Figure 8-32. - Triangular tower foundation.

will be determined by the size, the weight, and the construction characteristics of the tower and by the hoisting equipment.

Davit Method

Lightweight guyed towers are frequently erected with a davit hoist that is anchored to the previously erected section, providing a pivoted hoisting arm. The davit arm is swung away from the tower in hoisting the added section and swung centrally over the tower in depositing the section before bolting up the splice plates. Figure 8-33 shows a ground assembled unit being hoisted for connection to a previously erected tower section. A snatch block, secured to the tower base, transmits the hoisting line to a source of power

Figure 8-33. - Typical davit installation.

or hand winch. A tag line, secured to the base of section being hoisted, avoids possible contact with the erected portion of the tower.

Gin Pole Method

Light triangular guyed towers, furnished with a pivoted base, may be completely assembled on the ground and then raised to a vertical position with the aid of a gin pole. Figure 8-34 shows the lower section

Figure 8-34. - Pivoted tower-hoisting preparation.