Experimental Analyses of Mechanical Performance of CFST Column to Assembled Steel H-Beam Connections
The mechanical performance of a new proposed type of cross-shaped connection with concrete-filled steel tubular (CFST) column and assembled steel H-beam was investigated. Cyclic loading tests on the cross-shaped connections are carried out by using MTS servo loading system. Comparative analyses are conducted based on the experimental results including hysteretic curves, skeleton curves and stiffness degradation curves as well as ductility coefficients of cyclic loading tests. Furthermore, effects of geometric parameters of ring-stiffened plate, axial compression ratio and backing plate on the deformation performance of cross-shaped connections are analyzed. The results show that the increase of width of ring plate and the shape change of ring plate from square to circle can both significantly improve the ductility and the hysteretic characteristics of connection. It is emphasized that the specimen with square ring plates is of better deformation performance but lower bearing capacity than the ones with circular ring plates. Besides, the backing plates always have positive effects on the hysteretic characteristics, ductility and energy dissipation of the CFST column connections. Conversely, the increase of axial compression ratio contributes negatively to both the bearing capacity and deformation performance of the connection specimens. It can be concluded that the presented cross-shaped connection is of good deformation performance relating to hysteretic characteristics, energy dissipation and ductility, which can provide reference towards engineering practice with potential perspective application.
Cyclic behaviour of concrete filled steel tubular column to steel beam connections
An experimental investigation into the behaviour of composite column-to-beam connections using ten large-scale connections has been conducted, four under monotonic loading and six under cyclic loading. This paper presents the details and results of the six cyclic tests. Details and results from the monotonic tests are reported in a companion paper. All connections consisted of a concrete-filled steel tube (CFST) column (circular), a compact universal beam section and a shop fabricated connection stub. Monotonic testing was first carried out and the results, were used to conduct the cyclic tests. Each specimen tested cyclically had the same general form, consisting of a direct connection of the beam to the tube wall (using flange connection plates, and web cleat plates) and reinforcing bars welded to the top and bottom flanges, embedded into the concrete core. It was found that provided the connection to the face of the column had the capacity to force the hinge into the beam itself, the specimen behaved in a very stable fashion, and achieved ductility levels which were only limited by the beam and the nature of the test itself.
Strength and rotational response of moment connections to tubular columns using flowdrill connectors
Abstract Using the flowdrill process it is possible to form threaded holes in steel tubes even with wall thicknesses less than 12 mm. Ordinary bolts may then be used to secure endplate beam connections to tubular columns. A series of tests was conducted to investigate the strength and rotational stiffness characteristics of joints made in this way. The results of the tests described on both thick flush endplates and extended endplates show that strengths approaching the plastic capacity of the supported beam and large rotational capacities can be obtained. Deformation of the tube face gives excellent ductility but the joints have relatively low stiffness for a nominally rigid joint. Connections of this type are ideally suited for use in semi-rigid design methods.