斜拉桥肋板式主梁剪力滞效应研究

Research of Shear Lag Effect in Ribbed Plate Beam of Cable-stayed Bridge

大跨度斜拉桥剪力滞效应十分突出,在设计和施工过程中应考虑剪力滞效应的影响。根据能量变分原理,推导出肋板式主梁截面的剪力滞系数简易计算公式。以某460米主跨预应力混凝土斜拉桥为研究对象,采用大型空间有限元分析程序MIDAS FEA 3.3进行三维实体有限元数值分析,并与通过能量变分法计算得到的剪力滞系数比较发现,宽度较大的肋板式主梁剪力滞效应突出,且跨中处截面剪力滞系数小,而塔根处的截面剪力滞系数大,在设计和施工过程中应采取必要的措施保证结构安全。

The shear lag effect is very conspicuous among cable-stayed bridges with long span ,therefore the influence of shear lag effect should be taken into account in the design and construction of these bridges .Here ,a simple formula for calculating the shear lag coefficient of the ribbed plate beam section is derived from energy variation principle .Based on the research of a prestressed concrete cable-stayed bridge with the main span of 460 m ,the three-dimensional entity finite element numerical analysis was conducted by using large spatial finite element analysis program MIDAS FEA3 .3 .The comparison between the shear lag coefficient obtained from the analysis and that from the formula derived from energy variation method indicate that ribbed plate beams with larger width are subjected to prominent shear lag effect ,with smaller shear lag coefficient at mid-span section ,but larger shear lag coefficient at the root of tower section .Accordingly , necessary measures should be taken into consideration in the design and construction process of these bridges ,in order to ensure the safety of the structures .This research will provide some referential value for the research of similar bridges .