Construction and Design of Large Cooling Towers

Large natural-draft cooling towers are required for dry-type cooling of power plants having high capacity. Through the choice of an appropriate offset distance between the axis of the hyperbola and axis of rotation the stress distribution as well as buckling and vibration behavior can be influenced considerably. In order to keep the required buckling safety and lowest natural frequency as the dimensions of the cooling tower shell are increased stiffening of the shell becomes indispensable. Numerical investigations and tests carried out show clearly that the efficiency of the stiffeners is different, rings being more effective than meridional ribs. Stiffening rings can be built easily after slight modification of the existing climbing formwork. Reinforced concrete shells stiffened by rings can compete with cable network structures, even beyond a height of 200 m (656 ft).