| Concrete filled steel tube,steel structure and reinforced concrete structure,which have been developed for nearly one hundred years,are the main structural components of contemporary buildings.Their good mechanical properties,skilled construction technology and extremely high service life support a complete human society.But at the same time,due to the aging of the structure and the deterioration of the components can not be avoided,using new materials and new technologies to maintain and repair it has become a new research field.Carbon fiber reinforced polymer with good performance and excellent mechanical properties is a good matching material for concrete-filled steel tubular structures.In this context,the research and application of CFRP concrete-filled steel tubular,a new type of composite structure,is deepening in the field of scientific research and engineering.Up to now,the new composite structure not only avoids the defect of poor corrosion resistance of external steel tube of concrete-filled steel tube,but also reduces the weight of the structure,and greatly improves the bearing capacity of components or structure.In order to make up for the research gap in the field of hysteretic behavior of cfrp-cfst,the compression bending torsion hysteretic behavior of cfrp-cfst members with square section and circular section are tested and discussed in this paper.(1)A total of 9 specimens with square section and 9 specimens with circular section were tested.The manufacturing process,loading scheme,phenomenon,result analysis and parameter analysis of 18 specimens were described in detail.(2)The results show that CFRP can delay the bulging of the steel tube and improve the ductility of the specimen;before the fracture of CFRP,the steel tube and CFRP have a good ability to work together;whether the square section or circular section specimen,the more layers of CFRP,the higher the torsional bearing capacity.(3)The test results show that: no matter what kind of section,the bearing capacity will increase first with the increase of axial compression ratio;with the increase of moment ratio,the torsional bearing capacity of square section specimens is basically unchanged,while the torsional bearing capacity of circular section specimens will decrease;the torsional bearing capacity of members can be slightly enhanced with the increase of the number of longitudinal CFRP layers on the surface of specimens. |
