ABSTRACT
This chapter addresses the types of design practices normally required for the structural support system. An overhead transmission line is a complex electric/mechanical system designed to transfer electricity between power substations. Transmission lines are composed of many individual elements consisting of a variety of materials with a wide range of mechanical properties. Transmission line loads can be classified as weather-related, accidental, or caused by construction or maintenance activities. Traditional line design views the support structure as an isolated element supporting half span of overhead conductors and shield wires on either side of the structure. The function of a transmission foundation is to transfer applied steady-state and transient loads into the surrounding soil and rock while limiting structure movement. Foundation performance criteria result from deterministic evaluations of structure performance needs and can control final foundation size. Transmission foundation designers must balance cost-effective field investigation with the production of sufficient data for design of foundations that are economical and reliable.
