This job is one of the most challenging and exciting projects that we have ever done.
The demolition scope of works was to fully strip out from basement 4 to level 10 and demolish the top three levels, i.e. level 11, 12 and 13. The stripping out parts were simple to us. However, completely deconstructing three levels of concrete structure at the very top of the building and trucking it away was a new challenge.
We planned to use a 300 tonne crane to crane a spider crane and our demolition robot DXR270 to the top of the building for deconstruction.
However, by the time we got to deconstruction, the tower crane wasn’t available.
So, we changed the deconstruction methodology. We propped all three levels, and then developed a cutting plan which drew all sections of concrete that we were going to cut, lift and remove. Each section was calculated based on the maximum load capacity of the tower crane to achieve the most practical and efficient solution.
We drew all the cutting lines and did all the core drilling prior to lifting. We hooked the section of slab / beam / panel before we made the cut and used the tower crane to give the section a pre-tension which equalled the weight of it. This meant that when we cut the section out, it would not tip, fall or flip over.
Plus, we had propping to prevent any unexpected events. During the lifting, we had two spotters working along with the crane operator and dogman - one on the top, one on the ground - to keep the surroundings and public safe. Each section was laid directly onto the waiting truck, then trucked to the yard for recycle.
Although challenging, we still managed to safely deconstruct all three levels and remove them from site within the stated timeframe.