Bridges

VicRoads monitors a number of structures along its road networks through the structure monitoring program. In October 2014, VicRoads identified significant corrosion on two triple-cell corrugated metal culverts under the Mornington Peninsula Freeway over Tuerong Creek and Devilbend Creek.

The culverts, 1.8m and 3.0m in diameter and 120m and 137m in length respectively were constructed in 1993. The culverts were under VicRoads’ monitoring inspection program since 2010 due to the finding of excessive corrosion during a Level 2 inspection. The corrosion was found to be along the entire length of the culverts up to the top of the water flow level, which reduced the average thickness of the pipes. As the freeway is an important major link for outer suburban Melbourne to the Mornington Peninsula, these culvert structures were reassessed in 2014 and required strengthening by the end of 2016.

This paper discusses the option to strengthening of the culverts by applying full concrete structural lining that would act as a water proofing membrane while providing additional strength to the culvert structure. It explains the major pre-construction activities required under State Laws for environmental sensitivity areas where the worksites are located, including flora and fauna assessments, cultural heritage due diligence, permits and approvals. The performance and design requirements specified under VicRoads tender documentation are also discussed including the construction process using the Tunneline system which is often use for structural remediation of culverts and has a design life in excess of 100 years which meets VicRoads’ requirements.