Effects of Various Steel Grades of Vertical Shear Links on Cyclic Behavior of Vertically-Eccentric Braced Frames

Cyclic behavior of Vertically-Eccentric Braced Frames (V-EBFs) with shear links constructed of different grades of steel materials is investigated. Four steel grades with yield stress values between 100 MPa and 458 (MPa) have been considered for numerical modeling. The links constructed from Low Yield Point steel grades (LYP100 and LYP225) were modeled by utilizing isotropic pattern of cyclic hardening. Kinematic cyclic hardening material models were chosen for simulation of the links built of A709 Conventional steel grade 345 (C345) and A709 High Performance Steel grade 345 (HPS485). The links built with C345 and HPS485 steels were loaded until their Rupture Indexes (RIs) reached a specific amount, while the LYP links were loaded until an effective rotation of 0.14 (radians) was observed. The results showed that the links made of LYP steel grades (LYP100 and LYP225) have good hysteretic behavior and can withstand a high amount of rotation. It was also observed that the links constructed of LYP100 have significant over-strength values. On the other hand, significant web buckling under cyclic loading occurred in the links constructed of LYP225 steel grade, but the tension forces developed in these vertical shear links under huge deformations can prevent further decreasing of the shear strength

Keywords:

cyclic behavior , eccentrically braced frame , finite element method , low yield point steel , vertical shear link