Study On Wind Load Characteristics Of Large-span Overhanging Curved Roof

With the large-scale development of high-speed railways in China,the construction of high-speed railway passenger stations has gradually increased,and more unique in shape.The large span roof structure with large space,many functions,unique shape and other characteristics will often be used as the choice of high-speed railway station,but this type of structure has a light self-weight,vertical cycle is large,damping is small and other significant characteristics,belong to the wind load sensitive structure,so the wind load is one of the important factors affecting the destruction of the large span roof structure.At the same time,the development of commercial,residential and office buildings around high-speed railway passenger stations will be the development trend of comprehensive construction of high-speed railway passenger stations,so it is important to study the interference effect of surrounding buildings on the railway station roof structure.In this paper,the wind load distribution characteristics of the large-span overhanging curved roof structure and the interference effects of buildings of different heights and building groups on the roof wind load are studied mainly through wind tunnel tests and CFD numerical simulations,taking the railway station building of Qingdaoxi Station as the research object.The main research contents and conclusions are as follows:(1)Through the rigid model wind tunnel test,the wind pressure time range of each measurement point collected under 36 wind directions was averaged to obtain the average pressure coefficient of each measurement point,and the extreme wind pressure and body shape coefficient were calculated from this,and then the law of the three was analysed to obtain the characteristics of the wind pressure distribution on the roof surface of the station building.The wind pressure distribution of the roof is obviously influenced by the wind angle and the body shape of the roof,the net wind pressure of the roof is mostly negative under different wind angles;the typical parts of the roof such as the ridge,the edge of the roof and the variable section are the main areas where there are more wind load effects gathering obviously,under the unfavourable wind angle,the body shape coefficient of these parts exceeds 1.0,therefore,the design should focus on strengthening the wind uncovering resistance of this location.(2)The CFD numerical simulation method was used to calculate the structural model of the large-span overhanging curved roof,and the feasibility of the CFD numerical simulation method was verified by comparing the wind tunnel test results.The results show that the numerical simulation results are in high agreement with the wind tunnel test results,thus verifying the feasibility and reliability of the numerical simulation method in the study of wind pressure distribution in large-span overhanging curved roofs.(3)Further simulations were carried out to add single buildings and building clusters of different heights around the railway station at Qingdaoxi Station to investigate the interference effect of the surrounding buildings on the large-span overhanging curved roof,and to give reference advice on the design operation and maintenance by analysing the average pressure coefficient and interference factor of the disturbed roof under different wind angles.Under the disturbance of single buildings with heights of 40 m,100m and 150 m,the maximum increase in the average pressure coefficient of the east station roof is 8%,10% and 18%,the maximum increase in the average pressure coefficient of the main station roof is 13%,100% and 149%,the maximum increase in the average pressure coefficient of the west station roof is 46%,106%and 218%;under the disturbance of single buildings with heights of 40 m,100m and 150 m The maximum increase in the average pressure coefficient of the east station roof is-4%,33% and77%,the maximum increase in the average pressure coefficient of the main station roof is 102%,194% and 283%,and the maximum increase in the average pressure coefficient of the west station roof is 29%,417% and 493% under the disturbance of the building group of 40 m,100m and 150 m.When new buildings are developed around the station house,the wind resistance of the eaves should be further strengthened if the new building is of similar height to the station house.When the height of the new building is much higher than the height of the station house,not only should the eaves be strengthened,but the overall reinforcement of the roof should be considered,especially at the ridge of the east and west station houses to prevent the roof panels from falling off.Similarly,when new buildings with large span overhanging curved roof structures are built around other buildings,the wind loads applied to the eaves,ridge and corners should be increased appropriately during design.