An engineer made a plan for the renovations which included removing some floors, and an excavation of 5 metres. The council gave approval for the work to go ahead but did not require any strengthening or bracing of the brick facade while the work took place. If the fragility of brick to vibration is not known to current generations, particularly after the Christchurch earthquakes, it would be astounding, for engineers and a Council to not know borders on insanity and gross incompetence to the highest level. Anybody living in any sort of home which boarders a road on which heavy traffic travels feels vibration, and that vibration is dampened by soft soil, clay or other similar substrate, but concrete or rock is a conduit for the vibration.
If a hole is dug in the ground the faces of the excavation are the weak point until retained in some fashion, rain water or underground water table add to the weakness, so does vibration. The Palace was internally stripped, the floors that where removed weakened the integrity of the brick because they were working as a horizontal brace. An unbraced brick wall has no strength because unlike a block wall has no poured concrete centres of reinforcing steel pinning it to the foundation.
Today a council spokesman said it was not 'known' what caused the problem. Mayor Brown gave the order for it to be demolished despite the one of the owner Cho saying he wanted to time to have it assessed by another engineer. Christchurch was able to have building properly assessed it seems without haste using a range of experts and specialists. But the Auckland Council felt there was no time to do so, having already apparently failed to ensure the proper steps were taken and enforced during the renovation. Mr Cho told the owner of the demo company and the council engineer that he is going to sue them. I hope he does.