Graduation Year

2018

Document Type

Dissertation

Degree

Ph.D.

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Civil and Environmental Engineering

Major Professor

Gray Mullins, Ph.D.

Committee Member

Rajan Sen, Ph.D.

Committee Member

Delcie Durham, Ph.D.

Committee Member

Kathleen King, Ph.D.

Committee Member

Michael Stokes, Ph.D.

Keywords

Bridge Piling, Modulus of Elasticity, Prestress Losses, Service Life, Transfer Length

Abstract

Approximately 50% of the Nation’s infrastructure was built over 40 years ago for a 50 year service life according to the National Association of Corrosion Engineers [72]. To mitigate the cost of major repair or replacement at 50 years, AASHTO now requires all new bridge construction to have a 100 year service life. One of the main challenges in achieving this goal is avoiding corrosion, especially in warm, saltwater environments like those found in the Southeastern United States. Elements that cross the waterline (piles) are a weak link the infrastructure. Good quality concrete easily maintains a service life of 75+ years, and as such, a potential solution is to use corrosion resistant, high strength (150 ksi -240 ksi) stainless alloys which have been designed to resist stress corrosion cracking. This study builds upon earlier corrosion studies by using the same alloys compositions and determines/corroborates the limited information on their mechanical properties. In addition, the feasibility of replacing grade 270 strand with a stainless alloy strand with regards to both constructability and code provisions is discussed. The findings are that the duplex family, specifically Duplex 2205 has an advantage over other high strength stainless alloys. A limiting factor is the alloy has low ductility when cold worked to high strengths. A ductility of only 2% for Duplex 2205 was found, whereas the ASTM A416 standard requires 3% and typical grade 270 steel often exceeds 6% strain at fracture. Other than the limited ductility at fracture, the Duplex 2205 and other high strength stainless steels have the potential, including long term cost savings, to serve as an alternate strand material for elements exposed to corrosive environments.

Download

Share

COinS