當建築物底層支撐柱遭受外力破壞時，此時若結構物之垂直承載能力小於結構物的自重，將可能產生漸進式崩塌。本研究為了探討RC耐震建築物在底柱破壞時其垂直承載能力之參數影響研究，依據國內耐震設計規範，設計27棟RC耐震結構物，針對不同之樓層數、跨徑及震力係數，進行側推分析(Pushover)，可得其水平耐震強度，再移除不同位置之底層柱後進行下推分析(Pushdown)，並與擬靜態分析方式推估垂直崩塌強度，除了比較兩者垂直/水平強度比值外，再以簡易之崩塌評估方式，判斷27棟耐震結構是否能抵禦漸進式崩塌。分析結果顯示，跨徑為影響強度比值的主要因子，而樓層數、震力係數及移除不同柱位較無影響。當跨徑增加時強度比則會降低而樓層越高的結構物會越顯著，當樓層數增加時強度比提高。震力係數增加能夠提升耐震強度與抗垂直崩塌能力，但強度比略微降低。27棟結構物在三種不同移除柱位下，共有81棟模型，其中若以桿件的降伏強度計算時有13棟模型產生漸進式崩塌；若以極限強度計算時則會有6棟模型產生崩塌，而崩塌情形皆發生於跨徑較大之結構物，但前者的計算方式評估結果較為保守，因此可以得知，經耐震設計之結構物，同時能抵抗地震也能預防漸進式崩塌的發生。

Progressive collapse response of an RC building may be induced if one of its ground-story columns is destroyed and the load-bearing capacity of the structure is less than the weight of the structure. This study intends to investigate the influence of some structural parameters on the load-bearing capacity of RC building frames under column loss. According to the seismic design code in Taiwan, twenty-seven earthquake-resistance RC buildings frames were designed with varied number of stories, span length and seismic coefficients. Nonlinear static pushover analyses were conducted to examine the seismic performance of the RC buildings frames. Nonlinear static pushdown analyses were conducted to those frames under three column-loss scenarios. Ratios of column-loss to seismic resistance were used to evaluate the progressive collapse potential. Analysis results indicated that span length may be the most critical factor for collapse potential of seismically designed buildings frames. The resistance ratio increased with decreased span length and number of stories. However, it was insensitive to the seismic coefficient. Both the yield and ultimate flexural strengths could have approximate predictions for collapse potential. However, the former could have more conservative results than the latter. Therefore, it can be used to make conservative evaluation for the progressive collapse potential of seismically designed RC building frames.

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