Prestressed Towering Structure

At present, with the development of our society and economy, television and communication system has made a rapid progress in our country. Along with the construction of high-rising buildings such as TV towers is turning into the tendency characterized with large scales and multi-functions, the prestress technology is applied widely in the design of high-rising buildings because of their advantages. Since the current national standard , ((the standard of high-rising structure design)} ( GBJ135-90), was established at the end of 1980's according to the past engineering experience, it can not meet with the demand for the high-rising structure design. Especially there are no articles which deal with the design of prestress technology in the chapter of concrete tower drum. Just under this kind of background, new national standard of high-rising structure design is being set up.Referring the application of prestressed concrete tower drum in practice, this paper primarily focuses on a few problems mentioned below and the author hopes to offer some contribution to the revision of the new norm.Firstly, the paper sums up the application and development of high-rising buildings, and the advantages of prestressed concrete using in high-rising structures. Based on the conclusion, the author points out that the prestressed concrete structure would be the tendency in high-rising buildings.Secondly, according to the change of calculation formula when prestress were added to the chapter of concrete tower drum, the paper has given the calculation formulas of prestressed concrete tower drum in limited states of carrying capacity and normal serviceability.Thirdly, for the sake of convenience for calculating the section stiffness of prestressed concrete tower drum, this paper interprets the relationship between the stiffness dropping-coefficient of prestressed concrete tower drum cross and prestress degree. Based on the cross stiffness coefficient under different prestress, a brief method for calculating the stiffness dropping-coefficient is presented in this paper.Finally, with the research results, the author analyzes the two TV tower drums: the normal concrete tower and the presrtressed concrete tower. At the same time, the calculation reliability of prestressed concrete tower drum and dropping-coefficient of stiffness established in this paper has been proved.