Concrete Tension Anchorage System
A pre-stressed, pre-tensioned or post-tensioned, concrete structure has significantly greater load bearing properties compared to an un-reinforced concrete structure. Steel rods or tendons are used almost universally as the pre-stressing or post-tensioning members. The steel rods and associated anchoring components may become exposed to many corrosive elements, such as de-icing chemicals, salt or brackish water. If this occurs, the rods may corrode, thereby causing the surrounding concrete structure to fracture. Fibre-reinforced polymer (FRP) rods have been used in place of conventional reinforcing rods. The advantages of using a FRP rod include its light weight relative to steel, resistance to corrosion and its high tensile strength, which in some cases may exceed that of steel. However, FRP rods do not have correspondingly high transverse compressive strength which causes traditional steel rod clamping anchors to crush the rod at its load bearing area leading to premature failure of the FRP tendon at the anchorage point. Due to the lack of a viable anchorage system that can support the stress in the rod without crushing the rod, FRP rods have had limited use in post-tensioned and pre-stressed applications.The UW newly developed and prototyped FRP Anchor System utilizes a unique geometry to disperse the transverse stress at a single load bearing point, associated with current anchor systems, along a length of the FRP tendon housed in the anchor itself. This novel anchor system allows FRP tendons to be used to their maximum load potential (exceeding that of steel re-bar) thereby opening up a variety of new market applications, in particular pre-stressed and post-tensioning concrete building applications.
STAGE OF DEVELOPMENT:
A first generation prototype of the Tension Anchor System has been developed and 50 anchors have been installed in a post-tensioned bridge application as part of a research study. A second generation prototype has been developed and will also be field tested in a bridge re-habilitation project.
Type of Offer: Licensing
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