• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.1
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• pp.109-119
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• 2004

A design procedure for velocity-dependent supplemental dampers, such as viscous or viscoelastic dampers, required to meet the desired performance objectives was developed using displacement spectra. The amount of supplemental damping required to satisfy given performance limit state was obtained first from the nonlinear static procedure using displacement spectra, then dampers were appropriately distributed throughout the stories to realize the required damping. The proposed method was applied to multi-story steel frames, and the structures were analyzed by time history analysis to validate the accuracy of the design procedure. According to the analysis results the maximum displacements of the model structures retrofitted by the supplemental dampers turned out to be restrained well within the given target values.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.4
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• pp.1-10
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• 2022

In this study, to evaluate the possibility of using a steel spring as a displacement-dependent damping device, tensile loading and cyclic loading tests were performed. The main experimental variables were the type of steel (SAE9254 and SS275), the spring constant (700 N/mm, 1,000 N/mm, and 1,400 N/mm), and the presence or absence of heat treatment for SAE9254. As a result of the tensile test, the ratios of the measured spring constant to the design spring constant of the steel springs made with SAE9254 ranged from 1.08 to 1.13, while the ratios of the design spring constant and the measured spring constant of the steel springs made with SS275 ranged from 0.86 to 0.97. After yielding, the slope values of the load-displacement curve of the SAE9254 with/without heat treatment were about 240~251 N/mm and 92 N/mm, respectively, but the slope values of the load-displacement response of SS275 were almost zero. According to the uniaxial cyclic loading test results, all specimens were satisfied with three conditions for a displacement-dependent damping device in KDS 41 17 00 (2019): the maximum force and minimum force at zero displacement, the maximum force and minimum force at the maximum displacement, and the energy dissipation capacity. In addition, the equivalent damping ratios of steel springs made with SAE9254(non-heat treatment) and SS275 were approximately 2.8 times and 1.9 times greater, respectively, than that of steel springs made with SAE9254.