| This thesis deals with the innovative design, testing, and analysis of a novel wedge anchor system for gripping CFRP rods, thereby allowing the full load carrying capacity of the rods to be attained. The potential use of this technology lies in prestressing applications for new and rehabilitated structures.; A study of the gripping mechanism of CFRP rods was conducted through clamping and pull-out tests. The effects of several significant parameters were determined. Movement of the rod was characterized by the shear stress at the rod/enveloping sleeve interface. The stress increased with increase in contact pressure and with the use of soft sleeve materials resulting in more grip. Grip was further enhanced by sandblasting the contact surface of the sleeve and when smooth CFRP rods were used.; The contact pressure distribution over the rod surface was determined using 2D and 3D finite element analysis, in conjunction with a mathematical model. The contact pressure for any given transverse section was higher at the top of the rod and gradually decreased to zero in the horizontal plane. In the longitudinal direction, the contact pressure was higher at the entrance of the rod into the sleeve, indicating a potentially damaging stress concentration. The results of the mathematical model were compared with those of the finite element analysis and the two were found to be in good agreement.; Different wedge anchor systems were designed and tested. Analysis of the results was conducted using 3D, axisymmetric finite element and mathematical models. Using different presetting distances, the contact pressure distribution on the rod surface was determined for differential angle, variable thickness barrel and circular profile anchors. This last anchor allowed the maximum load capacity of the rod to be achieved without premature failure. This was attained with no presetting of the wedges. The relative displacement of the anchor components using a 3D finite element model showed good agreement with the experimental results.; It is recommended that further testing and analysis be carried out to determine the influence of loading time and frequency on the gripping behaviour. |
