Wind Load Of Curved Large Span Roof Envelope And Wind Vibration Response

Rapid social progress and great changes,Owing to the low self-weight,large span,free shape and convenient construction,the long-span roof structures are widely used in theaters,gymnasiums,halls,assembly halls,etc.These characteristics leads to their high sensitivity factor to wind.Wind disaster triggers structural cracking and collapse,and the stress of joints increases.At present,there are some norms in principle for the structural design of long-span roofs at home and abroad,and there are many studies on the envelope structure of curved long-span roofs.However,due to the different shape of long-span structures,it has a great impact on the distribution of structural wind load,so it is difficult to unify and clarify the provisions and methods,However,wind-resistant design and wind mitigation of long-span structures are the key factors related to engineering safety.Under the circumstances,it is of great necessity to study long-span structures.Taking the curved long-span roof of a theater as an example,this paper systematically studies the wind load distribution and wind-induced vibration response of curved long-span roof.the main contents are as follows:To ensure the accuracy of the numerical simulation,a wind tunnel test with similar conditions was referred to and the equivalent conditions were established by numerical simulation.The wind pressure distribution was compared,and the results were found to be close.On this basis,the wind load distribution on the surface of the curved large-span roof and the wind speed vector diagram were obtained by numerical simulation of this large-span roof using FLUENT software.Furthermore,the distribution of wind load was also studied under different conditions: the wind direction angle was constant,and six different wind speeds were selected for simulation according to local conditions.When the wind speed was constant,four wind directions were selected for simulation.Then,the wind load distribution,wind speed vector diagram,wind pressure factor,and shape factor of the curved long-span roof surface were obtained.It is found that the wind pressure factor in the edge and corner areas is larger than that in other areas.There are many positive pressure areas on the upper surface of the roof under the wind direction of 0°and 90°,and the shape factor of wind load has few variations,which indicates that this curved long-span roof can effectively reduce the wind load and make the roof suffer less negative pressure areas.Moreover,the modal analysis of the large-span roof of the theater was carried out by ANSYS software to analyze the wind-induced vibration types of the large-span roof,and the frequencies of first 40 orders were obtained.It is found that the high-order vibration modes of the roof plays a leading role.To simulate the pulsating wind,the AR method of MATLAB software was applied to simulate.Meanwhile,to ensure the accuracy of the simulation value,Davenport spectrum was selected as the target spectrum,and the wind speed time history curve was obtained,which was transformed into the wind pressure time history curve.The wind pressure time history was applied to the divided area,and the time history curve of regional displacement was obtained.By calculating its displacement mean and mean square error,the dynamic response of the roof was analyzed.It is concluded that with the increase of regional height,the mean square error of the displacement of the roof joint also increases,with the maximum displacement of 25～30m,while the maximum mean and mean square error being-0.07702 m and 0.0558,respectively.This paper summarizes the wind-resistant design and vulnerable parts of such long-span roofs,puts forward solutions to wind-induced failure,and proposes measures to improve wind-resistant performance mainly from structural measures and aerodynamic measures.