Pushover-based seismic performance assessment of unanchored steel storage tanks with different slenderness ratios

Vasquez Munoz, Luz Elisabeth (author), Može, Primož (author), Dolšek, Matjaž (author)

Unanchored steel storage tanks, commonly used in industrial facilities, can suffer damage during major earthquakes due to various failures. To better understand the seismic behaviour of such structures, a pushover-based seismic performance assessment of four tanks with varying slenderness ratios was performed. The emphasis was placed on understanding the relationship between engineering demand parameters, tank slenderness ratio, and wall geometrical imperfections, which were, however, imposed only to the lower course around the tank circumference to assess the upper limit of the effect of geometrical imperfections on the elephant-foot buckling (EFB). The findings reveal that axial compressive stress in the tank wall correlates with increased slenderness and geometrical imperfections. This implies that the axial compressive stress in the wall of broader tanks is relatively low, and the bulging at the bottom of the wall is mainly due to high hydrodynamic pressure and the resulting hoop stress. In contrast, the wall of slender tanks buckles primarily due to high axial stresses, leading to EFB. Through dynamic analysis, the study showed that the pushover analysis can underestimate the axial stress if the tank’s base plate is uplifted significantly before EFB occurs. The effect of the impact should thus be considered, especially in the case of slender tanks, because the base plate uplift mechanism is more pronounced than in broader tanks. Further research is needed for a more accurate prediction of the axial compressive stress in slender tanks. However, the safety margin in the post-yielding range is low because the yielding area of the tank wall rapidly increases after the occurrence of steel yielding. In the absence of a detailed 3D model of tanks, simplified formulas for estimating stresses in the tank wall may be used for the broader tanks but not for more slender tanks because of their inability to simulate the highly non-linear relationship between the ground motion intensity and the stresses observed in the plastic region of the tank wall.

• Language: English
• Keywords: engineering structures, civil engineering, earthquake engineering, unanchored steel storage tanks, pushover analysis, hydrodynamic pressure, elephant-foot buckling, steel yielding, base plate uplifting, axial compressive stress, circumferential membrane stress, hoop stress
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2024
• Number of pages: 16 str.
• Numbering: Vol. 305, art. 117742
• PID: 20.500.12556/RUL-156245
• UDC: 624.07
• ISSN on article: 0141-0296
• DOI: 10.1016/j.engstruct.2024.117742
• COBISS.SI-ID: 188733187
• Publication date in RUL: 15.05.2024

Record is a part of a journal

• Title: Engineering structures
• Shortened title: Eng. struct.
• Publisher: Elsevier
• ISSN: 0141-0296
• COBISS.SI-ID: 7750666

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: gradbene konstrukcije, gradbeništvo, potresno inženirstvo