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Sidney Sherman (East Loop Ship Channel) Bridge


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Are there any plans or efforts around to replace this bridge? It's fairly insufficient for shipping purposes, and it is nearing the end of its serviceable life at 41. Seems that the replacement of this bridge would be a prime candidate to give Houston an architectural landmark.

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Are there any plans or efforts around to replace this bridge? It's fairly insufficient for shipping purposes, and it is nearing the end of its serviceable life at 41. Seems that the replacement of this bridge would be a prime candidate to give Houston an architectural landmark.

Unfortunately government at all levels refuse to invest in infrastructure there are thousands of bridges naturally past their serviceable life. It will take a real tragedy to do something

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41 years is nothing for a bridge. There are overpasses on the Gulf Freeway that are 66 years old near downtown, though they were widened in the 80s. The northbound I-45 overpass over the railroad tracks just north of the Causeway was originally built in the late 1930s for US 75 and was later widened to interstate standards.

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Age isn't really a factor in structural failures, and it's more of an engineering failures. Remember, the famous Tacoma Narrows bridge was only 4 months old before it fell into the water taking Tubby the three-legged Cocker Spaniel with it. The I-35W Mississippi River Bridge is the one that really started discussion on bridges, but although it just shy of 40 years old, it had several flaws in retrospect that contributed to its collapse:

- A lack of redundancy in the trusses so any single structural failure would cause the entire bridge to collapse

- It was planned to be reinforced with more steel but canceled because it would weaken the bridge.

- Corrosion had taken a heavy toll on the bearings of the bridge. This happens with water bridges as opposed to road bridges.

- The collapse happened when heavy construction equipment was on the bridge for resurfacing.

- 16 of the gusset plates were too thin, underdesigned, and gave way, taking out the rivets of the bridge.

- There's a theory that spraying potassium acetate to prevent icing was corroding structural supports.

tl;dr Bridges don't tend to collapse unless poorly-engineering components give way, and age tends to be less of an issue.

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Age isn't really a factor in structural failures, and it's more of an engineering failures. Remember, the famous Tacoma Narrows bridge was only 4 months old before it fell into the water taking Tubby the three-legged Cocker Spaniel with it. The I-35W Mississippi River Bridge is the one that really started discussion on bridges, but although it just shy of 40 years old, it had several flaws in retrospect that contributed to its collapse:

- A lack of redundancy in the trusses so any single structural failure would cause the entire bridge to collapse

- It was planned to be reinforced with more steel but canceled because it would weaken the bridge.

- Corrosion had taken a heavy toll on the bearings of the bridge. This happens with water bridges as opposed to road bridges.

- The collapse happened when heavy construction equipment was on the bridge for resurfacing.

- 16 of the gusset plates were too thin, underdesigned, and gave way, taking out the rivets of the bridge.

- There's a theory that spraying potassium acetate to prevent icing was corroding structural supports.

tl;dr Bridges don't tend to collapse unless poorly-engineering components give way, and age tends to be less of an issue.

Age is part of it the government is unwilling to spend in infrastructure and at some point there will be a tragedy that will get everyone's attention

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"the government is unwilling to spend in infrastructure and at some point there will be a tragedy that will get everyone's attention" 

 

Let's rephrase that to say that "the current government is unwilling to spend in infastructure". I'm old enough to remember when the government was willing to spend in infrastructure.       

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Again, age isn't a huge factor in bridge failures. Here's some further adventures in American bridge failures courtesy of Wikipedia (2000 to present):

- Hoan Bridge in Milwaukee partially collapsed in 2000 (the bridge only about 23 years old, no casualties), engineers found to be improperly designed welds that were only made worse by extreme cold.

- Queen Isabella Causeway was damaged in September 2001 with four loaded barges hitting it, and drivers not noticing the missing part (it was the highest part of the causeway) until it was too late. At the time, the bridge was 27 years old, and the road was repaired and reopened.

- Interstate 40 Bridge Disaster in Oklahoma--towboat hit it in 2002 (couldn't find when the bridge was built)

- In 2004 in Connecticut, a car struck a tanker that was carrying oil, resulting fire melted superstructure and caused bridge collapse (because rebar won't sustain extreme heating without compromise--that's why they had to raze the Axis garage)

- An overpass in Michigan collapsed in 2009 because of another tanker...

- The San Francisco-Oakland Bay Bridge partially collapsed in 2009 and was the result of a botched 70-hour emergency repair from a component that was already failing (in a NEW bridge, natch)

- Last year, a bridge in Washington state, that was admittedly open in 1955, had been damaged by a too-tall vehicle, was not "structurally deficient" but rather "functionally obsolete". A newer type of bridge would've been able to sustain a hit like that.

- Another disaster in May 2013 in Scott City, MO happened when trains t-boned each other and knocked out structural components of the bridge.


There were other bridge failures too in other countries I'm not mentioning, but keep in mind that in developing countries, bridges are built cheaply, and aren't well-engineered.

The only American disaster I didn't cover was the 2007 Minnesota bridge collapse, but need I remind you that not only the numerous design/construction flaws were in the bridge but it was originally striped with two lanes in each direction with two shoulders, and those shoulders became full lanes later, meaning that it was carrying twice as many cars as it was originally designed to.

