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Component Manufacturing dverti$ dverti $ er
Don’t Forget! You Saw it in the
July 2020 #12252 Page #35
Adverti$$er
How Can Member to Member Gaps Be Corrected?
Background The Advertiser - June 2017 | Page #30 Compliance with ANSI/TPI 1–2014 requires maintaining member to member gaps at less than 1/8 inch. An exception would be for floor truss chord splices where the limit is 1/16 inch. While building trusses, the code calls for tight joints. In a roof truss where member to member contact exists, the joint calculation for design assumes one member is hard against the other members. In a compression situation, the force will compress the area consuming the gap. When this happens, it creates a change which effectively reduces the member length and changes the resultant geometry. Often this will create additional deflection that was not considered in the original design.
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ost readers are aware of the issues with member to member gap, but as a refresher it might be important to have a review. Recently, an evaluation was made of a fabricator via a video conference. In the review, the following truss was inspected. Figure 1 shows the actual photo. The truss was passed, and it was communicated to the manager that the truss looked great. Subsequently, a field audit was made the next day on-site. The trusses were reinspected (see Figure 2). Do you see the problem?
Figure 1. Photo audited by video conference.
While it might not have been apparent to the person looking at the photograph, the truss pitch transition joint needed a more thorough investigation. That on-site investigation led to the following findings. Figure 2. Photo from on-site audit. Continued next page
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