Effect of Rotation-Friction Dampers on Displacement and Base Shear of Steel Moment Frames

Dampers are incorporated into structures to improve their cyclic behavior against wind- and earthquake-induced loads. Rotation-friction dampers (RFDs) are a special type of friction dampers that offer numerous advantages and tend to dissipate energy through rotation and re-rotation. In this research, behavior of steel frames with concrete-filled tubes (CFT) was investigated considering cases equipped with RFD (designated as CFT-M) and those without such members (designated as CFT). In order to validate the modeling, results of Abaqus, a finite-element software tool, were compared to the experimental data reported by Movala et al. The hysteresis curves of the modeled sample were in very good agreement with those of the experimental model. In order to investigate performance of the CFT frame, as compared to the CFT-M frame, under the effect of some earthquake records, the two structures were modeled in Abaqus. In the Abaqus software, in order to load the structures laterally, earthquake excitations were applied to column bases. According to the results of modeling in Abaqus, under the effect of the considered earthquake records coupled with gravitational loading of the frame, incorporation of the RFD decreased structural displacement during the initial ۲۵ seconds of analysis by ۲۳ – ۸۳% for ۸ different earthquake records, while increasing the displacement by ۱۵ – ۸۱% for ۳ other earthquake records. From the second ۲۵ down to the end of the analysis window, the displacement decreased and increased for ۱ and ۱۰ earthquake records, respectively. Moreover, under the effect of the considered earthquake records coupled with gravitational loading of the frame, the use of RFD increased the base shear by ۱۲ – ۶۳% for ۸ different earthquake records, while the maximum base shear did not change significantly for ۳ other earthquake records. Elimination of column base-connected bracing member provides for larger free space across the frame plane, which is, architecturally speaking, very desirable and useful.

کلیدواژه ها:

composite steel moment frame ، base shear ، rotation-friction damper ، hysteresis curve.