OasisLMS

Abstract: Tanks are essential facilities in hydrocarbon complexes, used for storing various types of hydrocarbon products. These flexible structures can tolerate considerable settlement during loading without compromising performance. However, the higher allowable settlement often leads designers to overlook the need for detailed subsoil investigations and underestimate the importance of selecting an appropriate foundation system. This oversight can jeopardize the structural integrity and performance of tanks. This paper proposes guidelines delineating the types and quantities of field tests required to assess subsoil information for optimal tank foundation design. It also discusses various foundation types commonly used for tanks in refineries and petrochemical plants, along with selection criteria and critical considerations to equip engineers with the knowledge needed to make informed decisions during the design process. Additionally, the paper presents case studies of seven floating roof tanks with diameters ranging from 35 to 92 meters and heights ranging from 14.8 to 20 meters. The subsoil at the three project sites predominantly consisted of fill overlying rock, organic soil underlain by medium to stiff clay, and silty sand followed by medium to stiff clay, respectively. These case studies illustrate the application of different foundation systems, including sand pads, pile foundations, and sand pads supported by improved ground using dynamic compaction and stone columns. The case studies highlight geological conditions, subsoil characteristics, design approaches, ground improvement techniques, and limitations. Hydrotest results and performance analyses, including uniform settlement, planar tilt, and out-of-plane settlement, show that the observed settlements were within permissible limits. These results substantiate the effectiveness and continued relevance of ground improvement techniques, offering valuable insights into their application for tank foundations in challenging soil conditions.


Keywords: tank foundations, refineries and petrochemical plants, permissible settlement, ground improvement, sand pad foundations

Mr. SAMPAT RAJ; MRIGANABH CHOUDHURY

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