SKEW PLACEMENT OF ARCHES FOR ROAD BRIDGES

Abstract

This article describes a parametric study using a detailed finite element model of an arch bridge consisting out of a single arch with varying arch and hanger arrangement. The objective is to investigate the influence of overall arch dimensions, these different hanger arrangements and a variation of the skewness angle between the arch axis and the longitudinal bridge deck axis. The influence on the stresses, normal forces and bending moments in the main girders, hangers and arch cross-section is examined. Finally, a buckling analysis is performed for all variations of the base model and the change in critical buckling load is discussed. The displacements in the bridge deck are found to be the same for small angles of skewness. Starting from an angle of ± 13°, the location of the maximum deflection in the bridge deck shifts towards the ends of the bridge deck instead of being in the middle. This can be explained by the influence of the wind load acting on the arch structure combined with the direction of the horizontal resultants of the hanger forces. This can cause partial relaxation, thus ensuring a small uplift at the longitudinal girders of the bridge deck. This is also the cause for the higher displacements in the arch. The torsion effect in the arch results in a counter clockwise rotation of the arch. When performing a buckling analysis on the changing angle of skewness, it is found that this initially has only a small impact on the critical load factor.