STUDIES IN DESIGN MOMENTS OF TRANSVERSE SYSTEMS OF GIRDER BRIDGES

Abstract

Bridges of different forms and shapes have been used since the constructiton of first bridge. Decks of girder bridges consist of longitudinal girders and transverse systems. Transverse systems comprise deck slab and, if necessary, cross beams or diaphgragms in it. Function of deck slab is to transfer the imposed roads amongst cross beams and longitudinal girders. Cross beams and diaphragm in turn distribute the loads amongst the girders. In the present study, the deck slab, as a structural component of girder bridges has been studied from the design point of view. Deck slab is difficult to structurally analyse for all types of loadings and support conditions. The fourth order load deflection differential equations for plate has been solved for a limited type of loadings (uniformly distributed load and conCent4ted load) and support conditions. The solutions are available in the form of graphs and tables. Analysis of deck slab is done in a semi-empirical manner by suitably modifying the available elastic analysis. Prgeaud's coefficients, Effctive width of slab or Westergaard's results are presently used for the design of deck slab. However, the use of Pucher's influence surface is coming in vogue now. In this dissertation, all the above mentioned methods have been invesetigated in depth from the design point of view and the differences alongwith strong and weak points have been highlighted. Effort has been made to highlight difference in design moments obtained by using different methods.