Vertically laminated timber bridges

This paper reports on research to optimise the design and construction of various forms of stress-laminated timber bridges. Forty bridges, up to 24 m span, and over 60 deck panels have been built and monitored over the last 5 years. A research programme at Napier University has complemented the construction and, through a series of dynamic and static load tests, has helped develop better construction methods and stronger structures. The overall aim of this research programme has been to develop structural uses for low-grade, UK-grown timber and it has been shown that using timber in compression is an extremely effective technique for arch bridges. These bridges, on public roads, can help increase public confidence in timber as a viable primary structural material. This paper reports the development of factory-produced, timber-laminated modules for lorry bridges and footbridges. It explains the different fixings, spans, widths and load tests and summarises the conclusions. It finishes by showing the lowest cost, stress-laminated flat lorry bridge and reports the details of cyclic load tests for the development of timber arch bridges for heavy lorry traffic.