HYSTERETIC BEHAVIOR AND INFLUENCE FACTORS OF STEEL FRAMED-TUBE SUBSTRUCTURE WITH REPLACEABLE Q235 LINKS CONNECTED BY END PLATES

Two 2/3 scaled one-bay double-half-story steel framed-tube substructure specimens with replaceable Q235 links connected by end plates were subjected to two-stage low cyclic loading tests to study their seismic performance, replaceability of links and the influence of link length. The parameters of the nonlinear isotropic/kinematic hardening model were calibrated by conducting tension and compression reciprocating tests on the samples of link web. The results of the tests were used to verify the validity of the finite element models of the substructure specimens, and the influence of link length and link web area was analyzed. The results show that the replaceable maximum story drift angles of the links can reach 0.43% and 0.39%, respectively, and the replacement of the links can restore the performance of the structure to the original level; the overstrength factor of the links is greater than 1.5 which is recommended by Popov et al, and the failure plastic rotation angles is greater than the limit value of 0.08 rad given by AISC341; the substructures have good ductility, and the ductility coefficient and cumulative energy dissipation of the substructure with a long link are greater than those with a short link; the failure modes are web tearing caused by the crack propagation of the weld at the chamfer of link stiffeners; the link length is recommended to take (0.10~0.24) times the centerline spacing of the columns, and the length ratio takes 0.55~1.32; the link web area has great influence on bearing capacity and accumulated energy consumption of the substructures.