Research And Numerical Verification Of The Cascading Target Reliability Analysis For Existing Bridges

This paper aims to address the issue of significant load variation and inaccurate load detection and assessment in operating vehicles,which results in unknown reliability and significant safety hazards in small and medium-span bridges.Based on the reliability theory,this study proposes a method for determining the target reliability index of existing bridge structures.The research encompasses the following aspects:(1)Summarizing the similarities and differences between proposed and existing structures,and establishing the principles for determining the target reliability index of existing bridge structures based on this analysis.(2)Investigating the methods used to determine the target reliability index of existing structures in various countries,examining the factors that control target reliability,and proposing a methodology for determining the target reliability index that is compatible with the historical and current status of highway bridges in China.(3)Determining the target reliability index of existing bridges from both the perspective of economic cost optimization and social risk,and establishing a target reliability system for existing bridges based on the CSA specifications.(4)Considering the detection and assessment cycle during engineering operations,serializing the target reliability index and dividing the values of target reliability index according to equiprobability.(5)Preliminarily validating the rationality of the proposed method for determining the target reliability index of existing bridges through numerical simulation analysis.