Computer-Aided Retrofitting of a Damaged RC Cooling Tower Shell

Abstract

The role of numerical simulations in the design of the repair of damaged reinforced concrete structures is illustrated in the context of the retrofitting of a damaged RC cooling tower built in 1963. Nonlinear material behavior of concrete and steel as well as the state of damage, including the nonsymmetric spatial distribution of the cracks and the corrosion of the reinforcement at the end of the anticipated lifetime of the structure, are accounted for in the computational model. Two alternatives for the repair of the shell by means of stiffening rings are investigated. If the repair is based on the application of two cast in situ stiffening rings, structural failure of the RC shell is initiated by two failure zones located between the upper stiffening ring and the cornice. In these zones, the shell is severely weakened by the locally dense distribution of existing cracks and the corrosion of the reinforcement. The coefficient of structural safety of the retrofitted shell can be further increased if the existing cornice is strengthened. This coefficient is considerably larger than the one obtained for the uncracked shell.