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Resilience and response of the dual system moment frame and braced frame with friction damper
The purpose of this study is to investigate the structural characteristics of a dual system moment frame and concentric braced frame with friction damper (CBFD). This study involves the design, detailing, fabrication and shake table testing of a full-scale dual system frame. The dual system frame was analyzed, designed and detailed using current specifications from the ASCE 7, AISC-341 and AISC-360. The dual system utilized for this testing includes two ordinary moment resisting frames and a single ordinary concentric braced frame with and without an in-line friction damper. The testing methodology includes utilizing a uniaxial shake table. The external excitation applied to the frame included 16 scaled ground motions of various intensities and amplitudes, as well as 8 artificially generated sinusoidal, sweep and step functions. The results of this research presented a comparison of the ordinary concentric braced system and the in-line friction damped braced frame. Overall, the friction damped braced system decreased the system acceleration by 25 percent at the frame deck. The friction damped brace increased the damping of the dual system frame by 6.7 percent, while maintain story drift below 1.7 percent. The frame residual story drifts demonstrated that the ordinary moment resisting frames participated as re-centering frames correcting any residual elongation in the friction damper. Overall, the in-line friction damper assembled within the dual system frame demonstrated enhanced structural performance and resiliency.