IEEE 977-2009 pdf download IEEE Guide to Installation of Foundations for Transmission Line Structures
1. Introduction
1.1 Scope
This guide presents various approaches to good practice that could improve the installation of transmissionline structure foundations. This guide covers only the construction aspects of the installation of the foundations.
1.2 Purpose
The purpose of this guide is to present, in one document, the construction considerations necessary for theinstallation of transmission line structure foundations.
1.3 Application
This guide is intended to be used as a reference source for parties involved in the ownership, design, andconstruction of transmission structures. Since installation methods will be influenced strongly by the natureof each project, various methods that have been employed successfully are presented.
If any of the recommendations contained within this guide are to be adopted, they should be stated specifcally in the owner’s design and construction specifications. Any legal requirements of national, state, provin-cial, or local regulations must of course.be observed.
1.4 Legal Disclaimer
Ihe support data for this guide were collected from a great number of sources, and are believed to be reliableand true. Care has been taken during the compilation and writing to prevent error or misrepresentations. Theauthors make no warranty with respect to the accuracy, completeness, or usefulness of the information conained in this guide, nor assume any liabilities with respect to the applicability or use of any information.method, or process presented herein. The use of trade names is for the information and convenience of theuser of this guide and does not constitute an endorsement by the authors.
2. General Considerations
2.1 Overview
Transmission lines are linearized engineering systems that are composed primarily of the following threecomponents:
0Overhead lines, including the conductors, overhead ground wires, insulators, hardware, etc.2Structures that support the overhead lines at discrete pointsIn situ soil and/or rock that supports each structure through a foundation
Considerable interaction occurs among these three components during the planning, analysis, and design ofa transmission line. This process is necessary to optimize the design and result in an efficient and economicalsystem.
In recent years, a number of useful documents have been published that address overall line planning anddesign (see (B57’and B12), loadings ( B11, B91, and B10), structural design ((B6],(B7],[B8), andB11), and foundation analysis and design ((B2),(B3], and B4)) This document records constructionpractices for the installation of foundations of electrical transmission line structures. In the remainder ofSection 2, the overall problem is introduced, and general items are discussed that are pertinent to all foundation types. Much of this section is extracted from EPRI EL-2870 JB3]. Sections 3 through 6 address thespecific issues involved for each major foundation type used for transmission line structures.
2.2 Structure Functions and Types
2.2.1 Structure Functions
From a functional standpoint, there are three primary categories of transmission line structures:
0Suspension
2)Strain
3Dead-end
The diferentiation between these categories is made principally on structure function in the line, the lineangle at the structure, and the insulator configuration.
2.2.1.1 Suspension Structures
Suspension structures are used in line sections between strain or dead-end structures. The conductors aresupported by suspended insulator assemblies that permit the equalization of conductor tensions in the longitudinal direction. The line angles for these structures are typically light to perhaps medium. Normally, thesestructures are the lightest, least expensive, and most common in a line.