Full-Scale Cyclic Rotation and Shear-Load Testing of Double Web with Top and Seat Angle Beam-Column Connections

Partially restrained beam-column connections such as bolted double web with top and seat angle connections can be used in the gravity load system of steel buildings to develop secondary moment frame action and enhance seismic collapse prevention. To assess the gravity beam-column connection role in lateral reserve capacity, a comprehensive test program was conducted at Ecole Polytechnique Montreal to characterize the nonlinear hysteretic behavior of bolted angle connections subjected to simultaneous gravity shear and rotational demand from the moment frame action. Fifteen full-scale beam-column subassemblages of four different geometries were tested to characterize their deformation pattern and failure modes. The influence of the following critical parameters on the connection hysteretic behavior was investigated: The top and seat angle geometrical parameters, the beam and column sections, the gravity shear load, and the loading history. The envelope curve of each test was mathematically characterized to numerically reproduce the connection behavior. The tested connections exhibited large ductility and significant moment capacity, which translated into a substantial energy dissipation capacity. The use of bolted angles for gravity framing connections could thus be beneficial by enhancing the reserve capacity and providing lateral resistance to mitigate seismic building collapse.