Title: An Experimental Study of Flat and Tapered Elastomeric Bridge Bearings
Author(s): Joseph V. Muscarella and Joseph A. Yura
Publication: Symposium Paper
Appears on pages(s): 143-164
Keywords: bridge bearings; bridges (structures); compression tests; fatigue tests; plastics, polymers, and resins; Design
In this study, sponsored by the Texas Department of Transportation, bearing performance was analyzed on the basis of elastomer hardness, shape factor, reinforcing shim orientation, degree of taper, and compressive stress level. Emphasis was placed on comparing the behavior of flat versus tapered pads. Experimentation included shear, compressive, and rotational stiffness tests; shear and compression fatigue loading; long term compressive loading; and tests to determine compressive stress limits. Bearings were intentionally loaded nonuniformly to define safe limits for bearing/girder slope mismatches. Research showed that tapered bearings performed as well as flat bearings and that manufacturing tapered bearings with steel shims oriented parallel to one another, rather than radially, is advantageous. Bearings made from lower hardness elastomers displayed several advantages over those made from harder material, particularly, a greater ability to accommodate girder end rotations. More highly reinforced bearings performed better in compression fatigue tests and easily accommodated compressive stresses well over 7.0 MPa (1000 psi).