横张预应力混凝土简支箱型梁剪力滞效应分析

Shear Lag Effect Analysis of Cross-prestressed Concrete Simply-supported Box Beam

结合横张预应力简支箱型梁的构造特点,根据能量变分法所推导的对称单箱单室箱梁桥剪力滞效应理论、剪力滞叠加原理及等效荷载法,分析了跨中截面的剪力滞系数。结果表明:横张预应力混凝土简支箱梁中钢束布置形式以及有效预应力是影响恒载与预应力荷载共同作用下简支箱型梁剪力滞效应的重要因素;同时在结构跨径及构造形式一定的情况下,剪力滞系数与预应力布置形状及恒载作用存在一定的规律性。

Combining with the construction features of cross-prestressed simply-supported box beam ,the shear lag coeffi-cient of mid-span section is analyzed based on the shear lag effect theory and shear lag superposition principle derived from the existing energy variation method of symmetrical single cell box girder bridge as well as the equivalent load method .The results show that the steel beam arrangement and effective prestress of cross-prestressed concrete simply-sup-ported box girder are the important factors to affect the shear lag effect of the simply-supported box beam under the joint action of dead load and prestressed load ;when the structural span and constructed form are constant ,there is a certain regularity between the shear lag coefficient and prestress layout shape form as well as the dead load .