Climate Change May Cause Poorly Maintained Bridges to Collapse

Collapsed I−40 Bridge, near Webbers Falls, Sequoyah County, Oklahoma — in May 2002.
Collapsed I−40 Bridge, near Webbers Falls, Sequoyah County, Oklahoma — in May 2002. Xpda [Public domain], via Wikimedia Commons

Guest essay by Eric Worrall

According to a new study, if civic authorities don’t properly clean clogged bridge expansion gaps, warmer temperatures might hasten the failure of major support structures.

Climate change may see one in four US steel bridges collapse by 2040

ENVIRONMENT 23 October 2019
By  Ruby Prosser Scully

Bridges in the US and other high-income countries are ageing and deteriorating. Last year, a large portion of an Italian bridge built in the 1960s collapsed, killing more than 40 people.

One of the most common problems involves expansion joints. These allow sections of a bridge to swell and shrink in warmer weather without weakening the structure. But they cause major structural problems if they malfunction.

Hussam Mahmoud at Colorado State University and his colleague decided to model the effects of increasing temperatures on steel bridges around the US.

Mahmoud analysed data on the condition of around 90,000 bridges across the US and modelled how the expansion joints would be affected under temperatures predicted for the next 80 years.

They found that one in four bridges are at risk of a section failing in the next 21 years, rising to 28 per cent by 2060 and 49 per cent by 2080. Almost all are set to fail by 2100.

“These failures are very serious,” says Mahmoud.

Read more:

The abstract of the study;

Impact of climate change on the integrity of the superstructure of deteriorated U.S. bridges
Susan Palu,
Hussam Mahmoud 

Published: October 23, 2019

Bridges in America are aging and deteriorating, causing substantial financial strain on federal resources and tax payers’ money. Of the various deterioration issues in bridges, one of the most common and costly is malfunctioning of expansion joints, connecting two bridge spans, due to accumulation of debris and dirt in the joint. Although expansion joints are small components of bridges’ superstructure, their malfunction can result in major structural problems and when coupled with thermal stresses, the demand on the structural elements could be further amplified. Intuitively, these additional demands are expected to even worsen if one considers potential future temperature rise due to climate change. Indeed, it has been speculated that climate change is likely to have negative effect on bridges worldwide. However, to date there has been no serious attempts to quantify this effect on a larger spatial scale with no studies pertaining to the integrity of the main load carrying girders. In this study, we attempt to quantify the effect of clogged joints and climate change on failure of the superstructure of a class of steel bridges around the U.S. We surprisingly find that potentially most of the main load carrying girders, in the analyzed bridges, could reach their ultimate capacity when subjected to service load and future climate changes. We further discover that out of nine U.S. regions, the most vulnerable bridges, in a descending order, are those located in the Northern Rockies & Plains, Northwest and Upper Midwest. Ultimately, this study proposes an approach to establish a priority order of bridge maintenance and repair to manage limited funding among a vast inventory in an era of climate change.

Read more:

Naturally the study uses RCP 8.5 for its most dire predictions, though they also consider other scenarios like the relatively benign RCP 2.6.

Interestingly the study authors appear to have used average rather than peak minimum and maximum temperatures applied to a bridge with dysfunctional expansion gaps, to predict when each bridge will exceed its structural design tolerances.

The use of average is an interesting choice of metric. I have seen plenty of software systems fail because the hardware capacity estimates were based on average load rather than peak load.

Although peak temperatures would have made the modelled risk of future disaster seem more likely, I suspect the use of peak temperatures might have flattened the impact of global warming on their risk scenario, by raising the modelled risk of immediate bridge failure relative to future failure.

Leaving aside the fun with numbers, the real takeaway is, make sure politicians make an effort to maintain road infrastructure. Defective, poorly maintained bridge expansion gaps are a serious safety risk regardless of whether global temperatures rise. A bridge as poorly maintained as the study authors propose is a disaster waiting to happen. Global warming, if it occurs, might hasten that disaster, but the risk of failure of a poorly maintained bridge is severe regardless of what happens to global temperature.

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steve case
October 23, 2019 6:04 pm

According to a new study, if civic authorities don’t properly clean clogged bridge expansion gaps, warmer temperatures might hasten the failure of major support structures.

“If” and “Might” I didn’t read any further.

