Comparison of two novel HBS and SC-PC-FD steel beam–column connections

This paper presents a brief introduction on and comparative structural performance of two novel steel beam–column connections. One of them is a novel self-centering beam–column connection with circular friction pads, which eliminates residual drifts and has simple constructional details. In this regard, two full-scale experimental specimens of self-centering pinned connections with friction damper (SC-PC-FD) of two types were tested, one having two post-tensioned strands and the other having four. Moreover, using parametric analysis, the optimal characteristics of this connection were achieved, and its cyclic performance was compared to some existing steel beam–column connections. To enhance the seismic performance of moment beam–column connections without any reduction in their stiffness and removing the inelasticity far from the column face, a heat-treated hollow structural beam section (HBS) was introduced and was examined experimentally. For this purpose, the desired region of the HSS beam was heat-treated using a fabricated resistance furnace. Then, the cyclic performance of the HBS specimen was compared to an experimental specimen with the same properties, except the weakening approach of the HSS beam, in which the reduced beam section (RBS) was considered. The results showed that the four-strand SC-PC-FD connection was superior to the two-strand specimen, and SC-PC-FD connections exhibited a ductile and stable flag-shaped hysteretic behavior up to the interstory drift ratio of 7%. Regarding the observations obtained in the experimental study on HBS and RBS connections, it was concluded that the HBS connection could tolerate the applied cyclic loadings up to the interstory drift ratio of 6% without any occurrence of lateral–torsional buckling, which happened in the RBS specimen. Through a comparison of the SC-PC-FD and HBS connections, it was seen that SC-PC-FD connection can eliminate the residual drifts and provide higher ductility while keeping the main members in the elastic range.