Free‐Vibration Response of Column‐Supported, Ring‐Stiffened Cooling Tower

Abstract

The free‐vibration analysis of a column‐supported cooling tower with ring stiffeners has been undertaken using the finite element method. The tower has been modeled using anisoparametric quadrilateral shell of revolution element, and the rings and columns have been modeled using an isoparametric three‐dimensional curved beam element. The kinematic assumptions used in these elements to describe the displacement field correspond to the recently proposed high‐order shear deformation theories. Numerical results illustrate the advantages of providing the stiffening rings on the vibrational response of the cooling tower. These numerial results reveal that the provision of ring stiffeners significantly alters the modal characteristics of the higher modes with circumferential waves greater than 3. Also, it is concluded that under seismic excitation of the cooling tower the stiffening rings may not help increase the resistance of the structure because these rings have no influence on the modal characteristics of structures under such excitations and whereas the stiffening rings help increase the load‐carrying capacity of towers under wind excitations.