Railroad Routine Bridge Inspection

The past few weeks I've been busy working long nights for bridge and tunnel inspections. Our inspections were located in Revere, South Boston and Brookline and each had its own unique access requirements.

The Revere bridge spans over the Blue Line and was inspected using ladders since it was a short span consisting of prestressed concrete butted box beams in good condition. Using ladders allowed us more time for inspection since we did not have to wait for a hi-rail lift truck to be put on and driven to the bridge. We were able to get on track around 1am and finished just before they needed power back.

The South Boston bridge spans over the Red Line and MBCR commuter rail tracks and was inspected with ladders even though it was a larger span consisting of prestressed concrete butted box beams in good condition. We decided to use ladders since we could inspect the commuter rail portion starting at 10pm and finish before the MBTA would allow us access to the Red Line around 2am. There was also a small portion over a dirt road with no traffic at 1am. Working in all three sections could not be accomplished using a hi-rail lift since the truck would require traveling further south to be able to get onto the tracks.

The Brookline bridge spans over the Green Line near the Beaconsfield Station and was inspected with a 40 foot hi-lift since the bridge was wide and consisted of 57 rolled steel beams. We were able to get on right near the bridge just after 1am and finished the wide bridge just before power was needed back.

Rolled Steel Beams

The past two weeks I've been very working on the routine inspection of the Huntington Viaduct in Providence RI. The rolled steel beam superstructure with composite concrete deck spans across Route 10, AMTRAK and a lot of grass.

After this week when I have time I'll update with photos and more info but for the time being I need to crash since this will most likely be a 90 hour work week. 

Rolled Steel Beam Bridges

So at near the end of May (ya I've been pretty busy and lacking on the updates) I inspected two six rolled steel beam bridges and bottom flange cover plates.

The bridges carry Route 24 North and South in Tiverton. This was my first time in Tiverton and I have to say that it is a very picturesque spot locate right on the coast, if you have a chance check it out. 

The rolled steel beams had minor deficiencies with section loss to the bearing stiffeners. The were in pretty rough shape at the expansion end with heavy spalling to the backwall which extended throught to the wearing surface.

Nearing the end of the inspection the bucket truck started to have problems operating and needed to be reved (sp?) to allow the enough hydraulic pressure to move smoothly (or move at all)

Steel Beam Bridge

The other week on March 29th I was down in Providence inspecting a three simple span mutli beam bridge (Br. No. 060701) which carries Route 6 East and West. The second span carries route 67.9 feet over Killingly Street and has a structure length of 125 feet.

The bridge has 18 beams which are labeled A to R, which makes for a fun time when starting from the South and figuring out which beam you are at.

While finishing up the East side of Span 2 the bucket I was using started to leak hydraulic fluid and the bucket began to slowly twist upside down, luckily I was only 10 feet off the ground. We were able fix the problem quickly (just a new nut vibrated itself loose and needed to be tightened) and get back to inspecting.

The bridge has been struck several times in the past and all the beams have gouges and scrapes along the underside of the bottom flanges and cover plates. One of the beams has a bulge in the web and a small web crack. One of the beams was also twisted at the pier. 

Cumberland Pony Truss Bridge Inspection

So last week I ran out of time catching up on past inspections, so here are a few I missed. Last Monday I was out in Cumberland to complete two inspections which were post posted due to high water.

This first bridge is a small simply supported rolled beam bridge which 20 feet over Abbott Run Canal. During the inspection RIDOT stopped by to do a quality control check and one of them informed us that the nice house spanning over the canal has a glass floor to see down to the canal below.

The bridge was rebuilt in 2006 and replaced the previously posted bridge which was built in 1886. The rebuilt bridge incorporated the original exterior girders and rail for aesthetics and only support their own self weight. 

We inspected the bridge in waders and used a 16 ft ladder. We joked before the inspection after reading the previous inspection which stated "Exercise caution when wading in channel upstream and downstream of the bridge. The channel bottom is very soft consisting of decomposed organic material" seeing a channel which was just over 12 inches at most. Sure enough after taking an elevation photo and fell 4 feet into muck, good thing I'm over 6 feet or this could have been a bigger deal. Forgot to take a picture of the hole afterwards.

The rest of the inspection went smoothly tho and we were able to finish up and head down the street to our next bridge. 

Much like the last bridge, this is also a rolled steel beam bridge with a timber deck and also spans 59.5 feet over Abbott Run. This bridge was rebuilt in 2007 and replaced the existing bridge which was built in 1886. The original built up steel thru pony truss remains for aesthetic purposes and carries its self weight.

The bridge was quite noisy with a loose timber plank that had missing clamps on the underside to the steel beams. While wading in the channel we got freaked out when something swam between our legs and through the mucky water, but after we realized it was a fish we had a good laugh. 

  

Impact Damage with Broken Welds and Cracked Web

The past two days I was down in Taunton MA at a bridge which spans over Route 140. The rolled steel beam bridge with cover plates was built in 1959 and rehabilitated in 2004 with a new composite deck and railings.

With minor impact gouges on the underside of most of the beams it was only a matter of time before a truck not paying attention to the vertical clearance (14.90' Northbound and 14.74' Southbound) would hit the bridge. Something caused severe damage to Beam #8 (the South most beam in Span #1), deforming the web, bottom flange and cover plate. The impact also cause the web to crack at the diaphragm connections cracking the web to Beams #8 and #7 and braking the weld to Beam #6.

Checking out cracks

POV of a bridge inspector

The state added arrest holes to stop the cracks from propagating and to this date have not expanded past the arrest holes. One vertical rack along the weld on Beam #8 did not have an arrest hole and after doing a Dye Penetrant Test we determined that the crack had not change since the last inspection. 

Broken weld

  

Cracked web with arrest holes

Web pushed outward to the East

Cleaning crack for dye penetrant test prep

After adding dye

Dye Penetrant Test complete showing full extents of the cracking

Section loss at beam ends