Wind barriers are commonly adopted to prevent the effects of wind on high-speed railway trains,but their wind-proofing effects are greatly affected by substructures.To investigate the effects of wind barriers on the a...Wind barriers are commonly adopted to prevent the effects of wind on high-speed railway trains,but their wind-proofing effects are greatly affected by substructures.To investigate the effects of wind barriers on the aerodynamic characteristic of road-rail same-story truss bridge-train systems,wind tunnel experiments were carried out using a 1:50 scale model.Taking a wind barrier with a porosity of 30%as an example,the aerodynamic characteristics of the bridge train system under different wind barrier layouts(single-sided and double-sided),positions(inside and outside)and heights(2.5 m,3.0 m,3.5 m and 4.0 m)were tested.The results indicate that the downstream inside wind barrier has almost no effect on the aerodynamic characteristics of the train-bridge system,but the downstream outside wind barrier increases the drag coefficient of the bridge and reduces both the lift coefficient and drag coefficient of the train due to its effect on the trains wind pressure distribution,especially on the trains leeward surface.When the wind barriers are arranged on the outside,their effects on the drag coefficient of the bridge and shielding effect on the train are greater than when they are arranged on the inside.As the height of the wind barrier increases,the drag coefficient of the bridge also gradually increases,and the lift coefficient and drag coefficient of the train gradually decrease,but the degree of variation of the aerodynamic coefficient with the height is slightly different due to the different wind barrier layouts.When 3.0 m high double-sided wind barriers are arranged on the outside of the truss bridge,the drag coefficient of the bridge only increases by 12%,while the drag coefficient of the train decreases by 55%.展开更多
To overcome the limitations of structural height imposed by airspace restrictions in the design of maintenance hangar roofs with long spans,a new diagonal truss roof structural system is introduced for the first time....To overcome the limitations of structural height imposed by airspace restrictions in the design of maintenance hangar roofs with long spans,a new diagonal truss roof structural system is introduced for the first time.In the design of China Southern Airlines No.1 Hangar,4 main trusses were arranged diagonally along the depth direction,forming a W-shape truss.3 lineshaped trusses were arranged along the span direction,and double-layer space latticed structure is laid on them.The design optimized the height of the 183 m+222 m super long-span roof to 11.5 m,the maximum dimension the site could provide,so that the building height is within the permitted 40m.The steel consumption of the roof is only 165 kg/m^(2).The installation of diagonal trusses changed the unidirectional load transmission path of the roof and enhanced the spatial load transmission,effectively relieving the burden on the gate-side truss.This design enables the implementation of a maintenance hangar with a 222 m-span and heavy roof within the constraints of low airspace height.展开更多
基金Projects(52078504,51822803,51925808) supported by the National Natural Science Foundation of ChinaProject(2021RC3016) supported by the Science and Technology Innovation Program of Hunan Province,China。
文摘Wind barriers are commonly adopted to prevent the effects of wind on high-speed railway trains,but their wind-proofing effects are greatly affected by substructures.To investigate the effects of wind barriers on the aerodynamic characteristic of road-rail same-story truss bridge-train systems,wind tunnel experiments were carried out using a 1:50 scale model.Taking a wind barrier with a porosity of 30%as an example,the aerodynamic characteristics of the bridge train system under different wind barrier layouts(single-sided and double-sided),positions(inside and outside)and heights(2.5 m,3.0 m,3.5 m and 4.0 m)were tested.The results indicate that the downstream inside wind barrier has almost no effect on the aerodynamic characteristics of the train-bridge system,but the downstream outside wind barrier increases the drag coefficient of the bridge and reduces both the lift coefficient and drag coefficient of the train due to its effect on the trains wind pressure distribution,especially on the trains leeward surface.When the wind barriers are arranged on the outside,their effects on the drag coefficient of the bridge and shielding effect on the train are greater than when they are arranged on the inside.As the height of the wind barrier increases,the drag coefficient of the bridge also gradually increases,and the lift coefficient and drag coefficient of the train gradually decrease,but the degree of variation of the aerodynamic coefficient with the height is slightly different due to the different wind barrier layouts.When 3.0 m high double-sided wind barriers are arranged on the outside of the truss bridge,the drag coefficient of the bridge only increases by 12%,while the drag coefficient of the train decreases by 55%.
文摘To overcome the limitations of structural height imposed by airspace restrictions in the design of maintenance hangar roofs with long spans,a new diagonal truss roof structural system is introduced for the first time.In the design of China Southern Airlines No.1 Hangar,4 main trusses were arranged diagonally along the depth direction,forming a W-shape truss.3 lineshaped trusses were arranged along the span direction,and double-layer space latticed structure is laid on them.The design optimized the height of the 183 m+222 m super long-span roof to 11.5 m,the maximum dimension the site could provide,so that the building height is within the permitted 40m.The steel consumption of the roof is only 165 kg/m^(2).The installation of diagonal trusses changed the unidirectional load transmission path of the roof and enhanced the spatial load transmission,effectively relieving the burden on the gate-side truss.This design enables the implementation of a maintenance hangar with a 222 m-span and heavy roof within the constraints of low airspace height.
