Study On Shear Performance Of High Strength Bolts Of Assembly Steel-concrete Composite Structure

The prefabricated steel-concrete composite structure takes the advantages of both the prefabricated structure and the steel-concrete composite structure.It is manifested in many aspects such as superior mechanical performance,low environmental pollution,and convenient installation.Shear connectors are particularly important in achieving reasonable load transfer between steel and concrete for the composite structure and maintaining the installation accuracy.In the existing research,most of the connection methods of prefabricated composite structures still require cast-in-situ work.In this paper,a new prefabricated steel-concrete composite structure connection method using high-strength bolts as shear connectors is proposed.This method can greatly reduce or even eliminate cast-in-situ work,to achieve ‘full assembly’ on site.In this paper,6 specimens are used to study the shear resistance of high-strength bolts of the new fabricated steel-concrete composite structure connection.Results show that the ultimate load-bearing capacity of the high-strength bolt push-out specimen for the new prefabricated steel-concrete composite structure is equivalent to which of the traditional cast-in-situ stud push-out specimen under identical environmental parameters.The final failure modes were similar for those two kinds of specimens,while the ductility of the high-strength bolt specimens was higher.With different embedding depth of the high-strength bolt,the final failure modes of the pushed-out specimen were also different.Before the high-strength bolt was pushed out of the specimen,the load-displacement curve was basically linear.In this paper,the finite element analysis shows that the calculation results of the finite element model established by the author are in good agreement with the experimental results,so this model can be used for parameter analysis.The ultimate bearing capacity of high strength bolts increases with the increase of concrete strength,bolt diameter and bolt tensile strength,but does not change with the increase of pretightening force of high strength bolts.At the same time,the calculation method of ultimate bearing capacity of high strength bolts under new connection mode is put forward with reference to relevant specifications.