AASHTO LRFD 5.4.4.1 limits the size of prestressing steel to 0.6 inch diameter (See Table 5.4.4.1-1). This software supports prestressing steel with diameters greater than 0.6 inch, specifically 0.62 inch and 0.7 inch. The use of these larger strand diameters is to be considered experimental.

Important engineering parameters have not yet been established for the larger diameter strands. These parameters include bond, transfer length, development length, and relaxation. The forumations in the AASHTO LRFD specifications do not explicity support strands greater than 0.6 inch in diameter.

This software uses the AASHTO LRFD specifications assuming the forumations are adequate for 0.62 inch and 0.70 inch diameter strands. This should be considered experimental.

NCHRP Project 12-109 is investigating the use of 0.7-in diameter strands for pretensioned girders. This project is scheduled to be compled in December 2021. This software will be updated with the findings from that project and any recommendations that are subsequently adopted by AASHTO.