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
In design and construction of low/high rise buildings, different forms of construction can be applied such as concrete shear wall structural system and framed structural system without or with masonry infill walls. At...In design and construction of low/high rise buildings, different forms of construction can be applied such as concrete shear wall structural system and framed structural system without or with masonry infill walls. At present, most buildings in East Africa are constructed as reinforced concrete framed structures with strong masonry infill, but during design, engineers assume that the masonry infill panels have zero contribution in offering load resistance. Due to the problem above, a study with an objective of finding out the influence of masonry panels on the properties of reinforced concrete infilled frame under vertical load has been done. Three types of models： reinforced concrete frame model, masonry model and reinforced concrete frame with masonry infill, were investigated using finite element technique. In additional to the finite element analysis, laboratory models were prepared and tested so as to check the validity of the analytical results. The obtained results have led to an establishment of a mathematical model which may be useful to the design engineers since masonry wall panels can now be considered as load bearing elements. Such consideration of frame together with masonry leads to an accurate and optimal design of the frame, resulting into lesser amount of reinforcement and geometrical properties of the frame.展开更多
Location of the heavily loaded building on the ground of the small load capacity requires application of the appropriate foundation structure. The required foundation system is most often deep, it is expensive and its...Location of the heavily loaded building on the ground of the small load capacity requires application of the appropriate foundation structure. The required foundation system is most often deep, it is expensive and its cost increases significantly when the building is located in earthquake area or in mining damage sector. The proposed structural system of the combined foundation makes possible to design and to construct a very stable and relative inexpensive foundation structure, which can obtain an extremely large horizontal surface and which can be placed not deeply beneath the terrain level. It can be a very solid support structure for a tall building placed on very weak subsoil and at the same time located in seismic area. This system can be applied not only for new buildings but it can be used for the existing buildings and moreover for straighten of the inclined objects. Due to special arrangement of component parts the combined foundation possesses inherent features of a vibration damper, what is highly desirable if buildings have to be located in earthquake areas. When the aboveground storeys structure has some similar patterns with structural form of the combined foundation then the structural system of the whole building obtains coherent structural characteristics and it is called the combined structural system of the tall building. Suitable application of this system makes possible to design high-rise buildings having interesting and unique architectonic forms, what is presented on a selected example.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In design and construction of low/high rise buildings, different forms of construction can be applied such as concrete shear wall structural system and framed structural system without or with masonry infill walls. At present, most buildings in East Africa are constructed as reinforced concrete framed structures with strong masonry infill, but during design, engineers assume that the masonry infill panels have zero contribution in offering load resistance. Due to the problem above, a study with an objective of finding out the influence of masonry panels on the properties of reinforced concrete infilled frame under vertical load has been done. Three types of models： reinforced concrete frame model, masonry model and reinforced concrete frame with masonry infill, were investigated using finite element technique. In additional to the finite element analysis, laboratory models were prepared and tested so as to check the validity of the analytical results. The obtained results have led to an establishment of a mathematical model which may be useful to the design engineers since masonry wall panels can now be considered as load bearing elements. Such consideration of frame together with masonry leads to an accurate and optimal design of the frame, resulting into lesser amount of reinforcement and geometrical properties of the frame.
文摘Location of the heavily loaded building on the ground of the small load capacity requires application of the appropriate foundation structure. The required foundation system is most often deep, it is expensive and its cost increases significantly when the building is located in earthquake area or in mining damage sector. The proposed structural system of the combined foundation makes possible to design and to construct a very stable and relative inexpensive foundation structure, which can obtain an extremely large horizontal surface and which can be placed not deeply beneath the terrain level. It can be a very solid support structure for a tall building placed on very weak subsoil and at the same time located in seismic area. This system can be applied not only for new buildings but it can be used for the existing buildings and moreover for straighten of the inclined objects. Due to special arrangement of component parts the combined foundation possesses inherent features of a vibration damper, what is highly desirable if buildings have to be located in earthquake areas. When the aboveground storeys structure has some similar patterns with structural form of the combined foundation then the structural system of the whole building obtains coherent structural characteristics and it is called the combined structural system of the tall building. Suitable application of this system makes possible to design high-rise buildings having interesting and unique architectonic forms, what is presented on a selected example.
