Group effect of GFRP-timber bolted connections in tension

Steel plate bolted connections are frequently used in timber structures. However, these connections may incur durability problem due to the corrosion of the steel plates. This paper proposes using GFRP plate to replace steel plate in timber connections to mitigate the corrosion issue. The group effect of the proposed GFRP-timber bolted connection is studied. Tensile tests of GFRP-timber bolted connections were conducted considering a number of variables including bolt diameter, bolt pitch distance, bolt row number, bolt column number. The failure modes and the load–displacement curves of the connections were reported. Experimental results showed that the group effect of the GFRP-timber bolted connection is strongly affected by the bolt diameter and number of bolts, but little affected by bolt pitch distance. The effect of the number of bolt columns on the group effect was also discovered and quantified. The design equation of the timber bolted connection in Eurocode 5 was modified considering the effects of various parameters. The modified equation was then verified using the experimental data in this paper. Finally, detailed recommendations were provided for the design of the proposed GFRP-timber bolted connection.