Comparison between grillage model and finite element model for analyzing bridge deck

Abstract

Since its publication in 1976 up to the present day, Edmund Hambly’s book “Bridge Deck Behaviors” has remained a valuable reference for bridge engineers. During this period the processing power and storage capacity of computers has increased by a factor of over 1000 and analysis software has improved greatly in sophistication and ease of use. In spite of the increases in computing power, bridge deck analysis methods have not changed to the same extent, and grillage analysis remains the standard procedure for most bridges deck. In this study analysis bridge deck using grillage model are compared with the analysis of the same deck using finite element model. A bridge deck consists of beam and slab is chosen and modelled as grillage and finite element. Bending moment, Shear force, Torsion and Reaction force from both models are compared. Effect of skew deck is also studied. In general for practical skew bridge deck results from finite element model give lesser value in terms of displacement, reaction, shear force, torsion, bending moment compare with the results from grillage model. It can be concluded that analysis of bridge decks by using finite element method may produce more economical design than grillage analysis. This is due to the fact that the finite element model resembles the actual structure more closely than the grillage model.