As a result of flood damage, the existing 1950 3-span Elsterbrücke bridge in Halle-Osendorf needed extensive repair or replacement. After comprehensive surveys, it was concluded that the best economic solution would be to construct a new bridge.
This would also offer the opportunity to increase access and loadbearing capacity for the crossing, providing an additional local service. The local planning authorities decided to use a fairly new design concept for the new bridge that would entail the replacement of the original 3-span bridge with a single span 21 m bridge.
Prefabricated Composite Beam – (PreCOBeam)
The concept for this new type of composite beam was first designed nearly 20 years ago and in the last few years further research, testing and optimisation has been conducted into the viability of the design. The combination of steel and concrete offers an economic and versatile solution, with the standard design making use of a composite dowel that enables shear transmission without the need of shear studs.
The composite dowel is produced by cutting a rolled beam into two sections to form a “T”. The steel dowel is embedded into the concrete beam enabling a slimmer design to be implemented. One advantage of the design is that the concrete and steel combine to improve the performance characteristics of both materials and to reach a higher degree of prefabrication of the elements in order to reduce the construction time.
Key Design Features
- high degree of prefabrication, enabling quick erection and minimise disruption
- can be incorporated into existing structures galvanizing aids with overall corrosion performance
- adds flexibility to design.
The PreCOBeam concept was incorporated for their new bridge which resulted in a slimmer profile. The final 21 m bridge design is 4.5 m wide with a height of 0.7 m at the centre of the bridge and 1.4 m at the abutments. The steel dowels were hot dip galvanized to optimise the corrosion performance of the bridge structure.
Engineers | SSF Ingenieure AG
Image: Institut Feuerverzinken