Response spectrum modelling for regions lacking earthquake records

Abstract

The design response spectrum is typically the starting point of most codified seismic design and assessment procedures and is predominantly used to prescribe the applied inertia forces induced by earthquake ground motions. In a recent paper, the authors presented and discussed the key properties, limitations, engineering interpretation and modern concepts relating to various types of earthquake design response spectra, including the acceleration, displacement and velocity spectra. The present paper provides a critical evaluation of the various deterministic and probabilistic approaches to response spectrum modelling, including an introduction to the Component Attenuation Model (CAM). The CAM modelling approach was developed recently by the authors, with the express purpose of providing a novel response spectrum modelling technique for regions lacking earthquake records. Traditional approaches for the prediction of earthquake actions using design response spectra rely on accurate hazard models for the region concerned, which in turn depend heavily on the availability of strong ground motion data from the local seismic region, or from analogous regions with similar geological and seismo-tectonic features. In the case of regions with low to moderate levels of seismicity, such data is at best scarce and in many cases unreliable, and this presents unique problems for designers carrying out seismic analysis for new construction or assessing the seismic reliability of existing buildings, bridges and infrastructure. For such regions, novel approaches (such as CAM) which adapt local seismological information for the purpose of earthquake ground motion modelling may be considered. Further key issues including the determination of the Maximum Considered Earthquake, are also addressed in this paper.