Analysis of Rotational Column with Plastic Hinge

Michael Long, Rice University; Corey Bergad, Bates College; EERC Name: MCEER Host Institution: SUNY at Buffalo Faculty Advisor: Dr. Andrei Reinhorn ________________________________________________________________________ Abstract: A plastic hinge is a type of energy dampening device allowing plastic rotation of an otherwise rigid column connection. This device is composed of a weakened portion of the column prevented from rotating by relatively small steel members. These small bars are designed to yield and allow rotation before the capacity of the column is reached, thus acting as mechanical fuses protecting the column from fatigue. After a seismic event the fuse bars can be easily replaced, restoring the column to its original condition. To function properly the hinge must become plastic before the column above it yields, but limiting the deflection at the top of the column is also desirable for the stability of the overlying structure, necessitating a hinge with some degree of strength. The experimental setup of this study was constructed in the University at Buffalo’s Structural Engineering and Earthquake Simulation Laboratory in 2004 and was comprised of a steel column subjected to lateral displacement at the top with a plastic hinge fixed at the base, simulating earthquake-induced ground motion on a bridge column. The purpose of this research was to develop an accurate model of the column-hinge system in the elastic range of the fuse bars, allowing consideration of the above design criteria for later testing. Plastic behavior of the fuse bars was not tested. Experimental data was generated using a quasi-static cyclic loading pattern. The behavior of the system was shown to be in agreement with the analytical model.