Using the computer program of SAFIR

the influences of some parameters (i.e.

axial/rotational restraint ratio

sectional dimension

load ratio

load eccentricity ratio

reinforcement ratio

and heating time

etc.) were analyzed on axial forces in restrained concrete columns exposed to ISO834 standard fire with cooling phase

compared with those in the standard fire without cooling phase.Based on the simulation results of 2880 cases

a practical calculation method for axial force in column was proposed.It was shown that: (a) for axiallyandrotationally restrained columns in fire with or without cooling phase

the enhancement coefficient of axial force increased gradually first

and then reduced gently or kept constant

and finally decreased quickly.However

in the late stage

the enhancement coefficient corresponding to fire without cooling phase dropped more significant than that with cooling phase; and (b) the influences of the rotational restraint ratio

column length and thickness of concrete cover on the enhancement coefficient of axial force in axiallyandrotationally restrained columns were limited subjected to fire with cooling phase

while the peak value of the enhancement coefficient increased with the increase of the axial restraint ratio

load eccentricity ratio and reinforcement ratio or with the decrease of the load ratio and sectional dimension.