Column-base response under applied moment

In the emerging interest in the serice ability of steel structures, the ability to predict structural deflections under various loading scenarios requires knowledge of the response of the connections employed in the steel frame. Although there have been extensive research efforts for beam-column connections, surprisingly little is known at present about the behaviour of nominally ‘pinned’ baseplate connections. The paper presents the results of 10 moment reversal tests on nominally ‘pinned’ steel bases for 200 U B 25 columns and presents a simple mathematical model for the prediction of elastic stiffness of the connection. The model is based on the reported test results as well as on earlier tests on considerably larger column sections and thicker base plates. Both two-bolt and four-bolt connections are considered. A discussion of implications for practical design closes the paper.