ATTEN: Manager Liu
ADD: Longhua Development Zone, Jing County, Hengshui City, Hebei Province
China GB5009-2001 is based on the maximum wind speed within 10 minutes of a 50-year encounter on a relatively open flat surface, while UBC97 is based on the maximum wind speed within 3 s of a 50-year encounter 10 meters above an open flat surface. The difference is reflected in the wind pressure. The value of UBC97 is about 1.5 times larger than that of China. The basic wind speed in American code is 3 s time interval, smaller than that in China, and the value of wind speed is larger than that in Chinese code. But it can not be inferred from this that the result of Barbara wind resistance calculation in the United States is bigger than that in China, because the effect of discussion is to be compared by the total effect of wind load. It is smaller or more conservative than that calculated by American code. It is determined according to the requirement of structural reliability index in China. When using the U.S. UBC97 matching design, according to the local basic wind pressure! "According to the UBC97 value standard.
The calculation of wind loads in different countries can have different results, depending on the CBK project which is suitable for each country's own national conditions. The basic wind speed is 90 mph (144 kmh), according to the relevant chapters of Minimum Design Loads for Buildings and Other Structures of the United States Code, such as site type, importance coefficient, site impact coefficient, etc. According to the structural sustainability of this project and the specific provisions of the U.S. code, the wind coefficient is calculated to be 0.88. In Etabs software, a wind-loaded wind tunnel test structure is automatically defined according to 15_interval, which has an important impact on the wind load. The most accurate wind load measurement is determined to be based on the prototype structure. In order to get a more general conclusion, it is necessary to study the sound of important parameters, which is impossible in practice. Therefore, the most appropriate way to determine the wind load is to conduct wind tunnel tests on structural models.
Wind load tests on building models have fundamentally changed the traditional design methods and specifications. Large buildings such as bridges, TV sets and pupil buildings require wind tunnel tests, and the model must simulate the stiffness of the object (elastic model), measure the wind-induced vibration characteristics and wind tunnels, which are used in a pipeline. Force equipment drives a flow with controllable velocity, which is used for aerodynamic experiments on models. The basic principle of wind tunnel experiment is the principle of relativity and similarity. Generally speaking, the windward area of high-rise buildings is larger than that of kowtows. The actual size of the model is needed for wind tunnel test, and its power consumption will be astonishing. According to the principle of similarity, the small-scale model cBK project with similar geometry can be constructed. The project is located in the Middle East Gulf. It has 40 floors above ground and 2 floors below ground (excluding interlayer). The whole structure transits from L-shape at the bottom to triangle gradually. The elevation of the structure is 238.475m. Its appearance is shown in Figure 1.
The two right-angled sides of the building are steel-framed concrete shear wall structures. The inclined sides are designed step by step. The wind tunnel test center of Sydney University conducts scale wind tunnel tests on the whole tower. The wind tunnel test report gives the maximum bending moment, acceleration and deformation of sE-Nw square. According to 450, 2700 and 315 wind action, the nominal distribution of bending moment and shear force is given. Distribution of bending moment and shear force, according to the combination coefficient of shear force and bending moment corresponding to each wind direction at design time, six wind load conditions were defined and compared. At the same time, British BMT company was entrusted to conduct wind tunnel test BMT wind tunnel test reports of wind tunnel test units based on tower model. Nine kinds of BMT wind tunnel test reports of 3200, 2400, 33003100, 2700, 0o and 1000 were given. The shear force and torsion of each floor under unfavorable wind load are given, and the center of wind load is given. It is convenient to automatically define wind load in Etabs software. Except for the whole structure.