"Unavoidable Failure" and Other Alarming Facts about Fastening into FRP (and why Composite Metal Hybrid Systems are Best Practice)
"Unavoidable Failure" and Other Alarming Facts about Fastening into FRP (and why Composite Metal Hybrid Systems Like GreenGirt CMH are Best Practice)
Composite metal hybrid systems outperform FRP-only products for several reasons, particularly in their performance at connections and with fasteners. According to the American Society of Civil Engineers’ Design Guide for FRP Composite Connections and Composites Manufacturing Magazine, cladding support products made entirely of FRP often result in “unavoidable failure,” weakened joints, and reduced load capacity.
GreenGirt CMH and SMARTci are made of composite metal hybrid materials to leverage the best properties of both metal and fiberglass – thereby eliminating these four concerns of FRP-only products:
What the ASCE Structural Design Guide says about fastening into FRPs:
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“Improper ‘steel-like’ connection details: One of the major direct causes of rapid stiffness and strength degradation of pultruded members is the use of inadequate connection details. In this case, careful review of the engineering drawings revealed the fact that the majority of the connection details were improper… As a result, failure was unavoidable due to the low tensile and low flexural moduli and strengths of the isophthalic matrix.”
— ASCE Design Guide for FRP Composite Connections, page 371-2
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“A number of research studies were conducted on characterizing the structural behavior of pultruded composite connections. In general, there are three schemes for pultruded fiber-reinforced polymer joints: (1) bolted, (2) adhesively bonded, and (3) combined (bolted and bonded).”
“Drilling a hole in composites sacrifices up to 60 percent of the load carrying capacity. The minute you drill a hole, the fibers become discontinuous, you create stress concentrations around the hole, and you cause delamination, all of which act as failure initiation points, thereby weakening the resulting joints.”
— Composites Manufacturing Magazine, July/August 2017, page 15
Additional Resources:
Additional information and research are available through the following papers and videos from the A2P Technical Library:
