Experimental and Theoretical Study of Fire Resistance of T-Shaped Prefabricated Composite Reinforced-Concrete Beams

The performance of T-shaped prefabricated composite reinforced-concrete (T-PCRC) beams under fire conditions differs from that of T-shaped monolithic beams. Therefore, in this study, fire tests on eight T-PCRC beams were conducted, focusing on the effects of load ratio, compositing parameters, and concrete cover thickness on the fire resistance of T-PCRC beams. During the fire tests, the temperature field and vertical deflection of the beam cross section were measured, and the test phenomena and failure characteristics of the beams under fire were observed. The results indicate that the load ratio significantly affects the fire resistance limit of T-PCRC beams. The fire resistance limit of T-PCRC beams with a load ratio of 0.6 is reduced by nearly 50% compared to those with a load ratio of 0.4. Numerical simulations were subsequently performed to investigate the temperature field of T-PCRC beams, and the simulated fire resistance showed good agreement with the test results. Based on the moment–curvature relationship of T-PCRC beams, a cross-section analysis method for assessing the fire-resistant limit of T-PCRC beams under fire conditions is proposed.