新型外包波纹钢-混凝土组合梁抗火性能研究

Investigation on Fire Resistance of Novel Corrugated Steel-encased Concrete Composite Beams

文中利用ABAQUS建立了组合梁热-力耦合模型,通过分析组合梁跨中挠度、耐火极限随温度变化曲线研究了荷载比、波纹钢腹板厚度、下翼缘钢板厚度和预应力筋保护层厚度对其抗火性能的影响.结果表明:高温作用下,新型组合梁的钢腹板未发生鼓曲、角钢连接件起到较好的抗滑移,耐火性能显著增强.荷载比越大,临界温度越低,当荷载比取0.3~0.5时,新型组合梁具备较好的变形性能,临界状态为形成塑性铰的强度破坏.随波纹钢腹板厚度增加,新型组合梁的耐火极限提升,且提升幅度随荷载比的增大而减小;随下翼缘钢板厚度增加,新型组合梁的耐火极限提升,且提升幅度随荷载比的增大而增大;预应力筋保护层厚度小于40 mm时,组合梁的耐火极限随厚度的减小而降低,大于40 mm时,影响较小.

The thermal-mechanical coupling model of composite beams was established by ABAQUS.The influence of load ratio,thickness of corrugated steel web,thickness of lower flange steel plate and thickness of protective layer of prestressed tendons on the fire resistance of composite beams was studied by analyzing the curves of mid-span deflection and fire resistance limit with temperature.The results show that under high temperature,the steel web of the new composite beam does not bulge,and the angle steel connector plays a good role in anti-sliding,and the fire resistance is significantly enhanced.The greater the load ratio,the lower the critical temperature.When the load ratio is 0.3~0.5,the new composite beam has good deformation performance,and the critical state is the strength failure of plastic hinge.With the increase of corrugated steel web thickness,the fire resistance limit of new composite beams increases,and the lifting range decreases with the increase of load ratio.With the increase of the thickness of the lower flange steel plate,the fire resistance limit of the new composite beam increases,and the lifting range increases with the increase of the load ratio.When the thickness of the protective layer of prestressed tendons is less than 40 mm,the fire resistance of composite beams decreases with the decrease of the thickness.When it is greater than 40 mm,the influence is small.