Experimental seismic performance of CFDST- steel beam frames with different construction details

This paper proposes a novel splicing-type column-to-column connection and a novel block-strengthened beam-to-column connection to realize fully-prefabricated construction of concrete-filled double-skin steel tube (CFDST)- steel beam frames. To investigate the effects of such novel connections on seismic behavior of CFDST frames, a test program on three 1/2-scaled single-bay and single-story specimens was presented. Such specimens were constructed with different levels in using the novel connections and were tested subjected to cyclic loads. Among the failure modes, hysteretic curves, ultimate capacity and ductility of these specimens were obtained and compared in the test program. The results show that: (1) the proposed block-strengthened beam-to-column connection could enhance the capacity and ductility of the CFDST frames effectively; (2) the splicing type column-to-column connection has very few influences on capacity and initial stiffness on the CFDST frame, but it would slightly reduce the ductility of the CFDST frame; (3) three mechanical phases were proposed for analysis of the CFDST frames, and theoretical calculation was proposed to predict ultimate capacity of the CFDST frames and was validated by the test results. The proposed novel type of connections provide an effective plan to realize fully-prefabricated construction of CFDST structures and could be a feasible choice for engineering practice. (C) 2019 Elsevier Ltd. All rights reserved.