Theoretical And Experimental Studies On The Fire Resistance Performance Of Thin-walled Steel-Concrete Composite Frame

Thin-walled steel-concrete composite frame(TSCF) is a new kind of structural forms. At present, some researches of fire resistance performance and fire resistance design only focus on the single component, but there is no research focus on the whole structure.Considering the nonlinearity of the material and geometry, this paper adopt a combination method of finite element and finite-difference, composed a thermal-analysis program of ANSYS, calculated the temperature field of the components of the TSCF, calculation results are validated by related literature. Secondly, nonlinear finite element model was set up for calculating the ultimate capacity of TSCF, which provide basis for getting the level of load that bringing to bear on TSCF under fire, calculation results of the finite element fit well with the experimental results. And then, demonstrated the feasibility of using ANSYS to analysis fire resistance of structures by cases, economically and accurately studied the fire response of the composite structure in different times. At last, designed a TSCF with only one floor and one span, studied the fire resistance performance of it with a experiment, the experimental results validated that the theoretical analysis model is rational,exact and reliable.After theoretical analysis, simulated calculation by finite element method and experimental study, the paper give some conclusions as follows: (1) when exposed to ISO-834 standard fire curve, temperature distribution of TSCF sections is not uniform, so it is unreasonable simply using critical temperature to determine invalidation of the structure;(2) load ratios have great influence on fire duration of the TSCF, there is a fine load ratio which can make the TSCF get the longest fire duration; when the load ratio is constant, cover thickness has the most influence on fire duration, while other factors have little influences; (3) the destroy character of the TSCF under high temperature is the local buckling of steel slab; (4) the fire duration of unprotected TSCF are only about 8~15min, it always need fire proofing coating to reach the corresponding demand of GBJ50016-2006; (5) owing to decalescence of filled concrete which also can prevent local bulking efficiently, TSCF have better fire resistance than unfilled steel structures.