Investigating the effect of thermal loading on cooling tower shells

In regions where seismic activity is not high, the weight of the tower and the wind load are main loads for the cooling tower design. However, the effect of thermal load cannot be ignored. Due to the microcracks caused by thermal loads, the ultimate strength of the cooling towers at the end of wind loading may decrease. In this study, the cooling tower of Shahid Rajaee Power Plant was simulated using ABAQUS finite element software. Damage plasticity model which is capable of modeling cracks was used to model the tower shell. The effects of two load combinations were calculated and compared. In the first load combination, gravity, wind and thermal loads, and in the second, gravity and wind loads were applied to the given tower. According to the results, the differences of tower shell displacement toward the wind direction, compression-induced damage, and tensile damage in two loadings were 6.4%, 3%, and approximately 10%, respectively. It was revealed that compressive and tensile damages spread out over a wider area in the presence of thermal loading. The highest impact of thermal loading was upon the bending moment of the shell and the back-winded side, such that the difference of bending moment in two loadings was estimated to be more than 40%. Moreover, in the presence of thermal loads, the tower reached its ultimate strength with lower wind pressure.