| In order to meet the needs of rapid assembly construction of steel-concrete composite beams and easy disassembly when are deteriorated,this paper proposes an assembled composite beam with circular perforated steel tube connectors.Since circular perforated steel tube connectors are the key component of composite beam,but there is little research about them currently.In order to better understand the shear performance of such connector and the flexural behavior of this kind composite beam,the general finite element software ABAQUS is used to simulate push-off tests on circular perforated steel tube connectors and flexural loading tests of the composite beams,to explore the effects of various parameters on the shear performance of the connector and the bending performance of the composite beam.The findings may provide reference for future experimental research and practical application.The main research contents and related conclusions are as follows:(1)The structural details of assembled composite beam with circular perforated steel tube connectors were introduced and compared to that with welded stud connectors.The comparison results show that such composite beam can avoid the influence of welding residual stress and deformation caused by welded studs on the strength of the steel beam,also can achieve rapid disassembly and easy recycling of the composite beam.(2)Three-dimensional finite element models of circular perforated steel tube connectors were built using ABAQUS to simulate the push-off tests.The effects of the height,thickness and center angle of perforated holes,as well the strength of steel and concrete on the shear behavior were investigated.The results show that increasing the thickness of hole,the strength of the steel and reducing the height of the hole can improve the shear capacity of the connectors;changing the center angle of the hole and the strength of the concrete has little effect on the shear performance of the connectors.(3)Based on the plastic beam theory,a simplified calculation formula were proposed to predict the yielding shear strength of circular perforated steel tube connectors,and the predicted value is in good agreement with FE analytical one,which can provide a reference for future design on such connectors.(4)On the basis of elastic and plastic design methods of the composite beam,a full-connected composite beam with circular perforated steel tube connectors was designed.In addition,the ultimate flexural capacity and the required number of circular perforated steel tube connectors or stud connectors for full-connected composite beam were calculated using plastic theory.(5)Three-dimensional finite element models of composite beams with circular perforated steel tube connectors or stud connectors were built using ABAQUS to simulate the flexural loading tests.The influence of concrete strength,steel strength and number of connectors on the bending performance and slip characteristic of composite beam was investigated.The analytical results show that the change of concrete strength has little effect on the bending performance and slip characteristic of the composite beam;increasing the strength of the steel beam can significantly improve the bending capacity and slightly increase interface slip of the composite beam;when the connection degree does not exceed 1,the bending capacity of composite beam increases as the increasing of connector number,but the slip decreases.In comparison to composite beam with 13 mm diameter stud connector,the composite beam with circular perforated steel tube connectors has slightly better bending capacity but worse ductility.(6)The theoretical value of the ultimate flexural strength of the full-connected composite beams calculated by plastic theory is in good agreement with the FE analytical one,indicating the proposed calculation method can accurately predict the flexural strength of composite beam with circular perforated steel tube connectors. |
