Sponsor
Oregon Department of Environmental Quality (DEQ)
Document Type
Presentation
Publication Date
7-17-2026
Subjects
Structural risk, Fuel tank seismic stability
Abstract
Older fuel storage tanks, such as those in Oregon's CEI Hub, present significant seismic vulnerabilities, prompting proposals to limit storage capacity as a transitional risk mitigation measure before more permanent retrofitting actions. However, a critical knowledge gap exists regarding the applicability of standard analysis methods, like API 650, to low-fill conditions. This study utilizes the Veletsos-Yang iterative fluid-tank interaction procedure to evaluate the seismic demand of low-fill slender tanks. The analysis reveals that low-fill slender tanks exhibit slightly longer impulsive periods compared to fully-filled tanks with identical fill-height to radius ratios. Furthermore, the fixed roof mass of a low-fill tank (if available) can have a more substantial contribution to base shear and moment than the fully-filled counterpart (which has the same fill-height to radius ratio). As a result, while lowering fill levels effectively reduces overall seismic loads, current API 650 equations can underestimate the base moment for low-fill tanks by about 27% for the case study tank. These findings emphasize the need to re-evaluate existing mechanical analogs to accurately capture structural risk and inform fragility curve development for low-fill slender tanks.The presentation was given at the 13th National Conference on Earthquake Engineering (13NCEE), July 13-17, 2026, in Portland, Oregon.
Rights
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
DOI
10.15760/cee-presentations.03
Persistent Identifier
https://archives.pdx.edu/ds/psu/45008
Citation Details
Yang, David and Anderson, Sam, "Understanding Structural Risk: Seismic Demand for Low-Fill Slender Fuel Tanks" (2026). Civil and Environmental Engineering Faculty Publications and Presentations. 772.
https://archives.pdx.edu/ds/psu/45008