The ASCE Design Guide for FRP Composite Connections on page 371, item 3, states that using sheetmetal screw for connections results in “unavoidable failure,” as follows:
“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 371-3