Study of Reserved Strength Capacity of Concrete Shell

Abstract

Hyperbolic cooling towers have become the design standard for all natural-draft cooling towers because of their structural strength and minimum usage of material. The hyperbolic shape is particularly suited to cooling tower construction as the wide base provides a large space for the water and cooling system. As the tower widens out at the top, it supports the turbulent mixing as the heated air makes contact with the atmospheric air. Hyperbolic cooling tower is a tall structure with shells subjected to dead load and wind load. In absence of ground motion, wind becomes the major factor. In this study, 2 major models are studied with I and V column support. Each model is further divided into 2 models, i.e. one with SHELL element and another with SOLID element. All models were modelled and analyzed in ANSYS. The wind loads on these cooling tower have been calculated in the form of pressure by using the circumferentially distributed design wind pressure coefficients as given in IS: 11504 - 1985 code along with the design wind pressures at different levels as per IS: 875 (Part 3) - 1987 code. The analysis has been carried out using 8 noded shell element (SHELL281), 8 noded solid element (SOLID185) and 20 noded solid element (SOLID 186).