波形钢腹板PC组合箱梁受扭全过程分析

Analysis of the Whole Torsional Process of PC Composite Box Girder with Corrugated Steel Webs

为了揭示波形钢腹板PC组合箱梁的受扭作用机理,根据薄壁结构理论分析了截面扭矩分配及受扭变形协调条件,采用USTMT模型对波形钢腹板PC组合箱梁进行了受扭全过程计算,并在其基础上对混凝土抗压强度、波形钢腹板厚度和屈服强度、预应力钢束初始预应力及普通钢筋配筋强度比进行了参数分析,发现以波形钢腹板PC组合箱梁中混凝土板和钢腹板扭率相同为变形协调条件较为合理;开裂扭矩、屈服扭矩和极限扭矩均随混凝土立方体抗压强度的增大而增大,但波形钢腹板承担的扭矩几乎不变;波形钢腹板厚度对混凝土板承受的扭矩几乎无影响,但使波形钢腹板承担的扭矩增大;波形钢腹板屈服强度f wy对开裂扭矩和混凝土板承受的极限扭矩几乎无影响,但使屈服扭矩和波形钢腹板承担的极限扭矩增大,混凝土强度越高,能够使波形钢腹板发生屈服的钢材强度等级越高;极限扭矩随配筋强度比ξ的增大而增大,且存在一个ξ的敏感区域,同时随钢束初始预应力的增大而线性增加,但增幅较小,尤其是对波形钢腹板承受的扭矩几乎没有影响。

In order to reveal the torsional action mechanism of PC composite box girder with corrugated steel webs,the section torque distribution and torsional deformation compatibility condition were analyzed according to the thin-walled structure theory.The USTMT model was used to calculate the whole torsional process of PC composite box girders with corrugated steel webs.Based on this model,the concrete compressive strength,the thickness and yield strength of corrugated steel webs,the initial force of prestressed tendons,and the strength ratio of the reinforcement were analyzed.The results show that it is reasonable to take the same torsional curvature of concrete slab and steel web as the deformation compatibility condition in PC composite box girders with corrugated steel webs.The cracking torque,yield torque and ultimate torque develop with the increase of the concrete cube compressive strength,but the torque carried by corrugated steel webs is almost unchanged.The thickness of corrugated steel webs has little effect on the torque carried by concrete slabs,but increases the torque carried by corrugated steel webs.The yield strength f wy of corrugated steel webs has little effect on the cracking torque and the ultimate torque carried by concrete slabs,but it increases the yield torque and the ultimate torque carried by corrugated steel webs.The higher the concrete strength,the higher the strength grade of steel that can make the corrugated steel web yield.The ultimate torque increases with the increase of the ratio of the strength of the reinforcement,and there is a sensitive region toξ.At the same time,it increases li-nearly with the increase of the initial prestress of the tendons,but the increase rate is small,especially for the torque carried by corrugated steel webs.