Experimental Studies of Wide Flange Beam to Square Concrete-Filled Tube Column Joints with Stiffening Plates Around the Column

The strength and stiffness of wide flange beams to rectangular tube column joints are reduced significantly if the connections are not reinforced. However, the reinforcement for the connections can be complex and increase the fabrication costs significantly because the tube columns are closed sections. This paper describes the force transfer mechanism and the cyclic performance of wide flange beams to square concrete-filled tube column joints reinforced with stiffening plates around the column. The first phase of this research program was to assess the force transfer mechanism at the joint using an analytical yield line method. An experimental program was conducted to verify the proposed model. The test results showed that the derived nominal strength equation provided a reasonable prediction. As the second phase of the research program, full-scale joint subassemblage tests were conducted to assess the cyclic performance of the joints. A total of seven specimens were tested under cyclic loading. Test results showed that total rotation of 0.04 rad which is required for special moment resisting frames could be obtained.