By TrueNorth Steel
When the Eisenhower interstate highway system was developed in late 1950’s and early 1960’s many large diameter structural steel plate pipe were installed.
Standing the test of time these structures have survived nearly 60 years of service and are being extended to accommodate today’s traffic patterns.
Interstate Highway #200 is one of these highways. With increased traffic from North Dakota oil patch production heavy truck traffic is currently the norm.
As safety is always a concern, the highway was widened and additional turning 
lanes were added. Eight existing structural plate pipes were extended at various locations and sites.
Fill heights ranging from 2′ to 40′ were found. The exiting structural plate pipes were found to be in great condition so extending them was no problem.
The plates ranged in diameter from 96′ to 144′ and a were mixture of round and arch plate.
To get a jump on the construction season the contractor chose to extend these plates in the first quarter of the year when other construction activities had halted.
After the structural plate pipe was constructed the weather had warmed up enough for them to backfill and compact to the AASHTO standard outlined in the NDDOT project specifications.
For more information on this project, contact Roger Arenz at (701) 301-2544 or [email protected]. You can also visit TrueNorth Steel at their website.