超高层建筑三维风振的时域分析方法研究

以436m高的大连国贸中心大厦为例,着重介绍通过时域分析确定超高层建筑三维等效静风荷载的方法。首先结合风洞测压试验,采用广义坐标合成法和等效风振力法得出各层的位移响应时程和等效荷载时程。然后根据极值统计理论和相关分析确定等效目标,在等效荷载时程中与目标最匹配的值即可作为等效静风荷载。由此得出的各层荷载自动包含了不同方向的组合以及荷载空间相关性,不但可实现等效目标,其他相关响应通常也可达到最大值。由于采用了高效的广义坐标合成法,该时域分析方法在精度相同的前提下,计算量比传统的频域完全二次型组合(CQC)算法还要小。对大连国贸中心大厦的计算分析验证了该方法的有效性。分析结果表明大厦的横风向振动非常显著,在小角度斜吹的情况下,弱轴方向将由于强烈的横风向振动出现响应与荷载的最大值。

Time-domain analysis method for the wind-induced 3D responses of super high-rise buildings

Taking the 436m high Dalian International Trade Center as an example,a time-domain analysis method was introduced to obtain the 3D equivalent static wind load(ESWL) of super high-rise buildings.With the adoption of the Generalized Coordinates Synthesis and the equivalent wind-induced force methods,the displacement and equivalent wind load time history at each floor were derived from the wind pressure test.Subsequently the equivalent target was determined by the extreme statistical theory and cross-correlation analysis.The best match with the target in the equivalent wind load time history could be identified as the ESWL.Such ESWL was a combination of the wind load in different directions and the space correlation of the wind load was included naturally.Under the action of the ESWL,the predefined target was achieved and the corresponding response would also be close to its extreme values.Benefitting from the high-efficiency Generalized Coordinates Synthesis method,the calculation burden of such analysis was lower than the traditional CQC(Complete Quadratic Combination) method without loss of accuracy.This approach was verified by an analysis of the example.The results showed that the wind from a small angle with the strong axis resulted in the maximum response and the ESWL along the weak axis because of the prominent across-wind vibration.