Glass Fiber Reinforced Polymer Dowel Bar Evaluation

Glass Fiber Reinforced Polymer (GFRP) dowel bars were installed on one new construction project and two dowel bar retrofit projects to evaluate the performance of this type of dowel bar in comparison to steel dowel bars installed on the same contracts. The primary data collection site (I-82, Yakima River Br. Vic. to Granger) included 67 joints retrofit with GFRP dowels and an equal number of epoxy coated doweled joints that serve as the control section. Falling weight deflectometer (FWD) testing will be used to evaluate the load transfer efficiency (LTE) of the two types of dowel bars. Periodic coring of the concrete at the joints is also planned to examine the condition of the GFRP and epoxy coated dowels. Post-installation FWD testing of the primary data site revealed that the average LTE of the joints retrofit with epoxy coated dowel was higher than the joints retrofit with the GFRP dowels and that the difference was statistically significant. Preinstallation FWD testing showed no difference in the LTE of the joints in the areas where the GFRP and epoxy coated dowels were installed.