Performance-based fire assessment of a fully automated multi-storey steel parking structure: A computational approach

Conducting a structural fire analysis for automated steel parking structures present a complex challenge due to the vulnerability of steel structures to high-temperature exposure, the unpredictability of fire source locations, and the enhanced thermal loading due to high concentration of vehicles in a compact area. This study conducted a performance-based assessment (PBA) of a fully automated multi-storey steel parking structure under various fire scenarios. The assessment employed Fire Dynamic Simulator (FDS) to simulate the fire behavior in different scenarios and record the temperature developments within the structure. OpenSees was utilized to perform the subsequent thermo-mechanical analysis and obtain the fire responses of the parking structure. The fire analyses demonstrated that the ignition location and ventilation conditions within the structure considerably affects fire propagation and structural responses. Fire cases initiated on the first floor led to a slightly higher drift ratio than those initiated on the 9th floor. The PBA based on strain and drift ratio led to different results. Cases 1, 2, 4, and 6 maintained life safety based on drift ratios, and strain results indicated a collapse prevention level. For centrally located fire cases, the drift ratios were at collapse prevention level while based on strain values, the elements already exceeded the collapse prevention limit. Under all fire cases, the ultimate performance level of the structure has exceeded the collapse prevention level. The findings highlight the necessity of employing fire safety measures in multi-storey parking structures and enhancing their fire resilience.