Research On Monitoring And Calculation Methods Of Time-Varying Temperature Field And Thermal Effect For Supertall Structures

Supertall buildings are dazzling pearls in modern urban agglomerations,and they are also the mainstream choice for future urban development.In recent years,China has become the main battlefield for the planning or construction of supertall buildings in the world.Various supertall buildings with high structure height and complex structure are emerging in an endless stream.Supertall buildings will inevitably be affected by the ambient temperature.Continuous and dynamic ambient temperature will cause the structure to form an uneven temperature field and thus generate periodic internal forces and deformations.In severe cases,it may even cause damage or destruction of structural components,which poses a greater safety hazard.Therefore,in order to fully understand the mechanical state of supertall structures under the action of ambient temperature,this paper has carried out research on the monitoring and calculation methods of the time-varying temperature field and temperature effects for supertall structures,mainly including the following:(1)The establishment of an actual supertall structure’s temperature monitoring system and the analysis of monitoring data.The temperature monitoring system for the 335-meterhigh Wuhan Yangtze River Navigation Center was established,including the selection of monitoring content,system layout,data collection,transmission and storage,etc.The longterm,short-term and spatial distribution characteristics of temperature monitoring data and strain monitoring data were analyzed.The correlation between temperature and strain was also studied.(2)Research on the calculation method of time-varying temperature field for supertall structure based on "virtual sun method".Firstly,a parametric heat conduction finite element modeling method was proposed for supertall structures,and then a radiation calendar timing system was introduced to improve the relative position calculation formula of the sun.A structural model and a virtual sun were established on ANSYS platform.The radiation and shadow surface were discriminated by hemi-cube method.Different thermal boundary conditions were applied and the temperature field was calculated automatically.Finally,the feasibility of "virtual sun method" was verified by taking Wuhan Yangtze River Navigation Center as an engineering example.(3)Research on the derivation and application of the theoretical formula of temperature-induced strain for supertall structures.Drawing lessons from the derivation of the temperature-induced strain of the bridge structure,the theoretical formula of the temperature-induced strain of the supertall structure under the action of the non-uniform temperature field was derived,including the column temperature-induced strain formula based on the generalized cantilever column model and the core tube temperature-induced strain formula based on the multi-layer variable cross-section cantilever column model.The formula was verified by numerical examples.Finally,the temperature-induced strain formula was applied for the calculation of temperature-induced stress and the temperatureinduced strain.(4)Research on calculation model and prediction method of temperature-induced deformation for supertall structures.Based on the assumption that the supertall temperatureinduced deformation mode is curved,the mathematical relationship between strain and deformation was derived using the principle of virtual work.Combined with the temperature-induced strain formula,the temperature-induced deformation theoretical model for the supertall’s main structure was deduced.Then,the partial least-squares regression(PLSR)method was adopted to calculate the temperature-induced deformation coefficient.Finally,based on the numerical example of Wuhan Yangtze River Navigation Center,the effectiveness of the PLSR method in solving the temperature-induced deformation regression model was verified.The temperature-induced deformation calculation was successfully realized and forecast.This paper conducts a systematic study on the monitoring and calculation of the timevarying temperature field and temperature effects for supertall structures.It not only provides a wealth of on-site monitoring data,but also establishes a complete set of calculation methods for the temperature effects on supertall structures,which provides rich technical and theoretical guidance for design,construction and research personnel in China.