Experimental Verification of Inelastic Energy Demand Spectrum Using SDOF Steel Specimens on Shaking Table

In this study, an extensive experimental work was carried out with single degree of freedom (SDOF) system steel specimens on a shaking table. Actual scaled earthquake ground motion data was used to excite the SDOF specimens beyond their elastic displacement limits. The main aim was to verify the existing energy demand spectra, especially within the inelastic range. The damping ratios of the specimens were determined experimentally through free vibration after the excitation was completed and analytically checked through logarithmic decrement and Chopra’s (Dynamics of structures: theory and applications to earthquake engineering. Prentice Hall, Englewood Cliffs, NJ, 1995) methods. Finally, an energy spectrum with mass-normalized energy versus natural period of the SDOF system was determined experimentally with respect to varying damping ratios. The results were then compared with the existing Gullu’s energy spectrum where closely matching experimental data was observed.