Behaviour of through plate connections to concrete-filled stainless steel columns

Bond between stainless steel and concrete is not reliable for load transfer in concrete-filled stainless steel tubular (CFSST) columns. This paper proposes the use of a full-through plate for connecting the primary beam to a stainless steel composite column, whereas half-through plates are used to connect other secondary beams. In fabricating such connections, welding of through plates inside a steel tube can be avoided. This paper presents an experimental investigation of the properties of such through plate connections, and the test results are compared with those of blind-bolted endplate connections tested in our earlier research. Meanwhile, finite element models are developed with an aim to compare the behaviour of through plate connections with that of fin plate connections in terms of initial stiffness, flexural resistance and rotation capacity. It is found that the through plate connection with slab exhibits semi-rigid behaviour. Its initial stiffness and flexural resistance are lower than those of the blind-bolted endplate connection, but the rotation capacity is higher. Both the through plate and fin plate connections have similar flexural resistance, but the former has much higher initial stiffness. This study confirms that it is feasible to have a combined use of full-through and half-through plates for connecting beams to CFSST columns. This arrangement might also be suitable for normal composite columns if there is not sufficient bond to enable load transfer.