Durable Timber bridges
Durable Timber Bridges (DuraTB)
Start : February 2014
End : April 2017
Total budget: 2120 k€
Project Coordinator:
Professor Kjell A. Malo
NTNU, Norwegian University of Science and Technology, Dep. of Structural Engineering
e-mail: kjell.malo@ntnu.no
Project Partners:
Country
Partner
Email adresses
Norway
Norwegian University of Science and Technology, NTNU
Kjell.malo@ntnu.no
Norway
Moelven Limtre AS
Age.holmestad@moelven.no
Norway
Norwegian Public Road Authorities (Statens Vegvesen)
Otto.kleppe@vegvesen.no
Finland
VTT technical research centre of Finland
Stefania.fortino@vtt.fi
Finland
Aalto University
Lauri.salokangas@aalto.fi
Sweden
SP Technical research Institute of Sweden
Anna.pousette@sp.se
Sweden
Lund University
Sven.thelandersson@kstr.lth.se
Sweden
Moelven Töreboda AB
Erik.johansson@moelven.se
Sweden
Martinsons Träbroar AB
Peter.jacobsson@martinsons.se
Sweden
Limträteknik AB
Roberto@limtrateknik.se
Sweden
Trafikverket (Swedish Road Authorities)
Christine.eriksson@trafikverket.se
Finland
Finnish Transport Agency
Timo.tirkkonen@fta.fi
Finland
Confederation of Finnish Construction Industries RT
Tomi.toratti@rakennusteollisuus.fi
Finland
Finnish Wood Research OY
Jaakko.lehto@fwr.fi
Finland
Versowood OY
Esa.hynninen@versowood.fi
Finland
Late-Rakenteet OY
Veijo.lehtonen@late.net
Finland
MetsäWood
Jaakko.lansiluoto@metsagroup.com
Finland
City of Espoo
Vesa.rounty@espoo.fi
Finland
City of Helsinki
Ville.alajoki@hel.fi
USA
United States, Department of Agriculture, Forest Products Laboratory
jwacker@fs.fed.us
Webpage: NA
Abstract:
Many new bridges are needed due to altered use and bad conditions beyond repair. Most of these bridges have quite small spans, in the range 10 to 120 m, crossing roads and rivers. Bridges are vital components of the transport infrastructure and most of them have been made in concrete and steel during the last half of the 20th century. For the infrastructure, the closing time in case of renovation is critical. Timber bridges are well suited for this span range; they offer quick installation on site and can utilize existing foundation due to low weight. The research project aims to improve the general standing and applicability of wood as a structural material in environmentally friendly bridges.
The overall objective of the project is to develop durable timber bridges with a given estimated technical lifetime. The scientific and technological objectives cover; development of a performance based service life design model for timber bridges, validated computer models for prediction of moisture distribution and moisture traps and new design concepts for durable timber bridges with spans up to 150 m.
The service life performance model includes a risk of decay map for most locations in Europe, giving climate inputs to the model for microclimates on timber components. The model also includes a set of classified details typical for timber bridges. The model has the same format as most modern structural codes and is defined by a limit state, e.g. representing onset or a certain level of decay. For durability, this approach has the advantage that the exposure is expressed as a function of global and local climate, component design and surface treatment in a general way, independent of the exposed material. The material resistance is in the same way expressed in terms of response to quantified and standardized conditions.
The project run instrumented tests on typical bridge parts, collects data from instrumented bridges and make use of numerical FEM models to evaluate and classify typical details of timber bridge design. The models are in turn used to improve promising design concepts for durable timber bridges.
A new concept for long timber bridges has been developed using timber pre-stressed decks and glued and laminated timber arches in combination with inclined steel hangers in a special network pattern. The arches are stabilized by a double set of spoked hangers, which is a novelty. The developed design is very effective and is visualised by the computer model below.