Mechanical performance and shear constitutive model study of a new high-capacity polyurethane elastomeric bearing

Abstract

To develop high vertical capacity bridge isolation bearing, a new polyurethane elastomer (PUE) material with improved shear performance was introduced. This paper focuses on the mechanical properties and the shear constitutive model of the PUE material and the new bearings. Four isolation bearings with different design parameters made from the PUE material were produced to evaluate the vertical bearing capacity and horizontal shear performance. Further studies on the mechanical properties of the PUE material revealed that the new material has stable yield stress and strong rate-dependent features. From the experimental results, a rheological shear constitutive model was proposed for the PUE material to describe its highly non-linear rate-dependent properties. Parameter identification tests, such as multi-step relaxation tests, cyclic shear tests, and simple relaxation tests, were conducted to identify the model parameters. Finally, the accuracy of the proposed constitutive model was verified by the isolation bearings experimental. Results indicate the PUE bearing has a large vertical bearing capacity, promising horizontal deformability and energy dissipation capacity. The proposed rheological model accurately described the highly non-linear and rate-dependent shear mechanical properties of the new PUE bearing.