Simplified FRP footbridge model for Berlin City

Berlin City is short of footbridges and which has so many rivers and other interesting sites that are crying out for a bridge. This project is based on modelling of footbridges for Berlin City made of fiber reinforced plastic (FRP) sandwich deck panels with sinusoidal cores. FRP sandwich panels, comprising of two face plates separated by a core of stiffeners offer better performance due to high stiffness-to-mass ratio along with numerous impressive properties like corrosion resistance, high impact strength etc. Analysis of sandwich panels using exact three dimensional modelling is very much complicated and also time consuming. To overcome this problem, the whole deck panel can be assumed as an equivalent orthotropic continuum for simplified analysis.  This research is focused on a numerical study using finite element (FE) based software Abaqus to find equivalent elastic constants to replace FRP sandwich panel with a homogeneous orthotropic plate. Equivalent modulus of elasticities (Ex and Ey) have been calculated from the bending stiffnesses (Dx and Dy) of the deck modelled in 3D using Abaqus. Dx, Dy and Poisson’s ratios have been calculated from the curvatures of the deck panel due to application of bending moments. The present numerical model is applicable for the sandwich panels with any type of core geometry which is periodic in nature. To determine flexibility of the present model, equivalent orthotropic properties have been generated for FRP sandwich panels with three types of core configurations: rib, circular and triangular. Static and dynamic analyses have also been performed using the proposed equivalent model and it has been noticed that results are in good agreement with the results obtained from 3D FE model. N.B. This research work will be presented in 6th International Footbridge Conference in Berlin “FOOT BRIDGE 2017, Berlin” (Sept 2017).