REASEARCH ON ASEISMIC BEHAVIORS OF STEEL MOMENT-RESISTING FRAME INCLUDING OPENING IN BEAM WEB

Pseudodynamic (PSD) test and quasi-static test of full-size steel moment-resisting frame (MRF) including opening in beam web (OBW) closed to the connection, is introduced in the paper. PSD test stressed on the seismic response of steel MRF, and quasi-static test focused on the failure mode of steel MRF. PSD test results show that, the seismic behavior of test frame isn't weakened with appearance of opening in beam web. The strain distribution on beam flange shows that the maximum plastic zone always stays in the weakened area and the stress concentration in joint weld releases due to opening in beam web; but for the conventional connection without opening, the maximum plastic zone locates closed to column face, the stress concentration in joint weld is severe. It can be observed in the quasi-static test that weld fractures may appear in the conventional connection due to the stress concentration around joint; after setting opening in beam web closed to beam-to-column connection, the stress concentration in joint weld releases and Vierendeel mechanism is formed in the weakened area, which resulting in no fractures appeared in beam-to-column joint weld