Survey on Major Worldwide Regulations on Seismic Base Isolation of Buildings

Table 16

Parameters of the isolators (minimum/nominal/maximum) for the hospital buildings.

	Los Angeles		New Mexico
	NRB	LRB	NRB	LRB
Diameter (mm)	500	600	450	450
Rubber layer height (mm)	5	6	5	5
Rubber height (mm)	125	250	110	180
Lead core diameter (mm)	—	90	—	60
Rubber shear modulus (MPa)	0.392	0.385	0.392	0.385
Lateral initial stiffness (kN/m)	616/677/800	5867/5867/5867	567/623/737	5585/5585/5585
Yielding force (kN)	—	54.91/60.40/71.38	—	26.70/29.30/34.71
Lateral after-yield stiffness (kN/m)	—	451/496/587	—	430/473/559
Vertical stiffness (kN/m)	1228	1106	1043	811
Effective design stiffness (kN/m)	515	715	567	738
Effective damping (%)	—	20.38	—	25