Stainless Steel Strands for Prestressed Concrete Bridge Elements (2025)
Chapter: Summary
SUMMARY
Stainless Steel Strands for Prestressed Concrete Bridge Elements
Corrosion of carbon steel reinforcement and prestressing strands leads to the degradation of concrete structures and remains a significant challenge for bridge owners (Belarbi and Nanni, 2022). In recent years, highly corrosion-resistant stainless steel prestressing strands have become available as an alternative to conventional carbon steel strands. These materials also present an alternative to carbon fiber reinforced polymer strands. However, stainless steel prestressing strands have some differences in material properties, such as reduced strength and tensile strain, that require new approaches when designing concrete bridge elements prestressed with stainless steel (SS) strands. The lack of design guidance for SS strands, along with its significantly greater cost, has prevented the widespread use of these strands.
This report describes the research conducted under NCHRP Project 12-120, “Stainless Steel Strands for Prestressed Concrete Bridge Elements,” to develop requirements for design and construction using stainless steel prestressing strands, and design guidelines for use of the strands. The project involved both analytical and experimental investigations to characterize the behavior of stainless steel prestressing strands and evaluate their structural performance. With such information available to owners and designers, it is anticipated that this relatively new type of strands will become more widely used with their outstanding corrosion-resisting properties contributing to the construction of longer-lasting bridges. To assist designers in becoming familiar with the proposed requirements for SS strands, five design examples for pretensioned concrete bridge elements have been prepared, including (1) conventional bridge girders with composite slabs, (2) full-depth precast double-tee, (3) short-span stemmed and (4) solid slab sections, and (5) prestressed concrete piles. Posttensioned elements have also been addressed in the project and requirements. The report concludes with a summary of the research findings and recommendations for further research. As a result of this research, findings are documented in three key publications:
- NCHRP Research Report 1161: Stainless Steel Strands for Prestressed Concrete Bridge Elements;
- Proposed language for consideration by AASHTO, provided to AASHTO as “Proposed LRFD [Load and Resistance Factor Design] Guide Specifications for Design and Construction of Concrete Bridge Elements Prestressed with Stainless Steel Prestressing Strands” and “Guidelines for Design and Construction of Prestressed Concrete Elements with Stainless Steel Strands.”
