Webinar: Dual Banded Tendon Layout for Two-Way Post-Tensioned Slabs – A History and the Future-Webinar: Dual Banded Tendon Layout for Two-Way Post-Tensioned Slabs

Video Transcription

Video Summary

In the Post-Tensioning Institute's August webinar, Kyle Boyd, the Chair of the Education Committee, introduced the topic of dual-banded post-tensioning layout. The session, which included four presenters, aimed to explore the complexities, benefits, and implementation of dual-banded post-tensioning—an area Boyd has extensively researched. The presenters were Asif Baxi from the engineering consulting side, Tim Crissel, Executive Vice President of PTI, Jonathan Hirsch, lead software developer of RAMConcept, and Dr. Karen Roberts-Wollam from Virginia Tech.<br /><br />The session began with a historical overview by Tim Crissel, explaining the evolution from a cumbersome basket-weave layout in the 1950s to the more efficient banded-distributed layout adopted in the late 1960s and 70s. This was followed by Jonathan Hirsch's discussion on the analytical modeling of dual-banded layouts, which highlighted comparable or superior performance to traditional banded-distributed systems in various stress, deflection, and strength scenarios.<br /><br />Karen Roberts-Wollam presented on the experimental studies conducted at Virginia Tech, which compared the performance of banded-distributed and dual-banded specimens. The results showed very similar deflection and cracking behaviors, confirming the potential for dual-banded layouts to be used without the stringent spacing restrictions currently mandated by the ACI code.<br /><br />Asif Baxi wrapped up by detailing proposed code changes allowing for greater flexibility in tendon layouts, thereby reducing construction costs and enhancing design options. The session concluded with a Q&A, addressing detailing over column heads and the impact of shear lag effects in dual-banded systems.<br /><br />The next webinars will cover high-strength PT bar recommendations, bonded PT durability improvements in bridges, and slab on ground design. The full session recording and further resources are available on the PTI website.

Keywords

dual-banded post-tensioning

Kyle Boyd

Post-Tensioning Institute

Tim Crissel

Jonathan Hirsch

Karen Roberts-Wollam

Asif Baxi

historical overview

analytical modeling

experimental studies