Aerodynamic Study Of1000m-high Super Tall Buildings

In worldwide construction booms of super high-rise buildings, breakthroughs of building height appear continuously. Construction of kilometer-level super high-rise buildings will be placed on the agenda in China. Recent studies have shown that for super high-rise buildings, wind loads and vibrations on structures caused by strong wind are most important control indicators, the kilometer-level buildings more so. As height exceed600m, wind fields around buildings and structural characteristics change greatly, bringing changes of aerodynamic forces and wind-induced responses. Based on the background, this article first determines the wind field model for kilometer-level super high-rise buildings, then carrys out the research on aerodynamic forces of kilometer-level buildings by wind tunnel testing. The main contents are as follows.(1) Give a systematic summarization to mathematical models of wind fields in the ABL, point out that, at present stage, the D-H model and the model of hurricane boundary layer put forward by Vickery et al. respectively are models with greater applicable heights for normal and typhoon climates. Based on these two models, the author has simulated6kinds of wind fields in BJTU’s boundary layer wind tunnel.(2) In typical wind fields of normal and typhoon climates, HFFB tests have been conducted for5rigid models(H=600,800,1000,1200,1500m) with square-column shapes and slenderness ratio of8. Characteristics of aerodynamic base moment coefficients (mean and RMS value, probability distribution, normalized PSDs) and variation with building height are analyzed. Based on the quasi-steady hypothesis, give a summary to the method of estimating base moments according to profiles of wind fields, and verify its rationality. Based on the assumption of ideal mode shapes, wind-induced responses’variation trend with building height (from600m to1200m) is predicted. Impacts of structure’s natural period, wind speed and damping ratio on wind-induced responses are analyzed.(3) In6kinds of wind fields on behalf of different climates and different topographic types, HFPI tests have been conducted for rigid model of1km buildings. PSDs and correlations of wind pressure coefficients in different elevations are analyzed so as to conclude the formation mechanism of aerodynamic forces. On this basis, time-and frequency-domain analysis have been done for drag, lift and torque coefficients of kilometer-tall building. Influence of characteristics of wind fields on aerodynamic forces are analyze from two aspects:characteristics of profiles and the overall level of turbulence intensity.