| TV Tower is a typical high-rise structure. The television tower structure often can be the preferred solution because of steel structure’s own characteristics. In the past, the TV tower has single function, which is transmitting signal. With the development of society, TV Tower becomes a large-scale integrated one, which has many functions, including transmitting signal, exhibitions, tourism, advertising, and other cultural and commercial activities. TV Tower often can be a city landmark.TV tower structure is a high and flexible structure. The wind load is main and control load among of all loads acting on TV tower structure. Due to the multi-functional requirements of the television tower, the requirement of wind resistance for television tower structure increases higher. Steel structure television tower is more sensitive to the wind load and the examples of tower’s damage under wind load are not uncommon. So for the design of steel structure tower, dynamic effect of wind load calculation is particularly important.In this paper, first of all, this paper introduces the simulation method of a fluctuating wind load and the implementation process, using the linear filtering method (AR) simulate wind speed time history, wrote the pulsating wind simulation. The wind load time history curve of the program is suitable for simulation of a fluctuating wind load is generally tall structures. This article analyzes quasi-static wind load on two existing TV Towers, one of which is inaccessible (model1) and the other is accessible (model2). Here analyzes the two TV Towers wind load response analysis under0°and45°two wind directions by the code, which comes to a conclusion that wind load of tower is controlled by45°direction.This article compares the two different antenna stiffness TV tower wind load quasi-static analysis and dynamic analysis, which gets a conclusion that the TV tower with antenna according to specifications only consider the first mode to calculate the wind load will cause large errors. At the same time, here executes two TV Tower’s modal analysis in the two cases of an antenna and no antenna. By observing the modes of the two TV tower in two cases, we can find that the high mode effects on TV tower with an antenna can’t be ignored. While the antenna is removed, the high modes effects are very little. The antenna’s effect on the natural frequency of the TV tower structure is significant.Finally, by changing the three-dimensional finite element model’s antenna stiffness of the model1, a comparative research of degree of fit of TV Tower wind load between the quasi-static analysis and dynamic time history analysis is done. The Study shows that for small and medium-sized tower with an about20meters high antenna, when applied a unit force to the apex of antenna, the displacement ratio between the top of the antenna and the top of tower, if which is less than5times, the wind load of overall structure of the TV tower can be calculated according to code to only consider the first mode.but if the displacement ratio is greater than5times, the wind load of overall structure of the TV tower be calculated by time history analysis method or by multiplying a appropriate magnification factor as to code. |
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