Hoisting trusses with a crane is a common practice on jobsites, but it’s also a likely time when trusses can be damaged. This is due to improper techniques that can overstress the truss and its connections.
Hoisting Individual Trusses
Installers should not lift single trusses by the peak. Likewise, single trusses should not be lifted by the webs, which can cause lateral bending of the truss and damage to the truss plates and web member. Lifting devices should be attached to the truss top chord using only closed-loop attachments.
Individual trusses up to 30′ in length should have two pick-points near top chord joints spaced up to half the truss length apart. The line angle should be 60° or less. Spreader bars can help add rigidity to a truss while it’s being hoisted, lessening the likelihood of lateral bending. For trusses between 30′ and 60′, attach the truss to a spreader bar with lines that slope inward or “toe-in.” For trusses over 60′, use a spreader bar two-thirds to three-quarters of the truss length positioned at or above mid-height of the truss. Attach the spreader bar to the top chords and webs at 10′ intervals.
Hoisting Truss Bundles
The recommended industry best practices for hoisting truss bundles are a bit different than those for single trusses, but the same basic concepts apply. When lifting truss bundles, lift points are permitted anywhere along the chords. “Anywhere” means anywhere other than the peak. Trusses that are banded together into a bundle are stiffer in comparison to a single truss, but lifting a bundle of trusses by the peak can still cause undue stress and damage.
For bundles of trusses greater than 45′ and up to 60′ in length, at least two lift points are required. For bundles of trusses greater than 60′ in length, at least three lift points are required. Only one bundle should be lifted at a time. If a large bundle is comprised of smaller bundles, the large bundle should be taken apart and each bundle lifted individually.