Effects of Isolation Period Difference and Beam-Column Stiffness Ratio on the Dynamic Response of Reinforced Concrete Buildings

International Journal of Concrete Structures and Materials

Table 1 Details of isolation devices used in 1/10-scaled model.

Group	LRB 80	RB 80
Number	18	23
Diameter × height (mm)^a	80 × 79	80 × 79
Inner steel plate (mm)	19@1.0	16@1.0
Inner rubber plate (mm)	20@1.0	17@1.0
1st shape coefficient	17.5	17.5
2nd shape coefficient	3.5	4.12
Vertical stiffness (N/mm)	7830	3880
Effective stiffness at 50 % horizontal strain (N/mm)^b	78	103
Damping ratio at 50 % horizontal strain^b	0.12	0.05
Effective stiffness at 100 % horizontal strain (N/mm)^b	62	100
Damping ratio at 100 % horizontal strain^b	0.1	0.05
1st Stiffness (N/mm)	140	–
2nd Stiffness (N/mm)	52	–
Bucking load (N)	200	–

^aHeight: included the thickness of top and bottom plates.
^bEffective stiffness and damping ratio in this table are average value. Difference between effective stiffness of isolation devices is no greater than ten percent.