Influence of Cracking on Heat Propagation in Reinforced Concrete Structures

Abstract

Seven beams, four columns, and two single-bay one-story frames have been recently designed in order to create different crack patterns and to investigate heat propagation in cracked reinforced concrete structures. Commercially available finite-element software is adopted to describe the thermal behavior of precracked reinforced concrete structures in fire, and to evaluate the effect of cracking. Both the experimental and numerical results showed that heat propagation tended to increase in the cracked regions compared with undamaged regions. The ultimate bearing capacity of structures in question in fire was calculated by means of engineering-oriented methods, by introducing or neglecting the effects that cracking has on the thermal field. In the former case, the agreement between the calculated bearing capacities and the test results was better. In the analysis of cracked reinforced concrete structures in fire, therefore, assuming a uniform temperature distribution in each longitudinal fiber and the same thermal field in all sections is not correct and safe, as the temperature increase in the cracked regions is not taken care of.