EXPERIMENTAL STUDIES ON ALL-BOLTS AND DIAPHRAGM-THROUGH JOINT’S ASEISMIC BEHAVIOR OF CONCRETE-FILLED STEEL TUBULAR STRUCTURE

As the research object is all-bolts and the diaphragm-through joint between a concrete-filled square-steel tubular-column and an H-section beam, two full-scale specimens SJ1 and SJ2 with different eccentricities were subjected to a low-reversed cyclic load to obtain the failure mechanism and aseismic performance. The failure mechanism, hysteretic curve, skeleton curve, ductility factor, energy-dissipating capacity and the change rule of rigidity were obtained through the test data processing and analysis; the failure mechanism is also verified through the strain analysis of the partition. The result of the experiment shows that the type of a joint is characterized by a good aseismic behavior, high bearing capacity, a full hysteretic curve, a large ductility coefficient, and strong energy dissipation capacity; the deformation mainly takes place in a plastic hinge area, the end of the beam, and stress focus phenomena were easily seen at the connection of the partition and the beam. The anti-seismic requirements had been taken into consideration during the design of the two specimens. Both of the failure modes are basically same, which was mainly buckling failure of the beam flange edge at the end of the partition and web buckling. However, as a steel beam with eccentricity, specimen SJ2 was tore by the effect of loading at the connection of a bottom partition and a column.