南京长江第三大桥钢塔柱设计与加工

Design and Fabrication of the Tower Column of Nanjing No.3 Yangtze River Bridge

南京长江三桥钢混结合区置于索塔下横梁顶面。为避免涡激振动和驰振,通过10种切角方案和3种切角形式断面不同攻角情况下风洞试验对塔柱进行选型,并在塔端设置一组制振设备,以控制索塔架设过程中的振动。节段连接采用高强度螺栓。使用ANSYS程序进行结构有限元分析,对最不利的施工状态进行检算。在工厂制造板块和锚箱,在工地组焊钢塔柱节段,在桥位进行钢塔柱节段安装。通过焊接评定试验,确定焊接工艺和焊接顺序,采用大型数显端面加工落地铣镗床和精密测量设备,确保加工精度。

Nanjing No.3 Yangtze River Bridge is the first cable-stayed bridge adopting steel tower column in China. Its steel concrete joint is located on the top of the lower crossbeam under the cable tower. In order to avoid whirlpool-excited vibration and galloping, the pattern selection of tower column is carried out through air hole experiment under different situations of attack angle by 10 kinds of incisal angle solutions and 3 kinds of incisal angle type sections. A set of equipment is installed at the end of the tower to control the vibration caused in the process of cable tower erecting. Segments are connected by high strength bolts. Finite element analysis on the structure is carried out by ANSYS program. Check computation is done on the most unfavorable construction condition. Plates and anchor cells are manufactured in the factory. The segments of the steel tower column are group welded on the construction site and are installed on the bridge site. Welding process and welding sequence are determined by welding evaluation test. Large end face with digital display is employed to process floor type boring and milling machine and accurate measuring equipment so as to insure machining accuracy.