TIMBER BRIDGE REVIVAL

Timber bridges are increasing in popularity for vehicular, pedestrian, cyclist and equestrian crossings. Correctly specified, they have good weathering durability and are resistant to de-icing salts. Timber bridges are in empathy with the landscape. The history of timber bridges, which have been built since Roman times, is outlined. Examples of timber bridges in Norway, France, Bhutan, the UK, Switzerland, USA, Germany and Finland are discussed. A research project completed by TRADA Technology and TRL for the Highways Agency entitled 'The potential for timber bridges' assessed the opportunities for an increased use of modern timber bridges in the UK. The project emphasised the importance of developing architecture that enhances the relationship between people and the bridge. The location and terrain influence the fundamental form that is appropriate for the bridge. Most wooden bridges fit into one of five categories of structural form: arches, beams, cable stayed and suspension types, tension ribbons, and girders and trusses. The load-carrying and protective functions of timber bridge decks are outlined. Measures to ensure the durability and ease of maintenance in timber structures through incorporating protective design measures at the initial concept design stage are discussed.