Research On Mechanical Behavior Of Steel-concrete Long-span Frame Structure With Axillary Bracing

The large-span steel-concrete frame structure with axillary braces is a new structural form.In addition to the advantages of the conventional steel-concrete frame structure,it also has the following prominent features: 1)By setting the axillary support,the stress mode of the conventional steel reinforced concrete frame structure is changed,and the bearing capacity and stiffness of the structure are effectively improved,2)The setting of the axillary brace reduces the span of the large-span frame beam,so that the internal force of the beam is reduced,and the cross-sectional size and reinforcement can also be reduced.At the same time,Beam deflection and crack width are more easily satisfied.Therefore,the long-span steel-concrete frame structure with axillary braces has broad application prospects,but there is no research on the mechanical characteristics and seismic performance of the long-span steel-concrete frame with axillary braces.In order to study the mechanical and seismic performance of the new long-span steel frame structure with axillary bracing,this paper carried out tests on two specimens under vertical symmetric load and vertical asymmetric load,and analyzed them by finite element analysis stress performance and seismic performance were analyzed,the main work is as follows:(1)Then,the data are sorted and analyzed,and the test phenomena of two specimens are described in detail.At the same time,the crack development and failure modes of the two specimens are summarized.Finally,the load-displacement curves,strain laws of steel bars and section steels of the two specimens are analyzed.(2)The finite element model is established by using the finite element analysis software ABAQUS,and the nonlinear finite element analysis of the specimen was carried out to discuss the characteristics of the new structure under vertical load and compare it with the test results.Then use the established finite element model to further study its mechanical performance and seismic performance under horizontal load by applying horizontal load.Through experimental research and theoretical analysis,it can be seen that the steel-concrete frame structure with axillary braces is under vertical load,and the unfavorable II section on the beam is located at the beam axillary connection near the center column,and the unfavorable section on the column is located at the column axillary connection Office.Under the horizontal load,the unfavorable section on the beam is located near the horizontal loading point of the beam girder brace joint and the beam span,and the unfavorable section on the column is located at the foot of the side column away from the horizontal loading point.The longitudinal bars and section steel stresses at the beam end,column top and node area are relatively small.This shows that the mechanical performance of the node is improved,and it is easy to meet the "strong node" requirement.At the same time,the structure has good deformability and good ductility,which can meet the seismic requirements..