下承式钢管拱桥——空间倾斜系杆拱拱肋吊装技术

Hoisting and Installing Techniques for Arch Ribs of Spatially Inclined Tied Arches of a Through Steel Tube Arch Bridge

太原南中环桥主桥为主跨180 m的下承式倾斜钢管拱结构,主、副拱向外侧倾斜。钢管拱采用大型履带吊机配合支架法施工,吊装顺序为先上游侧后下游侧,先主拱再副拱。每条拱肋划分为5个吊装节段和1个嵌补段。为方便吊装及安装就位,吊装前,通过计算确定吊点位置与吊绳长度。由于是倾斜起吊,吊装时须进行2个方向的旋转,首次栓绳使拱肋由水平横卧旋转至竖直,二次拴绳使拱肋由纵向水平旋转至需要角度。在气温较低的时段吊装嵌补段。施工中重点注意吊装安全及线形控制。实践证明该桥的吊装技术切实可行。

The main bridge of the South Middle Ring Road Bridge in Taiyuan City is a through steel tube arch structure with a main span 180m and the main and auxiliary arch ribs of the structure are inclined outwards. The arch ribs were hoisted and installed by large caterpillar crane by the aid of scaffolding. The procedures of the construction were that the arch ribs on the upstream side were hoisted and installed first and the ribs on the downstream side late, the main arch ribs first and the auxiliary ribs late. Each arch rib was divided into 5 blocks plus a built-in block. To facilitate the hoisting and installing of the ribs in place, before the ribs were hoisted, the positions of the hoisting points and the length of the hoisting ropes were determined through calculation. Because the ribs were hoisted in a inclination way, the ribs had to be rotated in two directions during the hoisting. The ropes were connected to the ribs for the first time to hoist the ribs from the horizontally lying position to the vertical position and connected to the ribs for the second time to horizontally rotate the ribs to the required angles from the longitudinal direction. The built-in blocks were then installed in the period of low temperature and the key points of attention in the construction were the safety and geometric shape control. Practice proved that the hoisting and instilling techniques for the bridge were practical and feasible.