关键词: 桥梁工程, 桥梁冗余度, 大跨度悬索桥, 应变能, 吊索重要性系数, 应力响应增量

Abstract: To analyze the impact of the failure of different slings on bridge redundancy in the operation of a suspension bridge, a long-span suspension bridge being in construction was taken as example. By use of the variation of strain energy of the whole structure before and after the failure of slings of the suspension bridge, the importance coefficients of slings were determined. According to the importance coefficient, the failure slings were combined, and the failure condition of components were determined. And then, the quantitative calculation of the suspension bridge redundancy under the most adverse damage conditions was carried out. Combined with the stress increment of the damaged structure, the redundancy analysis method of a suspension bridge based on the sling importance coefficient was put forward. The results show that: when the sling failure is closer to the mid-span, its effect on long-span suspension redundancy is bigger. The failure condition of sling combinations with the bigger important coefficients is simulated. It is founded that when the redundancy is less than 0.201, the stress response of a long-span suspension bridge is enormous; and the bridge has a trend of total structural collapse, which is no longer available to bear the load.

Key words: bridge engineering, bridge redundancy, long-span suspension bridge, strain energy, importance coefficient of sling, stress response increment