Cable Stay Bridge Inspection

Last October I was part of a cable stay bridge inspection in Boston, MA. While I was away in Kentucky inspecting, the rest of my office was busy inspecting the underside and beginning the lower section of the piers and cables.

After I arrived home I had a day off and I began my part of inspecting the upper portion of the pier towers and cables which reached heights of 270 feet over the roadway. Since equipment could not efficiently inspect that high we used SPRAT climbers (myself and other guy from PA). We started by carrying over 1,000 feet of rope to the top of the north tower and rigging up our lines and rescue lines. That night we began to inspect the northern cables. With limited hours (11pm to 3am) we had little time to inspect since we were not allowed to enter the towers until lane closures were out. The first few nights were mainly learning what was the most efficient way to climb. The limiting factor for this bridge was our need for night work and thus lane closures. Luckily for us weather was good and winds were calm (less than 10 mph most nights).

As far as how we climbed, for the concrete pier towers we were able to climb out of the top at the aviation beacon and descend to the portion that was inspected by man-lifts and then ascend back up to the beacon. The first few nights we tried different ways such as ascending from a man-lift about 110 feet above the roadway (figured out that we can climb faster than a man-lift). Next we tried rope to rope transfers from the access vent located about 130 feet over the roadway. This was fast but each night we had to tie off the ropes which led to us ending almost an hour early for this.

For inspecting the cables we started off just like we did before from the aviation beacon but we carried a pair for rollers which were used to hold us ear the cables. This allowed us to stay within an arms reach of the cable we were rolling on and allowed us to see the cable below us. When we were low enough we exited the cable onto a man-lift which was waiting for us. Most nights we inspected 6 cables, we originally thought we could inspect more each night but due to less time each night we weren't able to inspect the 9 we thought we would be able to.

Overhead Tunnel Inspection

A few weeks ago we started the inspection of Tip O'Neill Tunnel in Boston. All of the work is conducted at night when the state is able to close down portions or all of the lanes in the tunnel.

The work from the bucket truck is pretty easy and clean. Mainly we have just had to worry about dressing warm since a few nights have dropped to 10°F (-12°C). 

The dirty work is having to inspect the exhaust plenums which are considered to be permit required confined space. Much like their name suggests they are full of exhaust and caked with soot.

Ohio River Bridge Inspection

This was my second trip to Kentucky to help inspect one of the Ohio River bridge crossings. I have now been part of four of the river crossings and look forwards to being part of many more.

For this inspection we were doing a detailed inspection of the floor system so the state would have a very detailed report of the current condition. They plan to use this report to justify their reasons for the new deck replacement and whether or not to keep the stringers, which currently control the rating for the bridge.

One detail which we noticed were the diaphragms over the floorbeams had cracks propagating from the toe of the weld. A few locations had  propagated into the web of the stingers.

We even got one day off which gave us time to check out the bourbon trail. We stopped by the Maker's Mark Distillery and the Jim Beam  Distillery.

Emergency Bridge Inspection

Had to perform an emergency bridge inspection last week for the first time in my career. I was already down in Louisville, KY for the inspection of the Kennedy Bridge which crosses the Ohio to Indiana. Soon after hearing that a bridge further upstream had been closed, we received a phone call from the state asking for our assistance. We assembled relatively quickly even with the hour long drive to the bridge site.

Early in the morning, while construction workers were preparing the bridge for it's future move to it's permanent concrete piers, a bearing at the southwest corner dislodged and injured a construction worker. After the bearing had dislodged, the upstream truss fell about 12" until it made contact with the temporary pier. Although there were signs of movement throughout the southern span the bridge remained in good condition.

Rigging Weathering Steel Truss

Early in the week I traveled out to Western Massachusetts to do a special member inspection for a truss. The truss has advanced section loss to the steel stringers.