| Pre-fabricated Floor System(PFS)is a new type of fabricated truss beam combined floor system.The floor system is composed of truss beams,secondary beams and profiled steel-concrete composite floor slabs.Because of its very convenient construction and fast installation,it is widely used in engineering.However,the force performance of the trussbeam composite floor system is not clear at present,and there are still certain safety hazards in engineering applications.Based on this,this paper applied unidirectional loading to the fabricated light steel truss beam floor system to evaluate its vertical bearing capacity and dynamic performance.This paper used a combination of experimental research and finite element simulation to systematically study the fabricated truss beam floor system.The main research work includes:(1)To evaluate the ultimate shear capacity of the web and chord members of the coldformed thin-walled steel section of the truss beam under the axial tension of the joints connected by self-tapping screws,firstly,the unidirectional tension of the bearing capacity of 16 single nail connections was completed.In the test,the test mainly considered the influence of the plate thickness and the diameter of the tapping screw.The ABAQUS software was used to establish a refined finite element model of a single self-tapping screw connection test piece,and perform finite element simulation verification.On this basis,16 models were designed to carry out the finite element analysis of the parameters of the system.Based on the test results,a suggested design formula for single-nail thick plate connection was given.(2)Experiments and finite element simulations were used to evaluate the ultimate tensile bearing capacity of the self-tapping screw connection nodes between the web members and the chord members of the truss beam.A total of 14 splicing joint specimens of the truss beam and web members were designed and considered.The number of self-tapping screws,whether to set welds,chord thickness and other parameters,and conducted unidirectional loading tests to evaluate the ultimate tensile bearing capacity of such joints.On this basis,the finite element simulation verification of the above-mentioned completed experiment was carried out,and the system parameter finite element analysis was carried out,and the reasonable structure and design suggestions of the splicing joint of the web and chord were put forward.(3)Considering the influence of factors such as the longitudinal span,the angle of the diagonal web member,the thickness of the chord plate and other factors,4 full-scale test pieces of the fabricated light steel truss beam floor system were designed.And the vertical bearing capacity test of the truss-beam combined floor system was carried out.Based on the ABAQUS program,a refined finite element model of 4 test specimens was established,and on the basis of verifying the rationality of the finite element analysis,the system parameter finite element analysis was carried out,focusing on the longitudinal span,the height of the truss beam,the thickness of concrete and the strength of steel.The reasonable structure and design suggestions of fabricated light steel truss beams were put forward due to the influence of other parameters.(4)Considering the influence of factors such as the span of the truss beam,the angle of the web members,the thickness of the chord plate and other factors,the natural frequencies of the full-scale specimens of the 4 fabricated light steel truss beam floor system were tested.The ABAQUS program was used to establish a refined finite element model of the fabricated light steel truss beam floor system,and a confirmatory analysis was carried out.Under the condition of normal use,the influence of parameters such as floor thickness,longitudinal span,and truss beam height on its dynamic performance was studied,and design suggestions were put forward. |
