FRP Z-Spike Repairing of Wood Railroad Crossties

Load tests of the effect of fiber-reinforced polymer (FRP) reinforcing rods (Z-spikes) on the flexural stiffness of deteriorated railroad crossties were conducted. Reinforcement was provided by installing 13 mm (0.5 in.) diameter polyglass polyester resin fiberglass rods bonded in place using epoxy-resin. The Z-spikes were inserted into the deteriorated railroad crossties perpendicular to the primary bending axis to provide horizontal shear reinforcement and improve flexural stiffness. They were installed in pairs starting at each end of the crosstie specimen and moving inward. A total of ten rows were sequentially inserted into each crosstie specimen with load tests performed after each successive row installation. Results from load tests show an average increase in effective flexural stiffness (EI) of 58% with all ten rows of shear spikes inserted into the crossties.