Inelastic Large Displacement Behavior and Buckling of Cooling Tower

Inelastic, large displacement behavior of reinforced concrete hyperbolic cooling towers is studied using a finite-element program developed on the Cray Y-MP supercomputer. The large displacement effects are formulated based on the Lagrangian approach in which the displacements are measured from the original configuration of the structure. The concrete cracking is modeled using the rotating smeared crack approach and the bending deformation is represented using the layering technique. The concrete constitutive behavior is represented by a biaxial inelastic material model. The tension stiffening of concrete is modeled using gradual linear unloading of the stress strain curve of concrete. Several nonlinear analyses of the Grand Gulf cooling tower are performed. Unlike the results of previous investigations that attribute the failure of the cooling tower to the yielding of the meridional reinforcement, the results of this investigation show that the failure occurs due to the circumferential buckling in the vicinity of the throat triggered by the reduction of the stiffness due to concrete cracking.