Study On Wind-induced Interference Effects Of Multi-tube Steel Chimneys

In the towering engineering structure, the struture of circular model are widely used in electric power, thermal, petroleum, mining and other industries. It is a typical high-rise wind-sensitive structure with high height, thin shell and light weight. Wind load is aways one of the main domainting load in chimney design. General specification for single chimney provides reference for calculating wind load, but the actual cases, the chimney structure does not exist alone. Hower, it is always constructed with group of multiple cylinders composed of cylindrical struture in practice. In this condition, the interference effect between the-chimney cannot be ignored.Based on the technique of simultaneous press measurement, the wind load characteristics of single chimney and when chimneys being an equilateral triangle and quadrilateral arrangement were carried out to test and analyze. The major contents of the dissertation can be summarized as follows.Firstly, wind pressure coefficient, shape coefficient, drag coefficient and lift coefficient of the single steel chimney are analysed from the circular cross section of the structure of the wind load characteristics and its influencing factors. Then point out the changes of drag coefficient with altitude and make a constrast with recommended value of load code.Secondly, the intererence effects of statics forceare of three tube vertical steel chimneys and four tube vertical steel chimneys are analysed base on the results of wind tunnel test. Then, the change of wind pressure coefficient on the surface of the chimney and shape coefficient under all kinds of chimneys form are reseaeched. Through the chimney of wind load characteristics from different spacing, wind angle of attack, and physiognomy types, pointed out the relationshape between the effect of interference effect and scope under different conditions.Finally, three tube vertical steel chimneys dynamic interence effects are analysed. Based on the requirements of design institute, the finite element dynamic response of the three tube vertical steel chimney with the finite spacing between the adjacent chimney were analysed by ANSYS. Then the natural vibration frequency, the along-wind equivalent wind-induced response and the change of wind vibration coefficient with height are analysised.