As Rush Limbaugh says, “You can’t make this stuff up.”

Reply to  steve case
October 23, 2019 7:42 pm

Well you can make and they do make this stuff up and horror stories go back a long way in our history.

Bryan A
Reply to  LdB
October 23, 2019 7:47 pm

Next up in the NEWS…
Poorly maintained bridges may fail due to poor maintenance, Climate Change to take the blame

Rhoda R
Reply to  Bryan A
October 23, 2019 10:31 pm

Probably. Since bridge maintenance doesn’t get named after a politician there is less interest in spending money in that direction rather than in things like bike paths that DO carry politicians’ names.

Reply to  Bryan A
October 24, 2019 4:21 am

So we should spend more money on properly maintaining infrastructure and stop wasting resources on fake problems which may or may not be a problem if we don’t maintain our infrastructure.

AGW is not Science
Reply to  Greg
October 24, 2019 9:46 am

Ding! Ding! Ding!

We have a winner!

Just think of how much government largess (read: taxpayer money) would be available to do the required road and bridge maintenance if it wasn’t being pissed away on useless windmill and solar panel subsidies which are supposedly going to “save” us from a non-existent “crisis”.

But hey, there’s no power, control, or “wealth transfer” (to the already filthy rich, politically connected scum) in performing road and bridge maintenance, so they go with the boondoggles instead of spending on things we actually need.

John Krill
Reply to  Bryan A
October 24, 2019 4:41 pm


Reply to  steve case
October 23, 2019 11:27 pm

If and might are part of the language and such “weasel words” are found in every legitimate paper. Failure to maintain infrastructure is not a rare event.

Bill Powers
Reply to  steve case
October 24, 2019 2:53 am

But they do make this stuff up. Hard to get grant money sans Hobgoblins.

old white guy
Reply to  steve case
October 24, 2019 5:24 am

Poorly built, poorly maintained and down they come warm, cold, wet or dry. Just ask Quebec.

Big T
Reply to  steve case
October 24, 2019 9:17 am

And climate change may cause me to have less sex. Oh the humanity!!!

Reply to  steve case
October 24, 2019 4:35 pm

A Shop Vac and Screwdriver to break crud apart would go a long way to solve the problem…
How do I get a multi million dollar grant to further study this possible solution?

John Krill
Reply to  steve case
October 24, 2019 4:40 pm


October 23, 2019 6:08 pm

That’s dealing with three over the top climate caused fears on October 23rd.

Bryan A
Reply to  ATheoK
October 23, 2019 7:51 pm

They found that one in four bridges are at risk of a section failing in the next 21 years, rising to 28 per cent by 2060 and 49 per cent by 2080. Almost all are set to fail by 2100.

So up to 100% of poorly maintained bridges are scheduled to collapse in 81 years…sounds about right.
Perhaps a little bit more attention to Maintenance could avoid this outcome regardless of Average Weather

October 23, 2019 6:14 pm

A fraction of degree °C rise during a century and suddenly during the near future, bridges and spans are suddenly going to fail.

Which means the authors built a mode that ignores the huge temperature changes from season to season and day through day.
That way, they can claim it’s all about climate. (send many more lavishly funded grants)

Reply to  ATheoK
October 23, 2019 8:30 pm

Good point. From the warmest day of the year to the coldest day could be 100 F degrees where I live in the North East and it is well known that most of the claimed warming is because there is less cool down over night.
I am an Engineer who has designed components for thermal expansion to temperatures of 1400 F and above and find the propaganda and admitted SPECULATION below is insulting the intelligence of a real engineer.

” Although expansion joints are small components of bridges’ superstructure, their malfunction can result in major structural problems and when coupled with thermal stresses, the demand on the structural elements could be further amplified. Intuitively, these additional demands are expected to even worsen if one considers potential future temperature rise due to climate change. Indeed, it has been speculated that climate change is likely to have negative effect on bridges worldwide. “

Reply to  Catcracking
October 23, 2019 11:45 pm

Exactly. Most of the “warming” is in rising nighttime and winter minima. Rising minima, combined with almost static maxima*, would result in less thermal expansion, not more. Warming is also concentrated more toward the polar regions, where there are not a lot of bridges. The use of average temperature minima and maxima is a bit odd. We might postulate that the thermal mass of a bridge could shift structural temperatures towards the average. I’d like to see the math. If there was any. Once again, though, Tmaxavg and Tminavg will probably be getting closer together, reducing thermal expansion. The entire paper is based on incorrect physics.

