Design developments for roadway bridges based on new hybrid structures - Part 1: girder bridges

Composite roadway bridges experienced a real resurrection after the reunification of Germany and, beside the often built trapezoidal cross-sections, there could succeed new designs with airtight welded box-sections or, in case of highway-bridges crossing deep valleys, with undivided cross-sections. But hybrid structures, understood as the structural combination of steel and concrete parts, have been restricted - with very few exemptions - to the use of concrete decks as upper cord of steel structures only, and therefore did not show the full range of their many possibilities. This paper will therefore present and describe some advanced hybrid designs for girder bridges which are characterized by technical strength, economical fabrication and construction as well as outstanding architectural qualities. These new hybrid bridge designs should thus be able to offer interesting options for the construction of new roadway bridges.