Melbourne Convention Centre & South Wharf Precinct

Melbourne Convention Centre & South Wharf Precinct
Brookfield Multiplex & Contexx
Techniques Used: 
Foundation piles, low headroom piles, contiguous pile walls, secant pile walls, bentonite / cement slurry cut-off wall, displacement piling (CMC), deep soil mixing, jet grouting, permanent anchors.

Project Brief: Valued at approximately AUD $1.8 Billion, the redevelopment of the Melbourne Convention Centre and South Wharf precinct was one of Melbourne's largest ever building projects.  The site was divided into two sub-projects with two separate builders: Brookfield Multiplex and Contexx.  The award winning Melbourne Convention Centre works comprised a 6 green star, 5000 seat convention centre and 5 star multi level hotel with associated infrastructure. The works comprised the restoration and redevelopment of heritage listed wharf structures, large multi-storey car park, commercial precinct and mixed use multi-storey tower. Vibropile and its sub contractor; Keller Ground Engineering, were awarded the foundation piling, temporary retention piling, ground improvement and cut-off walls for both projects.

Geological Conditions: Geology on the site was complex with discontinuous older volcanics of varying quality and depth across the site, underlain by Silurian aged mudstone (Melbourne formation) which also had dyke material present in several areas. The foundation solution was specifically designed to cater for these highly variable ground conditions while still giving uniform settlement performance.

Scope of Work: The design and construction of almost 4000 CFA piles (over 100km) of piling to depths of 30m to 40m. All piles were installed with full computer instrumentation to ensure pile quality and structural integrity. Due to the highly sensitive nature of Melbourne's Coode Island silt formation, approximately 1.6km of bentonite / cement slurry cutoff wall was installed around the perimeter of the site to ensure that dewatering inside the substantial basement of the Convention Centre did not affect the surrounding area during construction. A large number of permanent and temporary retaining walls were also constructed around the site to facilitate construction of the basement, lift pits, stairs and orchestra pit. Deep soil mixing, jet grouting and CMCs were utilised on the emergency access roads in and out of the site which had to be maintained for the duration of the project.

Conclusion: The use of full computer instrumentation on these projects allowed Vibropile to install CFA piles into highly variable geological conditions with a high degree of certainty on the founding conditions. Up to 5 rigs and 30 staff were on site and both stages of the project were completed ahead of program. Over 80 piles were also dynamically load tested on the project. All results indicated that both the ultimate load capacity and strength settlement criteria were met.