Developing a Technique to Predict Concrete Spalling of Tunnel Liner Exposed to a Major Fire

Abstract

Exposure of a tunnel concrete liner to a high temperature created as a result of fire will severely impact the performance of the liner. Heating up of the liner will result in degradation of strength and stiffness of the concrete and reinforced steel. Moreover, additional stresses and strains occur in the liner as a result of heat exposure which potentially could lead to spalling. These conditions may severely impact the structural integrity of the tunnel and related structures. This paper presents a method to predict the response of concrete liner during a major fire event in a tunnel. As a first step, temperature profile on the liner surfaces was determined using CFD analysis representing a major fire event within the tunnel. Then the temperature profiles were used as input for structural analysis of the liner. Structural analysis includes a model for pore-pressure build-up caused by heating of moisture.
The outcome of the model for spalling prediction is presented and compared against the experimental results .