Study on Residual Flexural Performance of Precast Prestressed Hollow Core Slabs After Exposure to Fire

The structural performance of precast prestressed hollow core slabs after exposure to fire was experimentally and numerically investigated in this paper. Four levels of fire duration were considered in the experiments. All specimens both loaded without heating and after exposure to fire exhibited flexural failure. The initial stiffness, cracking loads and ultimate loads were observed to degrade with increasing levels of fire duration. A numerical model was developed to predict the response of precast hollow core slabs after fire using ABAQUS. The user subroutine USDFLD available in ABAQUS was employed to consider the effect of the maximum temperature experienced by the concrete and cold worked wires on their material properties. The predicted temperature and load-deflection relationships from the numerical model were in good agreement with the experimental results. Calculation method was proposed for the precast prestressed hollow core slabs after exposure to fire based on the plastic analysis to predict their ultimate moment capacity. The predicted moment capacity compares well with the experimental results.