AOC 15 user manual Tower Erection

6.0 Tower and Wind Turbine Generator Installation 37

NOTE: A template identical to the anchor bolt template can be bolted to the bottom leg flanges during tower assembly to insure a proper fit during the tower erection. Using both templates should theoretically allow all bolts to be torqued before erection.

6.2Tower Erection

Appendix G contains the Installation QA checklist that should be used during the installation process.

Much time can be saved if a crane capable of lifting the tower as one complete unit is used. When considering crane capacity, the erection load and local wind conditions should be taken into account. The centerline of the drive train is approximately 1.2 m (4 ft) above the chosen tower height. The 24.4 m (80 ft) tower weighs approximately 3,180 kg (7,000 lbs) and the 30.5 m (100 ft) tower, approximately 4,550 kg (10,000 lbs). The wind turbine generator weighs approximately 2,480 kg (5,450 lbs). See Appendix E. The length of the crane ball, lifting sling and the height lost due to boom angle reach should also be taken into account.

Before the tower is set on the foundation, an anchor nut should be placed on each anchor bolt to serve as a base for the tower flanges to rest upon. These nuts should be leveled before the tower is placed on them, using a survey transit and straight rod or a long straightedge with a bubble level, for example. Tolerance is not important initially, as the nuts may need to be adjusted in order to level the gearbox.

The tower can be lifted using three appropriately rated, separate slings or cables of equal length, each of which is hooked to the crane ball at one end and to the tower, near the top of its top section legs, at the other. The lifting devices should be inspected for correct attachment before raising the tower. Special care should be taken not to damage the lifting webbing on sharp edges. The tower should be lifted slowly and set on the anchor bolts carefully. The tower base flanges may not fit the anchor bolts precisely, especially if a base template was not used.

WARNING

DO NOT HAMMER OR BEND ANCHOR BOLTS TO FIT THE TOWER BASE. THIS MAY CAUSE CATASTROPHIC STRUCTURAL FAILURE AND RESULT IN SEVERE INJURY OR DEATH.

The tower legs may have to be twisted along their axes, to obtain the correct alignment between the flange holes and the anchor bolts. This can be done using a come-along and pry-bar. As the tower is lowered onto the base nuts, the top locking nuts should be placed on the anchor bolts as soon as the first threads protrude from the flanges. The nuts should be tightened incrementally as the tower is lowered. Once the tower is in place, the lock nuts should be tightened hand snug,

NOTICE: Use of the material contained in this document is subject to the warning on page Iv and the disclaimer on page v of this document.

DOC012R02 AOC 15/50 User Manual Nov 2001