|
|
||
|
|
|
|
H-sub-L is the height of the liquid in the tank. The distribution of internal pressure along this “worst” meridian is shown three slides hence.
This and the next 4 slides are From:
Juan C. Virella, Luis E. Suarez and Luis Augusto Godoy (Dept. of Civil Engineering and Surveying, University of Puerto Rico at Mayaguez, Puerto Rico), “A static nonlinear procedure for the evaluation of the elastic buckling of anchored steel tanks due to earthquakes”, Journal of Earthquake Engineering, 08/2008, Vol. 12, No. 6, pp 999-1022, 2008, DOI: 10.1080/13632460701672714
ABSTRACT: Ground-supported steel tanks experienced extensive damage in past earthquakes. The failure of tanks in earthquakes may cause severe environmental damage and economic losses. This study deals with the evaluation of the elastic buckling of above-ground steel tanks anchored to the foundation due to seismic shaking. The proposed nonlinear static procedure is based on the capacity spectrum method (CSM) utilized for the seismic evaluation of buildings. Different from the standard CSM, the results are not the base shear and the maximum displacement of a characteristic point of the structure but the minimum value of the horizontal peak ground acceleration (PGA) that produces buckling in the tank shell. Three detailed finite element models of tank-liquid systems with height to diameter ratios H/D of 0.40, 0.63, and 0.95 are used to verify the methodology. The 1997 UBC design spectrum and response spectra of records of the 1986 El Salvador and 1966 Parkfield earthquakes are used as seismic demand. The estimates of the PGA for the occurrence of first elastic buckling obtained with the proposed nonlinear static procedure were quite accurate compared with those calculated with more elaborate dynamic buckling studies. For all the cases considered, the proposed methodology yielded slightly smaller values of the critical PGA for the first elastic buckling compared to the dynamic buckling results.
NOTE: Models A, B and C in this and the next 4 slides are labeled in the reverse order of the same tanks displayed 4 slides ago because this and the next 4 slides are taken from a different paper (the paper cited above) than the paper to which 4 slides ago corresponds, which is the following paper:
J.C. Virella, L.A. Godoy and L.E. Suárez,
“Dynamic buckling of anchored steel tanks subjected to horizontal earthquake excitation”, Journal of Constructional Steel Research, Vol. 62, No. 6, June 2006, pp. 521-531, doi:10.1016/j.jcsr.2005.10.001
Page 86 / 216