在彈性範圍，而無顯著的破壞產生。 本研究利用有限元素分析軟體ABAQUS進行結構試體非線性有限元素分析，以探討削切蓋板梁柱接頭之力學行為與機制，並針對單一的削切蓋板進行有限元素分析之參數研究，藉由改變其削切幾何形狀與厚度來探討壓力強度。 本研究結果顯示：(1) 削切蓋板梁柱接頭可確保塑性變形發生在削切蓋板上而非梁上，進而避免梁的挫屈發生，且四組試體在反覆載重作用下皆可達到位移角□□= 0.05弧度而無明顯的強度遞減，(2) 削切蓋板梁柱接頭試體的彈性勁度與傳統蓋板梁柱接頭相近，滿足剛性接頭的彈性勁度要求，(3) 接頭主要的梁端位移由梁因削切蓋板塑性變形所致之梁端位移分量所提供，柱、梁柱交會區及梁彈性變形所提供的比例較小，(4) 梁翼板最大應變發生在削切蓋板端部之梁翼板上，試驗結果顯示四組試體最大應變約等於降伏應變，(5) 在削切蓋板上加置三角型加勁板能提高試體整體強度，(6) 削切蓋板參數研究所得之非線性迴歸模型在預估削切蓋板的挫屈力量有一定的準確度。

The connection with flange plates to connect the steel beam flanges to the column has been recommended by FEMA 350 (2000) as a prequalified fully restrained moment connection. The flange plates are detailed to remain elastic and, therefore, force a plastic hinge forming in the beam, resulting in beam buckling at large deformation cycle. The objective of this study was to develop connection details, which limit energy dissipation in an easily repairable device instead of beam. The paper presents experimental and analytical results of the proposed moment connections utilizing steel Reduced Flange Plates (RFPs) as an energy dissipating mechanism. RFPs were welded to the Concrete-Filled-Tube (CFT) column and either bolted or fillet welded to the beam flanges. Cyclic tests were conducted on four full-scale subassemblies with a steel beam and a CFT column. The test results showed that (1) the specimens were able to develop full beam moment capacity and interstory drift angle in excess of 0.05 radians, (2) RFPs, which experienced buckling at large drift cycle, were also effective in dissipating energy, and (3) beam buckling was prevented from the test. A general-purpose nonlinear finite element analysis program (ABAQUS) was used to perform correlation study. The analysis showed that the proposed connection and the flange plate moment connection have similar force-deformation characteristics.