Experimental Tests on Steel Frames with Different Beam-Column Connections Subject to Falling Floor Impact

After several progressive collapse incidents, many researchers try to find the way to mitigate progressive collapse of building structures. In case of the failure of column, beam, and beam-column connection, the falling impact of failure members and debris from upper floor is an important reason to result in progressive collapse. In this paper, steel frames with five types of beam-column connections, i.e. fin plate connection, welded unreinforced flange-bolted web connection, reduced beam section connection, reverse channel connection with flush end plate, and reverse channel connection with extended end plate, were tested under impact loads. The impact tests were carried out by using high-performance drop weight machine. All impact loads were applied at the beam end. The main objective of the experiments is to study the impact resistance of steel frames with different beam-column connections subjected to falling floor impact. Failure mode, input kinetic energy, and residual displacement of each specimen were obtained and compared. The test results show that fin plate connection has the worst impact resistance. Both WUF-B connection and RBS connection have better impact resistance than fin plate connection. Different failure modes appear on reverse channel connection with flush end plate and reverse channel connection with extended end plate. Reverse channel connection with extended end plate dissipates more energy than it with flush end plate.