507 Murray Street, Perth
A very tough engineering challenge. This narrow site had neighbouring properties built to the boundaries on three sides and required a deep basement for an electrical transformer. One of the neighbouring properties was a heritage listed building in a very dilapidated state that also had some impact on the construction methodology.
Budget constraints required some out of the box thinking because grout injection for the basement and footing excavations would have put the project over budget.
A concrete caisson was used for the basement construction. Walls for the basement were cast at ground level, and an excavator lifted into it. As the excavator dug down the wall sunk into the ground, without the need for temporary retention of any kind. This may have been the first time that this methodology was used in Perth, and saved the client hundreds of thousands of dollars.