Icon Cancer Bunker – Moorabbin
About Project
Hutchinson Builders engaged us to complete the concrete package for the new Cancer Bunker that was to be constructed at the Holmesglen Hospital in Moorabbin. This was one of the most challenging packages that we had undertaken. This is because the 1.2m thick walls of the bunker had to be constructed within 300mm of the existing walls within the building. The walls were to be supported on a suspended slab on ground which was supported by 450mm diameter bored piers.
The solution that was decided upon was to shotcrete the external 200mm of the walls using lost formwork. Sacrificial Z bars were to be cast into the shotcrete wall with no conduits being used. This was it was deemed that the grouted conduits could be a weak point in retaining the radiation from the bunker. The spraying of the external wall was an extremely challenging process because the z bars, and some of the internal reinforcement was being cast into the first pour. The major risk was honeycombing near the top of the wall due to restricted access when pouring. Upon completion of stripping the formwork, it was discovered that the spray was to an extremely high standard with no honeycombing.
The internal formwork was then built with the external shotcrete wall being used as the external formwork. A platform was built to enable the in-situ wall to be poured with a line pump. A pour rate as per our formwork design was used. Despite extremely limited access and the fact that the pour was via a line pump the walls were poured to an exceptionally high standard.
The team lead by Shane Connaughton has recently completed the concrete package for the Icon Cancer Bunker at the Holmesglen Hospital in Moorabbin. The concrete package consisted of bored piers, slab on ground and 1,200mm thick in-situ bunker walls. The structure was to be constructed inside the existing hospital.
The most complicating aspect of the package was the 1,200mm wide bunker walls. This was due to the lack of access at the external face of the wall. The methodology that Shane designed had the external 200mm of the wall being sprayed with shotcrete which allowed the shotcrete wall to be used as the external formwork for the internal 1,000mm wide in-situ wall.
We were absolutely delighted with the extremely high quality of the walls. Overall, we found that Shane ran an excellent team who were easy to deal with and were very flexible when changes were made to the drawings. Excellent work from the crew, and in completing to satisfaction of follow on trades with no call backs for defects. We would have no hesitation in recommending Shane to other builders.