Tests and design of aluminum alloy compression members

A test program was performed on aluminum alloy columns of square and rectangular hollow sections that were compressed between fixed ends. In total, five series of tests were conducted that included columns with both ends transversely welded to aluminum end plates using the tungsten inert gas welding method, and columns without welding of end plates. The tests were performed over a range of column lengths in order to obtain a column curve for each series of test. Heat-treated aluminum alloys of 6063-T5 and 6061-T6 material were used for the column specimens. Nonwelded and welded material properties were obtained from various coupon tests. The column specimens failed by local buckling, overall buckling, as well as interaction of local and overall buckling. In addition, some welded columns failed in the heat-affected zone. The test strengths were compared with the design strengths predicted by the American, Australian/New Zealand, and European specifications for aluminum structures. Reliability of the design rules for transversely welded aluminum columns in the three specifications was examined using reliability analysis. It is shown that the design strengths predicted by the three specifications are conservative for the nonwelded columns. For the welded columns, the design strengths predicted by the American and Australian/New Zealand specifications are generally conservative, whereas the design strengths predicted by the European Code are relatively quite conservative. It should be noted that the design strengths predicted by the American and Australian/New Zealand specifications are unconservative in some cases for the welded columns.