The Use of Appropriate Finite Element Modelling Techniques for the Idealization of a Novel Hybrid Multi-girder Bridge Deck System

Examination into FEA techniques for modelling the performance of a specially designed hybrid multi-girder bridge deck system with three model configurations of varying complexities showed good correlation with experimental global load-deflection behavior as well as local strain behavior at the base of the bridge system. For ascertaining peak load conditions, the simplest of the three model configurations was found to provide the best accuracy of results where the peak condition was estimated within a 2–12 % accuracy range for the FEMs studied. However, the local behavior in the transverse composite system, particularly in the horizontal GFRP rods, obtained from FEA greatly underestimated (3.5–9 times) the tensile strain experienced, even when tube-in-tube elements were implemented to represent the unbonded movement of GFRP rod through the surrounding plastic ducts. Good representation of overall behavior in the transverse composite system, however, was obtained with tube-to-tube elements, with transverse curvature exhibited. Interestingly, the addition of tube-to-tube elements did not affect the overall global performance exhibited through FEA, resulting in identical load-deflection curves with a comparable FEM without the use of tube-to-tube elements. The computational time required to complete the model with tube-to-tube elements was also less than that required for the model without tube-to-tube elements. Further study is recommended to determine and eliminate the unknown constraint placed on the GFRP rods, to allow for greater accuracy in the prediction of tensile strain.