Three Dimensional Fem Calculation of Stress Ribbons on Saddles

Abstract

<p>The main objective of this paper is to discuss whether simple 2D calculations of stress ribbons on saddles will provide results for a safe design of stress ribbon footbridges. This investigation was carried out using different numerical models for a two-span stress ribbon bridge with intermediate supports. This paper compares the results of 2D FE models with those of full 3D FE models and provides conclusions for the practical design. It aims to show that there are some typical 3D effects of the steel stress ribbons which are mainly caused by the Poisson’s ratio. Those effects can only be found using a 3D FE model. The results of 3D FE calculations suggest that the effects for the chosen example spans and stress ribbons, particularly when made of steel, are of minor importance. It is therefore sufficient for a safe design to describe the behaviour of a stress ribbon bridge at saddle supports with a simpler 2D FE Model.</p>