Why, then, of all the bridges rated "structurally deficient", why aren't we seeing more spontaneous bridge collapsing? That's because "structurally deficient" does not mean "collapse imminent", it means that it's no longer has the same safety ratings (of what it can hold, etc.) of its original design. It's been more than 7 years since a major collapse like that, so until bridges start collapsing spontaneously on a regular basis, it can be a "freak accident".

Now, the Sidney Sherman East Loop Ship Channel Bridge--assuming there's no major structural flaws to begin with, the only way I can foresee a major disaster anytime soon is if something big and heavy crashes into it, but previous disasters have shown us that newer structures will not sustain "big and heavy crashes" either.

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- Last year, a bridge in Washington state, that was admittedly open in 1955, had been damaged by a too-tall vehicle, was not "structurally deficient" but rather "functionally obsolete". A newer type of bridge would've been able to sustain a hit like that.

 

 

If the bridge were newer and designed to current standards, it would have had a high enough vertical clearance to avoid being hit in the first place. It has a 18 ft clearance over all lanes now vs. the 15 ft 6 in clearance it had over the lane that the too-tall truck was traveling. Some of us can remember the old Hazard St. bridge over US 59. It was built in 1960 and only had a vertical clearance of 13 feet 11 inches. It was a cast-in-place concrete bridge and had been hit so many times that chunks of the outside beams of the superstructure were missing on the section over the northbound lanes.

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If the bridge were newer and designed to current standards, it would have had a high enough vertical clearance to avoid being hit in the first place. It has a 18 ft clearance over all lanes now vs. the 15 ft 6 in clearance it had over the lane that the too-tall truck was traveling. Some of us can remember the old Hazard St. bridge over US 59. It was built in 1960 and only had a vertical clearance of 13 feet 11 inches. It was a cast-in-place concrete bridge and had been hit so many times that chunks of the outside beams of the superstructure were missing on the section over the northbound lanes.

 

I have indeed seen a picture (Houston Freeways) of the "Hazardous" Street Bridge with the chunks missing. For a major highway, that is bad. Other bridges have low clearances as well--Syracuse, NY has a railroad bridge that goes at 11 ft. 9 in. (officially, it's signed as 10 ft. 9 in.), and a Megabus that missed an exit ended up having the top deck sliced off, with the state installing a warning system to keep taller vehicles off. But as for replacing bridges for safety reasons, that tends to be irrelevant. The old "steel truss" bridges in Texas that have been slowly replaced over the years (a few remain as pedestrian bridges, or at least in one case, a turnaround lane) have had more to do with lane width and traffic capacity than actual safety reasons.

 

I'm not saying bridges don't need to be replaced--the Oscar Colquitt (Yale) Bridge was opened around 80 years ago (I've heard both 1931 and 1936), and these older bridges were made before reinforced concrete and other modern building materials. It really does depend on the material--old stone bridges in Europe have been around for centuries.

 

However, since the Sidney Sherman Bridge isn't an octogenarian (yes, I personified the bridge there), has some critical design flaw, or even rated "structurally deficient", it should be fine for at least the next 3 decades. Again, of course, that's assuming there's not going to be something big and heavy smashing into it enough to seriously compromise it or anything.

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- The San Francisco-Oakland Bay Bridge partially collapsed in 2009 and was the result of a botched 70-hour emergency repair from a component that was already failing (in a NEW bridge, natch)

 

 

Actually, the Bay Bridge problems were in the old cantilever truss bridge portion.

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Actually, the Bay Bridge problems were in the old cantilever truss bridge portion.

In that case, it would've been previously compromised by the earthquake, which they did emergency repairs on back in 1989-90 and why they were building the replacement span to begin with.

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In that case, it would've been previously compromised by the earthquake, which they did emergency repairs on back in 1989-90 and why they were building the replacement span to begin with.

 

Not quite.  The section that failed during the Loma Prieta earthquake was at the transition out of the truss section.  The 2009 failure was, IIRC, a linking member with cracks that got picked up during evaluation check; a patch was applied because that section was going to be history within a couple years.  And then the patch failed, again IIRC, because of a metallurgical issue.

 

That entire 2/3 +/- of the bridge was found to be seismically inadequate.  The suspension bridge section from Angel/Treasure Island to the City, grounded on bedrock, could be reinforced (and was); the eastern part was on redwood pilings pounded into the mud of the bay.  Some projections had it that if the Loma Prieta quake had lasted about thirty seconds longer, pretty much all of the eastern section would have failed (a la the Cypress Structure in Oakland).

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  • 3 weeks later...

Anything infrastructure wise only becomes obsolete when it isn't able to perform its primary function such as being able to sufficient move traffic.

 

As far as failures bridges only due to structural design failure that doesn't take into accounts wind load, and load from passing cars or people. There are many examples of this where relatively new bridges either had complications or experienced complete failure due to failures in design. The biggest examples I immediately think about are the Tacoma Narrows Bridge in Washington where structural designs created the perfect storm of failure by not accounting for cross winds along the river combined with the bridge design being excessively light for a suspension bridge. The other major one I can think of is the Millennium Bridge in London. This was an interesting case because they did properly calculate for wind loads and designed the structure accordingly, but there wasn't enough people on the bridge at any given time to stabilize the bridge! They had to then go back and beef up the bridge and now it's perfectly safe.

 

Probably what kills most bridges (and all infrastructure for that matter) is bad maintenance, neglect, abandonment, or using the a bridge or infrastructure in ways where it wasn't intended to be used as such.

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