超高层建筑顺风向加速度的干扰效应研究

INTERFERENCE EFFECTS ON ALONG-WIND ACCELERATION BETWEEN TWO HIGH-RISE BUILDINGS

通过刚性模型同步测压风洞试验,获得了各种干扰工况下受扰超高层建筑表面风荷载,并对不同折减风速下的超高层建筑顶部顺风向加速度响应进行计算,详细研究了不同截面宽度、不同高度施扰建筑干扰下受扰建筑顶部顺风向加速度干扰因子包络值的分布规律以及涡激共振干扰机理,并进一步分析了不同截面宽度、不同高度建筑施扰下的干扰因子包络值之间的相关特性。结果表明,由于涡激共振的影响,宽度比为0.4及0.6时的最大干扰因子包络值分别达到2.3和2.06,在工程结构抗风设计中需重点关注高度相仿但截面相对较小的施扰建筑的潜在干扰影响。在非共振情况下,随着宽度比(施扰建筑与受扰建筑截面宽度之比)的增大,放大干扰效应显著的区域越来越大,相应的最大的干扰因子包络值也呈增大趋势。高度比(施扰建筑与受扰建筑高度之比)为1.2和1.0时的干扰因子包络值之间的相关系数达到91%,当施扰建筑高度达到受扰建筑的1.2倍后,包络干扰因子的分布基本不变。

External pressures on the surfaces of principal building were obtained by a series of wind tunnel tests on rigid models. Acceleration responses of the principal building were calculated at different reduced velocities. Envelope interference factor （EIF） distribution and vortex-induced vibration mechanism of the along-wind peak acceleration were detailed studied in different breadth ratios Br （Br=Bi/Bp） and height ratios Hr （Hr=Hi/Hp）. Furthermore, correlation analyses were carried out for the envelope interference factors EIF in different breadth ratios Br and height ratios Hr. Results show that the maximum values of EIF are 2.3 and 2.06 when Br equals 0.4 and 0.6 respectively, because of the influence of vortex-induced vibration. In wind resistant design process, the amplification effect of along-wind acceleration should be paid more attention when Br is small. In non-resonance cases, the remarkable amplification region becomes larger with the increase of Br, and the corresponding maximum values of ElF also gradually increase. Correlation coefficient of EIF between Hr =1.2 and 1.0 is up to 91%, and the distribution of. EIF nearly keeps unchanged when Hr ≥1.2.