Quantification of aerodynamic forces for truss bridge-girders based on wind tunnel test and kriging surrogate model

Abstract

This study presents an investigation to quantify the aerodynamics of truss bridge-girders via wind tunnel test and kriging surrogate model. Currently, the conventional methods documented in design specifications only take into consideration the mean drag force at null attack angle. To gain an in-depth understanding on the aerodynamics of truss bridge-girders, experiments on simplified bridge-girder models with various geometric parameters were carried out in uniform flow. A total of 15 truss bridge-girder models with aspect ratio (the ratio of width to height) B/D = 1.0, 1.3, 1.6, 1.9, and 2.2, solidity ratio (the ratio of projected to envelope areas) Φ = 0.20, 0.25, 0.30, 0.35, and 0.40, and two typical truss topologies (Warren and Pratt trusses) were examined in the most concerned range of wind angle of attack α = [–6°, 6°]. These truss bridge-girder models cover most of the high-speed railway bridges widely used in China. Experimental results show that the truss topology has limited effects on the aerodynamics of truss bridge-girders, whereas the effects of α, B/D, and Φ are significant. Based on these wind tunnel results, the ordinary kriging surrogate model was utilized to approximate the aerodynamics of truss bridge-girders. In using this model, aerodynamic force values for test cases can be interpolated with zero variance and uncertainties in unsampled design zones where geometric parameters can be quantified with Gaussian variance.