Durability And System Reliability Analysis Method Of Sea Port Wharf On Piles

The bearing capacity evolution and the safety analysis method of the reinforced concrete structures are the important issues to be resolved in the engineering structure design and maintenance of sea port wharf.The bearing capacity evolution of reinforced concrete structure under marine environment is mainly caused by steel bar corrosion resulted from chloride ion penetration.This dissertation studied the diffusion of chloride ion in the reinforced concrete and the influence of concrete material inhomogeneity and the steel bar block effect on chloride ion transmission under marine environment by physical experiments in laboratory to build the chloride diffusion model,steel bar corrosion rate model and the bond strength decline model between reinforcement and concrete;studied the effects of reinforced concrete mechanical properties evolution on the failure mechanism,the failure mode and the overall bearing capacity of the structure to build the overall bearing capacity time-varying model and the reliability analysis method of reinforced concrete structure in marine environment.It is aimed at providing the theoretical basis and technical method for the durability design,safety assessment and lifetime prediction of the seaport reinforced concrete structures.The main work includes the following aspects:(1)In marine environment,the performance degradation of reinforced concrete material is mainly caused by steel bar corrosion resulted from chloride ion penetration,and the chloride diffusion model is the important issue to be resolved.In this dissertation,the effects of coarse aggregate content,coarse particle size distribution,reinforcement content,rebar diameter and rebar spacing on the chloride diffusion were investigated by physical model experiments and the chloride diffusion model was established considering the influence of coarse aggregate and reinforcemen.(2)On the basis of the physical model experiments,the chloride diffusion coefficients in the hardened cement paste,on the interface between hardened cement paste and coarse aggregate,as well as on the interface between hardened cement paste and steel bar were analyzed.The meso finite element model which can simulated the chloride diffusion behavior in the hardened cement paste,on the interface between hardened cement paste and coarse aggregate,as well as on the interface between hardened cement paste and steel bar was developed and the corresponding numerical simulation method was presented.(3)By using the meso finite element numerical simulation method,which can simulated the diffusion behavior of chloride diffusion in the hardened cement paste,on the interface between hardened cement paste and coarse aggregate,as well as on the interface between hardened cement paste and steel bar,the effects of the steel bar corrosion resulted from chloride ion penetration,the bond strength reduction between concrete and steel bar,etc,on the performance of reinforced concrete materials was studied,and a more reasonable time-dependent model of reinforced concrete materials performance was established.(4)In view of typical reinforced concrete sea port piled wharf structure,the effect of the performance degradation of reinforced concrete material on the structure system bearing capacity was investigated,the basic principle and method of determining the structure system bearing capacity was presented,and the timedependent model of the structure system bearing capacity of reinforced concrete sea port piled wharf was set up.(5)Based on the reinforced concrete structure system bearing capacity,the system reliability analysis method for reinforced concrete time-dependent structure was presented,which can be used to the durability design of new reinforced concrete sea port piled wharf and the safety assessment of the existing reinforced concrete sea port piled wharf.