What factors affect the durability of laminated rubber bearings?

What factors affect the durability of laminated rubber bearings?

The durability of laminated elastomeric bearings is influenced by various factors such as materials, environment, loads, and deformation. The specific details are as follows:

I. Material Factors

1. Rubber Aging

1. Aging Mechanism: Prolonged exposure of rubber to oxygen, ultraviolet (UV) rays, temperature fluctuations, and ozone causes molecular chain breakage or cross-linking, leading to reduced elasticity, hardening, and brittleness (e.g., cracking).
2. Impact: Loss of elasticity diminishes the bearing’s horizontal deformation capacity and seismic isolation effect, potentially causing failure in severe cases.
   2. Steel Plate Corrosion
3. Corrosion Risk: If the steel plates lack proper anti-rust treatment or are exposed to humid, salt-laden environments (e.g., coastal areas), rusting occurs, damaging the bond between rubber and steel. This results in decreased overall stiffness or structural failure of the bearing.

II. Environmental Factors

1. Temperature Effects

1. High Temperature: Prolonged exposure to high temperatures (e.g., over 60°C) accelerates rubber aging, significantly reducing its elasticity.
2. Low Temperature: Rubber may harden at low temperatures, losing elasticity and restricting deformation (e.g., limited shear displacement).
   2. Chemical Corrosion
3. When the bearing contacts chemicals like acids, alkalis, or oils, the rubber corrodes, leading to performance degradation (e.g., swelling, reduced strength).

III. Load and Deformation Factors

1. Long-term Vertical Load

1. Sustained overloading causes permanent compressive deformation in the rubber layers, reducing the bearing’s height and altering its horizontal stiffness, which disrupts the structural force balance.
   2. Repeated Horizontal Deformation
2. Repeated shear deformation from earthquakes or wind loads induces fatigue damage within the rubber. Long-term accumulation may cause cracking, diminishing the bearing’s durability.

IV. Design and Construction Factors

1. Inappropriate Material Selection

1. Failing to choose suitable rubber types (e.g., not using low-temperature-resistant or high-damping rubber) based on the service environment, or insufficient anti-rust treatment for steel plates, directly shortens the bearing’s lifespan.
   2. Structural Design Flaws
2. Lack of effective protective layers (e.g., no neoprene sheath) fails to isolate UV rays and environmental erosion. Poor drainage design leads to prolonged water immersion, accelerating aging.
   3. Construction and Installation Errors
3. Uneven loading or positioning deviations during installation subject the bearing to extra stress, reducing its service life.

V. Maintenance and Management Factors

1. Lack of Regular Inspections

1. Failure to promptly detect early damage such as rubber cracking or steel corrosion allows issues to worsen.
   2. Inadequate Maintenance Measures
2. Delayed repair of damaged protective layers or neglect of rust removal and anti-corrosion treatment for corroded steel plates accelerates performance degradation.

Conclusion

The durability of laminated elastomeric bearings is a result of combined effects from material properties, environmental conditions, loading, and maintenance. Optimizing material formulations, enhancing structural protection, controlling loads and deformations, and implementing regular maintenance can effectively extend their service life (typically designed for ≥60 years).

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