How do the base isolators work in a building?
Putting in base isolators is done in a sequence. You need to strengthen certain areas one at a time to be able to fit the base isolators in.
The base isolators are put into existing columns that hold up the building. To put them in, we’ve had to lift each column one by one, and then fit the base isolator into the column.
As the columns and base isolators sit underground, we have had to do work underneath the building. This has meant digging deeper into the earth and pumping out sea water and putting structural steel, or piles, in place. To put in base isolators, you need hard soil and ground.
Strengthening is also done to the building itself to work on top of the base isolators. Previously Te Matapihi was a flexible building, so it would sway in an earthquake. Now, we have built Te Matapihi to be more rigid so that it doesn’t sway side to side but instead it moves as one on top of the base isolators.
Once the building moves back into place, there shouldn’t be damage as the building keeps the same shape and hasn’t hit anything on the sides because of the rattle zone.