鋼筋混凝土構架非線性動力分析

Abstract

常見用以分析結構非線性行為之樑柱模式為塑性鉸模式，以雙線性撓曲彈簧的降伏模式來 模擬桿件的非線性行為，此法雖為簡易，卻無法將進入非線性後的塑性行為作一個良好的 詮釋。因此，為修正其缺點，本研究所發展的非線性動力分析程式，依當時構材的應力分 佈、塑性區的長度、彎矩-曲率關係與遲滯迴圈的路徑，定義每一階段非線性撓曲彈簧的 勁度，合理的詮釋桿件逐漸塑化的過程。在逐步動力分析時，使用四階阮奇-庫特法(Rung -Kutta Method of Order 4)計算桿件內力，並以不平衡力修正每一階段的誤差，省去非 線性分析時大量迭代運算的時間。最後，與實驗結果比較，證明本程式之分析結果比Drai n-2D更接近實驗值。其主要的理由乃是Drain-2D對非線性撓曲彈簧勁度採雙線性的假設， 致使各桿件於降伏初始時，與結構的實際勁度不符。而本程式則實際的計算非線性撓曲彈 簧的切線勁度，模擬桿件勁度逐漸衰減的過程，使得本程式之分析結果比Drain-2D更接近 實驗值。 The nolinear behavior of reinforced concrete structures under dynamic load is investigated. Lumped plastic hinge model is common to model the nonlinear stru cture members. The stiffness of the hinge is always assumed to be bilinear. It is easy, but cannot have good description of the stiffness decay when the mem ber force is within the inelastic range. This paper is devoted to develop a pr ogram that considers the force distribution along the member, the le□}/ of th e plastic range, the moment-curvature relationship, and hysteresis loop to def ine the member stiffness of each step. The nonlinear dynamic analysis program uses Rung-Kutt method of order 4 to calculate the member force and the concept of unbalanced force to correct the error on each step.The results of the anal ysis of developed program are compared to those of an experiment to ensure the accuracy of the analysis. It is observed that proposed method can predict wel l the experimental response and even has a better result than Drain-2D program .