铁路预应力混凝土矮塔斜拉桥索梁锚固构造选型与力学性能研究

Study on Cable Beam Anchorage Structure Selection and Mechanical Properties of Railway Prestressed Concrete Low Tower Cable-Stayed Bridge

为优化铁路预应力混凝土矮塔斜拉桥索梁锚固形式,以成昆铁路攀枝花金沙江大桥为工程背景,提出新型索梁锚固形式-梁顶锚固结构,用以改进其锚固受力性质,利用大型有限元软件ANSYS对比分析该种新型受力形式与传统锚固结构受力性能的区别,并通过缩尺模型静载试验进一步验证该方法的可行性。结果表明:梁顶混凝土锚固结构的各向应力指标均优于传统锚固结构,其锚固点与腹板形心处同一垂直面,大幅减小了横向偏心弯矩和次应力,更有利于应力传递平顺。此外,现场试验显示各测点相对残余应变均小于20%,与数值模拟结果基本一致,验证了有限元模型的合理性。综上所述,新型索梁锚固形式在试验荷载下处于正常弹性工作状态,在设计索力工况下能够满足正常使用要求,并具备足够安全储备。

In order to optimize the cable and girder anchorage of the prestressed concrete low-tower cable-stayed bridge of the railway,a new type of cable and girder anchoring form with beam top anchoring structure is proposed to improve its anchoring stress properties based on the Panzhihua Jinsha River Bridge on the Chengdu-Kunming Railway.Large-scale finite element software ANSYS is used to compare and analyze the differences between the force performance of the new type and that of the traditional anchoring structure,and the feasibility of this method is further verified by static load test of scale model.The results show that all stress indicators of the new type are superior to those of the traditional.The anchor point is in the same vertical plane as the centroid of the web,which greatly reduces the lateral eccentric bending moment and secondary stress,and is more conducive to smooth stress transfer.In addition,field tests show that the relative residual strain at each measuring point is less than 20%,which is basically consistent with the numerical simulation results and verifies the rationality of the finite element model.In summary,the new type of cable-beam anchorage is in a normal elastic working state under the test load.Under the designed cable force conditions,it can meet the normal use requirements with sufficient safety reserves.