预应力箱梁底板纵向裂缝及横向应力影响研究

Research on Longitudinal Cracks and Transverse Stress of PC Box Girder Floor

横向拉应力是箱梁底板纵向裂缝产生的最主要原因,且底板横向应力的大小有多种影响因素。基于箱型截面梁的受力特征,分析计算各影响参数产生的横向应力,推导箱梁底板横向应力计算公式。以某大跨度预应力连续箱梁桥为背景,分析不同影响因素相对应的参数变化对底板横向应力产生的影响,并结合现场部分实际观测数据进行对比。研究结果显示底板预应力钢筋产生的径向力及底板顺桥向压应力在预应力箱梁底板处造成了较为显著的横向应力,同时底板横向长度等因素也会对预应力箱梁底板处横向应力产生较大影响。

The transverse tension stress is the main cause of the longitudinal cracks in the box girder floor,and there are many factors affecting the transverse stress.Based on the mechanics characteristic of box girders,the transverse stresses produced by various influencing parameters were analyzed and calculated,and the formula for transverse stresses was derived.This paper analyzed the influence of different factors&parameter variation on the transverse stress of the floor with a long-span continuous box girder bridge,and compared it with measured data.The results showed that the transverse stress caused by the radial force of prestressed steel bar and the compressive stress along the bridge direction was more obvious,and the transverse stress of the floor would be greatly affected by the width of the floor and other factors.