60 Ft Truss Span Installation Dangers
Question:
How do I, as a truss manufacturer, adequately advise my customer against the dangers of 60 ft. and over truss span installations?
Answer:
IBC 2012 and 2015 include the following requirement:
2303.4.1.3 Trusses spanning 60 feet or greater. The owner shall contract with any qualified registered design professional for the design of the temporary installation restraint/bracing and the permanent individual truss member restraint/bracing for all trusses with clear spans 60 feet (18 288 mm) or greater.
The recommendations in SBCA’s BCSI-B11 Summary Sheet are based on actual field experience but are only a guide for the qualified building designer, builder or erection contractor. It is not the responsibility of you, the truss manufacturer, to determine the exact handling, installing and bracing of the trusses you manufacture. Offer the summary sheet as a recommendation.
The summary sheet notes that for trusses over 60 ft., a professional engineer should be involved. This is because of the increased risk involved with trusses with large spans. When you achieve large spans like 60 ft. or more, temporary bracing becomes an extremely important issue! Hoisting 60 ft. and larger span trusses is also a challenge, and the summary sheet provides recommendations for this task as well (namely, that strongback/spreader should be used).
You should take extra caution with long span trusses. Know who is going to erect them, and go over the summary sheet with that contractor.