This
paper reports the results of an
experimental and numerical investigation on the
non-linear behavior and
load-carrying capacity of CFRP-
strengthened cold-formed
steel lipped channel columns. The
experimental program involved two test
series, comprising a total of 19 short and long fixed-ended lipped channel
columns - while the former buckle in local-plate modes, the latter exhibit
distortional buckling. The columns were strengthened with carbon fiber sheets
glued at different outer surface locations (web, flanges or lips) and having
fibers oriented either longitudinally or transversally - since the aim of the
study is to assess the influence of the CFRP sheets on the column structural
response, bare steel specimens were also tested. The experimental results,
which consist of non-linear equilibrium paths (applied load vs. axial
shortening) and ultimate strength values (most of them associated with
local-plate and/or distortional failure mechanisms), are subsequently used to
calibrate and validate geometrically non-linear numerical analyses based on
shell finite element models, carried out with the code ABAQUS and adopting an elastic-plastic
constitutive law to describe the steel material behavior. Finally, on the basis
of both the experimental and numerical results obtained, some relevant
conclusions are drawn concerning the most effective CFRP sheet location and
fiber orientation to strengthen columns affected by local-plate and
distortional buckling.