the strength and stiffness of the paraboloidal single-layer lattice steel cooling towers with stiff rings

the paper compares the effect of the stiff rings on the structural behaviour of a paraboloidal single-layer lattice steel cooling tower. in arid and earthquake prone countries such as iran, steel lattice cooling towers with ‘dry’ cooling system, are more advantageous than concrete cooling towers due to having much lower relative weights. for ‘light’ steel cooling towers then, wind load is one of the most important determining design loads. the paper therefore, focuses on the study of the structural behaviour of cooling towers under wind load. the mechanical and operational factors determine the general dimensions of a cooling tower. the addition of stiff rings has a decisive role in reduction of forces and displacements of the single-layer lattice cooling towers. the effect of the type and number of stiff rings, their depth and position within the height of the tower, on the stiffness and strength of a tower are studied. stiff rings significantly improve the overall stability of the tower. the addition of three stiff rings to the tower, for the studied conditions, reduced the maximum horizontal displacements and forces of the tower over 90%, and 60%, respectively.