Research on wind-induced vibration response of cooling tower considering structure-pile foundation-soil coupling effect

Super-large cooling tower is a kind of typical high-rise, large-span and wind-sensitive structure. The interaction between the lower foundation structure of the tower and soil mass influences wind-induced vibration performances of the tower body significantly. Nevertheless, the structure-pile foundation-soil coupling effect of the cooling tower is ignored in existing norms. The value of wind-induced vibration coefficient cannot accurately reflect the wind-induced vibration performances of the structure under wind load. Three different models of structure-pile foundation-soil finite element coupling effects were built for a systematic quantitative study of influences of tower structure-soil coupling modeling techniques on the dynamic characteristics and wind-induced vibration responses of the cooling tower. These three models are direct solidification between the herringbone columns and soil mass (Model I), coupling effect of herringbone columns, circumferential base (beam element) and pile foundation (soil spring) (Model II), and coupling effect of herringbone columns, circumferential base (solid element), pile foundation (base element) and soil mass (Model III). A comparative analysis on displacement of tower body and responses to internal force under wind loads was carried out. The value standard of wind-induced vibration coefficient under different target responses was discussed. Results demonstrate that the structural fundamental frequency of Model I is 0.884Hz, while the fundamental frequencies of Model II and Model III are decreased by 7.89% and 18.8%. For the maximum displacement of cooling tower under dead load and static wind load, Model I <Model II<Model III.The maximum error of response extremum of three cooling tower models to the meridian axial force under pulsation wind load is only 2.65%. The maximum means of radial displacement and circumferential bending moment are Model I<Model II< Model III.The Model I shows the lowest wind induced vibration coefficient under the response goals of radial displacement and circumferential bending moment, followed by Model II and Model III successively. On this basis, a value standard of two-dimensional interval wind-induced vibration coefficient for super-large cooling tower considering structure-pile foundation-soil coupling effect was established, which could provide scientific reference for wind-resistant design of similar structures.