By Emory Bryan, The News On 6

TULSA, OK -- The City of Tulsa is conducting safety checks on three bridges over the Arkansas River.  It's part of a regular inspection cycle that takes an unusual piece of equipment.  The state requires the inspections on the city owned bridges.  The challenge is not the inspections, it's getting to the right spot to do them.

An unusual truck is the only way to get a bridge inspector where he needs to be.  It's called a snooper.  And, since the city only needs one for a few days every other year, they hire the work out.

"We can't see the underside of these bridges, so we have to use this specialized piece of equipment to check the caps, the rollers, the piers, everything associated with this structure," said City of Tulsa Engineer Chris Cox.

The 21st Street Bridge was built in 1984 and the city is required to inspect the underside every two years.  It takes a full day to inspect the bridge.  If any problems are found, the repairs will come later.

An inspector is sent over and under the bridge on the snooper where the cracks, the rust and all of the other problems are visible.

"Looking for any cracks or exposed rebar," said bridge inspector Glen Watkins.

Inspector Glen Watkins says the bridge is in good shape, even though the concrete is cracking in ways that would be dangerous on a bridge over a road.

"If it wasn't over a river it would be, that cracked concrete would go through somebody's windshield, but it's OK because it's over a river," said bridge inspector Glen Watkins.

The 21st Street Bridge rates 77 on a scale of 100 which is better than most.

Even though traffic causes some wear and tear, the city engineer says the salt that's used to clear ice off the bridge causes the most damage.

"It will eventually leach through the pavement.  That's why it's so important to see the underside of the bridge to see how the pavement is holding up," said City of Tulsa Engineer Chris Cox.

The inspectors finished the 21st Street Bridge on Monday. 

On Tuesday, they'll work on the 11th Street Bridge.  The 71st Street Bridge will be inspected on Wednesday.