Experimental study on the residual load-bearing performance of prefabricated reinforced-concrete beams after exposure to fire

Purpose Aim to investigate the degradation laws of joint performance and flexural bearing capacity of prefabricated reinforced-concrete beams with two assembly methods after fire exposure, providing a theoretical basis for fire-resistant design. Design/methodology/approach Six full-scale prefabricated reinforced-concrete beams were designed (4 subjected to fire exposure and 2 as ambient-temperature controls), followed by fire exposure tests adhering to the ISO 834 standard heating curve and post-fire static bending tests. A thermo-mechanical coupled finite-element model was developed using ABAQUS to simulate their post-fire flexural bearing performance. Findings Significant temperature gradients in beam sections post-fire, with normal joint performance; all beams exhibited flexural failure (tensile steel yielding and compressive concrete crushing). Ultimate load and stiffness decreased with fire duration, with numerical results consistent with experiments. Originality/value First comparative study on fire resistance of two assembly methods, validating joint reliability; establish an effective model to offer data and methodology support for fire-resistant design and post-fire assessment of prefabricated structures.