小半径曲线“双窄箱”钢-混组合连续梁偏载效应分析

Analysis on Eccentric Load Effect of Small Radius Curved "Double Narrow Box" Steel-Concrete Composite Continuous Girder

摘要:

为研究车道荷载对小半径曲线双窄箱钢-混组合连续梁桥的偏载效应，以实际工程为背景，对该结构的弯曲、扭转和畸变效应进行了理论分析。建立了曲线半径外侧偏心活荷载、内侧偏心活荷载和对称活荷载三种荷载工况，结合ANSYS软件建立三维有限元实体模型进行分析，引入了应力放大系数的概念研究了该结构的偏载系数规律。结果表明：组合梁曲线半径外侧产生的翘曲正应力和剪应力大于组合梁内侧；组合梁的正应力放大系数近似为1.3~1.4之间，正应力的偏载效应在中支点处最为明显；剪应力放大系数近似介于1.5~1.6之间，剪应力的偏载效应在中跨1/4处最为明显。与直线梁桥相比，小半径曲线双窄箱钢-混组合连续梁桥在偏心车道荷载下的应力放大系数较大，对该类结构而言，由活载引起的偏载效应不容忽视。

Abstract:

In order to study the eccentric load effect of lane load on the small radius curved double narrow box steel-concrete composite continuous girder bridge, the bending, torsion and distortion effects of the structure are analyzed theoretically based on the actual project. Three load cases of eccentric live load on the outer side, eccentric live load on the inner side and symmetrical live load of the curve radius are established. A three-dimensional finite element solid model is established with ANSYS software for analysis. The concept of stress amplification factor is introduced to study the law of the eccentric load coefficient of the structure. The results show that the warping normal stress and shear stress on the outer side of the curve radius of the composite girder are larger than those on the inner side of the composite girder. The amplification factor of the normal stress of the composite girder is approximately between 1.3 and 1.4, and the eccentric load effect of the normal stress is most obvious at the middle fulcrum. The amplification factor of shear stress is approximately between 1.5 and 1.6, and the eccentric load effect of shear stress is most obvious at the quarter of the midspan. Compared with the straight girder bridge, the stress amplification factor of the small radius curved double narrow box steel-concrete composite continuous girder bridge under eccentric lane load is larger. For this kind of structure, the eccentric load effect caused by live load cannot be ignored.