Bridge deck rehabilitation using cross-laminated timber
|Forfattere||Rune B Abrahamsen, Trond Egil Nyløkken|
|Nøkkelord||rehabilitation, cross-laminated timber, connections, sustainability|
|Utgiver||Tapir Akademisk Forlag|
|Adresse utgiver||Tapir Akademisk Forlag Besøksadresse: Nardoveien 12 Postadresse: Postboks 2461 Sluppen 7005 Trondheim|
AbstraktHundorp Bridge is a 200 m long steel truss bridge in Gudbrandsdalen, Norway. The bridge is a typical single lane vehicular bridge and was constructed in 1924. Originally Hundorp Bridge had a concrete deck. This was later replaced by Bridge Plank – that is corrugated steel plates attached to the superstructure. The Bridge Plank deck system has proven to be inadequate and must be changed. The Norwegian Public Road Authorities (NPRA) hired Sweco for the rehabilitation design. The bridge deck rehabilitation will be done during the summer of 2010.
Using timber in the deck structure was desired to reduce the self weight, and thus improving the bridge’s load carrying capacity. Sweco and NPRA suggested an innovative deck system using conventional cross-laminated timber (CLT) plate elements. CLT is pretty common in the Norwegian building industry, but has not yet been used for bridge purposes.
The prefabricated elements are 1200 mm wide and are joined together on site to form a large 200 m long deck plate. Some pressure treated elements will have predrilled holes for water drainage. There will be a membrane and an asphalt surface layer on top of the plate. The timber deck and the steel structure have different temperature properties, which were taken care of by using slide bearings to assure free longitudinal translation.
Various element shapes have been considered. The traditional rectangular shape proved to be favourable. The shear force between each element is handled using timber screws. The tension force between each element is handled using two small glulam beams. The 113 m3 timber used in the deck stores about 102 tons of CO2.
ReferanserNorwegian Public Roads Administration. Handbook 184. Load regulations for public bridges and ferry quays. Version 2001-1.
Norwegian Public Roads Administration. Handbook 185. Design rules for bridges. Version 2001-1.
Norwegian Public Roads Administration. Handbook 238. Rating of bridges. Version 2003-1.
SINTEF Building and Infrastructure. Technical approval for CLT elements No2421 Version 23.11.09
SINTEF Building and Infrastructure. Technical approval for SFS WT-T timber screws No2449 Version 28.02.06
Eurocode 1995-1. Eurocode 5: Design of timber structures – Part 1-1: General – Common rules and rules for buildings. Nov 2004
Eurocode 1995-2. Eurocode 5: Design of timber structures– Part 2: Bridges. Nov 2004
Strusoft FEM-design version 8.0
Holmen AB Sweden
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