CAPACITY UTILIZATION STUDY OF 60M HIGH THREE-LEGGED HYBRID SELF-SUPPORTING TELECOMMUNICATION TOWER (INDIAN AND AMERICAN STANDARDS)

Abstract

There are different tower configurations like four legged angular, three legged angular and three-legged hybrid towers are popularly adopted in telecom tower constructions. Hybrid tower means the tower with main legs are pipes and other members like bracings, horizontals and redundant members are angular members. Selection of hybrid tower is mainly due to three-legged configuration and pipe sections have less drag coefficients compared to four legged angular towers which resulting less wind load on tower for structure weight optimization. Lattice towers are light weight structures and governed by wind loads due to tower body, antennas and other equipment. Current industry practice for design of telecom structures from the available general structures building loading and design standards like IS : 875 (Part 3) – 1987 for load calculations and IS 800-1984 for design of pipe sections and IS 802 (Part 1/sec 2) – 1992 for angular sections design. Recently the loading standard and design standard has been revised IS 875 (Part-3)-2015 and IS 800-2007. So, it is important to understand the effects of new standards on already designed and installed towers using old codes and understanding the provisions of revised standard in line with the international design standards like ANSI/TIA-222G. 60m high 3-Legged Hybrid self-supporting telecommunication tower with X pattern bracing has been selected forthe study. This paper explains the codal provisions for calculating wind loads [IS 875 (Part-3)-1987 &IS 875 (Part-3)-2015] and members capacities [IS 802 (Part 1/Sec 2)-1992, IS 800-1984 & IS 800-2007] using old and new Indian codes along with American Code (ANSI/TIA-222-G).Comparison statements and conclusions have been presented at the end of the paper.