Study On Fire Resistance Performance Of The Bolted Composite Assembly Floor

The bolted composite assembly floor is a new type of composite floor which is formed of cold-formed thin-walled steel beam and autoclaved lightweight concrete.Compared with general composite floor,this type of composite floor has the characteristics of light weight,high degree of assembly,good fire resistance,and less workload.At present,the frequency of building fires in China is high.Therefore,it is of great practical significance to study the fire resistance of this type of composite floor.In this paper,the fire tests and the remaining capacity tests after fire are performed on 6 bolted composite assembly floor.Based on the test results and numerical simulation,the effects of load size,heating time and thickness of thin-walled steel on the fire resistance and residual bearing capacity of the composite floor are analyzed.The calculation formula of the central deflection and the calculation formula of the ultimate bending bearing capacity of the bolted composite assembly floor were established respectively.Research indicates:(1)This type of composite floor has good fire resistance and the overall collapse does not occur when the deflection reaches L / 22 and autoclaved lightweight concrete shows good thermal insulation performance;(2)The remaining capacity of the combined floor after fire is greatly affected by the heating time rather than the load.The failure mode of the specimen is bending failure;(3)Numerical analysis shows that increasing the thickness of the steel beam can significantly enhance the residual bearing capacity of the composite floor;(4)The results obtained by the theoretical calculation model are in good agreement with the experimental values.