Research On Fire Resistance Performance Of Assembled Monolithic Composite Slab With Steel Bar Truss

In today’s society,the degree of industrialization is getting higher and higher,and the demand for fabricated buildings is increasing.The advantages of assembled monolithic structures set the prefabricated structures and cast-in-place integrated structures in one,and the construction industry is developing rapidly.The more popular it is.As one of the important components of the assembled monolithic structure,the research of its performance has become a hot spot,especially the composite slab with steel bar truss,which is the most widely used laminate.However,the research on composite slab with steel bar truss mainly focuses on the seismic performance and static performance of the slabs,while the research on the fire resistance of composite slab with steel bar truss is rare.In this paper,composite slab with steel bar truss is taken as the research object,and the fire resistance of composite slab with steel bar truss under high temperature is studied.The main research work of this paper is as follows:1.According to the research results at home and abroad,the thermal parameters and thermodynamic parameters of the materials were selected.The finite element analysis software ABAQUS was used to establish the temperature field model and mechanical analysis model of the assembled monolithic composite slab with steel bar truss,and the test results of fire resistance with 3 composite slabs were compared and verified to verify the rationality of the temperature field model and the mechanical analysis model.2.Using the above model,the temperature rise curve is carried out according to the ISO834 standard heating curve,and the temperature distribution law of the cross-section of the composite slab with steel bar truss at different stages is obtained.Furthermore,the effects of the thickness of the concrete protective layer of the steel bar,the thickness of the post-cast layer and the heating time on the temperature field are discussed.It provides reliable pre-defined temperature field data for the analysis of mechanical properties of composite slab with steel bar truss at high temperatures.3.9 composite slab with steel bar truss test pieces and 3 cast-in-place concrete slab test pieces were designed.The ultimate bearing capacity calculation and analysis of the shear performance of the composite slabs with steel bar truss were carried out by the mechanical analysis model.Analysis of steel stress and analysis of concrete stress in compression zone.4.The effects of different loading levels,post-casting layer thickness,concrete strength grade,longitudinal distribution of ribs,thickness of protective layer and thickness of protective layer on the fire endurance of assembled monolithic composite slabs with steel bar truss under high temperature are analyzed,according to deflection and deflection.The two criteria for the change rate are obtained from the fire endurance of composite slab with steel bar truss,and the fire resistance limits of the composite plates and cast-in-place plates under the same section and parameter control are compared.