Research into fiber reinforced polymers (FRP) for strengthening applications has an established tradition. Confidence in deploying the technology has increased over the years, and reliable design procedures are available (CNR, 2014; ACI, 2008). Nonetheless, areas of improvements still exist and require further investigation. Premature failure due to debonding is identified as a major limitation to the efficiency and ductility of externally bonded FRP strips (EB-FRP). A solution consists in mechanically anchoring the composite sheet to the concrete substrate, and spikes represent a commonly deployed anchoring solution. A quantitative approach to characterization and design of anchoring solutions is still at its early stage of development. An accepted strength characterization method for single anchors and coupled joints is missing, along with the definition and validation of design algorithms for flexural applications. The research presented in the following, focusing on anchoring spikes, lays within a comprehensive effort to address such challenges for a wider range of traditional and innovative anchoring shapes. A possible solution to the design problem is proposed in terms of a simplified algorithm. The proposed algorithm is validated on a small number of anchored slabs, flexural tested in a three-point-bending configuration. The slabs- behavior is discussed, and consistency with the proposed model is detailed. The proposed model features good experimental matching in the cases considered. Experimental validation over a larger dataset is beyond the purposes of this study, and shall be performed before application to real-case design.