| The construction of high-rise buildings in cities have become increasingly intensive because of the rapid urbanization in China.To guarantee the reliability of high-rise buildings,wind resistance is regarded an integral component in the design and construction of building structures.The wind pressure coefficient of buildings is an important parameter of wind resistance calculation.Existing research methods utilizing wind pressure coefficients mainly include wind tunnel tests,field measurements,and numerical simulations.Wind tunnel tests can simulate the wind fields of atmospheric boundary layers better than the other methods,and tests may be repeated many times.Compared with onsite tests,wind tunnel tests take lesser time to complete and thus have been mainly considered for the wind resistance research of buildings.However,wind tunnel tests in China are constrained by a number of limitations.On the one hand,although there are plenty of wind tunnel laboratories in China,their locations are not evenly distributed,as in the case of Henan versus other areas.On the other hand,although the driving process of vehicles can produce a wind effect,the results of wind tunnel tests are essentially driven by the wind of large fans.To ensure a convenient,economical,and reliable wind resistance research methodology,the wind tunnel test is applied to a scale model of a building roof test platform.Then,the wind pressure coefficient of the scale model is tested by using the relative wind field generated by a driven vehicle.This study particularly focuses on the wind pressure coefficient of a building by using the driving wind of the vehicle.Firstly,the hardware system for the transiting test method of the wind pressure coefficient is developed by using driving wind.The development of the hardware system includes the design of the transiting test device and the assembly of the apparatus and equipment.To ensure wind speed stability during the transiting test,a vehicle with a fixed speed cruise function is selected.Then,to properly affix the scale model on the roof in anticipation of different wind direction angles,a physical test platform for the driving vehicle is designed and the platform is assembled with the vehicle.Different heights are set for the Pitot tube measurement frame to manipulate the different roof heights and the wind speed characteristics.A simple integration technique for the wind speed(Pitot tubes),vibration(vibration pickup),and wind pressure(wind pressure sensors)testing instruments and other devices is adopted to achieve simultaneity in operations.The test steps of the vehicle are studied,and the suitable test road conditions are selected to ensure a stable working environment for the hardware system of the transiting test.The result of the study shows that the speed of the test vehicle is stable and can meet the requirements of the test.The result of the study shows that the speed of the test vehicle is stable and can meet the requirements of the test.The physical test platform can maintain a horizontal state and the wind direction angle can be adjusted.Designating a measurement frame for the Pitot tube and adjusting the Pitot height and position functions are applicable methods for the transiting test.The wind speed,vibration,and wind pressure test instruments can operate simultaneously to derive the wind pressure coefficient of the building.The test steps and road conditions of the transiting test meet the requirements of the test,and the instruments and equipment can operate steadily during testing.Secondly,a data processing software system is developed for the standard model of the wind pressure coefficient of the building.The software system mainly includes the pre-processing and processing of wind pressure data.Data pre-processing,which is developed using MATLAB,comprises two major modules: singular value elimination and data smoothing.Data post-processing,which is also developed using MATLAB,converts the voltage signals obtained from the data acquisition software to wind pressure signals.The mean wind pressure coefficient of 20 measuring points is considered for simultaneous calculation.Then,the time history and frequency domain of the wind pressure measurement points are analyzed.The results are as follows.The data processing software can eliminate abnormal data,and the data smoothing processing module can decrease random errors.The software can effectively pre-process the test data and improve data accuracy.Subsequently,the data post-processing software can easily calculate the mean wind pressure coefficient of multiple measuring points.Both processes can improve the testing efficiency of the transiting test method used for the standard model of the building wind pressure coefficient.Finally,the feasibility of the standard model used for the transiting test is verified.The self-designed Pitot tube measuring rack is used to study the wind characteristics at different roof heights and vehicle speeds(50,72,and 90 km/h).The effect of vehicle vibration on wind speed,which is measured by a transiting test with speed of 72 km/h,is determined.The dynamic pressure data corresponding to the vehicle speed of 72 km/h and the stability of three typical points of wind pressure data are derived,and the results of the three typical points of the pressure coefficients for the different speeds are analyzed.The vehicle speed of 72 km/h is selected for the roadster test method.Then,the mean wind pressure coefficients of the 20 test points of the CAARC standard model applied with the same speed of 72 km/h is used for the transiting test method.Findings from the validation show that the transiting test method is suitable for the wind pressure coefficient of the standard model.The results are as follows.When vehicle speed is increased,the evenness of the wind speed at different roof heights presents an increasing trend.The test speed of 72 km/h is appropriate for pressure measurement in consideration of the safety of vehicles and other factors.The influence of vehicle vibration on wind speed is minimal.In addition,the influence of vehicle vibration on wind speed at different wind directions can be ignored.The dynamic pressure time history curve is stable in relation to the different wind directions,and the wind pressure stability and the burr phenomenon are both improved as shown by the data.Different vehicle speeds generally have no influence on the mean wind pressure coefficient of the typical measurement points of the CAARC standard model,and the transiting test method can be repeated.Except for a few individual points,the standard wind pressure coefficient of the CAARC standard model is in good agreement with the wind tunnel test data.The transiting test method for the standard wind pressure coefficient of the CAARC standard model is feasible for driving wind. |
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