Bracing & Restraint

Installing Valley Sets

Question: 

What are the requirements for installing “valley set” overlay roof trusses? I am interested in nailing and support conditions. Some engineers ask for the bottom chord of the valley truss to be ripped to match the roof pitch of the underlying trusses. Is this necessary?

Valley Sets

Question: 

What are the requirements for installing valley sets over roof trusses? I am interested in nailing and support conditions. Some engineers ask for the bottom chord of the valley truss to be ripped to match the roof pitch of the underlying trusses. Is this necessary? How can I calculate values for uplift resistance for the building inspector?

Truss Bracing At Supports

Question: 

I almost always see wood trusses erected with no stability bracing at points of support. It seems to me that common sense and section 3.3.3.4 of The American Wood Council’s National Design Specification for Wood Construction (NDS) require that lateral support be provided at points of bearing. Plywood decking doesn't provide any more restraint for a wood truss than it does for a roof joist. I doubt if it was a concern with short span trusses having 4 in.

T-bracing

Question: 

The truss industry maintains that the design of truss roof and floor system permanent bracing is the responsibility of the building designer. System permanent bracing covers the entire structure and all bracing element interactions.

Gable End Bracing

Question: 

Is there a detailed table for gable studs that gives the maximum length a vertical member can be before a lateral brace is required?

Long Span Truss Installation

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.

Use of Resilient Channel or Hat Channel to Meet the Lateral Restraint/Bracing Requirements of the Bottom Chords of Wood Truss Floor Systems - Educational Program

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.

Parting Shots

NFC member shares proper bracing in action.

Resilient Channel or Hat Channel: Use to Meet the Lateral Restraint/Bracing Requirements of the Bottom Chords of Wood Truss Floor Systems

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.

Planning Ahead: What Issues Should SBCRI Explore?

The Industry Testing Subcommittee is making plans to keep SBCRI busy in the coming year.