Fire Behavior Of Restrained SRC Columns With L-shaped Cross Section

Steel Reinforced Concrete(SRC)Columns with special shaped cross section is a composite columns of steel and rebar embedded in concrete,generally in the form of(T???L)shaped cross section.Because of its advantages such as high bearing capacity,good seismic performance and flexible building layout,it is more and more widely used in modern buildings.In the past,when scholars studied the fire resistance of steel reinforced concrete special-shaped columns,they mainly focused on a single simply supported member.In the actual frame structure,the column is restrained by the surrounding beam-column members,and the actual state of stress is restrained at both ends.Compared with rectangular columns with the same cross-sectional area,L-shaped steel concrete columns have a larger fire area in a fire,and their fire resistance is worse than rectangular columns.Therefore,the fire resistance performance of L-shaped steel reinforced concrete constrained columns with two sides exposed to fire is studied in this paper,and the influence of various parameters is compared and analyzed,which can provide a reference for the fire resistance design of related components.The main research contents and achievements of this paper are as follows:(1)By consulting the relevant research literature at home and abroad,the thermal parameters and thermodynamic constitutive relations of steel and concrete are selected to calculate the model.(2)Established restrained SRC finite element columns with L-shaped cross sections subjected to both-sides heating under the standard temperature ISO-834 condition by ABAQUS,the rationality of the model was verified by experiment results of steel reinforced concrete constrained columns and L-shaped reinforced concrete columns.(3)The validated model was used to analyze the effects of load ratio,axial restraint stiffness ratio,rotational restraint stiffness ratio,eccentricity,and section size on the axial displacement and axial force of L-shaped steel concrete restrained columns.(4)Analysis the effects of load ratio,axial restraint stiffness ratio,rotational restraint stiffness ratio,eccentricity,and section size on the fire resistance of columns.