Bridges with UHPC precast girders

High-performance precast girders with innovative UHPC webs for single-span and multi-span medium-span bridge structures.

The research project will investigate the use of UHPC for practical applications of precast bridge girders. Primarily, prefabricated solutions are aimed at, since UHPC components have high requirements during fabrication. The UHPC construction method for bridge girders is intended to be an alternative to the currently common construction method and to be efficient in all areas. The components to be developed are to be used statically in an optimal way, be easy and quick to assemble and offer an economical and sustainable solution to compete with the currently common construction method.

In a first step, the geometric boundary conditions for a typical, frequently used system were defined. For safety and maintenance reasons, the highway authorities require that bridges spanning the highway in standardized 2-lane development span over 36m without a central pier. The structural design on which the research project is based is accordingly based on this bridge type in which the bridge deck rests on 4 to 8 UHPC longitudinal girders, depending on the bridge width.

For this bridge type, bending and shear force calculations are carried out and a suitable geometry of the UHPC girders is developed. One focus of the investigations is on the different joint design variants, which are then verified with the help of calculation approaches and tests. Only suitable joints allow the required high degree of prefabrication. The possibilities of a dry joint with shear cams and a grouted joint are considered in detail.