Normalized energy-based methods to predict the seismic ductile energy response of single-degree-of-freedom structures.

As energy-based methods could provide more insight into the ultimate cyclic seismic performance than traditional design methods, this research essentially focuses on the study of energy demands for single-degree-of-freedom systems. Starting from the basic idea that a typical dynamic earthquake excitation can be conceptually described as a complex sequence of pulses and sine-waves of various durations, frequencies and intensities, energy response spectra for simple pulses or sine-wave excitations are first constructed, the behaviour of each energy contribution is studied and two new energy normalization methods are proposed. Assuming that earthquake ground motion excitation can be simulated by pulses and sine-waves, by utilizing the simple-pattern-excitation energy spectral results, the structural energy demand under real seismic excitation can be predicted