高层建筑风载体型系数取值的探讨

Discussion of wind load shape coefficient over high-rise buildings

采用计算流体动力学软件FLUENT,对不同截面尺寸和高宽比的高层建筑模型表面的平均风压分布进行了数值模拟,探索了上述因素对立面风载体型系数sμ的影响规律.在数值模拟方法获得平均风压系数的基础上,分别利用规范方法(体型系数取总体加权平均)和精确方法(体型系数沿立面变化)计算各模型的基底剪力Fx和基底倾覆力矩My,发现规范方法将会高估模型的基底剪力和基底倾覆力矩,使设计偏于保守.为了获得合理的风荷载,又能包络表面局部的最不利风荷载,根据sμ沿立面的分布和变化规律,提出了轮廓尺寸为100 mm×100 mm×600 mm的高层建筑模型(实际尺寸为50m×50m×300m)按立面分区和取值的建议.

The mean wind pressure distributions of high - rise building models with different sectional dimension and height to width ratio are numerical simulated by the CFD software FLUENT, and the influence parameters of wind load shape coefficient（μs） on the surfaces of models are investigated. Based upon the data obtained from the numerical simulation, the base shear force and base moment of the models computed by the code method （the wind load shape coefficients are weighted averaged on the surface） and the exact method （the wind load shape coefficients are variable along the surface） are compared. The results indicate that the code method will overestimate the force because the even distribution of μs is not true. In order to obtain reasonable wind loading and cover the worst cases, the wind load shape coefficients on surfaces of the 100 mm × 100 mm ×600 mm model （the dimension of the real building is 50 mm ×50 mm ×300 m） are partitioned according to their distribution feature and changing regularity.