INVESTIGATION ON BEHAVIORS OF THE CONNECTION WITH OPENING IN BEAM WEB OF STEEL MOMENT RESISTING FRAMES

The opening in beam web (OBW) connection is a new kind of beam-to-column connection of steel moment resisting frames (MRFs). Numerical studies show that the OBW connection may have good properties under cycling loading, for instance, pipeline may go through the beam directly if the weakened parameters R (opening size) and b (opening location) are in a proper scope so as to increase the function of the building. Web weakened only affects local buckling of beam around the opening. The shear resistant capacity of beam with web opening may not decrease due to the contribution of the shear resistant capacity of flange. Vierendeel mechanism will be formed in the weakened area, which leads to yielding of connection, and plastic hinge always stays around web opening without significant decreasing of yielding load. Results drawn from experiments are in accordance with those from numerical analysis, i.e., brittle weld fractures appeared in the conventional all-welded connection of steel MRFs that lead to failure of connection; but for the OBW connection, Vierendeel mechanism is formed in the weakened area that lead to plastic failure of connections. The OBW connection can be divided into three parts according to its behavior, and aseismic behavior of the OBW connection depend on the weakened parameters, R and b.