Rubber Seismic Isolation Bearing for Bridge

Rubber Seismic Isolation Bearing

Rubber Seismic Isolation Bearing consist of a laminated rubber and steel bearing with steel flange plates for mounting to the structure. 90% of our isolators have an energy dissipating lead core.

The rubber in the isolator acts as a spring. It is very soft laterally but very stiff vertically. The high vertical stiffness is achieved by having thin layers of rubber reinforced by steel shims. These two characteristics allow the isolator to move laterally with relatively low stiffness yet carry significant axial load due to their high vertical stiffness. The lead core provides damping by deforming plastically when the isolator moves laterally in an earthquake.

Isolators from 200 to 1200 mm in diameter and capacities of up to 3000 tons are
manufactured. Custom dimensions are available for special applications.

The shims for isolators are cut to exacting tolerances by laser. The steel mounting plates are machined by computer controlled milling machines that give high production throughput and accuracy. Molding each bearing takes 8 to 48 hours depending on the size of the bearing. The curing phase is continuously monitored to ensure that the rubber is uniformly cured throughout the bearing





 

Standard		JT/T4-2004		BS5400 Section 9.2
Rubber		Natural Rubber	Neoprene CR	Natural Rubber	Neoprene CR
Hardness(IRHD)		60±5	60±5	50±5/60±5/70±5
Tensile Strength (M Pa)≥		18	17	17	15.5
Ultimate Elongation (%)≥		450	400	450/400/350	400/350/300
Compression Set		70oC×22h		70oC×22h	100oC×22h
		<30	<15	<30	<35
Heat Resistance	Test Condition	70oC×168h	100oC×70h	70oC×168h	100oC×48h
	Change in Hardness	-5,+10	0,+10	<10	<15
	(IRHD)
	Rate of Tensile Strength Reduction(%)	<15		<15
	Rate of Ultimate	<20	<40	<20	<40
	Elongation Reduction
	(%)
Ozone Resistance		25~50pphm,20% strain		25~50pphm,20% strain
		40oC×96h		30oC×96h
		No Cracks		No Cracks