Study On Wind Load Characteristics Of A Large-span Atrium Roof Considering Effect Of Connected Buildings

Wind loads are often the control loading for large-span or high-rise buildings.Real buildings are mostly constructed side by side or even connected,and the existence of adjacent buildings may result in considerable interference effect on wind load of the building studied.Therefore,taking the interference effect into account during the investidation of wind load will be helpful to better understand the wind loading variation rules,and furthermore to provide more valuable basis for engineering design and related research workIn this thesis,a complex shaped twin tower-atrium connection high-rise building is taken as an engineering example,and the wind load characteristics of the large-span atrium roof in this connection building are investigated using the wind tunnel test technique.Firstly the mean and extreme wind pressure distribution characteristics on the roof surface under the orthogonal wind directions,the variation trend of shape factors with the roof height,and the wind pressure distribution regulations under the most unfavorable oblique wind directions are examined,and also compared with the corresponding values obtained from the load code.The non-Gaussian characteristics of the extreme wind pressure on the roof surface are then studied.The single probability distribution model and the hybrid model are applied to fit the wind pressure time history respectively.Finally the interference effect of twin towers on the wind load and surrounding flow field of the large-span roof is investigated using the numerical simulation method.The obtained results indicate that the misalignment of twin towers and their one curved facade design make the mean and extreme wind pressures on the roof more unfavorable under the specific oblique wind directions than the orthogonal wind directions,in which the mean and extreme positive wind pressure peaks induced by the former are nearly 1.5 times those of the latter,and the negative wind pressure peaks are about 2 to 2.5 times and 3 to 4 times those of the latter respectively.When considering unfavorable wind directions,the shape factors and extreme wind pressure in most areas of the roof are significantly larger than the values obtained from the load codeNon-Gaussian characteristic of the pressure is not significant when the pressure measuring points are located at the inlet-flow dominating area,but it shows significant when the measuring points are located inside the separation bubble and separation flow,and the interference of twin towers to the airflow would complicate the distribution of non-Gaussian regions on the roof surface.As to the probability distribution fitting of non-Gaussian pressures on the roof,the hybrid model exhibits more effective than the single model,in which the KP(Kernel-Pareto)hybrid model exhibits the best.Under the action of orthogonal wind,the distribution regulation and peak location of the average wind pressure on the roof are changed with existence of twin towers.However,the peak value of wind pressure on the windward side is not changed significantly,while that of the negative pressure on the leeward side decreases by about 20%.Under the action of oblique wind,when the tower is located downstream of the roof or upstream of the windward roof,the roof pressure peak will increase significantly,and when the tower is located upstream of the downwind roof,the negative pressure on the downwind roof tends to be uniform and the peak value is reduced to some extent.