COMPRESSION TESTS AND ANALYSIS OF BUILT-UP COLD-FORMED STEEL COLUMNS

Resumo

The present article includes the results of the structural stability of laced built-up cold-formed steel
(CFS) columns, subjected to axial compression. The objective is to analyze the behavior of these
spatial laced columns through full scale experimental tests, in which the collapse is caused by the
interaction between local and global buckling in the compressed chord members. The spatial columns,
composed of four plane-trussed members designed with lipped channel CFS and fully connected with
self-drilling screws, were tested with 12200 and 16200mm length, 0.8 or 1.25mm plate thickness. In
addition to these tests, it was also carried out experimental tests of columns ́ chord members to obtain
the collapse loads and comparison with the analytical DSM equations (direct strength method). The

tested chord members were of 480mm length, double 88x86x40x42x12mm lipped channel cross-
section and 0.8mm thickness. The results showed that the DSM can be applied to obtain the collapse

loads of the chord built-up members, composed of two lipped channels connected with self-drilling
screws. Two analytical methods were applied to obtain global buckling load of the special laced
column and compared with numerical results. The obtained results indicated that critical buckling load
may be accessed with the help of available analytical equations. The final results of the investigation
indicate the adopted methodology, including the column global buckling nonlinear behavior combined
with the collapse mode of the double lipped channel CFS chord members connected by self-drilling
screws, is able to be applied for regular structural design of the CFS spatial trussed arrangement.