Report No.: CCEER-93-1

Authors: Y. Jiang, M. "Saiid" Saiidi, and D. N. O'Connor

Date: March 1993

Performing Organization:

Department of Civil Engineering/258

University of Nevada, Reno

Reno, NV 89557

Abstract:

This report describes an experimental and analytical investigation of one-way reinforced concrete hinges, frequently used at the base of highway bridge columns, when subjected to axial compression, shear, and uniaxial moment transfer in the strong direction. Attempts were made to develop recommendations for more reliable hinged column design, to conduct a preliminary study of the response of hinged columns with inadequate reinforcement development length, and to develop and test a repair method for damaged columns.

Many variables, including column aspect ratio, monotonic or cyclic loading, hinge steel arrangement, and hinge thickness relative to hinge width, were examined to study their effects on hinge flexural and shear strength, energy dissipation capacity, shear slip, and hinge throat concrete confinement.

A linear finite element analysis was performed to study stress distribution in the hinge throat area. Analytical studies also included inelastic analyses of bridges with hinged columns. Focus was placed on the influence of deck torsional stiffness and abutment spring stiffness on inflection point height. The inflection point represents the point where the lateral load should be applied for the purpose of calculating lateral hinge strength.

A new approach was developed for estimating the lateral load strength of hinged columns. This approach can be used for design purpose as well as for calculating the shear capacity for existing hinged pier columns (Abstract by authors).