Study On Flexural Behavior Of Sandwich Panels With GFRP Shear Connectors

With the development of economy and the optimization and upgrading of industrial structure,the construction industry has begun to develop towards the direction of low energy consumption,high efficiency and environmental protection.In the prefabricated building structure system,the steel structure system,because of its own prefabricated building nature,can well realize prefabricated construction,has become the development direction of prefabricated building.At present,the main factors restricting the development of steel structure buildings are the enclosure system,especially the exterior wall panels.Precast sandwich composite wallboard,used in combination with steel structure buildings,has the advantages of convenient on-site installation and construction,high factory production efficiency,heat preservation and energy saving,green environmental protection,high construction efficiency,and is an ideal enclosure structure for steel structure buildings.It has the advantages of convenient site installation and construction,high production efficiency,heat preservation and energy saving,green and environmental protection,and high construction efficiency.It is an ideal enclosure structure for steel structure buildings.The composite wallboard itself does not serve as a load-bearing structure,and only bears wind load and dead weight load in the use process.Therefore,in the design of the composite wallboard,we mainly pay attention to the weight and insulation performance of the wallboardIn this paper,sandwich composite wallboard composed of inner and outer concrete layer and intermediate polystyrene(EPS)insulation layer was studied.EPS provides the thermal insulation performance of composite wall panels,and the inner and outer concrete layers are connected by fiberglass reinforced plastic(GFRP)shear connectors to avoid the thermal bridge effect of wire truss,and enhance composite wall panels' combined effect,so that the concrete layer can work in coordination to form a complete composite wall panel,thus achieving better flexural performanceFour types GFRP shear connectors which consist of diagonal web members,webs with circular perforations,webs with slotted perforations and solid webs,respectively,were considered in this research.Five kinds of full-size specimens were designed for bending test,and the bending response of four kinds of GFRP shear joint and steel wire truss joint constituted the composite wallboard was studied.The test results showed that all the five specimens showed good flexural performance,while the GFRP joint composite wallboard showed better flexural performance,among which the GFRP shear joint of the solid webs further improved the ultimate bearing capacity of the composite wallboard.On the basis of the test,the flexural response analysis model based on the method of conversion section and the theory of elastic beam is established in the elastic phase of the specimen.An analytical model based on the relationship between ideal strain and stress was established in the plastic stage after cracking,and the ultimate flexural capacity of the specimen was calculated.These two calculation models are applicable to the composite wallboard and steel wire truss composite wallboard composed of four kinds of GFRP shear connectors used in this test.The finite element software ABAQUS was used to conduct numerical simulation of the specimen,and the simulation results were compared with the test results to verify the validity of the numerical model.The stress-strain simulation results of the specimen were analyzed and the fitting arrangement was analyzed,and reasonable design suggestions were put forward.