posted on 2024-07-13, 01:34authored bySrikanth Venkatesan, Nelson T. K. Lam, John WilsonJohn Wilson
The site natural period as a parameter for site classification has the attribute of providing an objective, and direct, representation of the risk of a soil site developing resonance behaviour. This parameter has definite advantages over the conventional approach of classifying soil based mainly on description of the sediments close to the ground surface (eg. the upper 30m of the sediment). This is particularly so if the site is characterised by high impedance contrast at the rock-soil interface, and more so in regions of low and moderate seismicity where non-ductile, lightly damped, systems are particularly prone to resonance behaviour. However, site natural period alone will not be able to accurately characterise potential soil amplification behaviour. This paper presents the recently developed Extended Component Attenuation Model (ECAM) which incorporates component factors to account for the effects of the shear wave velocity profile of the soil, damping properties of the soil, impedance contrasts with the bedrock (ie. radiation damping) and the frequency content of the earthquake excitation as transmitted from the bedrock. The presented model, due to its simplicity and generality, could potentially become standard manual calculation procedures that can be codified for widespread practical applications.
Annual Technical Conference of the Australian Earthquake Engineering Society: Earthquake Engineering in Australia, Australian Capital Territory, 24-26 November 2006