Parameters Influencing Performance of Elastomeric Bearings at Low Temperatures

Abstract

Experimental research was conducted to study the performance of elastomeric bridge bearings at low temperatures. Full-size natural rubber and neoprene bearings were tested by specially designed test setups inside a walk-in type environmental chamber. Steel laminated bearings were ordered with 2 specified shear modulus, 0.69 and 1.08 MPa. Tests were conducted at 23, -10, -20, and -30 deg C for a period of 21 days. The effects of cyclic compression, cyclic shear, rate of loading, type of elastomer compound, temperature history, creep, and slip coefficient on the performance were investigated. Approximately 500 shear stiffness tests were performed. Results indicate that the increase in shear stiffness at low temperature is a function of elastomer compound, temperature, and time. Rate of loading, amplitude of strain, coefficient of friction, and temperature history were identified as key parameters influencing bearing performance. Creep at low temperature was markedly different from that at room temperature, but had no major influence on overall performance. It was shown that cyclic compression force and shear strain do not have major influence on time-dependent stiffening of bearings.