Testing and analysis of pultruded GFRP continuous beams for the deflection serviceability limit state

An investigation of the deformation response of an unequal two-span pultruded glass fibre reinforced polymer (GFRP) wide flange (WF) beam up to the deflection serviceability limit is described. The beam was subjected to vertical point loading at the centre of the longer span. Mid-span deflections, support rotations and outer surface flange strains recorded during major- and minor-axis flexure tests on the beam are presented and shown to be both repeatable and linear. New closed-form shear deformation equations are presented for the forces and displacements of two-span continuous beams of arbitrary span ratio with the longer span subjected to a vertical mid-span point load. The equations have been used to predict the mid-span deflections, support rotations and surface strains recorded during the flexure tests. It is shown that the equations are able to predict the experimental deflections accurately. Depending on the particular support, the rotations (particularly the minor-axis rotations) are slightly under/over-estimated and, in general, the surface strains are over-estimated. It is concluded that this investigation provides further confirmation of the utility of shear deformation continuous beam equations for predicting the deformations of pultruded GFRP beams up to the deflection serviceability limit.