小角度斜交上跨铁路异型T构桥受力分析研究

Research on the Stress Analysis of T-shaped Bridge With Small Angle Skew Crossing Over Railwaye

随着铁路大规模的建设,线路间的小角度斜交交叉穿越不可避免。当桥下净空受限时,常用的门式刚构方案存在不适用性。本文结合西十高铁西安东站动走线上跨西十正线工程,将门式墩与小T构梁结合,采用空间异型框架T构梁桥满足净空受限情况下的线路间小角度斜交跨越。建立了全桥三维整体模型、纵向计算模型、横梁局部模型等有限元模型,通过不同模型间的比较,分析了异型框架T构梁桥的纵、横向受力计算方法,对纵向模型、局部横梁模型的适用性进行了论证,并对常用的局部横梁模型进行刚度修正,提出了修正刚度后的局部横梁模型。修正后的横梁局部模型受力明确,计算结果与三维空间模型一致,可满足设计计算要求。

With the large-scale construction of railways,small angle skew crossing between lines is inevitable.With the limited clearance under the bridge,the commonly used portal rigid frame scheme is not applicable.In this paper,based on the project of Xi'an East Railway Station crossing the Xi’an to Shiyan high speed railway main line,the portal pier is combined with the small T-frame beam,and the spatial special-shaped T-frame bridge is used to meet the requirements of small-angle skew crossing between the lines under the condition of limited headroom.The finite element models such as the three-dimensional whole model,the longitudinal calculation model and the local model of the beam are established.Through the co MParison of different models,the calculation methods of the longitudinal and transverse forces of the T-frame bridge with different forms are analyzed.The applicability of the longitudinal model and the local beam model is demonstrated,and the stiffness of the local beam model is modified.The local beam model with modified stiffness is proposed.The modified beam local model has clear force,and the calculation results are consistent with the three-dimensional space model,which can meet the design calculation requirements.