Old highways showcase CSP service life

From the day President Dwight D. Eisenhower signed the Federal-Aid Highway Act of 1956, the interstate system has been a part of our culture—both as transportation in our daily lives and as good-paying jobs on construction projects. The Interstate Highway System is an integral part of the American way of life, and a big contributor to this way of life from the beginning has been corrugated steel pipe (CSP) . Two good examples of where the original CSP installations are still providing service are under old Highway 44 in Walsh County, N.D., and old Highway 52 in Douglas County, Minn.

Old Highway 44 was originally designed and constructed around 1931 and remained unpaved until the early 1950s. As a result of the Highway Act, stretches of this road were used for the northbound lanes of the new I-29. The original blueprints for this project show that reinforced concrete pipe (RCP) was to be used for the center-line crossings, but the contractor inadvertently used corrugated steel pipe. The images shown are from a recent inspection of two CSP installations that date back to the mid-1950s. During the service life of these culverts, the Red River has twice flooded sections of this pavement, once in 1979 and again in 1996. Since then, the pavement sections have been elevated, but the CSP culverts have remained in place.

In 1959, portions of Highway 52 in Douglas County were redesigned into I-94, linking eastern North Dakota to the Minneapolis–St. Paul area. The section of interstate near Ashby, Minn., has rolling terrain, and plan drawings called for areas with high fill heights, sometimes in excess of 15 ft. Again, both reinforced concrete pipe and corrugated steel pipe were designed for cross drains in these areas. With now more than 50 years of service life, this section of highway has remained in good condition. Over the years, old pavement sections have been removed and replaced with new sections. However, the culverts have remained constant, allowing interstate traffic to continue to move virtually uninterrupted.

In November 2006, the Federal Highway Administration issued a memorandum on the pipe selection final rule to implement Section 5514 of the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A legacy for Users (SAFETEA-LU) that all states should be considering all available pipe products that are judged to be satisfactory and equally acceptable on the basis of engineering and economic analysis. All state DOTs have been encouraged to develop pipe-selection procedures that efficiently implement this policy. But this is nothing new for either North Dakota or Minnesota—pipe alternates have been successfully used in these states for more than 50 years.