Real Earthquake Accelograms as Input for Seismic Analysis

The earthquake ground shaking is usually presented in the form of a response spectrum of acceleration or displacement. The spectrum used as input to equivalent lateral force or spectral modal methods of analysis is usually obtained by scaling an elastic spectrum by factors that account for, amongst other phenomena, the influence of inelastic structural response. However there are problems in which the simulation of structural response using a scaled elastic response spectrum is not considered appropriate, and full dynamic analysis is required (buildings designed for a high degree of ductility ; structures with configuration in plan or elevation that is highly irregular ; structures for which higher modes are likely to be excited ; critical structures, the failure of which would cause unacceptable harm or disruption – dams, nuclear power plants etc).