Nonlinear behavior and ultimate load bearing capacity of reinforced concrete natural draught cooling tower shell

Abstract

In this paper, the ultimate behavior of a reinforced concrete cooling tower shell in hyperbolic configuration is presented. To include the geometrical nonlinearity due to large displacement, the Green–Lagrange strain tensor is taken into account. Material nonlinearities in the concrete are also taken into account, including tensile cracking, tension stiffening, and the nonlinear stress–strain relation in compression. The smeared crack model with the ability of crack rotation is employed to investigate crack propagation in the layered concrete shell. The biaxial stress state, which is the main stress state in the shell structure, is represented by the improved work-hardening plasticity concrete model. To improve the ductility increase effect in the concrete in the biaxial stress state, the hardening rule in the employed plasticity model is modified. Not only the crack patterns but the crack width as well is investigated to address more clearly the failure mechanism of the cooling tower under consideration. The ultimate load bearing capacity of the cooling tower under consideration is evaluated as 1.925 times that of the design wind pressure. The failure of the cooling tower is observed as commenced by the yielding in the meridional reinforcement, and the yielding of reinforcement propagates in the circumferential direction until the ultimate load is reached.