Computer aided analysis of a reinforced concrete waffle bridge deck using the method of grillages

Abstract

This paper aims to analyse a reinforced concrete waffle bridge deck using method of grillages where the topping and ribs are analysed as a monolithic unit in contrast to the conventional methods where the slab and beams are analyzed differently. In addition, the grillage approach accounts for the torsion that is usually lost in the conventional approach. The slab loading is in line with the HA loading of the BS 5400 part 2 for lightly loaded (accommodation) bridges. One of the strength of this approach is that it is amenable to computer application which has been demonstrated by using a code written in Matrix Laboratory (MATLAB) software and therefore easy for field use by practitioners. For the purpose of rendering this approach amenable to computer application, a program was used to determine the displacements, bending moments and torsional moments in the bridge deck. It is observed that the values of bending moments obtained from grillage analysis are lower than the moments from conventional beam-slab analysis carried out manually. Bending moments and other responses generated by conventional beam-slab approaches are usually exaggerated thereby reducing the anticipated benefits of waffle slab