Dynamic analysis of cooling tower considering two different column modeling approaches

Nuclear power plants use cooling towers, which are frequently hyperboloid in shape, to disperse excess heat created during power generation. Due to their ever-increasing size, the stability analysis by experimental means and finite element modelling has become more significant. There are different finite element modelling approaches. Often the columns are modelled as simple beam elements to save computational power and analysis duration. In other cases, the columns are modelled with a more realistic approach, thus modelling with the rebars embedded in the concrete with properties like bond and shrinkage. Little attention has been shed on the effect of these two different modelling approaches on the analysis results. In this study, two models of a hyperbolic natural draught cooling tower were made. One model was created with the more realistic Embedded Reinforcement Columns and the other was with Simplified Columns modelled with Timoshenko Beam-type members. The model was validated, and its natural frequency was identified. Subsequently, both models were exposed to seismic and wind excitations, and their responses were compared. The Embedded Reinforcement Column model exhibited greater flexibility and reduced stiffness, resulting in lower natural frequencies. As a consequence, it experienced larger displacements under both seismic and wind loads. While this model demonstrated improved stress dissipation during seismic analysis, it showed less favorable performance under wind loading. The findings of this study are important and relevant given Bangladesh's increased seismic susceptibility, especially in the area of the Madhupur Fault near the Rooppur Nuclear Power Plant. This study can thus help others in the judgement of which modelling approach is suitable for a particular research or analysis. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.