Design and Construction of Yarra River Crossing Cofferdam for Melbourne Main Sewer Replacement Project

The Melbourne Main Sewer Replacement (MMSR) is a major urban infrastructure project involving approximately 2.3km of tunnelling and construction works. The works extend from Docklands Precinct, on the west edge of the city, southwards to connect with the Hobsons Bay Main Sewer in Port Melbourne. A major component of the MMSR is the crossing of the Yarra River, upstream of the Charles Grimes Bridge. The works will be completed using a staged flooded cofferdam construction method within the weak alluvial sediments associated with the river delta geology. This paper reports on the development and method of construction staging and highlights the structural and geotechnical design aspects involved in building a new sewer in the Yarra River.