老舊建築物於設計時大多缺乏耐震設計觀念造成構件韌性能力不佳,例如箍筋為90度彎勾、梁柱接頭區無剪力筋、主筋搭接或錨定長度不足、梁柱構材端部箍筋間距太寬、混凝土強度不足或混凝土保護層厚度不夠等,產生構材韌性或強度不足之情形,容易發生脆性破壞。本文目的希望建立一套精確預測構材之塑性旋轉角值的方法,用於判斷結構物的韌性是否良好。因此以自行義之塑鉸值輸入SAP 2000作分析是相當重要的。對於鋼筋混凝土梁柱構材塑鉸值之計算是以Park【27】、Kawashima【14】及Mander【15】三個混凝土應力應變模式為基礎理論,各自發展出非線性分析程式以推算出梁、柱構材之彎矩-曲率關係,並使用不同方法將彎矩-曲率曲線雙線性化,再配合塑性旋轉角值及塑鉸長度之經驗公式求得塑鉸值,進而模擬梁柱構材之塑性行為。同時利用SAP2000之非線性推覆分析方法,求得建築物容量曲線並經由ATC-40所建議之容量譜法求得需求譜與容量譜的交點,推估老舊建築物之耐震能力以比較不同狀況下耐震能力之差異。
A lot of old buildings were designed without based on seismic requirement, thus they had not enough ductile ability for the buildings. Such as, transverse reinforcement was 90° hook, or beam-column connection was lack of shear reinforcement, or longitudinal reinforcement was spliced, or transverse reinforcement spacing was too large in the plastic hinge region of members, or concrete strength was poor and cover depth was not enough etc. These made members become less ductile ability and without enough strength, and caused brittle easily. The purpose of this research is to establish more precise predictable method of the plastic rotation angle value. And then we can judge further while the ductile ability is good or bad. Thus we use different stress-strain model to analyze and evaluate the moment-curvature curve of reinforced concrete members. And we try to get the curve linearity with different method. And then use the experience formula of plastic rotation value and plastic hinge to calculate plastic hinge value. Further more, we simulate the plastic behavior of members. At the same time, we concern nonlinear pushover analysis of SAP2000 to evaluate the capacity curve of the buildings, and also Use the result make intersections of the demand spectrum and the capacity spectrum by ATC-40 suggested method to estimated the difference the seismic evaluation of old buildings in the different situations.