Experimental Investigation of Lap Splices in Externally Bonded Carbon Fiber-Reinforced Plastic Plates

Laboratory tests were performed on large-scale reinforced concrete beams that were strengthened with externally bonded carbon fiber-reinforced plastic (CFRP) plates. The CFRP plates were spliced using butt joints reinforced by bonded lap splice plates. Results of the tests illustrate that the dominant failure mode for the splices was debonding of the lap splice plate that started at one end of the splice plate and progressed inward toward the butt joint. Failure of the splices resulted from a stress concentration at the end of the splice plate and was not due to excessive nominal shear stress on the splice. A small-scale tension test specimen was developed for evaluating splice performance, and the results of the small-scale tests are compared to the beam test results. Application of the results in the design of strengthening systems using butt joints with lap splices is discussed.