Session: SE-01-01 Earthquake Resistance and Seismic Margin

Paper Number: 123380

123380 - Seismic Sliding in Storage Tanks: An In-Depth Analysis and Design Insights 

The response of storage tanks to earthquake forces has been the subject of extensive research worldwide, resulting in a wealth of data that informs the design of tank components to withstand earthquake loads. This includes determining the necessary freeboard to account for sloshing wave heights, calculating base shear forces, and assessing overturning moments, among other considerations. However, there is a notable gap in the available information pertaining to a crucial aspect of tank behavior during seismic events: their ability to resist sliding. 

The absence of comprehensive experimental data or research findings in this area has led to the utilization of simplified static frictional force equations and the application of higher factors of safety for frictional factors in design standards like API 620. While these safety precautions are undoubtedly essential, they can sometimes result in impractical tank configurations, especially for large-capacity tanks. To address this significant knowledge gap, this study focuses on investigating the force required to initiate sliding under various friction coefficients. Additionally, the research delves into the evaluation of shear stresses occurring in the bottom plate and mechanical anchorage. To achieve this, static and transient analyses are conducted using nonlinear geometry and elastic-plastic material properties.

As a result of this comprehensive investigation, the study aims to compare the available factor of safety against sliding with the required factor of safety as dictated by existing tank design standards. Ultimately, the research intends to provide recommendations for accurately calculating shear stresses in the bottom plate, thereby contributing to the improved safety and reliability of storage tanks in seismic-prone regions.

Presenting Author: Vivek Manjrekar Bechtel Energy

Presenting Author Biography: Vivek has over 25 years of experience in the design and engineering management of various
types of storage structures, including ambient storage tanks, cryogenic storage tanks, and
spherical vessels. Vivek's key area of expertise is in the design of LNG tanks and the application
of finite element method to the plate structures.

Vivek holds a Master of Science in Structural and Foundation Engineering from Heriot-Watt
University in the United Kingdom. He has been an active member of the American Petroleum
Institute committee for Above Ground Storage tanks with contributions to Standards API 650,
620 and 625. In addition, Vivek is a member of the American Institute of Steel Construction
(AISC) and The Institute of Structural Engineers (IstructE) in the UK.

Authors:

Vivek Manjrekar Bechtel Energy
Neville Stokes Bechtel Energy, Houston
Junho Choi Wood PLC