沪通长江大桥直径7mm 2000MPa级钢丝试验研究

Test Research on 2000MPa 7mm Diameter Steel Wire for Hutong Changjiang River Bridge

沪通长江大桥主航道桥采用斜拉桥结构,斜拉索采用平行钢丝方案。为减小拉索迎风面积、减少重量,首次设计采用直径7mm 2 000 MPa平行钢丝斜拉索。对钢丝的关键技术指标进行了分析研究,提出了《沪通长江大桥用2 000MPa级平行钢丝斜拉索技术条件》,并对200t试制成品钢丝开展了性能试验,以保证斜拉索良好的力学性和耐久性,根据试制试验结果对2000 MPa钢丝抗拉强度计算公式的加工硬化率进行了拟合。试验结果表明,钢丝抗拉强度不低于2 000 MPa;扭转次数不小于12次;疲劳性能、锌铝合金镀层钢丝的镀层质量和均匀性等关键指标良好,满足规范和技术条件要求,综合合格率达到95.5%,可用于工程建设。

The main channel bridge of Hutong Changjiang River Bridge was designed to be cable-stayed bridge structure.The parallel steel wires were used for the stayed cables.In order to reduce the windward area and the weight of the cable,the parallel steel wire with 2 000 MPa and 7 mm diameter was designed for the first time.The key technical indexes of the steel wire were analyzed and Technical Specification for 2 000 MPa Parallel Steel Wire Stayed Cable of Hutong Changjiang River Bridge was presented.The tensile strength calculation formula was put forward and the work hardening rate was fit according to the test result.A performance test was conducted on the 200 ton specimen steel wires to ensure the good mechanical properties and durability of the stayed cables.The work hardening rate for tensile strength calculation formula was fit according to the test result.The experiment results show that the tensile strength of the steel wire is not less than 2 000 MPa and the number of twisting is not less than 12 times.The key indicators such as the fatigue stress,the coating quality and the uniformity of the zinc-aluminum alloy coated steel wire satisfy the requirement of the code and technical specifications.The comprehensive qualification rate is up to 95.5%.The steel wires can be used in construction projects.