NEHRP Clearinghouse

Title
Analytical Method for Determining Seismic Response of Cooling Towers on Footing Foundations.
File
PB82148008.pdf
Author(s)
Gould, P. L.; El-Shafee, O.; Lee, B. J.
Source
National Science Foundation, Washington, DC., October 1981, 169 p.
Identifying Number(s)
RR-60
Abstract
The development of a finite element model for the dynamic analysis of an axisymmetric thin rotational shell founded on a shallow ring footing is described. The model was developed using high-precision rotational elements for the shell, isoparametric solid elements for the soil, and an energy transmitting boundary at the ring footing. In a sensitivity study of the equivalent boundary system to the driving frequency, the stiffness components were found to be more sensitive than damping components and the rotational components were found to be more sensitive than the translational components. Free vibration, response spectrum, and time history analyses of a hyperbolic cooling tower shell showed that the overall flexibility of the shell increased with a decrease in soil stiffness, reducing many forces in the shell proper and especially in the column support from the values calculated when the interaction is neglected. It is suggested that the structural design and resulting behavior of rotational shells can be improved by considering soil-structure interaction.
Keywords
Ground motion; Footings; Earthquake engineering; Earthquake resistant structures; Foundations; Soil structure interactions; Soil dynamics; Cooling towers; Finite element analysis; Computer aided analysis; Mathematical models; Stiffness methods