* It’s hard to increase significantly the maximum T of a surface that’s radiating to space at T⁴

Reply to  jorgekafkazar
October 24, 2019 6:19 am

Catcracking and jorgekafkazar:
Excellent comments with specifics!

Reply to  Catcracking
October 24, 2019 3:48 am

‘Intuitively ‘: what is that word doing in a technical debate?

John Dowser
Reply to  ATheoK
October 23, 2019 10:34 pm

Helps to read first: “clogged expansion joints” are not as much related by any swing but simply by time and as the research claims: average temperature as clog accelerator and thus climate change.

Jeff Alberts
Reply to  John Dowser
October 24, 2019 7:50 am

Because the average temperature never EVER changes.

old white guy
Reply to  ATheoK
October 24, 2019 5:26 am

Have they stopped putting expansion joints in bridges?

Reply to  old white guy
October 24, 2019 6:01 am

No, but we motorists get all upset when the only bridge across a river within 20 miles gets closed to clean the expansion joints. Of course if we had built in a little redundancy, maintenance could be done with only minor inconvenience.

People don’t seem to understand that structures require regular maintenance or they fail. Adding climate change to the story is just a way to achieve greater funding by giving unscrupulous politicians the excuse they need to take more control.

October 23, 2019 6:14 pm

Ya know, this kind of stuff is getting really, really silly. There seems to be at least one of these moronic stories a week. Someone is apparently paying for this drivel. Who?

Reply to  eck
October 23, 2019 7:01 pm

If you pay tax, then you are.

Zig Zag Wanderer
Reply to  Hivemind
October 24, 2019 1:11 am

It’s very, very difficult NOT to pay tax. I’m retired, and my income is not taxed (since I’ve already been taxed on it several times). Unfortunately, unless I don’t spend anything, I pay at least 10% tax on almost everything, and 20% when I go to the UK or Europe.

When I buy fuel for my car, I’m taxed at between 100% and 200% (added to the base price), and everything that is transported also attracts this tax.

The only other certainty in life is death, as some wag pointed out.

old construction worker
Reply to  Zig Zag Wanderer
October 24, 2019 3:06 am

You must be one of the “Wealthy” that Warren wants to tax with a “Wealth Tax”. Progressive socialist definition of Wealthy; Anybody who isn’t on government welfare. By the way a “Wealth Tax” is unconstitutional. The U.S. Constitution only allows the Federal government to levy an “Income Tax”. That leaves progressive socialist coming after our 401Ks and IRAs type of retirement plans.


Reply to  eck
October 23, 2019 7:13 pm

Unfortunately, most of the funds supporting this fraud are coming out of your wallet (tax supported).

The Socialist Democrats are using our money to destroy us. Great strategy. I don’t see any way to turn the tables in this battle. The enemy has all the weapons and almost all the ammo.

Victory, if it comes will be the result of people everywhere resisting the elevated costs.

Reply to  eck
October 23, 2019 7:35 pm

The Green/Left people and groups create a market that left wing journalists and papers can sell into. Get enough people who believe something and someone is willing to target and sell to that market.

October 23, 2019 6:16 pm

Almost all are set to fail by 2100.

Yes… that’s correct. Bridges have an estimated life. Some 50 years, others 80 years, still others 100 years. A bridge built recently that fails 80+ years from now is not surprise. What the hell does climate change have to do with it?

Bryan A
Reply to  leowaj
October 23, 2019 7:53 pm

Of course it doesn’t help much if you pilot a barge into one of the pylons

Reply to  Bryan A
October 23, 2019 9:04 pm

It was climate change that caused the tug boat to ram his barges into the pylon!
17 years ago!

Who selected this image to accompany this article? It seems a bit disingenuous.

The image accompanying the linked article is equally disingenuous as it shows the I-35 bridge in Minneapolis. The NTSB cited a design flaw as the likely cause of the collapse, noting that a too-thin gusset plate ripped along a line of rivets, and additional weight on the bridge at the time contributed to the catastrophic failure.
The Genoa bridge collapse mentioned in the article was caused by cable corrosion within an upper coupling that had improper casing material.
Expansion joints do not cause bridge failures. The can cause tire failure though.
They are the flexible labyrinthine joints that ‘connect’ the bridge’s deck plates to each other. When they fail due to traffic load or poor design they simply need to be replaced. The big beef is some bridges experience more frequent failures.

