空间弯扭曲线钢桥塔的设计与施工

Design and Construction of Spatial Bending Curve Steel Pylon

柳州白沙大桥主桥采用跨径布置为(200+200)m的双索面独塔斜拉桥,桥塔高106.2 m,采用反对称空间弯扭门型钢塔。针对塔底弯矩和拉应力均相对较大的特点,在承台内设置了钢底座并与钢塔相连,通过增大钢-混结构之间的传剪面来确保钢塔锚固的可靠性。在塔、梁固结区的主梁内增设多道正交隔板,提高其整体刚性以保证固结区内力传递与分配的均匀性,避免因设置斜交横梁而产生的不利影响。采用ANSYS通用有限元软件对桥塔稳定性进行数值仿真计算,结果表明最小稳定安全系数为12.9。桥塔采用龙门架吊装的总体施工方案,配合节段制作、空中对位拼接等关键工序的工艺和措施,施工精度满足要求。

The main bridge of Baisha Bridge in Liuzhou is a double-plane single-pylon cable-stayed bridge with the span arrangement of 200 m+200 m.The pylon is 106.2 m high,and the anti-symmetrical spatial bending frame steel pylon is adopted.In view of the relatively large bending moment and tensile stress at the bottom of the pylon,a steel base is set up in the base slab and connected with the steel pylon.The reliability of the anchoring of the steel pylon is ensured by increasing the shear transmission surface between the steel and concrete structures.The multiple orthogonal partitions are added in the main girder in the consolidating zone of pylon and beam to enhance the overall rigidity,and ensure the uniformity of inner force transmission and distribution in the consolidating zone and avoid the adverse effects caused by the oblique beam.The ANSYS general finite element software is used to carry out the numerical simulation calculation on the stability of the pylon.The result shows that the minimum stability safety factor is 12.9.The overall construction scheme of gantry hoisting is adopted for the pylon.Combined with the key processes and measures of segment production,aerial alignment and splicing,the construction accuracy meets the requirements.