Cyclic load tests and analysis of bolted top-and-seat angle connections

The behavior of angles in a bolted angle beam-to-column connection is experimentally investigated. The purpose of this investigation is to determine how the angle size and bolt gage length, defined as the distance between the bolt line passing through the column and the heel of the angle, affect the connection stiffness, strength, energy dissipation capacity, and resistance to low-cycle fatigue. The test results show that the angles are capable of considerable strength beyond the point at which a yield mechanism occurs. The associated stiffness, i.e., postyield stiffness, is approximately linear and comprised of both geometric and material hardening. The bolt gage length greatly influences all connection characteristics studied. A larger amount of energy can be dissipated for connections with smaller bolt gage lengths. However, connections with smaller bolt gage lengths generally have a lower fatigue life. An analytical model is presented that predicts the behavior of bolted beam-to-column angle connections. The correlation with test results is good.