Timber Design Awards
Hauraki Rail Trail Bridges
The Hauraki Rail Trail, part of Nga Haerenga, the NZ Cycle Trail, was opened in May 2012. It follows an historic railway route.
Radiata Pine timber was selected for construction of the many cycleway bridges because of the benefits over traditional steel or concrete options and the fit with the ecological and economic objectives of Nga Haerenga. Traditional bridge styling with modern connection detailing and prefabrication methods produced 25 attractive bridges ranging in length from 4m to 75m.
Short spans consist of pole beams, glue-laminated beams for longer spans, and timber suspension bridges provide the longest spans. Innovative barrier detailing facilitated prefabrication and efficiency of construction.
Radiata Pine timber was chosen because:
– Timber offers a lightweight option ideal for weak soils.
– Timber enabled construction in difficult locations without heavy craneage.
– Costs were significantly less than concrete, steel or hardwood options.
– Timber is aesthetically consistent with the railway theme, providing useful function and interesting form.
– The suspension, glue-laminated and pole bridges use common construction detailing, giving the structures a consistent appearance.
– The bridges were built with basic timber construction equipment and skills, hence small local contractors were involved in the construction.
– NZ-grown timber is an environmentally sustainable material, and its use supported the local industry.
– Timber bridges require minimal maintenance.
This project demonstrates the sustainability benefits and advantages arising from use of timber for recreational infrastructure, rather than more common steel or concrete options, and exemplifies the opportunities and sustainability benefits that arise from the considered use of NZ Radiata Pine.