Patent attributes
Ultra-High-Performance Concrete (UHPC), owing to its superior mechanical and durability properties, presents a unique opportunity for innovative use in unbonded post-tensioned floor systems. In unbonded post-tensioned (PT) slabs and beams, the use of cast-in-place steel confined UHPC Bond Anchors (UBA) can be used to anchor steel prestressing strands for better durability, increased strand ductility, cost-effectiveness, and ease of installation. A conical, steel confining device is used as part of the UBA. The device resists hoop tension and eliminates splitting cracks in the UHPC during prestress transfer. It also helps to reduce the anchorage length. High average bond stress helps reduce the UBA length, and consequently, the material consumption. The bond stress at the strand-UHPC interface can be increased by intentionally roughening or indenting the strand.