Jeff Alberts
Reply to  Rocketscientist
October 24, 2019 7:53 am

Can anyone name one bridge that’s failed due to “climate change”?

Reply to  Jeff Alberts
October 24, 2019 8:18 am

Jeff, many bridges already have names.

Jeff Alberts
Reply to  Jeff Alberts
October 24, 2019 9:34 am

“Jeff, many bridges already have names.”

Any of them fail due to climate change?

Bryan A
Reply to  Jeff Alberts
October 24, 2019 5:20 pm

Galloping Gertie certainly failed from climate change, considering climate is bad weather or strong winds or heavy rain or drought or late monsoons or early monsoons or late spring or early spring or late winter or early winter or any weather pattern we say it is.
Since strong winds fall within the bounds of climate change, climate change it is.

John Dowser
Reply to  leowaj
October 23, 2019 10:36 pm

If I understood the article correctly: expansion joints would clog faster with higher average temperature and therefore needing more maintenance than so far projected.

Jeff Alberts
Reply to  John Dowser
October 24, 2019 8:05 am

I believe that hard freezes then thaws cause more damage to any structure than slightly more warmth.

Reply to  Jeff Alberts
October 24, 2019 10:15 am

Of course. Plus road salt.

mike the morlock
Reply to  leowaj
October 23, 2019 11:26 pm

leowaj October 23, 2019 at 6:16 pm
Tsk no. it is design and workmanship.
As well as materials.

You may want to check on bridges built in the U.S. in the 1930s


Jeff Alberts
Reply to  mike the morlock
October 24, 2019 7:55 am

I drive over one of those every day. The Deception Pass bridge connecting Whidbey Island to the mainland (or Fidalgo Island if you prefer). There are actually two bridges there, with a large rocky island in between. Built in the mid to late 30s.

October 23, 2019 6:20 pm

These kind of articles show the weakness of 21st Century Journalism as entertainment, not be informational. Granted, bridge maintenance in the US is truly scary, but the Morandi bridge in Genoa, IT was officially determined to have failed because of corrosion in the wires in one of the cable stays. These were grouted to protect the individual wires from corrosion . with gaps in the grout where water was able to penetrate.
Interestingly enough, the bridge used an older design methodology whereby a single point of failure could collapse a major section of a structure, not the more recent design methodologies requiring multiple points of failure.
However, trash in an expansion joint, potentially (but unlikely) shifting a deck section off its supports, is of the earlier design philosophy.
Water – corrosion? I thought global warming was supposed to cause droughts, not corrosion.

Reply to  Enginer01
October 23, 2019 8:55 pm

Some of those “old design methodologies” seem to have been intended for eternity.

In the 1970s “hundred year flood,” every bridge over the Salt River went down – except for one, built at the beginning of the century. More than 100 years old now – and still there. (Obsolete, of course, there were perhaps a half dozen horseless carriages in Phoenix when it was built – but it still takes at least some of the local traffic off of the 30 and 40 year old bridges.)

Reply to  Writing Observer
October 23, 2019 11:45 pm

That’s because the Tempe Mill Avenue Bridge is the only one in the Phoenix area where the piers set on bedrock. The rest have a concrete structure buried in sand that one hopes will support the bridge.

The same storm washed out the support for one of the piers of the I-10 bridge. So for a few weeks, the Mill Ave bridge and the SP railroad bridge were the only crossing over the Salt River.

Zig Zag Wanderer
Reply to  Enginer01
October 24, 2019 1:18 am

Regarding Genoa, I drive a lot in Italy, and have used that bridge myself a few times. When friends visited me there, one was deeply concerned about the state of Italian bridges, and actively concerned when we used one.

I tried to explain that 12 cars (iirc) were destroyed by the accident in genoa, but that many millions of cars had used that very bridge perfectly safely. If you continue to believe it is likely to happen to you, buy a lottery ticket! In any case, just driving in Italy is far more likely to cause you harm.

