Bracing & Restraint

We are finding it difficult to design permanent diagonal bracing for scissors trusses. The truss is often only a few feet in depth, which does not provide adequate room for diagonal bracing. Has SBCA come up with recommendations for permanent bracing of scissors trusses?

Are there any associations that have recommendations for the installation of wood trusses?

It is critical that permanent top chord bracing is supplied by proper nailing of the valley truss bottom chords to the carrying truss top chords, through purlins or properly installed rated roof sheathing. If the sheathing is not carried through under the valley framing, then the permanent top chord bracing must be supplied in another manner.

How much OSB can be stacked on a floor deck without damaging the trusses?

Manufactured gable ends are actually frames even though they are often referred to as trusses. The webs are “studs” oriented vertically and usually spaced at 12, 16 or 24 in. O.C. The gable end frame is designed to transfer vertical loads from the roof to the continuous bearing wall below. Another way gable end frames are different from trusses placed in the interior of the structure is that frames experience perpendicular wind loads. The sheathed frame transfers the wind loads to the roof and ceiling diaphragms and vice versa.

Long span trusses can pose significant risk to installers. The dimensions and weight of a long span truss can create instability, buckling and collapse of one or many trusses, if not handled, installed, restrained and braced properly. As such, they require more detailed safety and handling measures than shorter span trusses. This research report provides guidelines for proper handling and installation of long span trusses for both wood and cold-formed steel.

This presentation provides information on and requirements for the use of metal channel to meet lateral restraint/bracing requirements for metal plate connected wood trusses.

NFC member shares proper bracing in action.

Minimum top and bottom chord permanent lateral restraint/bracing of structural roof or floor trusses is assumed to be adequate when using code-compliant roof and/or ceiling diaphragms. This lateral restraint/bracing is typically accomplished with code-compliant roof /floor sheathing and fastener spacing and/or code-compliant gypsum ceiling material and fastener spacing or purlins at a given on-center spacing.