- A common mistake is thinking that the truss design drawing provides all of the bracing requirements for the truss.
- In the 2006 Edition of BCSI continuous lateral brace has been replaced in by the term “continuous lateral restraint.”
- Bracing the lateral restraint is critical for ensuring truss stability; failure to do so can result in serviceability problems or structural collapse.
- Using different wall bracing methods on the same structure is often acceptable.
- The IRC recognizes eleven total methods for providing wall bracing.
- The continuous wood structural panel sheathing section of the code has caused confusion in terms of whether other bracing methods can be used with it.
- Solar panels—devices that convert solar energy into electricity or heat—are often installed in trussed and conventionally framed roofs.
- To determine if a truss can withstand the load of a solar panel, add the value of the panel to the maximum top chord dead load capacity.
- If a panel can be applied to a conventionally framed roof with the same design load capacity as a truss system, the application should also work in the trussed roof.
- There are many guidelines and recommendations in place to ensure trusses are installed and braced properly.
- Truss Design Drawings show the truss calculation and engineer stamp, but usually show limited bracing.
- It is our hope that BCSI recommendations are followed in the field, but we cannot enforce them.
- The IRC 2006 references BCSI 1-03 in two locations—R502.11.2 and R802.10.3.
- In 2006, BCSI 1-03 was revised and retitled Building Component Safety Information; Guide to Good Practice for Handling, Installing, Restraining & Bracing of Metal Plate Connected Wood Trusses.
- Although BCSI 1-03 is referenced in IRC 2006, you should use the most recent version of the booklet—BCSI.
- When a truss member is damaged, the anticipated flow of loads through the truss is disrupted, and that load must be resisted by another member(s).
- Wood-framed buildings over three stories above grade should be designed under the IBC.
- These buildings fall outside the prescriptive/conventional construction provisions of the IRC and IBC and must be designed using engineering principles.
- A new provision was introduced to the wood truss section (i.e., R810.2) of the 2006 edition of the IRC that permits the use of roof snow load computed using 0.7pg.
- Engineered design, through ASCE 7, is required in instances where the limitations on which the IRC is based are exceeded.
- ASCE 7 snow load design provisions require the evaluation of other conditions that may produce load surcharges in addition to the balanced uniform loads of pf or ps.
- The required bearing length provided on the Truss Design Drawing is based on the lumber used in the truss.
- The bearing area for the wood wall or beam may need to be increased to prevent crushing of these members.
- Table 1 includes the maximum allowable reaction load that selected species of lumber used as wall plates can resist without excessive crushing.
- Toe-nailed connections are a common means of attaching wood joists, rafters and trusses to the top of a supporting wood wall or beam.
- Many applications go beyond the scope of the Conventional Light-Frame Con-struction provisions of the code.
- The resistance provided by a toe-nailed connection is governed by several factors including proper installation, lumber species, length of penetration, and type of nail.
