Report No.: CCEER-92-1

Authors: D.L. Straw and M. "Saiid" Saiidi, Professor and Chairman

Date: March 1992

Performing Organization:

Department of Civil Engineering/258

University of Nevada, Reno

Reno, NV 89557

Abstract:

This report presents the results of the second phase of an ongoing study at the University of Nevada, Reno. This phase involved laboratory and analytical evaluation of one-way reinforced concrete pier hinges subjected to a combination of uniaxial moment transfer, shear, and axial compression. Four one-sixth scale hinge models were built and tested in the strong direction. There were two primary variables in the testing sequence: shear-span to depth ratio (aspect ratio), and monotonic versus cyclic loading.

Analysis of the hinged specimens involved determining flexural and shear strengths, concentrated hinge rotations, and displacement of the column elements. A comparison between the measured and the calculated yield and failure loads is presented for each specimen. Various shear capacity equations and their accuracies are also examined relative to the measured data.

Hinge rotation and column deflection consisted of two components: reinforcement bond slippage and plastic deformation. Flexural displacements were determined from the curvature distribution along the column and included elastic deformation of the column and plastic deformation of the hinge. Empirical formulas used to estimate the rotations and displacements are discussed.

Results of the testing indicate that cyclic loading reduces the stiffness of the connection substantially and reduces the energy absorbing capabilities of the hinge (Abstract by authors).