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曲线上的铁路桥梁,由于活载及其引起的反力不通过梁体横截面的弯曲中心而产生约束扭转。据计算“702”工程中跨度40米的预应力混凝土单室简支箱梁,当桥上线路曲线半径为2,000米时,支座处梗胁根部纵截面上的扭曲应力达10公斤/平方厘米。在1976年以前未考虑扭转力的影响。本文根据“广义坐标法”对于曲线上预应力混凝土单室简支箱梁,导出了偏心竖直荷载及离心惯性力的影响函数。作者在理论计算中对于边界条件采用了比较完善的表达形式,即考虑了支点无横向水平位移。与此相应,固定铰支座截面处有纵向外双力矩作用。
Curved railway bridge, due to live load and its reaction does not pass through the center of curvature of the cross-section of the beam resulting constrained torsion. It is calculated that the prestressed concrete single-chamber simple box-girder with a span of 40 meters in the “702” project will have a torsional stress of 10 kg / cm at the root longitudinal section of the support when the curve radius of the bridge is 2,000 meters . Before 1976, the effect of twisting force was not considered. According to “Generalized Coordinate Method”, this paper derives the influence function of eccentric vertical load and centrifugal inertial force on curved prestressed concrete single-chamber simple-supported box girder. In the theoretical calculation, the author adopts a relatively perfect expression for the boundary conditions, that is, no horizontal horizontal displacement of the fulcrum is considered. Corresponding to this, the fixed hinge support section has a longitudinal external double moment function.