Timber-Concrete Composite Bridge, Lohmar DE

Lohmar, Germany

Photo © IB-Miebach

Engineers: Ingenieurbüro Miebach

Location: Schiffarther Straße, 53797 Lohmar, Germany
Year: 2014
Client: Rhein Sieg Kreis
Structural calculation, Project management and Execution: Schaffitzel Holzindustrie GmbH

Dimensions:
Length: 40,00 m
Width: 4,75 m

Structure:
Main structure consisting of block-laminated spruce glulam with TCC connectors. Main carrier has a stepped cross-section. Concrete slab with mastic asphalt and steel railing. Accoya handrail including safety rope.

Object planning:
Leistungsphasen 1-9

Structure planning:
Leistungsphasen 1-3
(according to German HOAI)

The bridge existing before had to be refurbished due to flood damage. Concept of the new bridge design was to pick the old timber bridge design and to interpret it in a contemporary and innovative way. The design derived particularly from the requirement, that the bridge needed to span freely over the river bed to ensure a broader cross-section of flood current flow and from the need for constructive timber protection. The result is a bridge that exhausts the structural potential of both main materials, timer and concrete, to the fullest.

The trepped profile secures the main carrier from drving rain and the road surface of mastic asphalt akts as sealing from above.

In the compressed zone of the bridge structure the road surface from concrete takes up the forces and in the tensile forces are handled by the timber girder underneath. One can clearly see the distribution of forces observing the form of the curved main glulam girder.