Ever wonder how a 16-story building can float?

Base Isolation Vision 2020

Base Isolation Vision 2020

Yes, you read that correctly, and it’s the latest and most advanced technique for seismic building safety. It’s called "base isolation".

Think of a big, rectangular box. The area inside the box represents the hole in the ground where the hospital’s foundation will sit. Now picture this: the building itself will be smaller than the space allows.

Why? To allow the ground to move under the building in the event of a massive earthquake. This allows the structure to safely absorb the force of the quaking by moving laterally inside the security of the box — up to 40 inches in any direction — rather than crumbling because it had nowhere to go.

The box, in the case of the future Adult and Children’s Hospital towers which are part of Vision 2020, is a hole of the following dimensions:

Depth: 50 feet, three inches
Width side to side: 260 feet
Width front to back: 410 feet

In this hole, the foundation — four feet of concrete reinforced with rebar — will support steel pedestals.

These pedestals, currently under construction in Arizona, will be installed by the end of 2017, on top of which will be placed the base isolators — the moving parts that will control the building’s motion during a quake. The primary steel structure of the building will sit atop the isolators.

If you’re ever a patient in this new hospital complex during an earthquake some movement may occur.

Rest assured, it’s a good thing.

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