Typhoon-induced Wind Pressure And Wind Vibration Response On Large Terminal Roof Based On Mesoscale/Microscale Coupling

Terminal is a multifunctional facility for air passengers to change from land transportation to air transportation.Lightweight and large-scale construction has caused wind and wind damage to the structural roof system to become more prominent,especially in southeast coastal regions with frequent occurrence of strong typhoons.Compared with type-A monsoon,the near-ground wind field has the characteristics of high turbulence,multiple mutations,strong shear and other wind field for the investigation of typhoon,which can significantly aggravate the turbulence of airflow movement on the near wall of the terminal structure,resulting in the sudden change of average wind pressure on the roof surface,excessive instantaneous extreme wind load,and non-Gaussian characteristics of fluctuating wind pressure.In addition,most of studies on typhoon resistance of structure are mainly based on theoretical analysis and measured data,it is inevitable to produce a too simplified theoretical system to reflect specific wind profile and landing attenuation effect of mesoscale typhoon field truly.In summary,Due to complexity of aerodynamic performances of large-span roof and immature analysis on climate mode and risks of typhoon,there’s no regulation on typhoon-induced wind loads on roof in existing wind-resistant design standards.Therefore,it has important engineering significance to study aerodynamic performance of large-span terminal roof structures under the action of mesoscale typhoons.In this study,this article took a domestic Xiamen International Airport terminal building as the engineering background.At first,near-surface wind field characteristics in the landing process of―Megi‖,including the distribution of potential vorticity,sea level pressure and wind speed,wind direction,wind strength,were analyzed by the multiple grids nesting technology in mesoscale mode.The simulation results of mesoscale typhoon megi were verified by comparing the measured data.Then,the three-dimensional solid model of long-span terminal structure under different wind direction angle was established.Combined with the Mesoscale / Microscale Coupling numerical simulation technology and the traditional large eddy simulation technology,the three-dimensional wind field simulation of the terminal structure under typhoon and type-A monsoon conditions was carried out respectively.The mechanism of flow around the two types of wind field was systematically explained from velocity streamlines,vorticity distribution and turbulent kinetic energy distribution in typical section of the structure.On this basis,the spatial characteristics of mean wind pressures,fluctuating wind pressure and extreme wind pressure on roof surface under monsoon and typhoon conditions with different wind direction angles were compared.Probabilistic Statistical Characteristics,non-Gaussian,correlation,coherence,power spectral characteristics of typical areas of terminal under different working conditions were analyzed emphatically.Finally,the full transient method was used to compare the wind vibration response of large terminals in monsoon and typhoon conditions at different wind angles.Based on four typical target responses such as displacement,axial force,bending moment,and torque,the typhoon and good state were studied.The distribution model of wind vibration coefficient in typical area of the roof of the terminal under the wind,and the comparison of the overall wind vibration coefficient for each working condition was suggested.Research shows that the WRF/CFD coupling mode can simulate typhoon field in terminals effectively.Mesoscale typhoon can increase the mean wind pressures,fluctuating wind pressure and extreme wind pressure on roofs significantly,with the maximum increase of 58%,126% and 39%.The non-Gaussian characteristics of wind pressures on terminal roof under typhoon conditions are influenced greatly by wind direction angle,but the correlation of time-frequency domain of wind pressures is weak.In structural design,it is recommended to consider different wind direction angles and different response target wind vibration coefficients to replace the value of a single unified wind vibration coefficient in the code,and the amplification effect of the wind vibration coefficient of the terminal building under the action of strong wind / typhoon cannot be ignored.In this paper,mesoscale weather forecasting models,computational fluid dynamics,and finite element analysis were used to study the wind load and wind vibration response characteristics of typhoon-induced large-scale terminal buildings in detail.The relevant results can be the structural resistance of such large-span terminal buildings.Typhoon design provides a reference basis,which is of great significance for preventing typhoon disasters and reducing strong wind / typhoon investment budgets.