An Investigation on Force Modification Factors in Cold-Formed Steel Structures

The Force Modification Factors defined in the Turkish Seismic Code (2018) for cold-formed steel structures are examined within the scope of this paper. Experimental and analytical studies are carried out on a real-life structure to investigate if the defined coefficients are practically applicable. An Ambient Vibration Survey is implemented to obtain the characteristic modal periods of the building, which is then modelled in computing environment through modal calibration. Additional laboratory experiments are carried out to determine a mathematical relationship for the connections between the bracing and the frame members of the building. Performance analysis is conducted to analyze the nonlinear behavior of the structure, and the force modification factors are evaluated. It is observed that the computed values from the analyses are generally within the range of what is defined in the Code, if not greater. Several suggestions as to where the Code content could be improvised are also included.