Herbert River Bridge has been identified by the TRC to need upgrading. Engineering testing, certification and analysis by PDR Engineers confirmed the projected lifespan of the existing timber deck to be short due to reduced structural integrity of the timber girders. TRC have developed a package to replace the existing timber bridge with a new culvert structure, and to widen the existing causeway formation.
Cashmere-Kirrama Road is a rural collector road and primarily services the grazing regions of the upper Herbert. The road also serves as a tourist drive between Mt Garnett in the west and Kennedy on the coast just north of Cardwell. The recently re-opened Kirrama Range Road by the Cassowary Coast Regional Council in December 2014 is expected to result in increased tourist traffic on the road. The roads construction varies significantly with well graded and formed sections on the western side of the Herbert River generally 8m wide and general poorly aligned, and narrow formation on the eastern side of the Herbert River in cases as narrow as 3.5m. The road is unsealed for its entire length, with seal ending approximate 12km from Mt garnet on Gunnawarra Road. The unsealed sections generally have very poor alignment with numerous sharp horizontal curves and a narrow formation width typically no greater than 6m. Traffic count data at the bridge site is not known however is estimated to be less than 50 vehicles per day. TRC will however endorse a full road closure of the project site. The construction date and construction records of the existing bridge are not known, however the typical drawing by the Department of Forestry for this style of bridge is dated 1984. The existing one lane, two-span bridge consists of concrete abutments and a concrete pier with steel brackets supporting timber girders. The deck is a composite structure consisting of timber girders with a reinforced concrete overlay. The bridge is located in dense rainforest and is adjacent to Wet Tropics World Heritage tenure. A sharp horizontal curve on the immediate approach to Abutment B (Southern approach) combined with the dense rainforest conceals the bridge to drivers.
A new procedure for Management of Change was introduced (MoC). This was to ensure all changes were captured and other areas of the project were not affected because of a change.
© Chris Dempsey Cranes 2020