They recommended seismic
base isolators (Ridg-U-Rak, ridgurak.com).
To calculate the required lateral force for superstructures, we need to compute the minimum and then the maximum effective stiffness of the
base isolators. In this regard, the equations are calculated as follows:
5)
Base isolators convey the vertical load undergoing no vertical deformation;
Also to check the performance of
base isolators by varying its properties such that time period and effective damping.
"Although we were able to install and remove
base isolators from this test structure," Hutchinson says, "you would need a relatively large moat around the hospital if it was base-isolated, and that in itself could be too costly." As the situation stands now, only 30 buildings in all of California are base-isolated, including two hospitals: the Mills-Peninsula Medical Center in Burlingame and the women's health center at Hoag Memorial Hospital in Newport Beach.
Jenny Christensen, spokesperson for Consonus Technologies (which recently merged with Strategic Technologies), says that the company's flagship data center in South Jordan is designed to weather a quake of up to 7.5 on the Richter Scale thanks in part to
base isolators, which she likens to giant Nike shocks, beneath the building's I-beams.
Designed to withstand magnitude 8.2, a catastrophic earthquake, the cathedral rides as a unit on rubber and steel
base isolators, primarily supporting the walls, while Teflon-bearing sliders on flawless faces of stainless steel support the nave floor.
Ever-Level's new technology includes
base isolators, a two-part system designed to separate a building from ground shock and movement during an earthquake.
As part of the facility's "earthquake-ready" status, the 950,000-squarefoot medical center is constructed with
base isolators and hydraulic shock absorbers, allowing the building to move 22 inches in any direction should an earthquake occur.
It has 392
base isolators which operate like giant shock absorbers to allow the building to move from side to side without extensive damage.
According to Eloy Retamal, the project's structural engineer, the entire building rests on 28
base isolators (elastomeric bearings) that allow the building to move 16 inches in any horizontal direction.