I also fly with Malaysia Airlines, because I understand statistics, a bit anyway.

October 23, 2019 6:21 pm

“Collapsed I−40 Bridge, near Webbers Falls, Sequoyah County, Oklahoma”

That’s one of the bridge collapses that alarmists may love to blame on climate…

May 26, 2002, was a typical Sunday for Jewell Horne of Webbers Falls, who was getting dressed for church that morning.
Horne recalls hearing something that morning, which she describes as a “bump.” From her Webbers Falls home, the sound was not loud, she said.
“I didn’t pay attention to it,” Horne said.

But Horne soon discovered that the bump she heard was actually the collapse of the far western span of the Interstate 40 bridge over the Arkansas River near Webbers Falls after a barge crashed into the bridge supports.

The barge was being pushed up the Arkansas River by a towboat, piloted by Capt. William Joe Dedmon. Dedmon, then 62, had collapsed unconscious in the wheelhouse before his boat sent the barge crashing into the bridge.”

Yup, global warming panicked the tug boat captain into unconsciousness…

Joel O'Bryan
Reply to  ATheoK
October 23, 2019 6:57 pm

Two very nice ladies in a truck pulling a trailer load of their beloved horses went over that edge. Fell 80 feet into the 40 feet of water in that dark night after the span collapsed in front of them as they traveled down I-40 returning from a horse show. Quite sad.

Reply to  Joel O'Bryan
October 23, 2019 8:53 pm

Very sad, Joel.
The article, I linked to, stated that approximately 40 people drove off those missing road sections. Apparently many were unable to see that span sections were missing.

Just like putting up signs that warn drivers when bridges freeze, how expensive would it be to wire up a continuity circuit that flashes ‘STOP! Bridge out! when the circuit is broken?
The same circuitry could immediately inform local emergency crews.

Areas that are high road salt users should be the first to install the signs; though areas subject to frequent earthquakes should also consider the idea.

Nah, they’d much rather hand trillions of dollars to bad science green trough researchers; instead of properly maintain infrastructure and prep roads with early warning systems.

Not too far from me, six miles, is a small railroad bridge. A few people have been injured and others and drivers have been terrified when concrete chunks break free and crash down.

Every few years, the newspaper prints another notice that the bridge is within the five year plan for major repair, renovation or replacement.
Except the bridge carries the only two Eastern Virginia North/South rails in an extremely busy transportation corridor. Which requires that the Feds/state and railroads build a replacement bridge first.
Every year, nothing is done.

No, it is not the only road/bridge infrastructure along the East Coast that is in desperate need of repair/renovation/replacement. There are many.

Reply to  ATheoK
October 23, 2019 11:51 pm

De tugboat controls should have included a dedmon switch.

Reply to  ATheoK
October 27, 2019 4:42 pm

Thank you. Exactly how it happens

John k. Sutherland
October 23, 2019 6:29 pm

I guess all of the Engineers walked off the job and didn’t bother inspecting any more then, or working on new materials or new monitoring methods? Time stands still for these people; no progress, no development once they put their brains in gear on the GW train You really can’t make this stuff up, can you.

October 23, 2019 6:41 pm

Poor design, poor engineering, cheap-skating, substandard materials, insufficient materials, poor construction techniques. poor execution, entropy, poor maintenance, institutional corruption, inexperience, incompetence and personal corruption all have nothing to do with it.

It’s all down to UHI effects, bad Stevenson Screen placements, ‘editing’ corruption of land T datasets, rogue interpolations of said sparse corrupted datasets, accompanied by northern hemisphere record snow fall, a greening planet, and reducing storminess in a period of relative T hiatus, and globe no hotter than the 1930s.

Calamity Jane.

Reply to  WXcycles
October 24, 2019 8:48 am


October 23, 2019 6:43 pm

They found that one in four bridges are at risk of a section failing in the next 21 years, rising to 28 per cent by 2060 and 49 per cent by 2080. Almost all are set to fail by 2100.

I wonder what the failure rate would be if the predicted changes in temperatures don’t occur.

Reply to  littlepeaks
October 23, 2019 7:31 pm

You wouldn’t be able to detect it or prove it, and at least think about it.

It is called attribution statistics and is junk whatever field it is used in. It was developed in marketing then crawled it’s way into insurance and medicine and now it’s crawling into “Climate Science” (TM).

