When the
confined concrete strength of FRP strengthened columns was similar to that of FS strengthened columns,
the ductility, energy absorption capacity and deformation capacity of the former were obviously lower
than those of the latter. In the light of a formula for calculating the ultimate load of concrete-filled steel
tube (CFST), an empirical formula for predicting the ultimate load of the FS strengthened concrete column
was proposed. The calculation results by using the proposed formula show a good agreement with the
test results.