Repair and Modification of PT Concrete Structures

Post-tensioning (PT) systems have been used to reinforce concrete structures in the United States since the mid-1950s, and investigation, repair, and design of these systems requires specialized training and experience. This presentation will provide an introduction and overview of the repair and modification of post-tensioned structures. A brief history of post-tensioning systems will be reviewed, as well as typical approaches to evaluating and repairing post-tensioning tendons. Four case studies will be discussed to demonstrate common repair techniques for historic button-head systems and historic and modern monostrand systems; strengthening using external PT; modification of existing PT structures; and examples of problems that may be encountered and prevented during new construction.

Speaker Biography

Tracy Naso is an Associate Principal at Wiss, Janney, Elstner Associates, Inc., in Honolulu, Hawaii, where she has 17 years of experience with the investigation, repair, and strengthening of existing structures. Her expertise is the evaluation, repair, strengthening, and protection of reinforced concrete, including post-tensioned and precast/prestressed systems. Ms. Naso is a member of ACI, ASCE, NCSEA, and the Post-Tensioning Institute (PTI). For PTI, she is a voting member of the Repair, Rehabilitation, and Strengthening Committee, and has served as Chair since 2016. She is also a voting member of the Field Personnel Certification Committee for Unbonded PT-Repair, Rehabilitation and Strengthening Personnel Certification.

Ms. Naso is a licensed Structural Engineer in Hawaii, Illinois, and Nebraska, and Professional Engineer in Wisconsin and North Dakota.