Behaviour of pultruded beam-to-column joints using steel web cleats

Response of pultruded Fibre Reinforced Polymer (FRP) beam-to-column joints with steel bolted web cleats is studied through physical testing. Two joint configurations are considered with either three or two bolts per cleat leg, as per drawings in a pultruder's Design Manual. Moment–rotation curves, failure modes and potential performance gains from semi-rigid action are determined from two batches, each having six nominally identical joints. Results show that initial joint properties for stiffness and moment can possess, at 19 to 62%, an extremely high coefficient of variation. All joints failed by fracturing within the FRP column's flange outstands. Because this failure mode has not been reported previously there is a need to establish how its existence influences joint design. As joint properties for the three- and two-bolted configurations are not significantly different, the middle (third) bolt is found to be redundant. Damage is shown to initiate within the column flange outstands when the mid-span deflection of a 5.08m span beam, subjected to a uniformly distributed load, is span/500. This is half the serviceability vertical deflection limit recommended in the EUROCOMP Design Code and Handbook. The mean joint moment resistance for design is established to be 2.9kNm and this is 1.5 times the moment for damage onset. •Moment–rotation response of pultruded joints with steel web cleats is studied.•Joints fail by delamination cracking in pultruded column flanges.•Damage can initiate at a mid-span deflection of span/500, which is half of the limit suggested in the design codes.•Due to practical applications of steel-cleated PFRP joints, it is crucial to study design implications of the joints' failure modes.