Nonlinear analysis of a RC cooling tower with geometrical imperfections acid a technological cut-out

The analysis of nonlinear deformation and ultimate load should be a vital e lement of the checking-design of cooling towers. This issue is discussed in the paper with respect to an existing cooling tower with large geometrical imperfections and a cut-out made for gas discharge. A brief theoretical ba ckground is given, with special attention paid to the finite element model and constitutive relations for reinforced concrete. The numerical analysis deals with three cases: (1) perfect hyperboloid shell of revolution, (2) ac tual shell with measured geometrical imperfections of the shell mid-surface , (3) imperfect shell with a cut-out. Two types of nonlinearities are consi dered: (a) material nonlinearity only, (b) material and geometrical nonline arities. The computations are carried out for a cooling tower shell pinned at the bottom contour. The dead load and wind pressure are applied to the s hell. Finite element code ANKA is used as the main tool for the numerical a nalysis. The results of computations for a perfect hyperboloid shell are co mpared with the results obtained using the DIANA package. It is noted that a considerably softer response corresponds to larger deformations and advan ced clacking. The geometrical imperfections only slightly influence the res ponse of the shell. The cut-out introduced into the imperfect shell does no t significantly change the shell deformations either. (C) 1999 Elsevier Sci ence Ltd. All rights reserved.