Preliminary design of standard prestressed bridges using box girders or hollow slabs

Abstract

This study uses a linear programming mathematical model to establish preliminary design charts for prestressed bridges using box girders or hollow slabs, giving the required prestressing force after losses for an interior girder for various spans and spacings. The structure is designed to carry the MS200-77 loading, and the design conforms with the Canadian Standards Association Standard CAN3-S6-M78 for design of highway bridges. The bridge considered is single-span, with a cast in situ concrete deck acting compositely with the prestressed girders under live load. The linear programming model is also used to determine the design criteria that will control the designs for the cases investigated, and to perform the parametric study to evaluate the effect of variations in deck thickness, girder concrete strength, and prestressing losses on the value of the required prestressing force. Key words: box girder, bridge, design, hollow slab, linear programming, prestressing.