Early tower installations for radio broadcasting offered problems similar to those met in guying stacks, poles, derricks and similar structures. Guys for these moderate-height structures were commonly made of regular wire rope.
The advent of television and FM broadcasting, however, created a need for towers of greater height. In fact, the idea of a tower being 2,000 feet tall or more is no longer uncommon. The guying of these larger towers presented problems not faced with the smaller towers. For example, wind and ice loads must now be considered, both during installation and tensioning after erection.
Structural strand is now used for guy systems. Where larger diameter wire rope was once used, structural strand, with its higher modulus of elasticity and lower diameter-to-strength ratio, allows for smaller diameter guys. This reduction in diameter reduces ice and wind loads, which may be important in the overall design of the tower. Structural strand’s higher modulus of elasticity (less stretch) also allows for less take-up of the bolts during tensioning.
Uniformity in tensioning and deﬂection is necessary for tower guys. Therefore, it is important that the structural strand guys have minimal constructional stretch, a high modulus of elasticity and accurate length measurements. Pre-stretching the strand eliminates most of the constructional stretch and contributes to the strand’s high modulus of elasticity. Proof loading may be used to prove the security of end attachments. Field tensioning of the guys is facilitated by our ability to supply precisely measured and completely documented strand assemblies.
Structural strand also is used for boom pendants on excavating equipment.