Considering The Aerodynamic Coupling Effect On Wind Resistance Study Of Tall Buildings

With the rapid increase in height and application of light and high-strengthmaterial, the structures of high-rise buildings present characteristics of low damping,large flexibility and low natural vibration frequency, which make the wind loads andthe wind-induced vibrations be the main controlling factors for the design of high-risebuildings. Previous studies show that damping has significant effects on the dynamicresponses of high-rise buildings. In addition to the structural damping, the influenceof aerodynamic damping on the wind-induced dynamic responses of high-risebuildings cannot be ignored.For a high-rise building, three kinds of test models were designed andmanufactured for wind tunnel test research in the study. And systematic studies on theequivalent static wind loads and wind-induced dynamic response of the high-risebuilding were conducted based on the results of aeroelastic wind tunnel test, highfrequency force balance test and synchronous multi-pressure scanning technique test.Effects of aerodynamic coupling on the equivalent static wind loads and wind-induceddynamic response of the high-rise building were studied by comparing the differencesamong the three kinds of test results.With the obtained time-history responses of acceleration and displacement of thestructure from the aeroelastic wind tunnel test, we could identify the structuraldynamic characteristics by spectral analysis and filter technique. The cross correlationfunction of vibration response which have been gotten from the natural excitationtechnique method (NExT), and combined with the ARMA method, made a modeidentification analysis in the time domain. Under the premise that the fitting curve ofthe model had been in good agreement with the experimental curve, changing themodes order tried to reduce the noise interference to obtain the aerodynamic dampingof the structure. Then, we could draw the curves of across-wind and along-windaerodynamic damping changing with wind speeds under0°and90°wind direction. Instrong wind situation, filter technique was used in analyzing the along-windtime-history acceleration response to eliminate the influence of the across-windenergy transfer. In the process of analyzing the responses of the structure, we foundthat wind speed and width of windward side had a great influence on the correlationof the responses. And the vortex-excited resonance existed in the process of identifying the aerodynamic damping.In the pressure test, the research works contained the studies of thecharacteristics of wind pressure distribution and along-wind and across-windwind-induced responses. It turned out that the wind-induced responses would changea lot under the consideration of the effect of aerodynamic coupling. In the study ofacceleration response, the results of the rigid pressure test considering theaerodynamic damping effect were in conformity with the results of the aeroelasticwind tunnel test, which validated the correctness of the aeroelastic wind tunnel test.In addition, a beat phenomenon was found during the study, which had an effect onthe increase of the along-wind response and decrease of the across-wind response ofthe structure.During the research on the high-frequency-force-balance test for base momentspectra, a “two peaks” phenomenon was found, which could greatly affect the testresults. After eliminating the resonance peak, there was an apparent decline in rootmean square of base pulsation bending moment coefficient. It proved that the usage ofa model made of light-weighted and high-strength material was very important. Atlast, by comparing the acceleration responses of the high-frequency-force-balance testwith the results of the aeroelastic wind tunnel test, a further verification was made toverify the accuracy of the aeroelastic wind tunnel test and the necessity of consideringthe aerodynamic coupling effect on the wind-resistant design of flexible high-risebuildings.