Wind Loads,Wind-Induced Response And Equivalent Static Wind Load On Canopy Of Small Or Medium-sized Railway Station

The canopy of railway station is a fully open long-span structure with light weight and large flexibility,and the structure is sensitive to wind loads.Although small or medium-sized railway stations are small in scale,they are widely used in engineering application.If wind tunnel tests and wind resistance analysis are conducted for each project,it will be time-consuming and economically costly.It is of great significance to conduct a systematic study on such structures and to give the determination methods of wind loads and equivalent static wind loads.At present,there is a lack of relevant research work.In this paper,the influence of the span of canopy,the width of the middle opening,the height ratio of the station building and canopy on the wind loads of the canopy of small or medium-sized railway station is systematically studied by wind tunnel tests.Then,employing the random vibration theory and the generalized force spectrum fitting formula based on wind tunnel tests,the analytical expressions of wind-induced vibration response and equivalent static wind loads of canopies with single span and three span frame structures are derived.The main contents of this paper include the following aspects:(1)Through a series of investigations on the layout of station yard,platform width,track size,streamline design,plane size of station buildings and structural systems of small or medium-sized high-speed railway stations,the parameter variables of platform canopy of small or medium-sized high-speed railway station and the commonly used range of the these parameters are determined.(2)In the simulated wind field of type B terrain,wind tunnel tests are carried out on six canopy roof models considering different single side canopy spans,middle opening widths,height ratios of the station building and canopy,and the distribution of mean wind pressure coefficients,root mean square coefficients and extreme wind pressure coefficients on the roof surface under typical wind directions are analyzed.At the same time,the variation of wind load characteristics under the typical section with differenct spans of one side canopy,the widths of the middle opening and the height ratios of the station building to the canopy are studied.(3)For the platform canopy with single span frame structure,by comparing the wind-induced response results calculated using different vibration modes,it is found that the second vibration mode dominates the vertical displacements and member stresses of the single span frame.Then,based on the random vibration theory and the generalized force spectrum fitting formula based on wind tunnel tests,the analytical expressions of wind-induced vibration response and equivalent static wind loads of single span frames are derived,and the accuracy of the analytical formulas is verified.(4)For the platform canopy with three span rigid frame structure,it is found that the first vibration mode dominates the horizontal displacements and the stresses of rigid frame column,and the second vibration mode dominates the vertical displacements and the stresses of the frame beam.Based on the random vibration theory and the generalized force spectrum fitting formula based on wind tunnel tests,the analytical expressions of wind-induced vibration response and equivalent static wind load of three span rigid frame are derived,and the accuracy of the analytical formulas is verified.