Seismic design of pile foundation for oil tank by using PLAXIS3D.

Abstract

Analysis and design of pile foundations in soft soil strata to support any geotechnical structures especially oil tanks are very important for geotechnical practitioners and more so in earthquake prone areas. In this paper, a complete design of pile foundation for oil tank in Iraq is mentioned by providing the details of soil strata at the site of oil tank construction which is in seismically active region. A finite element analysis by using PLAXIS3D for the design of pile foundation for oil tank in Iraq is carried out for both static and seismic loading conditions. In-situ soil at the site varies from loose fill material followed by soft to stiff clay layers and then by dense sand layer. First, the basic static design of suitable pile foundation which is based on field observed ground details have been carried out in PLAXIS3D. A group of 89 piles of 26m length with 400mm radius each is proposed for the oil tank of height 15m and 23.5m diameter to withstand a maximum credible earthquake (MCE) of 0.15g. Results for pile foundations in terms of settlements, differential settlements between piles, bending moments are obtained by using finite element numerical modeling using PLAXIS3D and proposed as final design of the foundation system for oil tank at the specific soft soil site in Iraq.