A numerical study on the cyclic behavior of special truss moment frames with X-shaped pipe damper

Special Truss Moment Frame (STMF) is a type of steel moment frames that has high lateral stiffness due to deep girders and can be used over long spans. For an STMF subjected to cyclic loading, energy dissipation is provided through the yielding of the special part located in the mid-span. This paper presents a numerical study on the cyclic behavior of STMFs in which the special part is equipped with yielding damper as a means of energy dissipative device. For this purpose, it is aimed to investigate the effect of the parameters of X-shaped pipe damper (XPD) on the cyclic behavior of STMFs. The application of these dampers has been investigated in two configurations; once with clamped and again with pin-ended beams at the special part. The results of finite element analysis are compared based on the parameters of cyclic behavior (stiffness and strength), the amount of maximum cumulative plastic strain and the energy dissipation capacity of the specimens. Based on the results obtained from the analysis of the STMF with pin-ended beams at the special part, the use of proposed X-shaped damper increases the energy dissipation capacity of the frame by 70%. Increasing the thickness of the X-shaped pipe damper increases the yield and ultimate load bearing capacity of the frame. In addition, the stress and strain concentration in the frame members is reduced which in turn prevents the damage evolution in these members.