Probabilitic Design Method Of Steel Bridges Based On Reliability Theory

Based on domestic and foreign relevant specifications, documents and experimental results, through comparing and analyzing to bending behaviour and existing formulas of steel beam, the basic formula that is used in statistical analyses of resistance for structure component of steel bridges is determined.According to the indirect method of statistical analysis of resistance for structure components, statistical analyses to three main factors influencing resistance for structure components are separately presented. Firstly, statistical parameters of indeterminacies of material behavior and statistical parameters of that of geometry parameters are determined, that influence resistance for structure components of steel bridges; to the indeterminacy of calculating mode, test results of 108 steel beams are collected. On the basis of these test data and statistical calculation, statistical parameters of indeterminacies of calculating mode of flexural load capacity of steel beams are given.The calculation formula of flexural load capacity of steel beams is obtained by using the error transfer formula of mathematical statistics. According to this formula, and statistical parameters of three main factors influencing resistance, statistical parameters of flexural load capacity of steel beams are proposed on the basis of calculating and analyzing.On the ground of statistical parameters of flexural load capacity of steel beams, and that of dead load and traffic load effect of highway steel bridge, the first order second moment method is used to calculate the partial safety factor of resistance corresponding to two combinations for action effects, and limit state design expression of flexural load capacity for steel beams of highway bridges is determined. Analysing example demonstrates that this dissertation's achivemnts are economic and reliable.