铁道建筑

为研究铁路部分斜拉桥拉索两端索梁及索塔锚固区受力特性，以主跨216 m的金建铁路新安江特大桥——外倾式桥塔部分斜拉桥为背景，采用有限元软件ABAQUS建立拉索锚固区局部细化的全桥有限元模型，通过Midas荷载追踪器确定活载加载位置，分析多工况下索梁及索塔锚固区应力分布规律。结果表明：各工况作用下的索塔锚固区最大主拉应力均较为显著；S4索最大索力工况下出现最大量值为14.4 MPa理论锚点集中应力，其影响范围集中在斜拉索管径20 cm范围内，不会引起锚固区混凝土开裂；索塔锚固区应力在竖桥向呈现出近似正弦式的波动特征，主拉应力值在0.2-14.4 MPa区间波动；修正后索塔锚固区横桥向不均匀系数η在1.8-2.1之间，主拉应力横桥向不均匀分布显著。索梁锚固区在S9索最大索力工况下出现整体最大拉应力，齿块与主梁腹板相交处后端主拉应力达12.8 MPa，沿纵桥向路径持续下降，此类局部尖角处的计算高应力可通过实际配置的普通钢筋有效抑制；锚固齿块受力的横梁主拉应力呈现“两端低、中间高”的横向分布规律；索梁锚固区局部应力集中程度较索塔锚固区相对不显著。

To investigate the stress characteristics of the cable-girder and cable-pylon anchorage zones at both ends of stay cables in a railway extradosed bridge， the Xin'anjiang Super-large Bridge on the Jinan-Jianyang Railway with a main span of 216 m， a extradosed cable-stayed bridge with outward leaning bridge pylons， was taken as the engineering background. A refined global finite element model of the bridge with locally detailed meshing for the cable anchorage zones was established using the finite element software ABAQUS. The live load positions are determined via the load tracker in Midas software， and the stress distributions of the cable-girder and cable-pylon anchorage zones under multiple loading cases were analyzed. The results show that the maximum principal tensile stress in the cable-pylon anchorage zone is relatively significant under all loading cases. A theoretical concentrated stress of 14.4 MPa at the anchor point occurs under the maximum cable force condition of S4 cable， and its influence range is concentrated within 20 cm of the stay cable pipe diameter， which will not cause concrete cracking in the anchorage zone. The stress in the cable-pylon anchorage zone exhibits an approximate sinusoidal fluctuation in the vertical bridge direction， with the principal tensile stress ranging from 0.2 MPa to 14.4 MPa. The transverse non-uniformity coefficient η of the revised cable-pylon anchorage zone varies between 1.8 and 2.1， indicating an obvious non-uniform transverse distribution of principal tensile stress. The maximum tensile stress in the cable-girder anchorage zone appears under the maximum cable force condition of S9 cable， with the principal tensile stress of 12.8 MPa at the rear end of the intersection between the toothed block and the main girder web， which decreases continuously along the longitudinal bridge path. Such high calculated stress at local sharp corners can be effectively restrained by the arranged steel bars in practice. The principal tensile stress of the crossbeam cooperating with the anchorage toothed block shows a transverse distribution pattern of "low at both ends and high in the middle". The degree of local stress concentration in the cable-girder anchorage zone is relatively less significant than that in the cable-pylon anchorage zone.