An experimental study on the interfacial bonding performance of horizontally embedded CFRP strips to concrete

Abstract

The near-surface mounted (NSM) carbon fiber-reinforced polymer (CFRP) strengthening method has a good efficiency in regard to strengthening aging or damaged concrete bridges. To prevent the end debonding failure of NSM CFRP-strengthened beams and simplify the construction, the authors propose a near-end enhanced embedded (NEEE) CFRP strengthening method. In this method, the CFRP strips are horizontally embedded in the grooves that are prefabricated on the surface of concrete structures. To investigate the interfacial bonding performance of the horizontally embedded CFRP strips, a total of 17 single-lap shear test (SST) specimens are fabricated to study the failure mode, ultimate capacity, load–displacement response, and distribution of interfacial shear stress. Moreover, the effects of the groove width, groove depth, embedding depth of horizontal CFRP strips, and concrete strength are analyzed and discussed. Then, a local bond-slip model with characteristic parameters (i.e., the maximum bond stress, critical slip, and residual bond stress) is proposed to describe the interfacial bond behavior. These characteristic parameters are independently determined according to the experimental results of each specimen. Furthermore, a generalized bond-slip model is proposed and validated, which can directly predict the characteristic parameters according to the geometry and material properties of SST specimens.