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DOT finds less clearance than planned under new I-40 bridge

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Wednesday, September 1, 2010

(Updated 3:00 am)

By Mark Binker
Staff Writer

GREENSBORO — Call it the case of the missing 8 inches.

N.C. Department of Transportation engineers are trying to figure out why part of a bridge installed over I-40 this weekend has only 16 feet 4 inches of clearance when it was designed to have 17 feet between the bottom of the bridge and the road surface.

The bridge is part of an $8.8 million extension of Bridford Parkway that is scheduled to be completed in June 2012.

“The bridge is totally safe,” said Patty Eason, a DOT division construction engineer for the Guilford County area.

Oddly enough, the contractor hired to build the bridge may have done everything right.

“The contractor fully constructed the girders and the bridge piers as per plan,” Eason said. So, it’s not correct to say the bridge is shorter than designed. Rather, there’s just not as much clearance as there should be.

“We’re in the process of figuring out how and why the mistake occurred,” said Mike Fox, a Board of Transportation member from Greensboro.

The best guess, according to Eason, is that the road under the bridge is higher than when the bridge design was drawn. A recent road-widening project or unrelated repaving in recent years could have added to the amount of concrete and asphalt that is now part of the road.

In fact, the reason the bridge was designed to give 17 feet of clearance — 1 foot more than federal standards and 6 inches more than state standards — was to give a cushion in case future roadwork did raise the level of the road surface.

The average commuter and even the average tractor trailer driver won’t notice the difference. There are other bridges on the same area of I-40 that have only 16 feet 1 inch of clearance. If a truck can get under those bridges than they can certainly get under the Bridford Parkway bridge.

Also, any truck that can’t get under a 13-foot-6-inch bridge has to get a special permit from the state to travel on the highway, officials said.

That’s not to say engineers won’t try to bump the bridge section up a bit. When DOT workers closed lanes on I-40 this weekend, they only installed a bridge over the eastbound part of the road.

When they come back to do the span over the westbound lanes, Eason said engineers may insert some steel plates to give the bridge 16 feet 6 inches of clearance that is state standard.

Contact Mark Binker at (919) 832-5549 or mark.binker@news-record.com

Accompanying Photos

Joseph Rodriguez (News & Record)

Photo Caption: The new bridge in place over the I-40 eastbound lanes in August.

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raypric

September 1, 2010 - 7:30 am EDT

If the state dot says when they install the other part of the I Beams and add spacers to it why can they not
add the spacers to the side they just installed to raise the bridge to the required specified height that they
were airming for. That is a no brainer, all they need to do is to add spacers to it before putting the road bed
down on the bridge I beams ... When they were working on the New I-40 in Winston-Salem the Old Lexington bridge that spans across I-40 was raised by use of spacers to the newly required height at the time of the bridge was being raised was a finished existing bridge that crosses the new interstate that was being constructed.

Panacea

September 1, 2010 - 8:26 am EDT

It's called the laws of physics. If you try to put "spacers" under a bridge that is already built, you throw it off its center of balance; its own weight is part of what keeps it stable. The other girders would have to take the load, making the whole thing unstable, and creating a risk for cracks.

Try this experiment. Build a large bridge out of wooden blocks; the kind a toddler plays with. Then put a shim under the girders and watch what happens to the blocks. They shift.

It's not as simple as you make it sound.

countryboy

September 1, 2010 - 9:14 am EDT

Measure twice...cut once.

glenwoodresident

September 1, 2010 - 10:42 am EDT

Several years they added spacers to an existing bridge with a road way Florida Street and Highway 29. i think if they are going to do it now is the time. I also think they should have someones head for the mistake. Did no one catch the road was now higher. Lets hold people accountable

Panacea

September 1, 2010 - 1:10 pm EDT

The DOT plans the roads. The contractor follows the plans given. It was a simple and honest mistake.

Larry the Engineer

September 1, 2010 - 4:41 pm EDT

Not always does the contractor follow the plans and specifications for the project and can cause A LOT of heartache for the DOT engineers. The contractor is more worried about making money instead of building a safe bridge

Bosco

September 1, 2010 - 10:45 am EDT

Read the entire article in the print edition of the N-R this morning. The DOT explanation is the dumbest thing I've ever read. Must have been caused by continental shift. If I thought they were this smart I would think it was all planed to get I-40 shifted back to the Urban Loop where it belongs

Leonard

September 1, 2010 - 1:04 pm EDT

Lots of surveying had to have taken place on the current road to ascertain height and width and other factors. I think this is just another "mess" the State DOT has gotten themselves into.... again... and refuse to admit! Watch out all you poor "northern loop" residents. Your turn is coming soon.

Larry the Engineer

September 1, 2010 - 4:55 pm EDT

You should be pleased that the DOT came out and said they made a mistake because it takes more guts to do that than just forget about it and deal with it later when someone life could be at risk. As for the northern portion of the loop there should be nothing to worry about because everyone wants to get from place to place quickly in today's society. Without more roads and a growing Triad population Greensboro and the surrounding area will only get worse to travel around

Anonymouse

September 1, 2010 - 3:02 pm EDT

Somehow I am not suprised by this. The new loop's bridges are completely over-engineered and built poorly. Do we really need 10 lanes of width for Friendly Ave underneath? No joke, take a look how wide it is.

And yet, if you drive on the bridge at the speed limit your car is likely to bottom out due to the very large dips on ALL of the new bridges. Correct me if I'm wrong - but a bridge shouldn't have that kind of problem in it's first couple of years...

Not only that - why do we need 40 acres of grass surrounding each and every entrance and exit from the new loop? GSO needs to go visit some areas up north where space is a concern and see how an entrance ramp can be built without requiring a team of landscapers to maintain the wasted space.

I've been here for enough years to be completely fed up with the waste, poor engineering and don't get me started about the traffic light patterns... If I spend one more Saturday stopping at EVERY light on my way downtown, I'm going to scream... Guys - please do some research or find someone from a more urban area to help you design your infrastructure...

PLEASE!!!

Larry the Engineer

September 1, 2010 - 4:45 pm EDT

As a matter of fact the Urban loop bridge over West Friendly was actually a STATE Record at the time of completion if you didn't know. This steel plate girder bridge that spans 310 feet should be looked at as a modern engineering marvel. If you don't think the design is very sufficient then let me see you go out there and come up with a better design that will serve the same purpose and not cost a bunch of extra money

dusenberry

September 1, 2010 - 6:36 pm EDT

NCDOT is responsible for the survey. The contractor follows a set of NCDOT approved drawings, so does the fabricator. NCDOT just bought this boo boo. The anchor bolts limit the the thickness of the shims.

MissV

September 1, 2010 - 7:49 pm EDT

Not to worry. Just charge the taxpayers twice (like repaving I-40). Makes the jobs report look good.

jeed

September 1, 2010 - 8:42 pm EDT

"If a truck can get under those bridges than they can certainly get under the Bridford Parkway bridge"

It's if/then, not if/than.

Doug Johnson

September 2, 2010 - 7:20 am EDT

Miss V,
Are you speaking of that dot, screw up on 40 near Raleigh?
That little screw up cost us 20 million. Cement screw up !
Are the bypass, that they put the asphalt down to thin?
With the dot, there's always something.
Expect, some good firings!

gsotec

September 2, 2010 - 12:19 pm EDT

You have to appreciate DOT coming clean with the mistake, if they had not issued a press release about the mix up would anyone here even know or care about it.