RESPONSE AND DESIGN OF R/C ONE-WAY PIER HINGES IN STRONG DIRECTION

This paper presents the results of an experimental and analytical evaluation of one-way reinforced-concrete pier hinges subjected to a combination of axial compression, shear, and moment in the strong direction. Thirty-four specimens consisting of columns, shear specimens, and compression specimens were tested. The variables were the aspect ratio of columns, arrangement of steel in the hinge region, and thickness of hinge throat. The columns were subjected to cyclic loads, but other specimens were subjected to monotonic loads. Analyses of the hinged columns involved the determination of lateral-load strength, energy-dissipation capacity, shear slippage, and the compressive strength of the concrete in the hinge region. The test data showed that the behavior of column hinges with bundled and diagonal bars was similar to that of the hinges with equally spaced straight bars. Regardless of the reinforcement detail, flexure dominated the lateral load even in specimens with an aspect ratio of 1. It was also shown that the column and footing confine the concrete in the hinge throat, and that the strength of the concrete is enhanced by at least 25%. A simple method to determine the moment capacity of one-way hinges is presented and evaluated using the measured data.