Experimental study on seismic behavior of angle connection joints for concrete-filled square steel tubular column to steel beam

In order to study the mechanical behavior of concrete-filled steel tubular column to steel beam angle joint under seismic action, three beam to column joint specimens were designed for a low cycle reversed load test, respectively. The influences of the ratio of the angle of short limb to long limb and the thickness of angle on the joint stiffness, loading capacity, energy dissipation capacity, ductility and shearing deformation of panel zone were analyzed. The experimental results show that the plastic hinge of angle joint appears at the contact point between the angle and the wall of the column, leading to tearing apart failure of angle at its welded connection to column wall under cyclic loading. Increasing the ratio of angle of short limb to long limb and angle thickness can be make the plastic hinge moved outwards, so as to protect the core zone of the joint effectively. With the increase of the angle thickness, initial rigidity and loading capacity of the specimens and the joints increase obviously. Increasing the ratio of angle of short limb to long limb can improve the energy dissipation capacity and stiffness of the specimens and the joints. The joints in this form have good strength, strong rigidity and large deformation capacity. The design of the joints conforms to the seismic design concept.