Barwon Heads is a picturesque coastal town located at the mouth of the Barwon River on the Bellarine Peninsula. The original 300 metre long timber road bridge was built in 1927 and much loved by the local community. It had been adapted and repaired so many times that by 2006 it was rapidly reaching the end of its operational life. The original bridge was beyond repair and so began the difficult process of designing its replacement. The local community mounted a campaign to save the Bridge but when no clear outcome could be reached the State Government appointed an independent “Barwon Heads Advisory Committee” to advise on its future. The final report from January 2007 recommended that the existing bridge be widened and upgraded subject to hertitage approval. Subsequently heritage approval could not be obtained and so the second recommendation was adopted being a two bridge solution, a reconstructed road bridge and a new contemporary pedestrian & cycling bridge located downstream of the road bridge.
The original 1927 timber beam bridge was constructed from turpentine gum (no longer available) and included all structural components – piles, crossheads, pier bracing & whalers, stringers, corbels, cross frames, the deck, railings and barriers. The long term impacts of sand scouring and teredo worm infestation to the piles had led to much of the bridge being replaced or encased in concrete. Steel girders were added to strengthen the bridge along with a concrete road deck laid over the original timber planks.
The reconstructed road bridge is a very innovative composite steel/concrete/timber structure and a rare example of the extensive use of structural timbers in a major estuarine road bridge with a 100 year design life. Timber components include blackbutt piles (above water), blackbutt crossheads, Forest red gum whalers & cross braces, with the outer stringers and corbels being a mixture of spotted gum, white mahogany and grey ironbark. Given the marine environment bridge timbers are generally double treated with copper-chromium arsenate & pigment emulsified creosote.
The new pedestrian/cycling bridge is clearly differentiated as a contemporary concrete/timber/stainless steel structure which is fully clad in timber with a boat hull-like cross section. The design intent was to construct a pair of parallel causeway bridges as companion structures each expressing the importance of timber in estuarine coastal environments.
The new bridge timber cladding includes bridge decking planks, battens and raised fishing platform in a mixture of spotted gum, blackbutt & forest red gum, tallowood & blackbutt handrail cappings, with the fascia and underside raking battens being mostly spotted gum with some blackbutt. The bridge expresses the beautiful tactile and aesthetic qualities of timber in an extraordinary coastal setting. The underside of the bridge has a complex warping geometry where the timber battens rake and interlock to create visual interest and detail.
Prior to on-site construction, a prototype bay of the bridge was assembled in a factory to test the timber cladding systems. The timber cladding systems were designed to be assembled in prefabricated sections to reduce on-site labour and achieve a very high quality finish.
An independent expert timber consultant was employed to specify all of the timber products for both bridges and to follow the project through all stages of compliance, evaluation and auditing. This has resulted in an exceptional outcome in timber design and quality.