Posted on 01/14/2018 8:11:58 AM PST by Tolerance Sucks Rocks
A crack that closed the Delaware River Bridge between Philadelphia and New Jersey last January has prompted the Pennsylvania Department of Transportation to plan repairs to 13 other bridges across the state.
The crack in welding material, which created a 2-inch gap in a major truss, was so serious that officials thought they might have to permanently close the span owned by the Pennsylvania and New Jersey turnpikes. As a result of that problem, PennDOT looked for similar issues in other bridges; the repairs will involve drilling out areas where welding occurred to fill improperly drilled holes, called plug welding, and installing bolts to eliminate the potential for cracking at weld sites.
The practice of filling holes drilled in the wrong place to salvage a piece of steel, common in construction projects decades ago, is no longer permitted in high-tension situations because heating the steel for welding can create a weakness that results in cracking.
Lou Ruzzi, PennDOT’s bridge engineer for Allegheny, Beaver and Lawrence counties, said engineers inspected 13 bridges that have steel pieces with plug welds. They didn’t find any problems, but the agency will issue a contract in April to drill out more than 650 plug welds and fill the holes with bolts to eliminate the possibility of cracking in the future.
The bolts won’t attach to anything, but putting a bolt through the hole and a nut on the other end will increase the strength of the pieces, experts said. The contract will be issued in April and the work will cost from $1 million to $1.5 million.
“We haven’t found any bridge with any cracks,” Mr. Ruzzi said. “But we don’t want to take that chance, so that’s why we will repair them.”
(Excerpt) Read more at post-gazette.com ...
Duct tape. Fix it right up.
At $1000000, that’ more than $1500 per bolt.
Someone must have flunked welding school.
No kidding. I learned this as a young welder in the machine shop in 1968...taught to me by an uncle that was a US Navy welder in WW2. He said it was forbidden then.
Not a welding issue but a drilling issue.
To paraphrase the old saying, “measure twice, drill once.”
More like flunked morality school.
My dad was a welder. Back in the day welders had to take a test for each job they did - even the experts. How many defective welds are in strategic spots in bridges, skyscrapers, etc.?
The bolts won’t attach to anything, but putting a bolt through the hole and a nut on the other end will increase the strength of the pieces, experts said.
I’m a civil engineer and a bolt through a hole attached to nothing else adding strength is news to me. Something is missing in this story.
>>Something is missing in this story.
Washers? Oversized nuts?
And how much would you charge to hang suspended under a bridge, hoist up drilling equipment, drill through 1/2”+ steel, insert a bolt and have another guy hoisted on the other side to hold the nut?
Oh - don’t forget the guys on the ground keeping you safe, and all the special equipment you need. Everyone on the project will probably need a 60-hour OSHA card too.
There are probably anti-corrosion and environmental issues as well.
$1500.00 sounds about right.
Union labor, no doubt.
I don’t understand how putting a bolt through the hole strengthens the piece of steel that the hole is in.
If the heat from the weld plug has already weakened the steel it seems that the damage is already done.
No some one flunked where to put the holes
Leave it alone. Inspect. If cracks apear then fix it.
I’m guessing they might have meant that the bolt and nut restore the strength lost when the hole was drilled.
WHO made the "improperly drilled holes"??? They need to be made to pay for the fixes and prosecuted!
Does little good.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.