Collapse seismic risk assessment for irregular mid-rise buildings

Mid-rise buildings, which may be used as office or apartment buildings, are very common structures in urban areas. Because these buildings are usually heavily populated, the casualty caused by the collapse of these structures in an earthquake could not be overestimated. Therefore, developing a suitable assessment method to identify these buildings with high collapse risk is an important issue. This paper presents a probabilistic assessment method, which involves nonlinear response-history analysis together with incremental dynamic analysis (IDA), to assess the collapse risk of a mid-rise building, so high-risk buildings and their damage patterns can be identified. This methodology is developed based on the procedure of collapse fragility analysis proposed by FEMA P-58, while the local and damage global criteria that define collapse failure are adopted from ASCE 41-13 and PEER-TBI, respectively. Finally, for demonstration, the proposed procedure is applied to assess the collapse risk of a mid-rise RC building that collapsed in a major earthquake occurred in Taiwan, 2016.