节段预制拼装波形钢腹板箱梁桥偏载作用下扭转性能试验研究

Experimental Study on Torsional Behavior of Precast Segmental Box Girders Bridge with Corrugated Steel Webs under Eccentric Loading

为研究节段预制拼装波形钢腹板组合箱梁桥偏载作用下的扭转性能,通过4个缩尺试验模型试件及8个足尺数值模型试件,考察节段式箱梁在偏载作用下的挠度及应力发展规律,分析成型工艺、接缝数量、横隔板布置、波纹形状等参数对节段式箱梁扭转特性的影响.结果表明,相对于整体式梁,节段式梁偏载作用下的挠度增大效应可提高10%~15%;节段式箱梁因偏载引起的剪应力增大系数可达1.5倍,尤其需引起注意;成型工艺、横隔板布置对其扭转增大效应影响较大,而波高、接缝数量则影响较小.根据能量法提出考虑接缝影响的该类型桥梁抗扭刚度实用计算方法,同时给出了一些设计建议.

In order to study the torsional behavior of precast segmental box girders bridge with corrugated steel webs under eccentric loading,four 1:10scaled models of segmental beam are manufactured for the first time,and eight full-scale FEA model are built considering the joint between segments.Deflection and stress variations in the segmental box girder under elastic stage are investigated.The influence of key parameters to torsional behavior,such as,forming processes,number of joints,layout of diaphragm,web shape,is analyzed.The results show that the torsional enlargement effect of deflection can improve more than 10%~15%in segmental beam,compared to monolithic beam.The torsional enlargement effect of shear stress,which can be increased by 1.5times due to the eccentric load,must be taken seriously consideration for segmental beam.The forming processes and layout of diaphragm have significant influence to torsional enlargement effect,while the numbers of joints and web shape have little influence to it.Finally,based on the energy method,apractical calculation method considering the joint,for the torsional stiffness of this bridge is proposed,and some design suggestions are given.