Study And Analysis On Durability Of Cable System Of Long-span Suspension Bridge

It has reached world advanced level for the technology of design and construction for the large-span suspension bridge in China, but it is still not enough for the research on the durability, which could not meet the rapid development of long-span suspension bridge. As the main structural style of long-span suspension bridge, durability of the cable system determines the safety life of entire bridge directly, so the study on durability and safety of cable system is significant. In this paper, based on existing research, the main works include:1. The theory of structural reliability is concluded, the reliability analysis method suitable for suspension bridge is introduced, and the application of reliability analysis method in the safety coeffieint design is summarized.2. The corrosion mechanism and influencing factors of main cables and hangers of the suspension bridge is studied, the corrosion protection measures of main cables and hangers are summarized and compared, and a reasonable cable corrosion protection program is proposed.3. The fatigue behavior of steel wire of main cables and hangers of suspension bridge is investigated; the characteristics and laws of the fatigue fracture are summarized, and various factors influencing the wire fatigue are analyzed. On this basis, the assessment method of fatigue life based on SN curves is proposed to provide the design reference of cable fatigue.4. By finite element calcualtion, the structural mechanical properties of the long-span anchored suspension bridge is analyzed, the change regulation of hangers in different loading patterns of fatigue loading standard car is analyzed, the reasonable loading program of evaluating the durability of suspend cable is summarized, and the safety life of hangers is estimated.5. Influence of structural parameters on mechanical properties of the cable systems is summarized, and the influnce of increasement with service life on structural safety of long span suspension bridge when structural damage occurs is analyzed. Whole process of changing cables of the suspension bridge is calculated and simulated, the stress regulation during the course is summarized, and a reasonable program for changing cables is proposed.Maintaining main cables and hangers of suspension bridge, and enhancing their durability are long, continuous and systemic work in whole process of the use of the suspension bridge structure. For bridge designers and engineers, durability analysis should be taken as design guide, corrosion and fatigue prevention should be chosen as research basis, and constant inspection is also needed during service life to maintain the cables and hangers working in good conditions, achieve structural durability and security, and create social and economic benefits.