Experimental study on blind bolted connections to concrete-filled stainless steel columns

This paper studies the performance of blind bolted connections to concrete-filled stainless steel tubular columns. An experimental investigation was conducted on seven full-scale joints to study the effects of the following parameters: (a) presence of the floor slab or not; (b) with or without binding bars in the connection region; (c) type of steel used for the column (stainless or carbon steel); and (d) loading type (monotonic or cyclic). The experimental results demonstrated the good performance of the blind bolts in this type of connection. No bolt shank fracture was observed in any of the test specimens. The presence of the binding bars slightly enhanced the performance of the blind bolted connections, whereas the presence of composite slabs significantly affected the failure mode, initial stiffness, flexural resistance, and rotation capacity of the joints. Owing to the use of flush end plates, the joint without floor slab can be classified as nominally pinned joint according to EC3. But in the presence of the floor slab, the joint nearly reached its full strength and the stiffness was also significantly increased close to the limit for rigid sway frames. In addition, the test results indicated that the material type of the steel tube had no obvious influence on the joint performance. In contrast, the cyclic loading led to slightly decreased joint strength, but had more obvious detrimental influence on the joint stiffness.