The uniform‐load fire behaviors of four full‐scale integral composite beams with superposed slabs were tested, considering the post‐cast‐slab thickness, shear‐connector spacing, and precast‐slab overlap length on the steel‐beam upper flange. The concrete temperature distribution along the slab thickness, the temperature of the rebar inside the slab, the temperature distribution along the steel‐beam height, the bending stiffness, and the overall integrity of the superposed slabs and steel beam were studied. ABAQUS simulations of the temperature‐field and deformation behaviors of the composite beams with superposed slabs under coupled thermal and mechanical loading were performed. No damage to the post‐cast and precast slab bonding interface during the heating process was apparent. The post‐cast joint had no obvious influence on the structure, which could still bear loads. The composite‐beam temperature field and bending stiffness were not significantly affected by the bonding interface of the new and old concrete and the post‐cast joint. Overall, the post‐cast slab thickness and shear‐connector spacing predominantly influenced the composite‐beam fire resistance. The experiment and numerical results agree well, verifying the numerical‐model validity and feasibility.

中文翻译：

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叠合楼板整体组合梁的耐火性

考虑了钢梁上翼缘上的浇铸后板厚，剪切连接间距和预制浇铸板重叠长度，测试了四个全尺寸叠合板的整体组合梁的均布荷载性能。研究了沿板厚的混凝土温度分布，板内部的钢筋温度，沿钢梁高度的温度分布，弯曲刚度以及叠置板和钢梁的整体完整性。进行了ABAQUS模拟，模拟了热力和机械载荷作用下叠合板叠合梁的温度场和变形行为。在加热过程中，对预制板和预制板的粘结界面无明显损坏。铸后接头对结构无明显影响，仍然可以承受负荷。新旧混凝土与后浇缝的粘结界面对复合梁的温度场和弯曲刚度没有显着影响。总体而言，浇铸后的楼板厚度和剪力连接器间距主要影响复合梁的耐火性。实验与数值结果吻合良好，验证了数值模型的有效性和可行性。