Hybrid bridges with decks from carbon prestressed concrete and carbon structure
Themes: Process- and Joining Technology, Leichtbau
Prestressed carbon concrete slabs under the brand name cpc for (carbon prestressed concrete) have been used in about 90 projects already. Now ZHAW and Silidur AG have developed a novel hybrid structural system from cpc-concrete slabs rigidly connected to carbon beams. Two bridges of this type have already been erected in Switzerland: at the Zugersee and in Turbenthal.
The system carries the loads solely by mechanical interlocking, similar to mortise and tenon joints in timber construction. The contoured edges of the carbon beam are placed in slots that are cut into the concrete slabs. The remaining spaces are filled with a mortar-based concrete adhesive to join both parts. The Carbon beam is very lightweight and can be handled easily during assembly. The joint carries all shear, tension and compression forces acting between the bridge deck and the beam. Feasibility has been proven by Master thesis and on that basis the system was configured to be used for bicycle and pedestrian bridges. The joints were tested in laboratory testing and in addition in a large load bearing test with scale 1:1.
The developed bridge system is lightweight and allows for the re-use of existing supports without modifications when replacing timber, steel and concrete bridges. The bridge deck protects the carbon beam underneath from the environment and mechanical damage. The bridges are completely metalfree and therefore safe from corrosion.