Bridge Inspection, Part Three: Coordinating River, Rail, & Road

Accessing a bridge for inspection requires several entities to work together. From the Coast Guard to a railroad owner to the highway owner, bridge inspection entails close coordination to gain safe and proper access.

In this third and final part of our Bridge Inspection series, GAI Transportation Technical Manager Mike Beresford, PE, CBSI and Senior Project Engineer Brad Kughn, PE, CBSI tell us what it takes to gain access to a bridge for inspection and exemplify a unique challenge at the Kinzua Bridge Walkway in Mt. Jewett, PA.

Can you give us an example of an in-depth inspection?

Mike: Yes, the inspection of the New Martinsville Bridge in West Virginia that goes over the Ohio River. It took three weeks with two inspectors on site, which is our company policy: two people minimum for safety concerns. An in-depth inspection requires the physical inspection of all primary structural members at “arm’s length.” Because the bridge goes over a major river, we had to coordinate with the Coast Guard to let them know we would be hanging off the bridge and may encroach on the clearance envelope for passageway of boats or other watercraft coming through the river.

For this bridge, to get within arm’s length of structural members, we used an under-bridge inspection crane commonly referred to as a “Snooper” among bridge inspectors. It’s a truck-mounted crane that sits on top of the bridge and uses a four-piece articulated boom arm to reach underneath the bridge. We also had a lift bucket truck on top of the deck that went 100 feet up to the truss portions above the roadway. We worked both inspection access vehicles together during the inspection.

Bridge inspection
Snooper cranes provide the bridge inspector access beneath the bridge.

Brad: We did a similar effort for the Port Authority on the Panhandle Bridge that goes over the Monongahela River, the Norfolk Southern Railroad and Penn DOT’s highway Interstate 376. There was a lot of coordination effort required.

Mike: Because the Panhandle Bridge carries a light rail system (LRT), we had to coordinate with the Port Authority as well in case we needed to shut down some tracks during the hours of inspection. So we had to coordinate with the railroad, the Port Authority, our subcontractor, and the Coast Guard—a challenging effort that had to be accomplished well in advance of the actual inspection.

Brad: The LRT system that the Port Authority uses has an overhead catenary system to power the vehicles. This prevents the use of a Snooper, so we needed to use a subcontractor to install under-bridge structure rigging comprised of cables and scaffolding. Then we proceeded with inspecting the underside of the bridge from the scaffolding along with free-climbing techniques.

Bridge inspection
GAI inspector on the Pan Handle Bridge over the Monongahela River.

Mike: We also do emergency inspections. One of the piers on the Pan Handle Bridge was hit by a barge a few years ago. In that event, they called us immediately and asked if we could come out and look at the pier. They closed the bridge until we got there to make sure there were no safety concerns.

Brad: It was early—4:00 a.m. when we got the call. We also had another impact issue on that same bridge when a barge snagged a cable that was hanging off the bridge. That happened around midnight on a Friday night. I got the call and I was there in 10 minutes—I lived pretty close by at the time. It was exciting to be on site that early after an accident and working directly with our client.

What was the most interesting or unique bridge project you worked on?

Brad: Definitely the Kinzua Bridge. We were doing a lot of small bridge inspections for the Pennsylvania Department of Conservation of Natural Resources (DCNR), but part of the contract was to inspect the Kinzua Sky Walk, which is a remaining portion of the original Kinzua Viaduct railroad bridge after half of it collapsed during a tornado in 2003.

Mike: It was a huge historic railroad bridge that crossed the Kinzua Gorge in McKean County, PA.

Brad: DCNR turned the remaining part into a conservation walkway platform now call Sky Walk. Tourists can walk out and see the valley below through Plexiglas panels that make up the walkway floor. Some of the tourists noted that there was a lot of swaying on the free end of the bridge, which would have been the middle of the original bridge. That’s probably due to the fact that there’s only one half of a bridge there now.

So we went up and looked at it and did the inspection. To access the structural members, we took some of the deck planks off the walkway and went down on a rope, much like a rappelling system. There really wasn’t much wrong with the beams, there was just more sway than someone was used to feeling. It was very interesting.

Mike: They had to rappel about 300 feet down through the legs and towers in December with winds up to 20-30 miles an hour. That was something I could never do. But Brad and another GAI employee both did it with no issues.

Bridge inspection
This inspector fearlessly rappelled 300 feet down the Kinzua Bridge Sky Walk structure.

Mike Beresford, PE, CBSI, a 26-year GAI veteran, is currently leading the GAI team for a four-year, $11M agreement with the Port Authority of Allegheny County. The team will provide inspection and engineering services for 79 bridges that are owned and maintained by the Authority.

Brad Kughn, PE, CBSI started with GAI in 2009, when he was awarded a scholarship by GAI toward his senior year at Point Park University. Brad is currently working as a senior project engineer on the I-10 Improvement project in Duval County, Florida, and previously contributed to the design of new prestressed concrete bridges as part of Florida’s I-95 Improvement project.

To learn more about GAI’s Bridge Inspection and Design services, contact GAI Transportation Technical Manager Mike Beresford, PE, CBSI at 412.399.5326 and Senior Project Engineer Brad Kughn, PE, CBSI at 412.399.5350.

Read all the articles in this series and learn more about GAI’s bridge inspection services:

Bridge Inspection, Part One: The Dizzying Heights of Bridge Inspection

Bridge Inspection, Part Two: Working Safely to Ensure Public Safety

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