experimental study on the seismic behavior of steel beam to box-column moment resisting connections with different column stiffeners

In steel moment resisting frames with built-up box-columns, continuity plates have a crucial role as a part of the load path in the panel zone. they also prevent the column flanges from excessive flexural deformations and local yielding. due to lack of accessibility, proper welding of the continuity plates to all sides of the built-up box-columns is a difficult task. therefore, engineers are interested in alternative details which can appropriately transfer the bending moments in beam-column joints. in this study, the use of an internal vertical stiffener in the box-column parallel to the beam web, which turns the section into a boxed i-section in the connection region to eliminate the common continuity plates, is assessed through an experimental study. for this purpose, two full-scale exterior i-beam to box-column moment connections are tested under reversed cyclic loading. the test results in terms of hysteresis moment-rotation curves and observations during the tests indicate that the connection with the vertical stiffener could survive story drifts of up to 4% without any strength loss and brittle failure such as weld fracture.