Multi-index assessment of road blockage risk due to seismic event-induced building debris

The accessibility of road systems is key to facilitating emergency responses in the aftermath of a severe disaster. However, collapsed buildings and debris may cause road blockages, impeding disaster relief efforts after a major earthquake. This study aims to present an efficient and generic assessment method for evaluating the risk of road blockage due to seismic event-induced debris. First, the probability of building collapse in city blocks and the effects of building debris after an earthquake scenario are estimated based on building types, seismic design levels, soil conditions, and local ground motion intensities of the adopted earthquake scenario. Subsequently, the seismic risk of road sections is assessed by considering the collective effects of nearby street profiles, including building materials, heights, and the shape factor of city blocks. This study considers various interpretive building environment parameters and employs three post-earthquake risk indexes to represent different aspects of seismic risk of a road system, including passability loss, affected road length ratio, and road interruption severity. To demonstrate the applicability of the proposed method, the rescue routes in Taipei City, Taiwan, are adopted as a case study. The proposed method can effectively distinguish high-risk roads as valuable information, and the results have been provided to local government disaster relief units for reference.