Effects of splice joint geometry and bolt torque on the serviceability response of pultruded glass fibre reinforced polymer composite beams

Thirty-six, four-point flexure tests on simply supported pultruded glass fibre reinforced polymer composite (GFRP) Wide Flange (WF) beams with mid-span bolted splice joints are described. The joints were fabricated with two and six pultruded GFRP splice plates. Three splice plate lengths were investigated and two bolt torques were used to tighten the bolts. Each of the twelve splice joint combinations was subjected to three repeat tests up to the serviceability deflection limit. Their load versus deformation responses were shown to be linear and repeatable. During each test loads, support rotations, splice joint end rotations and mid-span surface strains were recorded for each mid-span deflection increment. The beams' transverse stiffnesses and splice joints' rotational stiffnesses were derived from the test data. The variation of the stiffnesses with splice plate length, number of splice plates and bolt torque was also quantified. A simple analysis was developed for splice-jointed beams and was used to predict the transverse and rotational stiffnesses determined from the test data. It was shown that the transverse stiffnesses could be predicted to within 10%, provided a rigid-body rotational correction was applied. The correction also provided an estimate of the splice joint's slip displacement.