Experimental research of replaceable Q345GJ steel shear links considering cyclic buckling and plastic overstrength

Coupon tests confirmed that Q345GJ steel had good ductility and rarely cyclic hardening. Therefore, 12 shear links using such steel were designed and tested. The explored parameters included web aspect ratio, flange width-thickness ratio, the equivalent link length coefficient eVp/Mp, stiffener spacing and thickness, hysteretic loadcase, and welding details. Discussions and analysis on the failure mode, the hysteretic behavior of shear load and displacement angle, the strain distribution, the bearing capacity and stiffness, the plastic overstrength, the deformation and energy dissipation capacity, were also conducted. The shear links had satisfactory energy dissipation capacity under multiple hysteretic loading with almost no cyclic hardening. Web aspect ratio and stiffener spacing had determinate influence on cyclic web buckling, as well as the ultimate deformation capacity. Yet, more intensive stiffener spacing was prone to result in more serious stress concentration in the web, and caused web fracture. Also, smaller coefficient eVp/Mp was harmful to the ultimate deformation capacity. The ultimate plastic overstrength Vu/Vp of the shear links was about 1.35 to 1.5, influenced by web aspect ratio, the coefficient eVp/Mp, and stiffener spacing. To avoid cyclic flange fracture, the coefficient eVp/Mp was also suggested be within 1.7.