南京长江五桥钢壳混凝土桥塔足尺模型工艺试验

南京长江五桥主桥为主跨600m的中央双索面三塔组合梁斜拉桥,桥塔采用内外钢壳-混凝土组合结构,采用工厂内分节段制造拼装、桥位现场整节段吊装并浇筑混凝土的施工工艺。为验证施工工艺的可行性与适应性,开展桥塔足尺模型工艺试验,重点进行钢壳吊装定位、钢筋现场连接、钢壳节段间环缝焊接和混凝土浇筑工序,并测试混凝土的工作性能及温度、应变变化规律。结果表明:钢壳节段制造及桥位施工所采用的工艺方案总体可行;钢壳节段现场吊装及混凝土浇筑等作业基本反映实际情况;混凝土温度仿真计算结果与实测值相吻合,能够指导实际施工;混凝土内部变形基本均匀。

Full-Scale Model Test of Construction Process for Steel Shell-Concrete Composite Pylon of Fifth Changjiang River Bridge in Nanjing

The main bridge of Fifth Changjiang River Bridge in Nanjing is a cable-stayed bridge with a main span of 600 m, which possesses a composite girder, central double cable planes, and three pylons. The internal and external steel shell-concrete composite structures are adopted for the pylon. In the construction process of the pylon, segments are manufactured and assembled in the factory, the entire section of the pylon is hoisted in situ, and the fresh concrete is poured. In order to verify the feasibility and adaptability of the construction process, we performed the process tests of the full-scale model of pylon, focusing on the steel shell hoisting and positioning, on-site connection of steel bar, circumferential seam welding of steel shell segments, and concrete pouring;moreover, we tested the work performance of concrete, and analyzed the variation law of temperature and strain. The results show that the technological scheme for the manufacture of steel shell segments and the construction of bridge position is feasible;the on-site lifting of steel shell segments and concrete pouring basically reflect the actual situation;the simulation calculation results of temperature are consistent with the measured values, which can be adopted to guide the actual construction;the internal deformation of the concrete is basically uniform.