Dynamic Response Analysis of Simply Supported Steel Beam Under Natural Fire Field Load

Abstract

The outbreak of fire has a great influence on. the carrying capacity of structure. the elastic modulus, flexural rigidity, yield strength and natural frequency of structural steel are discussed on the effects of fire temperature in this paper. The simply supported steel beam to form a plastic hinge when the ultimate moment changes in the first phase of the beam movement and the dynamic responses of simply supported steel beams under different loads were analyzed. Specific to the Q235 H-shaped steel case of H-shaped steel was calculated in high temperature structural steel bending stiffness, yield strength and natural frequency of simply supported steel beam in the two stages of movement of the dynamic response is analyzed. The analysis showed that the fire duration was 2.5h, the yield strength of steel is only 85.63N/mm2, a drop of 63.56%, while the component in the fire field in two phases dynamic deflection is also rapid growth, an increase of over 50%, almost lost capacity, in addition to members of this excessive plastic deformation is a serious cause of the damaged component. Dangerous. Therefore, in order to ensure the safety of steel structure design, the adverse effects should be taken into full consideration in the design of simply supported steel beams.