Analytical and Numerical Reliability Analysis of the Pratt Steel Truss

Abstract

The main aim of this paper was to investigate a variation of the reliability index β for some steel truss girder depending with respect to its length and to check the differences in numerical results obtained with the use of numerical and analytical probabilistic calculations. Some small Pratt truss, which includes vertical members and diagonals that slope down towards its centre was selected to make such a comparison. The span of this truss has been adopted as the Gaussian input variable in this study, which is motivated by in situ observations and measurements statistics as well as by its nonlinear impact on the Serviceability Limit State. The basic probabilistic characteristics of the structural response have been determined using the 10th-order Iterative Generalized Stochastic Perturbation Method and using Monte-Carlo Simulation also. The very important aspects in this work are (i) a contrast of analytical and numerical results and (ii) stochastic analysis of the load capacity in this truss joints, i.e. the stresses in the welds. Numerical results presented here have been obtained by the Finite Element Method system Robot Structural Analysis Professional 2021 and also via symbolic computer algebra environment MAPLE.