Simulation Analysis And Countermeasures For Typical Diseases Of High-speed Railway Concrete Girder Bridge

As an important part of civil engineering in the construction of high-speed railways,the bridge project is the key to ensure the safe operation of high-speed railways with its safety and reliability.Through the investigation and analysis of high speed railway bridges at home and abroad,it is found that because of inappropriate design,construction,poor maintenance or natural disasters,the high-speed railway bridges already built and operated have shown a lot of diseases.If they are not promptly taken reasonable measures,they will have a direct impact on the performance and safety of the bridge structure,resulting in direct or indirect economic losses.This thesis summarizes the disease types of high-speed railway bridges at home and abroad,analyzes their occurrence mechanism,and makes a detailed analysis of concrete girder bridges.The common diseases in the concrete beam bridge of high speed railway are selected,such as the loss of prestress and the big deflection,and the numerical analysis is carried out by the numerical modeling of software Midas/Civil.(1)Long-term loss accounts for the largest proportion of prestress loss,especially the effect of shrinkage and creep of concrete on the loss of prestress.The loss of prestress caused by loss of prestressed tendons has developed rapidly within 1 year after completion of the bridge and is basically completed.The shrinkage and the creep of concrete have a long-term effect on the loss of prestress.In the early stage of the completion of the bridge and the period from 1 year to 5 years after the completion of the bridge,the concrete shrinkage and creep has a great influence on the loss of prestress,and it develops rapidly.After 5 years,the effect of concrete shrinkage and creep on the loss of prestressing gradually slowed down.(2)By analyzing the influence of construction factors,prestress loss,concrete shrinkage and creep,stiffness loss on the long-term deflection of the prestressed concrete continuous rigid frame bridge,the increase in deflection of the prestressed concrete continuous rigid frame bridge has a long-term effect.And the growth rate is uncertain;the influence of the above factors on deflection is not negligible and must be taken seriously into account.(3)In view of the existing diseases of high-speed railway concrete girder bridges,the prevention and improvement measures for high-speed railway bridge diseases were proposed from the aspects of design,construction and existing disease remediation measures.(4)Based on the current high-speed railway bridge disease information,the urgency and necessity of the establishment of the disease prevention and control system for high-speed railway bridges and the related issues established are discussed in terms of management system and technical system.