Analysis The Life Cycle Cost And Research The Anti-corrosion Maintenance Strategy Of Steel Bridge

Steel bridges have the advantages of large rigidity,light weight,strong spanning ability,short construction period,long service life,and low carbon emissions.They have been widely used in bridge engineering construction.In recent years,domestic and foreign scholars have carried out a lot of research work on the life cycle cost theory of Bridges and anti-corrosion maintenance strategies of steel Bridges.But there are few studies on the life cycle cost and reliability of structure for steel bridges based on different anti-corrosion maintenance strategies.In this paper,the main ramp highway bridge of Jingzhong Expressway and Zhongchuan Airport Link as the case,I will use the methods of theoretical analysis and numerical simulation to conduct an in-depth analysis of the life cycle cost and structural reliability of steel bridges under different anti-corrosion maintenance strategies.The main work and research results are as follows:(1)Based on the principle of equal volume,by equating the corrosion amount of the coated steel in the local area to the average corrosion depth on the surface of the steel component.A corrosion analysis model of the coated steel in which the degradation of the coating and the corrosion of the steel occur simultaneously is proposed.Using Monte Carlo simulation method to compare the corrosion analysis model of coated steel proposed by foreign scholars with the corrosion analysis model of coated steel proposed in this paper in C3 atmospheric corrosion environment.It is found that the corrosion analysis model of coated steel proposed in this paper is more in line with the objective law of corrosion of coated steel.(2)Using the MATLAB finite element work platform,based on the design checking point method,compile the structural reliability index analysis program.Under the action of four anti-corrosion maintenance strategies,the structural reliability of the corrugated web steel box-concrete composite simple-supported box girder and the corrugated web steel box-concrete composite continuous box girder is analyzed.It is found that necessary anti-corrosion maintenance is helpful to improve the reliability of the coated steel bridge structure.When the degradation rate of the coating reaches 10%,a partial repair and painting maintenance is most beneficial to the reliability of the coated steel bridge structure.When the degradation rate of the coating reaches 50%,performing all recoating maintenance at one time is the most unfavorable for the reliability of the coated steel bridge structure.(3)By dividing the life cycle of the coated steel bridge into three stages: construction investment period,operation service period,and demolition payback period,the life cycle cost analysis model of the steel bridge is established.Using Monte Carlo simulation method,under the effect of traffic flow and four anti-corrosion maintenance strategies,the present value of the life cycle cost of the coated steel bridge is simulated and analyzed.It is found that as the average annual growth rate of the traffic volume increases,the present value of the cost of the coated steel bridge during the operation and service period has increased significantly.When only partial repair and painting are carried out,the present value of the cost of the coated steel bridge during the operation and service period is the most favorable,and the present value of the life-cycle cost increases the least.When partial repair coating and full recoating are carried out,the present value of the cost of the coated steel bridge during the operation and service period is the most unfavorable,and the present value of the life cycle cost increases the most.(4)Based on the discount rate of different cost analysis,the present value of the life cycle cost of the coated steel bridge and the present value of the life cycle cost of the A1010coating-free weathering steel bridge are compared and analyzed.It is found that the present value of the life cycle cost of the coated steel bridge is mainly composed of the present value of the cost during the construction and investment period and the present value of the cost during the operation and service period.As the discount rate of cost analysis continues to increase,the present value of the life cycle cost of the coated steel bridge and the present value of the cost of the operational service period gradually decrease.However,the A1010coating-free weathering steel bridge does rarely require corrosion protection during operation.The present value of its life cycle cost is mainly composed of the present value of the cost of the construction investment period.As the discount rate of cost analysis continues to increase,the present value of the life cycle cost of the A1010 coating-free weathering steel bridge is relatively stable.