DISTORTIONAL STRENGTH OF COLD-FORMED STEEL PINNED-FIXED LIPPED CHANEL COLUMNS

Resumo

This work addresses the buckling behaviour, ultimate strength and Direct Strength Method (DSM) design
of pinned-fixed (bolted-fixed) cold-formed steel lipped channel columns, selected to fail in distortional
modes. The end-connections consist of a pair of cylindrical high-strength bolts with hexagonal head and
nut, which are inserted in two standard-size holes located at the intersections of the flanges with the
principal centroidal axis parallel to the web – on the other hand, the fixed end support consist a welded
end-plate. After selecting the columns with various combinations of geometry (length and cross-section
dimensions) and yield stresses, Ansys Shell Finite Element (SFE) analyses are used to investigate the
failure modes of selected columns and assemble ultimate strength data. Together with experimental failure
data previously reported by authors out at the Federal University of Rio de Janeiro, these values are then
employed (i) to assess the merits of the current DSM design curves and, in view of their inadequacy, (ii)
to propose new strength curves that provide efficient failure load predictions for the whole set of columns
considered.