The theoretical method for analysing the behavior of restrained steel beams subjected to temperature increasing is validated by experimental results.The behavior of the steel beam in cooling phase obtained by the theoritical method presented in this paper is similar to that obtained by previous theoritical methods.The restrained steel beam subjected to temperature increasing and descending is parametically studied by the proposed method.Parameters investigated include the stiffness of the axial restraints

the stiffness of the rotational restraints

load ratio

depth-span ratio of the beam

the yield strength of the steel

load type and the distribution in the section.Through the analyses

it is found that all the parameters mentioned above take important role on the behaviour of the restrained beam with temperature increasing

especially for the load ratio

the axial stiffness of the restraints at the ends and the depth-span ratio of the steel beam.When temperature descends

because the contraction of the beam is restrained

very large tension force will be produced

besides the load ratio and the axial stiffness of the restraints

the parameters effecting the behaviour of the beam also includs the highest temperature the beam undergoing in the fire.