Utilizing analytical transfer functions to gauge the effect of velocity reversals

Abstract

The effect of "velocity reversals'' (soft soil layers confined between stiffer ones) over 1D Site Response calculations has been studied for many years now, but a complete characterization of their influence is still pending. In a recent article titled "Never Fear Velocity Reversals", Yagoda-Biran, Kerpel and Kamai analyzed a set of three-layer systems with different properties. Their study was focused on numerical calculations leading to insights concerning the influence of the reversal over the fundamental resonant mode. The same systems are analyzed in this note, yet from a theoretical standpoint in this case, working directly with the analytical transfer functions. A new interpretation of their results is provided, along with a reasoning that evinces difficulties when it comes to extrapolating insights to more complex layerings.