Seismic Performance of Welded Steel Beam-to-Column Connections with Initial Weld Defects

摘要

Based on the research of steel structures destroyed in earthquakes, it is often found that brittle fractures of the bottom beam flanges of welded beam-to-column connections are caused by welding defects. In this study, artificial surface notches in the welds of single beam flanges were prepared, and four experimental specimens of welded steel beam-to-column connections were tested to explore the effects of the initial crack and three different connection types on the seismic performance of the connections. Through extended finite element methods, the factor of the depth of the initial crack was discussed. The results showed that the fracture mode and the rate and location of crack propagation are significantly changed, and the seismic performance of the connections is reduced when there is an initial crack existing in the weld of a single beam flange. The fracture in box beam to box column connections shows brittle failure regardless of the initial crack, but the depth of the initial crack has the least influence on their seismic performance among the three connection types. The seismic performance of H-shaped beam to H-shaped column connections is the most sensitive to the depth of the initial crack. It should be noted that the weld quality of steel beam-to-column connections, especially the connections with H-shaped columns, should be carefully checked and monitored during the welding construction process and after earthquakes to ensure the bearing and deformation capacities meeting the requirements.