Atypical structural systems for mobile communication towers

Abstract

The improvement of the structural forms of mobile communication towers is an important and actual task in the modern world with growing needs in quality of mobile communication. The task of developing support structures for installation in a dense urban environment requires particular considerations, which must satisfy both the requirements for ensuring the reliability of structures and aesthetic requirements. Based on the results of the critical analysis of the design experience for supports, atypical structural solutions of the towers are proposed to cellular communication equipment. The prismatic towers are chosen for the study. The procedure for calculating towers is formalized in the form of a step-by-step system. For the uniform initial data on climatic and averaged technological loads for a given class of facilities, the loads on the towers were calculated; forces were determined; the cross-sections of tower elements in accordance with the requirements of two limiting states were received to be accounted for the effect of the most unfavorable design load combinations. The ranges of the stiffness characteristics variation are established for various types of towers structural solutions. The characteristics of the advantages and disadvantages are received for each constructive solution on the basis of the analysis of applicability of the existing and proposed towers structural solutions and evaluation of the stress-strain state performed. According to the criterion of metal consumption, the most economical version is chosen between the four towers structural solutions which include the triple leg frame system, the lattice tower of triangular cross-section (classical solution that has proved itself in practice), the spatial unflanged system and the cable system with the central trunk. The criteria for optimizing towers geometry and their elements are proposed and consist in simultaneously ensuring the requirements of limiting states. The new tower design solution in the form of the cable system with a central trunk has been worked out while varying the significant factors, such as the width of the base, the number of cable elements and the value of initial tension. Some dependencies have been proposed that are based on the numerical study results for the towers with a pre-stressed trunk and allow for regulating the stress-strain state and rigidity of the support at the design stage. The ways for improving tower structural form of structural solutions adopted are indicated. It is established that the unflanged system is inefficient as a support of small and medium height for the equipment for mobile operators.