The Post-Tensioning Institute (PTI) is an American nonprofit organization committed to advancing the quality, safety, efficiency, profitability, and use of post-tensioning systems. PTI's manuals and technical guides are designed to provide guidance on the design, construction, maintenance, and repair/rehabilitation of post-tensioned concrete structures. Additionally, PTI aims to ensure that specifiers and purchasers of post-tensioning materials receive products and services that meet a standard of quality through its plant and field personnel certification programs. Members of the Institute include major post-tensioning companies, as well as more than 500 professional members, engineers, architects, and contractors from around the globe.