单调荷载下体外预应力钢-混凝土组合梁的受力性能

基于3根模型梁试件的单调静力试验,对体外预应力钢-混凝土组合梁的受力性能进行了研究.研究表明:施加体外预应力可以有效提高组合梁的抗弯承载力,但试件的延性有所降低;试件纯弯段截面应变分布符合平截面假定;增大栓钉间距可以提高试件的极限变形能力,但对其抗弯承载力的影响不大;试件的抗剪连接程度越低,达到极限荷载时栓钉滑移值越大.结合试验并通过有限元建模,分析了混凝土强度等级、有效预应力、预应力筋线型、栓钉间距等对体外预应力组合梁受力性能的影响.最后,在考虑了预应力筋作用的基础上,提出了体外预应力组合梁抗弯承载力的简化计算方法,该方法可为体外预应力组合梁的设计计算提供参考.

Static behavior of steel-concrete composite beams prestressed with external tendons under monotonic loading

According to the monotonic loading experiment of three specimens,the static behavior of steel-concrete composite beams prestressed with external tendons was investigated.The results show that adding prestressing with external tendons can effectively improve the bending capacity of composite beams with reduced ductility at the same time.Strain distribution at the cross section in pure flexure zone remains approximately linear.Increasing the spacing of studs welded on steel beams can improve ultimate deformability of prestressed beams with slight effect on bending capacity.With the decrease of shear connection degree,the slip of studs increases at ultimate load.According to different finite element models of composite beams prestressed with external tendons,the effects of concrete compressive strengthen,effective prestress,external tendons profile and studs spacing on the static behavior of composite beams were discussed.A simplified calculation method of bending capacity was proposed based on prestress effect to provide references for the design and calculation of composite beams prestressed with external tendons.