Various abiotic and biotic agents have a negative effect on the service life of materials used for bridge constructions. Corrosion of steel, carbonization of concrete and decay of timber are limiting their service lives. It is a common perception that the expected lifetime of a timber structure is only a fraction of that of a concrete or steel structure. In spite of this there are numerous timber structures remaining since centuries such as Norwegian stave churches, half-timbered oak houses, and covered bridges in Switzerland – commonly accepted as consequence of proper design and workmanship. In contrast, many untreated timber structures show severe decay after only a few years in service due to wetting.
The WoodWisdomNet research project DuraTB (‘Durable Timber Bridges’) aims therefore to significantly improve the durability of timber bridges. A modern and innovative concept is sought to provide design solutions being among the best alternatives with respect to environmental friendliness, initial and life-cycle costs, showing excellent results in life- cycle analyses.
The paper gives an overview about objectives and research activities of the project. Work on the development of performance and climate models performed at Lund University, Sweden, and Leibniz University Hannover, Germany, are presented in the latter part of the paper. Various details were evaluated regarding their moisture-induced risk for decay, which was identified as key element for service life prediction of bridge structures in the absence of chemical wood preservation.
Keywords: Decay modelling, glulam, moisture risk, Network arch bridge, Norway spruce
Authors
Brischke C.
Leibniz University Hannover, Faculty of Architecture and Landscape Sciences, Institute of Vocational Sciences in the Building Trade, Hannover, Germany
Meyer-Veltrup L.
Leibniz University Hannover, Faculty of Architecture and Landscape Sciences, Institute of Vocational Sciences in the Building Trade, Hannover, Germany
Thelandersson S.
Lund University, Division of Structural Engineering, Lund, Sweden
Malo K.A.
Norwegian University of Science and Technology, NTNU, Department of Structural Engineering, Rich. Trondheim, Norway
Login to download the PDF