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Introduction to Civil Engineering
Published in P.K. Jayasree, K Balan, V Rani, Practical Civil Engineering, 2021
P.K. Jayasree, K Balan, V Rani
A very tall structure which is not intended for living is called as a tower. There are different types of towers such as transmission tower, clock tower, bell tower, communication tower, radio tower, etc. A tower is built for definite purposes as follows: Bell tower: for hanging bells in churchesCommunication tower: for transmission of communication signalsRadio tower: for transmission of radio signalsTourist tower: as a tourist attractionTransmission tower: for distribution of electricity
Small-scale wind power energy systems for use in agriculture and similar applications
Published in Jochen Bundschuh, Guangnan Chen, D. Chandrasekharam, Janusz Piechocki, Geothermal, Wind and Solar Energy Applications in Agriculture and Aquaculture, 2017
Wojciech Miąskowski, Krzysztof Nalepa, Paweł Pietkiewicz, Janusz Piechocki
During start-up, generators are connected to the grid by thyristors with shunt contactors. A microprocessor controller monitors turbine operation and carries out precision diagnostics on the principal turbine components. The nacelle also houses lubricating systems, cooling systems and a brake disk. The nacelle and the rotor are moved in the direction of the wind by the yaw drive and yaw gear, which are mounted on top of the turbine tower. The tower is made of steel or reinforced concrete. Most towers are built from large-diameter pipes; lattice towers are less frequently encountered.
Wind
Published in Dorothy Gerring, Renewable Energy Systems for Building Designers, 2023
Most turbines have a tower to get the blades and nacelle (where the generator is located) high enough that it is located in a good, steady wind resource. Tower heights for small wind may be as low as 35’–100’ (11–30m) while utility towers can be over 260’ (79m) tall. Towers for smaller wind have a variety of configurations while large wind always have a self-supporting single pole. Maximum tower heights may be regulated by local or regional zoning requirements.
Development and Validation of Empirical Formulations for Predicting the Frequency of Historic Masonry Towers
Published in International Journal of Architectural Heritage, 2023
Francesco Testa, Alberto Barontini, Paulo B. Lourenço
The analysis of the information of the towers belonging to the training set (Table 1) reveals that the total height ranges between 7.2 m (the Squat Masonry Tower of the Trani Castle) and 112.0 m (the Torrazzo in Cremona), the minimum side length varies from 3.0 m (the Bell Tower of S. Giorgio Church in Trignano) to 14.5 m (the Giotto Bell Tower), and the thickness of the base masonry walls from 0.4 m (the Bell Tower of S. Giorgio Church in Trignano) to 4.0 m (the Bell Tower of St Maria del Carmine Church). Moreover, the aspect ratio is found to range between 1.7 (the Squat Masonry Tower of the Trani Castle) and 12.6 (the Torre del Mangia). The value of the first natural frequency is plotted against the total height of the towers, in Figure 4, where a colour map is included to show different aspect ratios. The fundamental frequencies range from 0.33 Hz (the Asinelli Tower) to 7.50 Hz (the Squat Masonry Tower of the Trani Castle), presenting a clear inverse non-linear trend for increasing values of the height. A similar trend appears for increasing values of the effective height (Figure 5), suggesting a likely good fitting with a power regression. The correlation between the first natural frequency and the other geometrical features (minimum and maximum side length and wall thickness), as illustrated in Figure 5, is poorer, presenting a slightly similar non-linear inverse trend, but with larger scatter of the data.
Optimum Selection of Communication Tower Structures Based on Wind Loads & lifecycle cost analysis
Published in Cogent Engineering, 2022
Yasmin Elhakim, Tawfik Ismail, Irene Fahim
According to Gao et al. (2018), failure of monopole towers or guyed mast usually happens because of guys rupture or overall turning. However, for the case of the latticed tower, a progressive collapse analysis under design and accidental loads should be carried out, as it is more complicated to determine the causes of failure. In their study, they conducted progressive collapse analysis for latticed communication towers under wind loads with different wind directions. This analysis was conducted on two different configurations of 50 m latticed towers, namely, standard tripole tower and standard angle tower (as defined by the Chinese government standard drawing collection of a telecommunication steel tower, DCTST 2014) using ABAQUS software. According to their findings, in order to minimize the telecommunication towers and collapse probability due to wind loads, first unfavorable wind direction should be avoided through proper design. Second, critical leg member that tend to trigger collapse should be protected. Third, anti-collapse design should be done using an alternative load path or bridge-over method to protect the tower against collapse.
Vibration-Based Investigation of a Historic Bell Tower to Understand the Occurrence of Damage
Published in International Journal of Architectural Heritage, 2022
A. Tomaszewska, M. Drozdowska, C. Szymczak
The natural frequencies of the bell tower are in the frequency band typical for masonry towers. Comparable results obtained for other structures can be found in (Bull 2001; Cabboi, Gentile, and Saisi 2017; Ferraioli et al. 2017; Ivorra and Pallarés 2006). In the considered case convergence between the numerical model and the tower is observed as far as the first five natural frequencies are considered. No error occurs between the first two theoretical and experimental natural frequencies (first bending mode shape) and 2.5% due to the second bending mode shape (the fourth and fifth natural frequencies). According to the third natural frequency, related to the torsional mode shape, the error equals 9.0%. The numerical model requires validation of the torsional mode if it is used in further analysis. It can be performed e. g. with the use of an elastic support, as presented in (Tomaszewska and Szymczak 2012).