Cross-section strength of concrete-filled HSS columns at simple beam connections

Tests are described in which short, rectangular steel columns filled with concrete are loaded to failure under axial load. Part of the load is applied at typical beam connections within the column length; and part is applied at the top, representing the load from upper stories of a building. The length of the column near the connection over which slip takes place is examined, and the ultimate strength of the columns is compared with that of stub columns loaded uniformly over their length. A small reduction in strength is found to occur, which depends upon the proportion of total load applied at the connection. An empirical means of accounting for this strength reduction is given. Key words: columns, composite construction, connections, tubular columns, axial compression.