Tuesday, March 31, 2026 11:00 AM - 1:00 PM, DFW
This session will cover the use of a dual banded PT tendons layout in two-way slabs in concrete buildings. It will provide historical information on the evolution of this tendon layout through analytical study and academic laboratory research study. The connection between these studies and the eventual code provisions that are now in ACI-PTI 320-25 will be discussed. Details regarding the code provisions will be explained, and example applications will be illustrated. Historical and contemporary case studies of projects using a dual banded tendon layout will also be highlighted and featured.
Learning Objectives:
(1) The reasons and advantages associated with implementing a dual banded tendon layout instead of a banded-distributed tendon layout;
(2) Understand the results of the analytical studies and research testing that informed the new code provisions;
(3) Understand how to apply the ACI-PTI 320-25 code provisions to a new two-way slab design;
(4) See how the historical and contemporary case studies using dual banded PT highlight real world performance.
History of PT Tendon Layouts in Two-Way Slabs
Presented By: Tim Christle
Affiliation: Post-Tensioning Institute
Description: This presentation will discuss the historical evolution of PT tendon layouts for two-way concrete slabs, ranging from the original "basket weave" concept to today's dual banded alternative. The research, analysis and testing that occurred to develop the classic banded-distributed layout will be revisited, and the many reasons for pursuing a dual banded layout will be highlighted. The pros and cons of each layout derivative will also be discussed to provide a comparative perspective.
Dual Banded Analytical Studies and Research Testing
Presented By: Carin Wollmann
Affiliation:
Description: This presentation will discuss the analytical studies performed over time to evaluate the viability of a dual banded tendon layout alternative. It will also present the results of the laboratory research testing performed at Virginia Tech under the leadership of Dr. Carin Roberts-Wollmann, which expanded the studies of this alternative tendon layout. The information highlighted in PTI Technical Note No. 22, "Dual-Banded Post-Tensioning Tendon Layout", will be shared, and the combination of conclusions from the analytical and lab testing studies will be summarized as they then lead into what would become a code change proposal.
ACI-PTI 320-25 Code Requirements (Current/Upcoming) for Dual Banded PT
Presented By: Don Kline
Affiliation: Kline Engineering and Consulting, LLC
Description: This presentation will cover the new code requirements in ACI-PTI 320-25 which provide the first ever opportunity for designers to utilize a dual banded PT tendon layout in two-way concrete slabs. The specifics of these code provisions will be described in detail, aligning them with the analysis and testing that informed the structure of the provisions. The development of additional provisions in the current ACI-PTI 320 code cycle, allowing for flexible solutions somewhere between fully dual banded and traditional banded-distributed will also be discussed, with context for the importance of this additional design flexibility.
Case Studies Using Dual Banded PT Layouts
Presented By: Martin Cuadra
Affiliation: Uzun Case, LLC
Description: An overview of historical case studies where "pseudo" dual banded tendon layouts were used, plus new case studies where contemporary dual banded layouts were used will be shared. Design considerations, detailing of non-prestressed reinforcement to go along with the PT reinforcement, lessons learned, and successful outcomes will be discussed, spotlighting design and construction goals and strategies. Recommendations for incorporating these strategies into future building projects will also be shared.