## 9 Discussion  
This section provides further explanation and discussion for the most relevant items in this study:  
* FRP anchors were designed using the strength model by [PERSON] and [PERSON] (2010), the only available model at the time. Although those equations were calibrated using test data for CFRP anchors made from rolled carbon fiber sheets and are only strictly applicable to straight anchors, they constituted the best design model at the time and were considered appropriate for this project given the ample inclination angles adopted in both applications.
* FRP anchors were designed to develop the allowable design strain in the FRP laminates, that is, 0.004 for full-wrap and anchored U-wraps schemes per \(\mathrm{ACI}\,440.2\mathrm{R}\), as opposed to a design for FRP laminate rupture. The arguments supporting this specific design approach, which was also used by [PERSON] et al. (2010), are twofold: first and foremost, FRP laminates used to strengthen the yielding region of an MRF beam in shear should not be designed to reach a strain level close to rupture, given the brittle nature of both FRP materials and shear failures and the catastrophic consequences of an MRF beam collapse. Second, anchors designed to fully develop the tensile strength of the FRP laminates are in many cases impractically large, with the drilling of large holes in RC members becoming a concern.
* The development of a full-wrap strengthening scheme for the end-yielding regions of the deficient MRF beams was justified by the following: (1) the ineffectiveness of the embedded FRP anchors added to S1B at the end-yielding region due to premature anchor pullout, resulting in S1A and S1B failing at a similar shear load and rotation demands, (2) the lack of intermediate vertical crossties affecting multiple MRF beams in the building, (3) the reversible nature of seismic demands, and (4) the consequent potential for buckling of the top flexural reinforcement if only a U-wrap were implemented.
* The saw-cut grooves on specimen S5 were intended to force the formation of an even distribution of thinner flexural cracks between the FRP strips to mitigate premature FRP debonding by minimizing concrete cracking behind the FRP reinforcement and, second, to enhance the ductility at the hinging region. Despite the limited data from only one specimen, the authors believe that the evenly spaced crack-control joints promoted a distribution of the plastic rotations across the hinging region that contributed to a more ductile behavior compared to a flexural failure with the plastic rotations concentrated at one dominant crack.  
Figure 26: Field-prepared test samples to validate cured tensile properties (ASTM D3039).  
* Strains in the FRP reinforcement applied at the end-yielding regions were not monitored in any of the tests presented in this paper; thus, the adequacy of the prescriptive maximum allowable strain of 0.004 per ACI 440.2R cannot be discussed, and the shear contribution of the FRP (V\({}_{\text{f}}\)) cannot be verified from the experimental data.
* Due to budget constraints and the high cost of each of these nearly full-scale tests, the performance of the retrofit concept on S5 had to be evaluated without a control specimen (i.e., identical to S5 but with no shear retrofit).