Post-Tensioning Technologies

Post-tensioned bridge construction has become increasingly popular and financially competitive with traditional prestressed concrete and steel plate girder bridges. Unfortunately, Indiana has experienced several construction-related problems in the few post-tensioned structures built, some of which have caused significant long-term durability concerns. Indiana's problems have generally been attributed to a lack of a standard set of specifications for post-tensioned construction as well as inexperience and inadequate training of contractors and inspectors. These types of issues, however, were once more prevalent throughout the industry and much work has been accomplished in recent years to address these issues. This research program had two primary objectives: (1) to improve the quality of post-tensioned bridge construction in Indiana and (2) to provide the State with more confidence when using this type of construction. First, past problems related to post-tensioned construction were identified, and for each, case studies were conducted. Each case study includes an overview of the bridge, a summary of the problems related to post-tensioning, and possible sources and remedies to those problems. Next, a standard post-tensioning construction specification was developed. The specification addresses problems specific to Indiana which were found in the case studies and common problems experienced in the industry as a whole. Specifically, the specification addresses industry standards of practice, requirements for certification and experience of personnel, and proper testing and sampling procedures. In addition, specific recommendations are provided for training programs and certification of INDOT construction personnel to ensure they are properly trained to inspect post-tensioned construction.