Durability Assessment of In-service Railway Concrete Bridges Based on Field Measurement
Carbonization is the main cause of corrosion and decrease in bearing capacity of internal steel bars in concrete structures.Conducting durability assessment and remaining life prediction for existing railway bridges is of great significance for their subsequent maintenance and reinforcement.This paper evaluated the durability of several prestressed concrete beams in experimental railway super large bridges,and tested their concrete strength,carbonization depth,and protective layer thickness.Combined with measured data and durability models,the remaining durability life of the bridge was predicted.The results show that the average strength of prestressed concrete with a service life of 32 years is around 38.5 MPa,and the average carbonization depth is around 10 mm.Compared to the flange and web plates,the actual thickness of the protective layer at the bottom of the beam is relatively small,and the probability of corrosion of the internal steel bars here is higher.The durability model based on in-situ testing and carbonation depth correction indicates that the bottom of the prestressed beam began to experience steel corrosion after 29.5 years of service.Finally,based on the durability criterion of 7%critical steel corrosion rate,the service life of different parts of the prestressed bridge was predicted.
万方数据
维普
