Lateral deflection of piles in a multilayer soil medium. Case study: The Terengganu seaside platform

Vibrations from earthquakes can be felt through structures on the ground. One of the characteristics of soil is that it can absorb vibrations to varying degrees depending on its type and properties. The soil profile and depth of each layer of soil is not the same for every place. Therefore, consideration of soil profile and the depth of each layer is important in structural design, especially for offshore structures. In this article, the lateral deflection of piles constructed in a multilayer soil medium is assessed. The evaluation was performed on the Terengganu seaside platform located approximately 350 km away from the Sumatran seismic zones, the Sumatran subduction and fault zones. To model an earthquake, a recently developed attenuation equation was used, and the effect of the shear wave velocity was investigated, considering the soil profile. The results showed that the effect of the wave reduced as it moved further from the epicentre of the earthquake. The piles experienced complete failure when the magnitude of the earthquake was 8.0, with some loss of pile capacity for a magnitude of 7.5 and below. Considering the effect of shear wave velocity (Vs) of the multilayered strata, and using the new attenuation equation, accurate pile deflections, which were in excellent agreement with previously used methods, were obtained.