A NEW STEEL ANCHORAGE SYSTEM FOR POSTTENSIONING APPLICATIONS USING CARBON-FIBER-REINFORCED PLASTIC TENDONS

During the past half century, the use of prestressing in different str uctures has increased tremendously. One of the most important techniqu es of prestressing is post-tensioning. The main problem associated wit h post-tensioning in different structures is the corrosion of the pres tressing steel tendons even with well-protected steel. New materials, fibre reinforced plastics or polymers (FRP), which are more durable th an steel, can be used for these tendons/strands and thus overcome the corrosion problem. However, different shortcomings appear when FRP ten dons are introduced to post-tensioning prestressing applications. For carbon fibre plastic tendons (CFRP), there is no suitable anchorage sy stem for post-tensioning applications. Some of the anchorages develope d by others for use with FRPs are therefore described and assessed. A new anchorage system developed by the authors, which can be used with bonded or unbonded CFRP tendons in post-tensioning applications, is de scribed. The results of direct tension and fatigue tests on CFRPs anch ored with the new system are presented.