鋼結構同心斜撐構架簡化模型之靜動態分析

Abstract

在地震發生頻繁的台灣，結構行為數值模擬近年來已被廣為應用於鋼結構建築的耐震設計上，隨著結構複雜度的增加及結構行為模擬精確度的要求，簡化模型的使用需求日增。本研究使用國家地震中心所開發的非線性分析軟體Platform of Inelastic Structural Analysis for 3D Systems(PISA3D)來建立三層樓與六層樓典型鋼結構同心斜撐構架之簡化模型，以Fishbone及本研究提出的Brace-Column作為簡化方式，透過非線性靜態側推分析（pushover）以及非線性動力分析結果，比較不同模型之樓層位移、加速度、遲滯消能行為等參數，探討簡化模型的精確度。 分析結果顯示，簡化模型與原結構之結構週期相似度高而側推分析之強度與勁度差異則低於10%，而樓層位移除了最大考量地震以外，差異值都不超過10%；不同模型最大樓層加速度具有合理的精確度，遲滯消能反應則顯示Fishbone模型可以準確模擬出完整Frame模型之消能行為。

Numerical analysis has been widely used to design steel structures in seismic areas. As the complexity of structures and the demand of analysis accuracy increase, it is required to develop more efficient numerical models. This study used simplified models for concentrically braced steel frame, namely Fishbone model and Brace-Column model. The analysis program is PISA3D (Platform of Inelastic Structural Analysis for 3D Systems), which is developed by National Center for Research on Earthquake Engineering. According to the results of nonlinear static analysis (pushover) and nonlinear dynamic analysis, we compare the story drift, floor acceleration, and hysteretic responses of different models and investigate their accuracy. The model buildings are typical three- and six-story SCBF. Analysis results show that the structural periods are similar among different models. Also, the results of nonlinear static analysis show that the difference of both strength and stiffness between different models is less than 10%. The results of nonlinear dynamic analysis show that the difference of story drift is less than 10% for service-level and design-level earthquakes; the floor accelerations of different models are similar under most circumstances; the hysteretic responses suggest that Fishbone models is the most accurate to capture the behavior of complete Frame model for SCBF structures.