High Damping Rubber Bearing with Long Lifespan & Extensive Applications

High damping rubber bearing, short for HDRB, is a kind of seismic isolation bearing that is much similar to natural rubber bearing in shape and structure. The difference between HDRB and NRB lies in that the HDRB offers better damping property by adding graphite filler (carbon black), reinforcing agent, vulcanizing agent, plasticizer and other compounding agents in natural rubber.

It not only maintains the good mechanical properties of natural rubber bearing, but also offers a high damping ratio, which allows the HDRB to absorb and dissipate the seismic energy in the earthquake, thus reducing the impact of the earthquake.

HDRB can be used in the seismic isolation systems separately and adjust the damping by regulating the amount of various compound agents added and the mixing ratio of these agents. Generally, damping ratio can reach up to 10% to 25%. Therefore, it is an economic and durable new seismic isolation device for buildings.

Working Principle
Features
Category
Structure
Specification

Working Principle

By introducing HDRBs in the structure, a soft seismic isolation layer is created to separate the superstructure from the lower foundation. In this way, it lowers the overall stiffness of the structure, extends its natural vibration period and reduces its natural vibration frequency, thus avoiding the highest frequency range of energy in the earthquake and reducing the input of seismic energy.

Meanwhile, the high damping characteristics of the seismic isolation layer ensure the absorption and dissipation of seismic energy and facilitate to reduce the response of the structure. In this way, the relative displacement will be concentrated in the seismic isolation layer with lower stiffness, thus limiting the upward transfer of seismic energy, and lowering the response of the superstructure.

When the earthquake comes, the vibration energy of the lower foundation is transferred to the high damping rubber bearing first. When the bearing is subject to a horizontal deformation, the HDRB offers certain resistances that can effectively absorb and dissipate seismic energy, to avoid or reduce the transmission of seismic energy to the upper structure, thus protecting the superstructure and personnel & equipment inside from earthquake damage.

After the earthquake, the bearing will restore to its original position through the recovery force of the rubber.

The different results of buildings with or without high damping rubber bearings in the earthquake.

Features

It has high strength and vertical stiffness to allow the HPDR to withstand higher vertical load and support buildings stably.
High damping rubber has great horizontal deformation capacity, horizontal restoring force as well as amazing seismic energy absorption and dissipation capacity.
The designed maximum damping ratio can reach up to 25% and can provide damping required in seismic isolation design without adding additional dampers, requiring a low maintenance and management costs.
Its smooth hysteresis characteristics allows the HPRB to reduce both the seismic response and high frequency vibration of the supper structure in the earthquake.
Its higher initial horizontal stiffness provides excellent resistance to wind-induced vibration.
It has minimal residual deformation after severe earthquakes and does not require replacement. It is economical and durable and enjoy a long service life, typically up to 60 years and above.

It demonstrates the relationship between shear displacement and shear force of the HPRB.

The curve shape is full, indicating that the HPRB has great energy dissipation capacity to ensure an amazing seismic isolation effect.

Category

High damping rubber bearings are divided into round and rectangular high damping rubber bearings by shape.

Round high damping rubber bearing

Rectangular high damping rubber bearing

Structure

High damping rubber bearing consists of top and a bottom connecting steel plates, internal high damping rubber layers, internal steel plates, a rubber cover and a top and a bottom sealing plates.

Internal steel plate layer: Provide a higher vertical load bearing capacity that allows the HPRB to support buildings stably.
Internal high damping rubber layer: Offer great horizontal deformation capacity, horizontal restoring force as well as amazing seismic energy absorption and dissipation capacity.
Cover rubber: Protect the inner rubber from ozone and UV damage and offer great aging resistance.

Round high damping rubber bearing structure

Rectangular high damping rubber bearing structure

Specification

Cross section of high damping rubber bearing

Floor plan of high damping rubber bearing

Table 1: High Damping Rubber Bearing Specification (G4)
Item		HDRB (G4)	HDRB (G4)	HDRB (G4)	HDRB (G4)	HDRB (G4)	HDRB (G4	HDRB (G4)	HDRB (G4)	HDRB (G4)	HDRB (G4)
Item		Φ300	Φ400	Φ500	Φ600	Φ700	Φ800	Φ900	Φ1000	Φ1100	Φ1200
Shear modulus of elasticity N/mm²		0.39	0.39	0.39	0.39	0.39	0.39	0.39	0.39	0.39	0.39
Vertical load (kN)	F_z	500	1200	2200	2700	4000	5900	8800	10000	14000	16000
Displacement (mm)	V	150	200	250	300	350	400	400	400	400	400
Horizontal equivalent stiffness (kN/mm)	K_H	0.37	0.51	0.65	0.76	0.90	1.03	1.31	1.57	1.90	2.26
Equivalent damping ratio (%)	H_eq	8–12
Dimension (mm) T_e = rubber thickness	D	300	400	500	600	700	800	900	1000	1100	1200
	H	200	230	265	295	345	395	395	430	430	430
	B	350	450	55o	650	750	850	950	1050	1150	1250
	T_e	80	104	128	156	180	204	204	210	210	210
Notes: Other specifications are available upon request.

Table 2: High Damping Rubber Bearing Specification (G6)
Item		HDRB (G6)	HDRB (G6)	HDRB (G6)	HDRB (G6)	HDRB (G6)	HDRB (G6)	HDRB (G6)	HDRB (G6)	HDRB (G6)	HDRB (G6)
Item		Φ300	Φ400	Φ500	Φ600	Φ700	Φ800	Φ900	Φ1000	Φ1100	Φ1200
Shear modulus of elasticity N/mm²		0.55	0.55	0.55	0.55	0.55	0.55	0.55	0.55	0.55	0.55
Vertical load (kN)	F_z	500	1200	2200	2700	4000	5900	8800	1000o	14000	16000
Displacement (mm)	V	150	200	250	300	350	400	400	400	400	400
Horizontal equivalent stiffness (kN/mm)	K_H	0.51	0.70	0.88	1.04	1.23	1.42	1.79	2.15	2.60	3.10
Equivalent damping ratio (%)	H_eq	8–12
Dimension (mm) T_e = rubber thickness	D	300	400	500	600	700	800	900	1000	1100	1200
	H	200	230	265	295	345	395	395	430	430	430
	B	350	450	550	650	750	850	950	1050	1150	1250
	T_e	80	104	128	156	180	204	204	210	210	210
Notes: Other specifications are available upon request.

Send A Message

If you are interested in our seismic isolators, or if you want to get a customized seismic isolation solution for your projects, just send use an email, we are ready to help you 24/7.