Field measurement on secondary stress of main cable of long-span suspension bridge in the process of construction
Yan Kun1 Shen Ruili2
1. China Merchants Chongqing Transport Research & Design Institute Co., Ltd., Chongqing 400067, China;
2. Southwest Jiaotong University, Chengdu 610031, China
Abstract：The real stress of strand wires related to safety reserve of main cable. To study the stress state of main cable of long-span suspension bridge during construction process and in the finished bridge state, the stress of main cable is measured on site for several sections which are near pylon saddle during stiffening girder lifting process of Nanjing Yangtze River Fourth Bridge. The results show that secondary stress is mainly composed by non-uniform axial stress. Secondary stress accumulates gradually in the fixed-end with construction process, and its tendency is consistent with rotation angle change of main cable at the pylon saddle. According to the test data, secondary stress formula with rotation angle is fitted, and secondary stress is calculated by the fitting formula for a small amount of construction cases in which there is no test data. Finally, the variation curve of secondary stress of main cable is obtained for whole construction process of Nanjing Yangtze River Fourth Bridge. The maximum secondary stress of main cable at both sides outlet of pylon saddle is 171MPa and 136MPa respectively in the finished bridge state. Ratio of secondary stress to average axial stress is 0.26 and 0.21 respectively. The research can provide valuable reference for design and determining safety reserve of main cable of long-span suspension bridge.
严琨 沈锐利 . 大跨度悬索桥施工过程中主缆二次应力实测研究[J]. 土木工程学报, 2018, 51(4): 62-68.
Yan Kun Shen Ruili . Field measurement on secondary stress of main cable of long-span suspension bridge in the process of construction. 土木工程学报, 2018, 51(4): 62-68.
