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T. Huemer, C. Kropik, H.A. Mang, G. Meschke:
"Repair of a Cracked Cooling Tower Shell Based on Numerical Simulations";
in: "Proceedings of the IASS-ASCE International Symposium 1994 on Spatial, Lattice and Tension Structures", ASCE, 1994, 887 - 896.

The present condition of a 30 years old cooling tower shell made of reinforced concrete is characterized by a relatively large number of long, thermally induced meridional cracks. For the purpose of designing the planned repair of the pre-damaged cooling tower by stiffening rings, a comprehensive numerical investigation has been performed by means of FEM. It is based on realistic material models for the concrete and the reinforcing steel. The degree and the spatial distribution of corrosion as well as the distribution of the cracks and the actual thickness of the shell are accounted for. Comparative ultimate load analyses have shown that a repair based on attaching two stiffening rings to the shell results in a sufficient degree of safety against collapse of the structure within the guaranteed residual lifetime of 25 years. The paper contains a description of the repair with special emphasis on the connection between the stiffening rings and the shell.

Keywords: finite element, reinforced concrete, repair, strengthening, cracking, stiffening ring, fem, retrofitting, corrosion, cooling tower