Commuters using the aging Bismarck-Mandan Liberty Memorial Bridge possibly had second thoughts about crossing it following Wednesday's collapse of the interstate bridge in Minneapolis.

Although the 84-year-old bridge has been closed for safety concerns in the past, the state transportation director said motorists don't need to worry.

North Dakota Department of Transportation Director Francis Ziegler said Memorial Bridge is safe. Still, in the wake of Wednesday's tragedy in the Twin Cities, Gov. John Hoeven has asked Ziegler to review the inspection protocol of the state's bridges and other critical transportation infrastructure to ensure continued public safety.

There are 5,026 bridges in North Dakota, which are inspected on a two-year cycle.

Ziegler said he has total confidence in the state's inspection program, and that safety is the foremost concern at NDDOT. If problems are found on bridges, the frequency of the inspections is increased until the problems are solved.

While Ziegler assures motorists that there are no risks in traveling the old Memorial Bridge, not everyone is so sure. Local resident Mike Miller sent this letter to the Tribune on Thursday:

"In the wake of the bridge collapse, I35W, in Minneapolis, which was 40 years old, I, for one, will no longer cross the Memorial Bridge, which is much older and is in the process of being replaced, for good reason, I am sure. I think, in light of the Minneapolis collapse, perhaps the Memorial bridge should be reevaluated. Perhaps avoided? Perhaps closed?"

Ziegler was assistant director at DOT two years ago, when Memorial Bridge was closed for safety concerns. Steel bands were added to the bridge to support weakened sections of support piers. The bridge is scheduled to be replaced next year by a new span, which is being constructed just to the south of it.

"(We) wanted to make sure we knew what was going on with the bridge with an inspection,"Ziegler recalls. "When we got the call that they had drilled through the piers and were only finding gravel inside, we knew it was in really bad shape. Immediately we made the call to director Dave Sprynczynatyk and said it had to be closed."

The support bands were put in place. Ziegler has no doubts that the bridge will remain intact until the new one is completed.

Joe Larson, project manager for Lunda Inc., the contractor building the new bridge, says he has driven over the Interstate 35W bridge in Minneapolis-St. Paul many times. He's heard that between 140,000 to 200,000 vehicles cross it every day.

"It's a terrible tragedy and my heart goes out to those people involved," Larson said. "It was a strange situation and I don't know enough about it to really comment."

Larson pointed out that this part of the country puts additional stress on structures because of the weather.

"One good example is that it was 103 degrees this week and in the winter we had temperatures exceeding 40-below,"Larson said. "That kind of temperature swing causes havoc on structures like bridges, and that's why they are closely monitored."

Memorial Bridge averages about 15,000 vehicles daily, and the new bridge is expected to handle between 18,000 to 19,000, the NDDOT said.

"Bridges are designed for 50 years of life and you can always get a lot more out of them if they are well maintained," Ziegler said. "The Memorial Bridge has lasted 84 years, and there are people that would like it to last a lot longer. But it does have a lot of traffic and in order to maintain safety it has to be replaced."

Ziegler acknowledged the stress put on Memorial Bridge by the weather and that it goes through some amazing expansion and contraction rates. He also noted that a lot of sanding and salting is done on the bridge, which also degrades its integrity.

There are concerns that the federal aid program for transportation is not keeping up with the cost of inflation for construction and efforts are underway to make sure the program provide adequate funding in the future.

"The interstate system is 50 years old and in need of rehabilitation and construction," Ziegler said. "In North Dakota, bridge replacement is one of the bigger-ticket items. The Four Bears bridge cost $57 million. We're spending $43 million on the Memorial Bridge, and we're designing another bridge at Drayton which will cost an estimated $30 million."

In construction of the new Memorial Bridge, every precaution is being taken to ensure the material, engineering and construction meet the highest standards.

"We even have a consultant at the girder fabrication plant watching the beams being made to make sure they meet our specifications," Ziegler said.

Larson also points out that a lot of inspections are done on the new bridge to make sure of its quality.

(Reach reporter Gordon Weixel at 250-8255 or gordon.weixel@;bismarcktribune.com.)