NEHRP Clearinghouse

Title
Theoretical and Experimental Studies of Cylindrical Water Tanks in Base Isolated Structures.
File
PB91217976.pdf
Author(s)
Chalhoub, M. S.; Kelly, J. M.
Source
National Science Foundation, Washington, DC., April 1988, 95 p.
Identifying Number(s)
UCB/EERC-88/07
Abstract
The report presents the results obtained from an experimental study of two similar cylindrical water tanks, and a corresponding theoretical solution. One of the tanks was directly fixed to the earthquake simulator, the other was mounted on the base of a scaled nine-story steel structure. The structure was isolated on eight multilayered elastomeric bearings. Because the base accelerations were lower for the tank in the isolated structure, the dynamic pressure was reduced for the tank. Free surface water elevation was slightly higher because of the lower frequency that characterizes the motion of base isolated structures. The problem can be overcome by appropriate selection of the isolation system or by the addition of dampers at the locations of maximum water particle velocities. For the tank in the isolated structure, the accelerations and displacements at the tank rim were lower than for the tank directly fixed to the shake table. A theoretical solution developed from linear wave theory correlates very well with the experimental results. The advantages of using base isolation for large storage tanks are investigated.
Keywords
; Dynamic response; Bearings; Vibration isolators; Earthquake resistant structures; Steel structures; Earthquake engineering; Simulators; Structural vibration; Frequencies; Experimental data; Vibration damping; Water tanks; Mathematical models