Performance Based Seismic Design Using Normalized Hysteretic Energy

摘要

The content of the paper is the formulation of normalized hysteretic energy, which may be capable for quantifying performance criteria under varying earthquake ground motions as the basic requirement of performance based seismic design during severe earthquakes. In this context total input seismic energy is visualized as the sum of strain, kinetic, damping, and hysteretic energy. As a philosophy of seismic resistant design for multi-level seismic design, the frequent earthquake may be quantified through sum of strain and kinetic energy only because the structure is understood to be linearly elastic. For moderate earthquake, energy may be partially damping and kinetic in addition to the strain energy and rare earthquake effect shall be equated with the sum of strain energy, kinetic energy, damping energy and effectively by hysteretic energy. Thus the controlling energy for the rare earthquake is the hysteretic energy. As a result, the hysteretic energy is recorded as damage energy, which may be obtained as the difference of the total input seismic energy and the sum of the strain, kinetic and damping energy. For this a simple expression for hysteretic energy has been derived. Using the equilibrium equation in terms of energy parameters-hysteretic energy has been estimated through analysis, design of steel building frames under varying earthquake ground motions. Subsequently, a method for evaluation of performance criteria using normalized hysteretic has been proposed.