Study On Wind Load Characteristics And Wind Effect Of Irregular Shape Long-span Roofs

With the advancement of science and technology,the continuous development of the economy,more and more large-span flexible roofs with beautiful appearance and novel structure are widely used in theaters,conference centers,hangars,stadiums and other large public buildings.With larger space,the structure of the large-span roof can only continue to develop in a higher,larger and lighter direction,which makes the wind effect of the large-span roof structure more prominent,and the loss and impact caused by the wind disaster is more serious.Therefore,the study of the wind effect of the complex large-span roof structure is one of the driving forces for the development of the roof structure in the direction of super large and soft.At present,there are few researches on the wind effect of complex large-span roof structures at home and abroad.This paper studies the wind load and wind-induced vibration characteristics of the large-span roof structure with the large-span roof truss structure of a conference center in Shaanxi as the engineering background.Combined with the results of the wind disaster investigation,it provides effective suggestions for the wind-resistant design of the large-span roof structure.The details are as follows:1.Wind pressure distribution characteristics of large span roof structures.Based on FLUENT software,the average wind pressure coefficient and body shape coefficient of the large-span roof surface of a conference center in Shaanxi were analyzed in detail.The effects of wind direction angle,wind speed and aspect ratio on the wind load characteristics of the large-span roof surface were discussed.The results show that when the wind direction angle is 0 degree,the average wind pressure coefficient on the roof surface is the largest;when the wind direction angle is fixed,the net wind carrier type coefficient of the cantilever corner increases with the increase of wind speed.It is recommended to consider the local wind carrier type coefficient.In order to prevent damage under extreme weather;when the plane size of the building is fixed,as the aspect ratio increases,the negative wind pressure on the roof surface increases.It is recommended that China's load specification consider the aspect ratio to the surface of the large span roof.The influence of wind pressure makes the wind-resistant design of the large-span roof more reasonable.2.Wind-induced vibration response analysis of large-span roof structure.Based on ANSYS software,the finite element model of the large-span roof structure of a conference center in Shaanxi was established and the modal analysis was carried out.The natural vibration frequency of the large-span roof structure is 0.1?1,which is close to the pulsating wind speed and the vibration caused by the pulsating wind.It can not be ignored;the pulsating wind speed time history is simulated by MATLAB software,and the pulsating wind speed time history is converted into the pulsating wind pressure time history and loaded onto all the nodes of the truss of the large span roof structure truss to study the wind vibration of the large span roof structure.Response characteristics.The analysis results show that the vertical displacement wind vibration coefficient of the large span roof is larger than the lateral displacement wind vibration coefficient.The large span roof structure is mainly vertical vibration;the overall variation of the displacement wind vibration coefficient of the large span roof structure Not large,it is recommended that China's load code to calculate the equivalent static wind load for the large-span roof structure using the displacement wind vibration coefficient.3.Wind resistance research on large span roof structure.Based on the field investigation results of the large-span roof damage caused by wind damage and the wind load characteristics of the large-span roof structure of a conference center in Shaanxi,the problems in design and construction of the large-span roof structure were analyzed and summarized.The large-span roof structure was analyzed.Wind resistance analysis was carried out and several wind-resistant concept designs and wind-resistant construction measures were proposed.