Research Of Accelerated Test Environmental Spectrum Study For Bridge Structures Under The Coupling Of Environment And Load

In recent years,the corrosion problem of bridge structures in China is very prominent.The research on the anticorrosion of bridge structures and the evaluation methods of calendar life have attracted more and more attention from domestic engineering and academic circles.Among them,the service environment spectrum of bridge structure is the technical basis of the research,and the research in this area has just started.This paper relies on the support of the National Natural Science Foundation's major scientific research instrument development project "Structural fatigue experimental system development under complex environment(project approval number:11627802)" to study the accelerated test environmental spectrum under the bridge structure environment/load coupling,and to serve the bridge structure.A series of key technologies related to environmental spectrum are the focus of research.The theoretical analysis and experimental research on environmental database establishment,environmental spectrum compilation method,accelerated corrosion environmental corrosion correlation,corrosion damage characteristics and corrosion variation are carried out.In the following aspects:Firstly,In the aspect of bridges in China,the design method of bridge structure environment database was proposed for the first time.The database of service structure environment of bridge structure in China was established by using mature database software.Secondly,Based on the bridge structure environmental database,through the simplification of environmental parameters and the statistical processing of data,the establishment method of the service environment spectrum of bridge structure is proposed,and a bridge structure service environment spectrum is compiled and made in practice.The quantitative treatment provided a basis for the subsequent accelerated corrosion test environmental spectrum and laid the foundation.Thirdly,In order to allow the test piece to reproduce the corrosion process in the actual service environment in the accelerated corrosion environment spectrum,the same damage characteristics and forms appear,and comprehensive consideration of various factors,based on the service environment spectrum of the bridge structure,The environmental spectrum of the accelerated corrosion test of the bridge structure corresponding to it was established.Lastly,The main material steel wire of the stay cable,which is one of the important load-bearing members of the cable-stayed bridge,was selected as the research object.The accelerated corrosion test was carried out in the laboratory to simulate the corrosion process in the service environment.Probability and statistics were used to analyze the probability distribution of corrosion damage measurement data and the variation law of etch pit depth.The mathematical expression of etch pit depth with corrosion time was proposed.Then,the method of comparing the degree of corrosion is used to determine the corrosion equivalent relationship between the accelerated corrosion environment spectrum and the actual service environment,which provides an important reference and reliable basis for determining the calendar life of the bridge structure.