Research On Fire Resistance Of Cold-Formed Steel Concrete Composite Floor

In the past many years,Chinese steel production generally is low,so the thin-walled steel and other supporting technology has not been developed for a long time.In recent years,more and more thin-walled steel-concrete structures have emerged in the existing building forms in China.The quality,strength and construction speed of this kind of composite floor are better than that of traditional concrete floor,which has been studied and applied in foreign countries,but in the 80-90 years of the last century,we began to study the steel plate concrete composite floor,from the room temperature performance to the high temperature performance.Up to now,the research on the fire resistance of this kind of steel-concrete composite floor is still in the initial stage,mainly through the experimental method to study the fire resistance of the floor,although the experimental research method is direct,but there are still deficiencies,because the experimental fire load is preset and actual fire temperature field is not exactly the same,Therefore,the fire-resistant method deduced from the experiment and the predicted fire-resistant design limit can not be completely accurate.Therefore,in this paper,the fire resistance of cold-formed thin-walled steel-concrete composite floor is deeply studied from the angle of simulation and theoretical calculation.In this paper,the specific research work is as follows:(1)Introduce the research status of fire resistant structure and fire-resisting floor at home and abroad,and put forward the research content of this paper:study on the fire resistance of cold-formed thin-walled steel-concrete composite floor;(2)To study the mechanical properties and thermal parameters of steel and concrete materials,enumerate the relevant expressions of different countries and different norms,and choose the appropriate calculation parameters to provide the basis for the simulation and theoretical calculation of this paper;(3)The paper introduces the construction method of thin-walled steel-concrete composite floor,puts forward the calculation model and boundary condition of floor at high temperature,deduces two kinds of high temperature theoretical deformation calculation methods according to the basic principle of structural mechanics,and gives the expression of theoretical calculation.(4)Using the ABAQUS finite element software to simulate the fire in the composite floor,and get the distribution of the temperature field inside the cover of different fire conditions;(5)Using ABAQUS Software simulation and theoretical formula to calculate the center deformation of the floor,by comparing the experimental values of the simulation and the theoretical calculation with those in the literature[54],and verifying the correctness of the simulation and theoretical calculation method,the simulation and theoretical calculation of the floor subjected to the fire deformation are carried out on the basis of the temperature field of the section.(6)This paper compiles the software of ABAQUS fem to simulate the floor fire,deduces the theoretical calculation method,analyzes the internal temperature field and center displacement of cold-formed thin-walled steel-concrete composite floor under high temperature,and sums up the deformation development law and the refractory limit time of the downstairs cover under different fire conditions,The research on fire resistance of composite floor is prospected.