SUSTAINABLE PEDESTRIAN BRIDGE CONSTRUCTION WITH MATERIALS BY COMBINATION

摘要

The bowstring arch bridge concept has been realized with thermoplastic Carbon Fiber Reinforced Polymer (CFRP) tendons for six longitudinal arranged bowstrings and glulam (glued laminated timber) for the finally arch shaped bridge deck. This deck is stress-laminated as a flat plate. It is constructed by placing sawn lumber laminations on edge and stressing the laminations laterally together on the wide face with thin high-strength thermoplastic CFRP tapes. It is causing the deck to act as a large orthotropic wooden plate. The bowstrings are composed of non-laminated pin loaded thermoplastic CFRP strap elements. These elements enable the individual layers to move relative to each other which allow an equalization of forces in the layers as the strap is tensioned. The approach allows excellent use of the strength of CFRP and great flexibility in terms of the geometry of the strap elements as tendons. After prefabrication of the flat glulam plate and the CFRP straps the bow has been drawn. The bridge deck, which has the arch function, was axially loaded with the CFRP straps and elastically bent with a deflection of 1/75 of the span. The described very sustainable bowstring arch concept allows an extremely slender and therefore very elegant bridge design. The first bridge of this kind with a span of 12 m was built end of 2006.