2018-11-062018-11-061987-4FHWA-OK-87-3Oklahoma Department of Transportation State Planning and Researchhttps://hdl.handle.net/11244/301998Twelve skewed elastomeric expansion bridge bearings were supplied by the Oklahoma Department of Transportation. To evaluate the performance of these skewed bearings, the following six phases of testing were conducted on each of the twelve bearings: I. Shear and compressive stiffness tests, II. Fatigue cycles representing 50 years of service with parallel bearing surfaces, III. Shear and compressive stiffness tests, IV. Shear stiffness tests with bearings at sub-freezing temperatures, V. Fatigue cycles representing 50 years of service with rotated bearing surfaces, and VI. Shear stiffness tests Phase I formed the basis of comparison with the post-fatigue results from Phases III and VI, and the low temperature tests from Phase IV. It was found that the fatigue loading with parallel bearing surfaces had very little effect on the compressive and shear stiffnesses of the skewed bearings. Some degradation of shear stiffness was found after the fatigue loading with rotated bearing surfaces, Phase V. However, the combined degradation due to both fatigue loadings was considered insignificant. It was found that the simple shear equation for estimating the shear stiffnesses of the twelve bearings was very conservative and no correlation was evident between predictions and the experimental results of Phase I. In general, the shear stiffness changed more rapidly than the change in bearing area as the skew angle decreased from 900 (rectangular) to:300. As an outgrowth of the experimental work, design expressions for determining the effective shear stiffnesses of both skewed and rectangular bearings with turned axes were developed. Excellent correlation was found between shear stiffness predictions from the proposed equations and the experimental results.30 pages856,011 bytesapplication.pdfTechnical ReportSkewBearingsElastomericBridgesShear stiffnessExpansion deviceShear modulus