铁路小半径曲线连续梁桥设计研究

武汉到咸宁的城际铁路中采用了大量的小曲线半径连续梁桥,最小半径达320 m,为目前我国曲线半径最小的铁路连续梁桥。本文采用ASCB和BSAS建立平面模型以及采用Midas2006建立空间有限元模型,对跨径组合为(24.65+24.65)m预应力混凝土连续箱梁分别进行施工阶段及运营阶段分析,计算恒载、活载、预应力、收缩徐变、体系温度、局部温差、支座不均匀沉降等荷载,得出支反力及内力、应力、强度、变形等,并进行了分析比较。由于"弯-扭"耦合作用、剪力滞效应及畸变挠曲效应、预应力损失等,使得曲线梁腹板内侧和外侧受力不同、支座的内侧和外侧受力也不同,因此不能单一采用以直代曲或者平面代替空间的计算结果,尤其是当曲线半径较小的情况下,尽量采用多种计算手段相互校核。并且通过采用箱形截面设计、加横隔板、降低曲线上车辆通过速度等可降低曲线效应对梁的影响。

Design and Research of Railway Curved Continuous Girder Bridge with Small Radius

A lot of curved continuous girder bridges with small radius are adopted in Wuhan to Xianning Intercity Railway with the minimum curve radius of 320 m which is the smallest one in domestic railway curved continuous girder bridges. Prestressed concrete continuous box girder with span of （24.65 ＋ 24.65 ） m in and after construction is studied by means of plane model which is established by ASCB and BSAS and spatial finite element model established by Midas 2006. Support reaction and internal force, stress, strength and deformation are obtained and analyzed by the calculation of bridge load which includes dead load, live load, prestress, concrete shrink and creep, system temperature, temperature difference, differential settlement of support and so on. Because bending-torsion coupling effect, shear lag effect, distortion effect and loss of prestress, inside and outside stresses of curved girders web plate are different, and inside and outside stresses of support are also different. Therefore, a variety of computational methods should be adopted to confirm mutually instead of choosing the results of single method especially when curve radius is small. And the influence of curve effect on girders can be lowered by the design of box section, adding diaphragm and reducing the passing speed of trains on railway curve.