Otago University Med School

The Otago University Med school Christchurch Campus is a 5 story development with a single level basement with the building founding on a raft slab resting on the dense gravels. To facilitate the excavation of this basement a secant pile retaining wall solution was adopted. The client’s designers had originally considered a sheetpiled solution, however the required driving depth and dense gravels made this option untenable. The site was located at 21 Oxford Tce, in Christchurch’s CBD. 

The project scope involved an initial some initial technical assistance from March with Leigh’s to develop the final retaining wall solution to ensure it was best optimised in terms of layout and reinforcing cage detailing. 

The final solution settled on was: 

• 195lm of 600mm deep concrete guidewall
• 406nr 600mm diameter CFA secant piles constructed to a depth of 14m

For this project, March Construction utilised on of their large Liebherr LB28 drill rigs to undertake the piling.