RC構架桁架化之耐震能力擬彈性分析

Abstract

本文旨在探討鋼筋混凝土構架之耐震能力，為修正耐震分析在構架初始勁度預測上之正確性，並改善擬彈性法在應變能計算上之便利性和精確度，利用傳統桁架模式和鋼筋混凝土之受力行為將原始構架轉換成為等值桁架模型，再針對此桁架模型進行擬彈性分析，以評估鋼筋混凝土構架之耐震能力。 構架耐震能力分析之流程，首先定義鋼筋與混凝土之應力應變模式，並對此模式進行簡化以利軸力應變能之迅速求得，再利用桁架化方法將原始鋼筋混凝土構架構件轉換為等值桁架桿件模型，進而應用SAP程式逐步放大地震側力求得結構物之擬彈性反應以及不同地震側力下之各桿件軸向受力情況，配合擬彈性法能量守恆之觀念，將超過軸力彈性範圍之應變能置換為塑性應變能，即可得到結構物之非線性反應，並求出極限基底剪力與頂層側位移作為耐震能力評估之依據。 本文中採用一系列具有實驗資料之鋼筋混凝土構架進行耐震能力分析，藉由桁架化擬彈性分析和非線性靜力側推分析之結果與構架實際實驗數據相互比對，得以驗證此桁架化方法配合擬彈性法進行耐震能力之分析可獲得良好結果。

The objective of this paper is to investigate the seismic capacity of RC frame. In order to modify the forecast to the initial stiffness of frame,and improve the conveniency and accuracy for the calculation of strain energy. The original RC frame can be transferred into an equivalent trusslized model according to RC member behavior dealing with the concrete and steel stressed properties. Then, the seismic capacity of RC frame can be assessed by adopting the Pseudo-elastic analyss to the equivalent trusslized model . Firstly, the stress-strain behavior model for steel and concrete should be defined, and this model can be simplified and applied to calculate the strain energy of axial force quickly. Secondly, the original RC frame can be transferred into an equivalent trusslized model. Then, the member behavior and the Pseudo-elastic response can be figured by using the SAP program and magnifying seismic lateral force step by step. According to the concept of Pseudo-elastic approach, the nonlinear strain energy can be transferred by the strain energy exceeding the linear range. Finally, the nonlinear response of structure can be obtained. Thus, seismic capacity can be assessed according to ultimate base shear and roof displacement. A series of RC frames with experimental data are analyzed for seismic capacity in this thesis.The acceptable accuracy and reliability of trusslized Pseudo-elastic approach for seismic capacity can be verified by comparing with experimental data and Pushover analysis results.