Promoter: City of Schwäbisch Hall
Competition year: 2018
Length: 31,00 m (11,50/18,50)
Width: 3,00 m
Construction: Composite construction of overhead concrete slab and block-glued laminated timber girders. Composite over curbs and glued steel hangers. Two-layer mastic asphalt as surfacing. Railing made of flat steel posts with filling stainless steel cables and steel bars, handrail made of acetylated glulam.
Our service: Basic determination, variant analysis, design planning - Service phases 1 - 2 according to German HOAI
The city of Schwäbisch Hall intends to build an additional development on the island "Großer Unterwöhrd" a bridge over the western part of the river Kocher. The bridge will serve as a connection for pedestrians and cyclists and be used in addition for the delivery of the Globe Theater. The existing access routes are not suitable in the long term use of heavier traffic. The intended location of the bridge lies in the extension of the street "Im Lindach" from the "Bahnhofsstraße".
The chosen variant remains transparent above the road and obstructs neither the view, nor does it represent a major intervention in the landscape. The support structure is protected under the pavement and outside the mean water level. This allows a shift of the center of gravity of the structure to the center of the bridge, where a greater height is possible due to the elevation of the bridge. For the timber construction results from the dense deck slab optimum protection, which is visible by the accessibility of the stove, the structure from below and the sustainable building material wood is experienced. The influence of the column on the flood level is reduced by the narrowest possible view. Because of these advantages, this variant is selected for the preparation of a preliminary design.
Due to the support concept with an intermediate support, the load on the listed retaining wall on the lower Wöhrd can be minimized by the formation of a cantilever. This causes little intervention on this shore.
For the structural roadway cross section, the materials wood and concrete are combined into a hybrid cross section. The wooden girder bears in combination with the reinforced concrete slab on top and is thus reliably protected from the elements. The hybrid construction ensures a long service life and combines the advantages of both building materials: the high compressive strength of concrete and the resistance of wood to tensile stress in the fiber direction. The use of wood is due to the environmental benefits including the storage of C02 within the construction. The existing local value creation chain can be optimally utilized by the timber construction and forestry companies based in the Schwäbisch Hall area and a minimal ecological footprint is achieved. In addition, wood has a considerable tradition as a bridge material in Schwäbisch Hall: in the urban area, 7 out of 12 bridges are made of wood.
In the sense of using sustainable building materials, the bridge on the side and the bridge pier are also made of a natural material:
The material granite with its high strength and longevity is a sensible addition to the timber structure. The side caps of the carriageway continue the layered shape of the beam and form the lateral pathway termination even in the bridge connection. The bridge pier receives a shape through lateral cuts, which requires minimal space in the embankment and harmoniously blends into the natural environment thanks to its materiality.