| Today,when the country vigorously advocates the industrialization of construction,various types of prefabricated structural systems and prefabricated components have been developed rapidly and among which the light steel structural systems are increasingly widely used in my country’s construction industry.The light steel keel fire-resistant composite floor slab researched by this research group has the advantages of reduced structural deadweight,simple construction,shortened construction period,good seismic performance,safety and reliability,fire resistance and heat resistance,and environmental protection.However,the node connection problem of this kind of composite floor system has not yet been effectively solved,and it is urgent to study and improve it.This paper takes the light steel keel fire-resistant composite floor system as the research object,and in view of its beam-slab and slab-side nodes,a connection method is designed for each.The beam-slab and slab-side node connection specimens of 14 full-scale light steel keel fire-resistant composite floor slabs were tested on the mechanical performance under vertical load.Observing the failure characteristics of the specimens and analyzing the load deflection,etc.Based on the data curve,the calculation formula for the bending bearing capacity of the beam-slab connection of the light steel keel fire-resistant composite floor was extracted and summarized.Furthermore,it provides a theoretical basis for the calculation of light steel keel fire-resistant composite floor slabs in the future,and also provides a basis for the formulation of relevant specifications in the field of composite floor slabs for fabricated building structural systems.The main research contents of this paper are:（1）A connection method of beam-slab joints for the composite floor was proposed,and the mechanical performance of 11 full-scale beam-slab joints connection specimens was experimentally studied.A hydraulic jack was used to apply static load to the specimens.Based on the analysis of the test results,the influence of the designed joint lap length,the thickness of the joint,the number of self-tapping screws and bolts used in the connection,the size of the joint and the steel used in the joint on the bearing capacity of the beam-slab connection node was explored.The analysis of the deformation coordination ability and the dangerous section displacement changes of the node connectors and the C-shaped light steel keel of each connection test piece was made.（2）According to the theoretical analysis of the beam-slab connection test designed in this paper,combined with the basic principles of mechanics,the theoretical calculation formula for the bearing capacity suitable for this connection method was gradually derived and summarized,and the test results were compared to verify the applicability of the calculation formula.（3）A slab-side node connection method for the composite floor was proposed,and three full-scale slab-side node connection specimens were tested to verify the safety and reliability of the slab-side node connection method.Based on the test data,the failure characteristics of the test piece,the relationship of load deflection,the change law of the deflection along the width direction of the slab span and the change law of the amount of staggered joints in shearing of the slab seam were analyzed,The influence law of the lap length of the connecting piece on the mechanical performance of the test piece was explored,and finally an optimization suggestion was put forward. |
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