预制预应力混凝土楼梯抗弯性能试验研究

Experimental research on flexural behavior of precast prestressed concrete stairs

通过沿跨度方向增加配置螺旋肋钢丝并施加预应力,提出预制预应力混凝土板式楼梯和梁式楼梯。对6块预制混凝土楼梯构件开展了静力加载试验,包括3块板式楼梯和3块梁式楼梯,得到其破坏特征、开裂荷载、挠度曲线及应变分布等。结果表明:增加螺旋肋钢丝并施加预应力后,板式楼梯和梁式楼梯的抗裂性能均得到显著改善,其承载能力均提升25%以上;在适当减少普通钢筋用量后,板式楼梯和梁式楼梯的抗裂性能和承载能力也得以提升。与普通钢筋混凝土板式楼梯相比,预应力混凝土梁式楼梯实现降低自重25%以上。对比构件理论计算结果与试验结果得出,采用混规设计公式得到的预制预应力混凝土楼梯的开裂弯矩和极限弯矩计算值均小于试验值,误差在10%内,满足实际工程精度要求。

By adding spiral rib steel wires along the span direction and applying prestress,precast prestressed concrete slab stairs and beam stairs were proposed.Static loading tests were carried out on 6 precast concrete stair components,including 3 slab stairs and 3 beam stairs,and their failure characteristics,cracking load,deflection curve and strain distribution were obtained.The results show that after adding spiral rib steel wires and applying prestress,the crack resistance of slab stairs and beam stairs are significantly improved,and their load-bearing capacity is increased by more than 25%;after appropriately reducing the amount of ordinary steel,the crack resistance and bearing capacity of the slab stairs and beam stairs have also been improved.Compared with ordinary reinforced concrete slab stairs,prestressed concrete beam stairs can reduce their own weight by more than 25%.Comparing the theoretical calculation results of the components with the experimental results,it is concluded that the calculated values of the cracking and ultimate bending moments of the precast prestressed concrete stairs obtained by the mixed-plan design formula are less than the experimental values,and the error is within 10%,which meets the actual engineering accuracy requirements.