台灣混凝土彈性模數折減對鋼筋混凝土結構耐震與崩塌性能評估影響研究

台灣混凝土實際彈性模數E_c根據過去的研究，應為現行規範（E_c=15000(f_c')^(0.5)）的80%左右，即為（E_c=12000(f_c')^(0.5)），台灣混凝土結構設計規範未來將會據此修正，修正時除了跟規範相關的彈性模數條文須一併因應檢討外，本研究希望探討現在即存鋼筋混凝土結構物，當其彈性模數折減時，受地震力作用下的耐震與崩塌性能之影響。本研究參考FEMA P695報告，建立原型構架（E_c=15000(f_c')^(0.5)）及E_c折減為80%後的實驗構架（E_c=12000(f_c')^(0.5)），進行非線性靜力側推與動力歷時分析和增量動力分析法，藉此比對原型構架與實驗構架的行為。由分析結果可初步推斷，彈性模數折減雖會稍微降低構架的結構耐震與崩塌性能，但構架依舊能夠符合現行耐震與崩塌性能規範的需求。

關鍵字

彈性模數；耐震評估；崩塌評估

並列摘要

According to recent research, the actual elastic modulus E_c of concrete in Taiwan is 80% of E_c calculated by current design code. Current codes which relate to E_c would be modified in the future because of the reduction of E_c. The objective of this research is investigating the influences of reduced E_c on current RC structure designs. Furthermore, this research also evaluates the seismic and collapse capability of structure with reduced E_c under the seismic load. Based on FEMA P695 report, this research builds control frame models (E_c = 15000 (f_c')^(0.5)) and experimental frame models (E_c = 12000 (f_c')^(0.5)) to conduct nonlinear push-over analysis, time history analysis and incremental dynamic analysis. The results show that the nonlinear responses of structures with reduced E_c would indeed lower both seismic and collapse capability. Although the capability of Experimental Frames (0.8 E_c) slightly decrease according to nonlinear analysis, all of them still meet the requirements of current code in Taiwan.