Wooden Bridges: Strategies for Design, Construction and Wood Species - From Tradition to Future

Wooden bridges are traditional building structures with a history almost as long as the history of mankind. Different designs, often related to the technical possibilities and cultural aspects of the time and building site, have been developed and built over the centuries. These developments represent a very valuable basis for the future design and construction of wooden bridges. This paper deals with the influencing factors: design, construction and material, starting with a brief summary of the historical development of wooden bridges including the used wood species. Twenty-one built examples are mentioned with four, which found to be particularly relevant for future developments, being analysed more in detail. Based on the findings, three main areas influencing the design of wooden bridges are defined: (1) The design, specifically the function and interaction with the surroundings, (2) the structural design and (3) the used material/wood species. The results show that many current examples lack in design and structural efficiency. An important issue for future developments will be the transfer and transformation of the traditional knowledge into the future, including new design findings and new construction approaches using for example computer numerical controlled joinery machines and robotic fabrication approaches within prefabrication and assembly on site.