- 學位論文
露出型柱腳遲滯行為之有限元素分析
Finite Element Analysis of Hysteretic Behavior of Exposed Column Base Connections
摘要
本研究利用有限元素分析軟體ANSYS探討不同型式之柱腳配置，受軸壓力及反覆載重共同作用下之力學行為，以釐清接頭區複雜的機制，並建議改善其束縮行為，使露出型柱腳有足夠的韌性消散地震力所產生的能量。柱腳配置的研究參數包含基板厚度、錨定螺栓數量、加勁板的設置與否及是否於錨定螺栓施加預拉力，共11組分析模型。研究結果顯示，增加基板厚度或設置加勁板雖可提高柱端彎矩強度，卻不利於能量消散；額外配置第三排錨定螺栓或施加預拉力不僅可提高彎矩強度，亦有助於能量消散。整體而言，當基板採用0.9倍設計厚度並於錨定螺栓施加預拉力時，相較於設計原型可增加約28%之能量消散。露出型柱腳之消能機制在於使基板或錨定螺栓可發展出足夠的塑性變形，又以基板之貢獻較為顯著，因此當露出型柱腳配置額外之加勁板時，建議酌減基板厚度以期更佳的能量消散並有助於提高自復位能力。
並列摘要
This research was conducted to investigate the mechanical behavior of exposed column base connections subjected to axial compression and flexure through finite element analysis, and further to clarify the complex mechanism within the connection as well as to recommend the improvement for pinching behavior and more energy dissipation. Parameters considered for exposed column base connection included thickness of the base plate, quantity of the anchor bolt, with or without stiffener, and anchor bolt with preload or not. Analysis results indicated that increasing thickness of the base plate or installing the stiffener could enhance the column flexural strength but harm to the energy dissipation. However, setting the third row of the anchor bolts or preload the anchor bolts could increase not only column flexural strength but also energy dissipation. Overall, the column base connection adopting 0.9 times of the designed thickness of the base plate with preload on anchor bolts resulted in 28% higher energy dissipation, compared to the prototype. The energy dissipation mechanism of exposed column base connections is controlled by the plasticity deformation capacity of the base plate and anchor bolts while the base plate dedicate more significantly. Hence, to increase the energy dissipation and self-centering capability, it is suggested to reduce the thickness of the base plate appropriately when the exposed column base connection strengthened by the stiffener.