Evaluation of Flexural Capacity of RC Elements Exposed to Fire

When Reinforced concrete flexural members of a structure are exposed to fire they tend to lose their original flexural capacity. It is important to assess the reduction in flexural capacity. This paper presents a simple numerical model for prediction of residual moment capacity of fire damaged RC flexural element after cooling to ambient temperature. The prediction of residual moment capacity of fire damaged RC element has been carried out by assessing the residual properties of fire affected concrete and steel. The proposed prediction model has been arrived at by comparing various constitutive models available in literature for the residual strength of steel rebar and concrete. A total of 9 fire damaged RC beams (tested after cooling) were selected from literature for this study. It is seen that the predicted results were then compared with the experimental results. The predicted results using this proposed model have better agreement with the experimental results as compared to those by existing methods.

Keywords: Fire Exposure; Residual Mechanical Properties of Steel rebar and concrete; Loss of Strength; Air cooling; Residual Moment Capacity; Residual Strength Constitutive Models