Posted on 01/24/2017 8:11:35 PM PST by Tolerance Sucks Rocks
An apparent construction error six decades ago could have caused the fracture discovered Friday in a steel beam that forced the closure of the Delaware River Bridge, an engineering expert who viewed pictures of the cracked truss said Sunday.
An image of the cracked truss - a supporting piece - on the bridge that runs between Bucks County in Pennsylvania and Burlington County in New Jersey shows signs of holes that had been mistakenly drilled into the steel beam and then filled with plug welds, a typical solution in the 1950s when the bridge was built, said Karl Frank, professor emeritus of engineering at the University of Texas at Austin. His areas of study include fractures and fatigues in metal structures and welded and bolted joints, according to the university website.
The image is on the website of the Pennsylvania Turnpike Commission, and Frank viewed it there.
"What we do nowadays, we don't do that," he said. "If you have a misdrilled hole, you would just put a bolt in and tighten it up. The problem is they welded it up."
The plug welds created a weak point, Frank said, and the stress of traffic crossing the bridge continuously since it opened in 1956 could have led to a sudden crack, splitting the beam at the welds.
A spokesman for the commission, which operates the 1.2-mile-long bridge jointly with the New Jersey Turnpike Authority, did not dispute Frank's conclusion, but said turnpike engineers had too little information to confirm anything about the crack's cause.
"Don't want to make premature assumptions without science," said Carl DeFebo Jr., the spokesman.
(Excerpt) Read more at philly.com ...
Ike’s Fault.
Interesting picture of the fractured beam in the article. You can just make out what looks like two of the weld plugs along the fracture line. The fracture is also rust red in color, so it is not newly exposed steel. The fracture must have been frowning for a long time.
Frowning => growing (*sigh*. Autocorrect)
If it was a typical solution at the time, it was not a mistake.
Hindsight is 20/20.
Frowning is not a bad description of a fracture’s demeanor....
That should buff right out....
Wonder how many more mis drilled weld filled holes in beams getting ready to fail? Ruh Ro.
My quick look showed that about 1/2 of the fracture was rusted. That seems reasonable.
Enough redundancy in the structure to prevent a catastrophic failure.
In third world counties, they ignore this sort of thing, and just let it fail.
Why put money into maintenance when you do not have enough in your Panamanian bank account?
Live and learn, unless you die first.
Rode over that bridge plenty o’ times in the ‘56 Buick we had.
One suspects that the stresses from today's traffic and loads just might be exceeding the design limits; or, close to them.
Don't know, just guessing.
.
I haz HAZ...
Feel the freedom.
Bridge ahead has one cracked truss
If it doesn’t bother you
It doesn’t bother us.
Proceeding forthwith will indicate
You prefer the risk
to being late
Though if you continue straight ahead
and the bridge does fall
and you end up dead
The choice was yours and we’ll agree
You waived our
liability
Burma Shave.
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.