Sumit Singhal loves modern architecture. He comes from a family of builders who have built more than 20 projects in the last ten years near Delhi in India. He has recently started writing about the architectural projects that catch his imagination.
Alfenz Bridge in Montafon, Austria by Marte Marte Architects
July 9th, 2013 by Sumit Singhal
Article source: Marte Marte Architects
The entry to the Montafon Valley is a topographical bottleneck. The railway, the federal highway and the new cycling path offer access to the southernmost valley of Vorarlberg, which is surrounded by high Alpine mountain ranges. Running parallel with the valley, the raging Ill River, prone to flooding, crosses the Alfenz River from the east and channels the Alfenz River into its current. A few meters before the confluence, the new concrete bridge structure spans the tributary and grants pedestrians and cyclists safe passage.
The inclination of the trusses is determined by the shear force and is thus steeper the closer the struts are to the bridge bearing. There are more walls on the side facing the heavily travelled road, whereas on the Ill River side the triangles of the framework offer a view of nature. The structural wall frame responds to environmental influences and supporting loads by means of the different sized openings.
The character and overall aesthetic are a result of structural logic and the efficient use of materials. Thus, the connection to the Bludenz-Schruns cycling path has been, literally, “massively” improved, since the bridge, through its concise design, is certainly a hard-to-miss landmark in the network of car-free mobility.
Character and appearance result from static logic and efficiency in materialization. 30m clear span, 206m³ concrete, 100m³ foundations, 36m³ framework sidewalls and 70m³ floor and ceiling, in total 33t steel. In regard to cubage and span nothing extraordinary for a bridge. But general local conditions lead to great challenge – power line, floodwater security, effluent cross section and constructing phase during floodwater periode; circumstances that made a common making impossible.
At that high architectural demands come along concerning the slimness of the sidewalls and the quality of face concrete. To ensure the claimed quality of exposed concrete the framework sidewalls were built horizontally and 250m away from the constructing site. The erection, the transport and the replacement of the very filigree sidewalls were the most precarious moments in the process of emerging.
Three “Telekräne” and one “Spezialtransportgerät” were necessary. Arrived at the riverside the support structure of the bridge was completed by concrete the support structure plate and ceiling. After curing when the concrete was hard the whole structure with its 300t got “slided in” during one day, also not a everyday issue.
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