Probabilistic evaluation framework for fire and fire following earthquake

This work provides a probabilistic framework to evaluate the performance of a structure under fire and fire following earthquake, by studying response of the structure for several limit states and incorporating uncertainties in demand and capacity parameters. The multi-hazard framework is then applied to a steel moment resisting frame (MRF) to evaluate the structural performance of the MRF under post-earthquake fires. The study develops probabilistic models for key quantities with uncertainty including fire load, as well as yield strength and modulus of elasticity of steel at elevated temperatures. The MRF is analyzed under several fire scenarios and fire locations. Results show that the location of fire in the frame (e.g., lower vs. upper floors and interior vs. exterior bays) affects the element response. Compartments in the interior bays reach limit states faster than those on the perimeter of the frame, and upper floors reach limit states sooner than lower floors. The post-earthquake damage does not affect the structural response under fire for the considered limit states, but post-earthquake fire increases the drift demand on columns located at the perimeter of the structure.