The seine net is an important part of the outdoor stadium. However, in the actual project management, the author discovered that some designers did not pay enough attention to the design of the seine net, and the design method was simple and random, and even the phenomenon of instability and destruction occurred. The author summarizes the project management experience and lessons from multiple outdoor stadiums, discusses the design method of the stadium fence with typical examples, and proposes some structural requirements. 1 Introduction With the development of the national economy, people are increasingly pursuing a healthy life. Physical training and activities have become an important part of fashion and high quality of life. To meet the needs of citizens and students for sports venues, many cities, schools and communities are Outdoor stadiums are being built or are being prepared. Outdoor stadium with multiple fences Protection. The main function of the fence is as follows: (1) Separate the stadium from the off-site venue; (2) Separating different project areas in the stadium so that different projects will not interfere with each other at the same time; (3) Convenient for stadium management; (4) Beautify the environment. The stadium fence is an auxiliary facility of the stadium, but it is also an important part of the stadium. It directly relates to the service level of the stadium, the safety of the personnel in the stadium and the service life. Because there is no specific design specification that stipulates the design method of the purse seine, and some designers do not pay enough attention to the design of the purse seine, the purse seine is also happening from time to time. Based on the management experience of the stadium project, the author discusses the design method of the stadium fence structure and puts forward some requirements for the construction of the fence. The following calculation process data values ​​take the Tianjin Haihe Education Park as an example. 2. The style of the common fence The following figure is a common fence style for the stadium. The design method presented below is also based on the concept of this style. 3. The characteristics of the load on the fence Seine stands in the outdoor environment, the main load is the wind load; football, basketball and other ball impact load is reflected in the partial coefficient in the strength calculation, can not be considered separately; seine net distance from the competition area has a certain safety Distance, under normal circumstances do not have to consider the impact of people and the impact of off-field vehicles, but there should be a certain amount of safety reserves. The seine net must be firm and stable under the action of wind load. If overturning or destruction may cause casualties of people in the vicinity of the seine net, bending and pulling strength of the fence column must be checked during design, and the seine net should be guaranteed according to the structural requirements. The stiffness and stability. 4. Seine strength check (1) Determine the standard value of wind load Wk-wind load standard value (kN/m2) β gz - gust factor at height Z Îœst-wind load conversion factor Îœz-wind pressure height variation coefficient W0-basic wind pressure (kN/m2) Î’gz, μst, and μz can be obtained directly from the Schedule of Building Structural Load Codes or calculated and analyzed based on actual conditions. W0w can also be taken from the Schedule of Building Structure Loads and the basic wind pressure map. When it cannot be found in the specifications, it can be taken with reference to a nearby similar area, or according to the maximum wind speed observation data of that year in accordance with the basic wind pressure. Definition, determined by statistical analysis. The stadium is built in the urban area. The ground roughness is Class C and the height of the fence is less than 5m. Therefore, the gust coefficient βgz should be 2.30, and the air pressure height change coefficient μz should be 0.74. The current specification does not stipulate the calculation method of the volumetric coefficient of the network structure, and it can be determined by referring to the similar structure calculation and taking into account the wind blocking properties of the fence. For example, the grid of the fence has a square shape, a size of 5x5 cm, and a wire diameter of 4 mm. Each frame has a frame (contour) size of 3 x 2m. The windshield coefficient of the mesh is: Where An is the projected area of ​​the mesh and A is the mesh outline area. Body coefficient Us is taken as 1.2 Then calculate the body size coefficient Usj=φ·us=0.16×1.2=0.192 The fence is a network structure. When the air flows through the fence, it will produce a “mesh effectâ€, that is, the area of ​​wind resistance is greater than the sum of the net area of ​​the fence wire, the fence frame, and the column. The reason for the net effect is that the fence wire, the fence frame and the column are all small round sections with a small net distance from each other, and small circles with small pitches around the fence wire when the air fluid passes through the fence grid. The cross-sections form complex turbulences and interfere with each other. This turbulence and interference creates an additional “dragging†effect on the purse seine surface, as if the diameter of the purse wire increases and the mesh opening becomes smaller, so that the windage area increases. . This dragging effect cannot be ignored for the fence. According to experience, the calculation of the body shape coefficient should be appropriately increased. It is appropriate to increase the coefficient f value to 1.8 to 2.0. The area with a large wind speed takes a high value, and the area with a small wind speed takes a low value. The conversion body coefficient μst = f · μsj = 2.0x0.192 = 0.384 The basic wind pressure refers to the one-time access for 50 years in Tianjin city, and W0 takes 0.50 kN/m2. Substituting the above coefficient and basic wind pressure into Equation 4-1, (2) Calculate the area of ​​windage As shown in the figure above, in order to achieve aesthetic effect, the pillar is to adopt Q235B material Φ76 steel pipe, which is 4.0m high, and the fence frame is to adopt Q235B material Φ48 steel pipe. Take one column and two half plates on both sides for calculation. The wind resistance area is the sum of the net projected area of ​​the column, mesh frame, and mesh. Therefore, (3) Calculate the wall thickness and strength of steel columns According to the most unfavorable situation that the wind load law acts on the purse seine consideration. The fence is a symmetrical structure, which means that the wind load will form a concentrated load at the centroid of the column. The size of the concentrated load is: The bending moment produced by the concentrated load P at the column foot is: Φ76 Sectional modulus W of steel pipe with a wall thickness of 3 mm is 12.08 cm3 The formula for calculating the strength of one-way bending members is: Flexural strength meets requirements. (4) Checking shear strength Shear strength calculation based on the formula Meet shear strength requirements. In fact, the shear stress generated by the wind load on the fence column is relatively small compared to the shear strength of the steel pipe, so the designer does not need to check the shear strength. 5. Construction and construction requirements (1) In order to ensure that the fence has enough rigidity to avoid worrying about shaking, the diameter of the fence column should not be less than 70mm, and the wall thickness of the column should not be less than 3mm. The author suggests using a wall thickness of 4mm as much as possible. (2) The size of the independent foundation under the pillar shall not be less than 300 × 300 × 450mm, and the concrete strength shall not be less than C30. During construction, the formwork should be poured or prefabricated. If you do not support the template directly cast in place with the soil, the foundation pit excavation must be regular, to avoid dug "pot bottom-shaped" foundation pit, otherwise it is easy to form a sliding surface in the base, under the influence of wind load easily overturned. (3) The column and embedded iron can be bolted or welded. When welding, it must be welded along the circumference of the pipe and welded symmetrically to prevent excessive deformation. Lunch Box,Hot Lunch Box,Bentgo Box,Cute Bento Box MeMe Baby Product (GZ) LLC , https://www.kupbo.com
