| As a transportation hub,the port plays an important role in economic development,and the safety of the port is particularly important.During the service period,because of a variety of factors,the piers will suffer from a decline in the structural bearing capacity of the wharf.In addition,the operational level of the wharf is improved,and the wharf will need to be repaired and reinforced.The time-varying reliability theory is used to evaluate the safety of the wharf,which can effectively determine the time for repairing the wharf and evaluate the reinforcement effect.The dissertation analyzes in detail the influencing factors of performance degradation of the service wharf structure,and comprehensively considers the decline in structural bearing capacity of the wharf components and the increase of load level,and calculates and analyzes the reliability index of the service wharf during the design base period.For the three methods of reinforcement,such as sticking steel plates,sticking carbon fiber sheets and adding crossbeams,the time-dependent reliability calculations were carried out after the reinforcement of the components,and the reinforcement effects of different reinforcement schemes were compared.The main work and conclusions are as follows:(1)This paper summarizes and analyzes the theory of reliability and the research results of the reliability of concrete structures considering the durability of materials,selects the theoretical model that is applicable to this study,and lays a theoretical foundation for the reliability analysis of service quay structures.(2)The influencing factors of the degradation of loading capacity of service wharf were studied.According to the environment characteristics of the service wharf,the material performance degradation model was determined,and the time-variation analysis of concrete strength and the critical time point of durability were analyzed under different environments.Studies have shown that:in the inland environment,the concrete strength does not change much during the design reference period,and its performance degradation is mainly caused by the increase in variability,while the strength of the concrete in the marine environment has decreased by about 25%;according to the latest "Structural durability of waterway engineering Sexual Design Standards"(JTS153-2015)ensures that steel bars will not rust during the design and use period of the wharf structure in the river environment.However,other durability measures need to be taken to protect the durability of the wharf structure in the marine environment to prevent corrosion of steel bars.(3)By analyzing the time-varying reliability of structural members in service wharf,the results show that,in addition to the decline in structural bearing capacity of the wharf,the increase in operational levels will also lead to a decrease in structural reliability.The influence of the variability of the load effect on the reliability index is analyzed.The change of the variable load has a significant effect on the reliability of the service structure.When the coefficient of variation increases by 0.05,the reliability index decreases by about 15%.(4)Based on the reliability analysis method,the safety problems of the carbon fiber sheet and steel plate reinforced components are analyzed.Through the study,it is found that the reliability indexes of the two sheets are similar after the reinforcement,but the carbon fiber sheet reinforcement efficiency is higher.Combining ANSYS finite element analysis,a comparative analysis of the reinforcement methods using additional beams found that proper modification of the original structural system of the pier,addition of support points,comprehensive carbon fiber reinforcement and steel plate reinforcement,make the wharf force more reasonable and reliable for the dock structure.The reinforcement method of additional beam is even more significant to increase reliability index,and it can reduce the amount of reinforcement workload on the dock. |
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