• For glu-lam beams that are installed at a pitch and need to have the bottom cut to be level, make sure that the end of the bottom cut closest to the bearing edge receives full bearing. (See “Cut Edge Full Beaning" illustration.)
• Ends of beams should not be notched unless approved by the engineer. (See “No Notching End of Glu-Lam Beam" illustration.)
• Glu-lam beams will shrink as they dry out.
If the top of the beam is connected in a way that doesn’t allow for shrinkage, the glu-lam beam will split. (See “Glu-Iam Beam Shrinkage" illustration.)
• When a lateral support plate is used to connect two glu-lam beams, the holes should be slotted horizontally to prevent splitting. (See “Lateral Support Plate" illustration).
• Glu-lams are also used for posts. It is important to keep them away from concrete, which contributes to their decay. Placing a steel shim under the beam will keep it from touching the concrete. (See “Decay Prevention Next to Concrete" illustration.)
• Hinge connectors should be installed so that they don’t cause splitting of the glu-lam
beams. This can be done by using a strap that is independent of the hinge connector, or by vertical slotting the holes in a strap that is connected to the hinge connector. (See “Hinge Connector Slotted Holes" illustration.)
• Glu-lam beams rest on metal post caps that often have a weld or radius in the bottom corner. If you don’t ease the bottom corners of the beam, the beam will sit up in the pocket. Often, the glu-lam beam’s bottom corners are already rounded and won’t need attention.
• In some cases, the sides of the metal post caps are bent in so that the beams will not slide in properly. Check all the sides of the metal post caps before they are installed, so you won’t have a forklift or boom truck and crew standing around waiting while someone labors on top of a ladder to widen the sides of the post cap. (See “Forklift setting glu-lam beams" photograph later in this chapter.)
• Glu-lam beams are often attached to metal caps with bolts. The holes can be drilled either before or after setting the glu-lam beams. If the holes are drilled after the beams are set, use a drill with a clutch. It’s easy to break a wrist or get thrown from a ladder when a W drill motor without a clutch gets caught on the metal.
Splitting can be caused by shrinkage on large splice plates.
Top bolt prevents shrinking and causes splitting. Splitting can also occur from limiting beam end rotation as the beam deflects under load.
Shrinking or beam rotation due to deflection under loading can cause splitting.
If holes are not slotted, splitting may occur due to beam rotation as the beam deflects under load.
Contact with concrete exposes untreated wood to decay.
