Breakwater Road forms part of a major east-west connection across the Barwon River and is a vital freight link between Geelong and the Bellarine Peninsula in Victoria, Australia. The existing two-lane single carriageway bridge over the river is carrying around 20,000
vehicles each day but is subject to periodic closures due to flood inundation in winters. To reduce the flood impacts on road users, VicRoads, the state road and traffic authority pro- posed to realign a 1.3 km section of the Breakwater Road and construct a new 640 m bridge over the Barwon River. The 19-span structure commences at a distance of approximately 180 m from the west bank of the Barwon River to the eastern end connection. Approach to the western end of the structure is via a 170 m long earth fill embankment and a bank of culverts of 130 m long to allow passage of flood water. The earth fill embankment together with the culverts is to be constructed over a floodplain immediately west of the Barwon River where soft and compressible alluvial deposit is expected.
Due to the need to complete the project within the nominated timeframe, conventional ground improvement techniques such as surcharging were considered unviable. As a result, other types of ground improvement techniques were investigated. Deep soil mixing (DSM) and semi-rigid inclusion were both considered suitable options by VicRoads. Con- trolled Modulus Column (CMC) as one of the semi-rigid inclusion techniques was finally adopted by the Contractor. Project construction has commenced in late 2010 and expected to complete in mid 2012.