Seismic response of unanchored and partially anchored liquid-storage tanks. Final report
- Rice Univ., Houston, TX (United States). Dept. of Civil Engineering
Ground-mounted vertical storage tanks are important components of nuclear plant safety systems. A systematic study is made of the principal effects of base uplifting on the seismic response of laterally excited, unanchored and partially anchored cylindrical liquid-storage tanks. The study consists of two parts: the first deals with the static uplifting resistance of the flexible base plate, and the second deals with the dynamic response of the uplifting system. An insight into the behavior of the uplifting base plate is first gained with the help of a prismatic beam solution. In Section 2, the solution is implemented exactly, whereas in Section 3 it is implemented approximately by use of the Ritz energy procedure. Solutions are next presented for axisymmetrically and asymmetrically uplifted base plate of tanks, in Section 4. For the axisymmetric case the solution is implemented exactly, as well as approximately by modeling the plate by a series of semiinfinite prismatic beams. The accuracy of the latter approach is confirmed by comparing its predictions with those of the former. In Section 5, a highly efficient and rational method is presented for the dynamic response analysis of uplifting tanks. Both unanchored tanks and partially anchored tanks, for which the number of anchor bolts at the base is insufficient to ensure full fixity, are considered. It is shown that base uplifting may reduce significantly the hydrodynamic pressures, but these reductions may be associated with increased axial compressive stresses in the tank wall and large plastic rotations at the plate-shell junction. For partially anchored tanks, energy loss due to bolt yielding is found to be small.
- Research Organization:
- Electric Power Research Inst., Palo Alto, CA (United States); Rice Univ., Houston, TX (United States). Dept. of Civil Engineering
- Sponsoring Organization:
- Electric Power Research Inst., Palo Alto, CA (United States)
- OSTI ID:
- 257314
- Report Number(s):
- EPRI-TR--105809
- Country of Publication:
- United States
- Language:
- English
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