Abstract
Wind damage on lightweight roofs of industrial and commercial buildings appears to be quite common in North America. One of the primary reasons for the observed damage is inadequate design against wind uplift. This paper describes the load mechanism and testing methodology of mechanically attached single-ply roof membranes and presents a newly designed fastener system incorporating the consequences of the load mechanism. The new UEAtc approval test, which will be discussed, is based on the observed load mechanism. Using a method to determine the deflection of the roof membrane under wind suction, the reduction in fastener load due to the test apparatus constraint may be calculated. This leads to a correction factor, which will be incorporated in the UEAtc guideline to account for the limited size of the test specimen. The same computational method may be used to calculate the increased load of a fastener if the neighboring fastener fails. Based on such a calculation, a physically meaningful safety factor has been specified and will be used in the UEAtc guideline. Finally, a design methodology for an optimal attachment system will be described.
Wind damage on lightweight roofs of industrial and commercial buildings appears to be quite common in North America. One of the primary reasons for the observed damage is inadequate design against wind uplift. This paper describes the load mechanism and testing methodology of mechanically attached single-ply roof membranes and presents a newly designed fastener system incorporating the consequences of the load mechanism. The new UEAtc approval test, which will be discussed, is based on the observed load mechanism. Using a method to determine the deflection of the roof membrane under wind suction, the reduction in fastener load due to the test apparatus constraint may be calculated. This leads to a correction factor, which will be incorporated in the UEAtc guideline to account for the limited size of the test specimen. The same computational method may be used to calculate the increased load of a fastener if the neighboring fastener fails. Based on such a calculation, a physically meaningful safety factor has been specified and will be used in the UEAtc guideline. Finally, a design methodology for an optimal attachment system will be described.
Date
9/1991
9/1991
Author(s)
Hans Gerhardt; Rainer Gerbatsch
Hans Gerhardt; Rainer Gerbatsch
Page(s)
276-284
276-284
Keyword(s)
approval testing; fastener load; mechanical attachment; wind load
approval testing; fastener load; mechanical attachment; wind load