Study On Deformation Monitoring Method Of Large Area Eaves Board Of High-speed Railway No-plateform-column Canopy With Distributed Optical Fiber

No-plateform-column canopy has been widely used in high-speed railway stations in China.Under the long-term influence of load,roof panels,eaves board and other positions easily warping and loosening.If there is no timely repairing,once it falls or is blown by the wind and put on the power grid,it will have a very serious impact so that affect the safety of railway’s operation.In the daily maintenance and repair of the canopy,there is still a lack of time and means: due to the skylight point of high-speed railway line,the maintenance operation time is extremely limited;although the abnomal condition of the top and bottom of canopy can be found through manual visual inspection,the interior of the canopy is basically in the blind area.In addition,the current maintenance means can not quantitatively evaluate the damage or destruction of the roof panel,eaves board and other positions of the canopy.In order to monitor the damage status of the canopy plate structure,this paper takes a no-plateform-column canopy eaves board of a high-speed railway station as the research object.Based on the principle of fiber grating and distributed fiber sensor,through finite element simulation and model test,the deformation monitoring method of canopy eaves board in large area is studied.The main research work and results are as follows:(1)According to relevant specification and the force form of canopy eaves board that field measurement when the high-speed railway passes through the station,the aerodynamic force distribution of the train passing through the canopy at a speed of300km/h is analyzed by using finite element software,and the load arrangement form,position and size are determined;(2)Finite element model is established,according to the modal vibration mode of eaves board and load displacement changes of eaves board under the static and dynamic,set the fiber optic sensor layout and paste solution,and has carried on the experiment,through analysising the data,the fiber layout scheme can effectively monitor the area of damage and deformation on the eaves board,and through the changing rate of fiber optic strain can determine the number of rivet head loose;(3)The effect of stiffener on the eaves board is studied.It is shown that the stiffener can restrain the deformation and deformation transmission of the eaves board obviously,and can prevent the expansion of riveting damage area to some extent;(4)Combined with the relevant specification in the "Steel Structure Design Standard",the finite element simulation data and the test monitoring results,the early warning threshold is determined to realize the deformation overrun warning,which puts forward a new monitoring idea and a method for the deformation monitoring of large area canopy eaves board,and has important significance for the protection of the safety of canopy operation,but the primary warning value is small,and the overrun warning under the small damage that is realized requires the quasi-distributed series of FBG.