Overview of the new PTI/ASBI M-50 Technical Note on Unducted External Post-Tensioning with Epoxy Coated Strand-Overview of the new PTI/ASBI M-50 Technical Note on Unducted External Post-Tensioning with Epoxy Coated Strand

Overview of the new PTI/ASBI M-50 Technical Note on Unducted External Post-Tensioning with Epoxy Coated Strand

Video Transcription

Video Summary

The webinar introduced PTI’s new M50 technical note on unducted external post-tensioning using epoxy-coated strand, an emerging bridge technology that is already well established internationally, especially in Japan. Speakers explained that the tech note was developed by the PTI-ASBI M50 committee and task group to fill a gap in the current M50.3 specification, which does not specifically address this system.<br /><br />The presentation covered the benefits of the technology, including improved durability, direct inspectability, and the potential for future strand replacement. John Cornelius described epoxy-coated strand as a factory-applied, ASTM-controlled product that protects both the outside and internal voids of the strand. He also explained its history, performance testing, and differences from epoxy-coated rebar.<br /><br />Shaheed Islam focused on system-level considerations such as anchorage detailing, bite-through wedges, seating loss, friction, vibration, deviators, sealing, corrosion protection, and installation methods. He emphasized that the system must be qualified as a whole, not just the strand alone. He also shared project experience from the Kishwaukee River Bridge in Illinois, where 24 external tendons were successfully installed in cold weather conditions.<br /><br />Greg Hunsaker concluded by explaining Appendix A of the tech note, which provides sample special provision language for project use. The webinar closed by noting that the tech note will soon be published on the PTI website as a free resource.

Keywords

PTI M50 technical note

unducted external post-tensioning

epoxy-coated strand

bridge technology

PTI-ASBI M50 committee

durability

inspectability

anchorage detailing

corrosion protection

Kishwaukee River Bridge