Effect of Clamping Force on the Strength of Bolted Joints in Pultruded GFRP Laminates
Takeshi KISHIMA
Abstract:FRP might be widely applied to infrastructures in coast areas, because it is a corrosion-resisting material. Joints such as adhesive joints and bolted joints are required in application of FRP to infrastructures. Pultruded FRP is desirably applied to infrastructures because its mass production could bring about lower cost. The purpose of this paper is to obtain the effect of clamping force on the strength of bolted joints in pultruded GFRP laminates through the experiment. The two types of bolted joints are focused, friction-type bolted joints and bonded-bolted joints. The strength of friction-type bolted joints increases with the clamping force. The failure mode is bearing failure for joints without clamping force and shear-out failure for joints with clamping force. The strength increase with clamping force is brought about by the increase of bearing strength and the friction between the specimen and the attached plate. The strength of bonded-bolted joints also increases with the clamping force. The failure mode is adhesive failure for adhesive used joints and bearing or shear-out failure for adhesive tape used joints, because adhesive tapes have lower strength than adhesives. The strength increase of adhesive used joints with clamping force is brought about by the increase of failure stress at the end of adhesives. On the other hand, the strength increase of adhesive tape used joints with clamping force is brought about by the increase of bearing strength. Key Words:FRP, Friction-type bolted joints, Bonded-bolted joints, Clamping force, Failure mode