Abstract:
Existing reinforced concrete structures are frequently deemed to be prone to severe damage and/or collapse as a result of the loads that the structure is expected to experience if it were to be subjected to large intensity earthquake shaking. Among the different approaches to elevate the seismic capacity of existing reinforced concrete structures is the use of externally bonded Fibre-Reinforced Polymer (FRP) systems. The use of FRP materials as Externally Bonded Reinforcement (EBR) to strengthen and/or repair existing Reinforced Concrete (RC) structures is widely documented, and various methods exist to increase the bond strength and/or ensure load-path continuity between FRP composites and the concrete substrate. The use of FRP anchors to increase the capacity of EBR systems offers a number of critical advantages compared to other existing methods. However, premature debonding often occurs before the ultimate strength of the carbon fibre sheets is reached, compromising the reliability and/or the efficiency of the intervention. One of the methods to ameliorate premature debonding is the use of fibre reinforced polymer anchors to connect the FRP sheets to the concrete structure, ensuring continuity of the load path. Despite the growing use and research attention given to FRP anchors a corresponding design guideline has not yet been produced, which is the main impediment to the implementation of FRP anchors in EBR-FRP systems (Kalfat et al. 2013). The first step to develop the necessary design methodology is to identify the different failure modes that the anchors may exhibit, depending on the anchor part that fails. Initial efforts have been made to identify the possible failure modes of straight anchors (Ozbakkaloglu & Saatcioglu 2009; Kim & Smith 2009) and failure modes related to the dowel and the fan component have also been investigated to a certain level (Kim & Smith 2010; Kanitkar et al. 2016). No comprehensive research has been undertaken to investigate the failure of the fibre in the key portion of FRP anchors for a range of anchor size and fanning angle α, depending on the material properties of the resin and the FRP materials. The objective of the current research is to develop a design methodology to calculate the anchor capacity when exhibiting fibre rupture failure mode and to verify that methodology with a case study.