From a science point of view the basics of it are simple you remove any and all controls, you assume there is a 1:1 correlation with absolutely no moderators between two things. Then you apply a variation based on a random assumption (its sort of good form for it to be believable but not essential) and then you run the statistics …. then you have your attribution.

Using this junk I can prove that eating XYZ cereal will add 45 days to your life or that CO2 above 450ppm will take 40 days of your life. There is no end of the uses for this dark art of number wrangling.

The best take on it was done on an old TV show called the Goodies in the “It Might as Well Be String” episode.

Reply to  LdB
October 24, 2019 7:43 am

To add to the “fun with numbers”, what is the probability of scenario 8.5 occurring?
Even though I don’t buy the “1 in 4” estimate, if they were honest they should report the likelihood of the outcome as the product of the two probabilities, no?

October 23, 2019 6:44 pm

Clean out the expansion joints and put up sun screens, teach people to “drive right” and we’ll have another autobahn.
Right here in America.
We’ve got some really smooth roads, what could go wrong ?
The cops would love it, they would demand interceptor cars, and training in them.

October 23, 2019 6:45 pm

“Climate Change May Cause Poorly Maintained Bridges to Collapse”

Rational Solution: Pay more attention to bridge maintenance
Irrational Solution: Cut fossil fuel emissions

Reply to  chaamjamal
October 23, 2019 7:41 pm

Come on can’t you see the good news story headline

“cutting fossil fuel emissions saved thousands of lives from bridge collapses”

When pushed how you get thousands you show the maths, multiply the fictional millions of climate refugees who will be walking across them by the fictional increased collapse rate and you will get a number in thousands.

AGW is not Science
Reply to  chaamjamal
October 24, 2019 10:25 am

And as a result of pursuing the second option, in addition to accomplishing absolutely nothing climate-wise that could be measured, when “cutting fossil fuel emissions,” a necessary side effect would be to make all of the types of materials used in bridge and roadway construction and repair, like steel, asphalt, and concrete, more expensive and less available, thereby guaranteeing even less necessary maintenance will get done and exacerbating the original (and ACTUAL) problem.

D. Anderson
October 23, 2019 7:02 pm

Bridges don’s last forever. They have a designed life span. Every year hundreds of bridges reach that age. They should be replaced but generally they aren’t.

Plus up until about the 90s they designed bridges without redundant support members. One breaks the whole thing comes down. There are 10s of thousands of these timebombs.

October 23, 2019 7:03 pm

GAT’s are rising but Highs are not (slight down trend). Overnight Lows are rising, and that doesn’t seem like a problem. That would lengthen growing sessons.

Bridges should age better than expected with the slightly lower highs and higher lows.

The bigger threat to bridges would be a cooling trend. Cooling is not unlikely the next several decades with Ocean cycles turning negative…under a quiescent sun.

Jeff Alberts
Reply to  DocSiders
October 24, 2019 8:15 am

“GAT’s [sic] are rising”

There’s more than one?

John F. Hultquist
October 23, 2019 7:05 pm

Do bridge surfaces and the expansion joints get hot from
air temperature or from direct solar energy?
Is expansion a linear function of temperature, or perhaps a
logarithmic function.
Do bridges expand without limit until they melt?
comment image

Bengt Abelsson
Reply to  John F. Hultquist
October 24, 2019 1:05 am

1. Both
2. Linear
3. No

Jeff Alberts
Reply to  Bengt Abelsson
October 24, 2019 8:16 am

What do hard freezes do to expansion joints, or any other joint in the structure where water can enter?

October 23, 2019 7:05 pm

The correct statement should be “Poor Maintenance May Cause Poorly Maintained Bridges to Collapse”

The root cause is probably because the authorities wasted all of the maintenance budget on climate change virtue signalling.

October 23, 2019 7:12 pm

If we enter a Solar Minimum or, don’t, wouldn’t water retained by debris in the joints cause equal or greater damage expanding in the joints than expansion due to heat?
I’m not an engineer and I really don’t know so, please don’t beat up on me. It just seems that if one is a problem, the other must be a problem, too. Thanks.

Zig Zag Wanderer
Reply to  kcTaz
October 24, 2019 1:23 am

Freezing water is definitely one of the most destructive forces in nature, but seldom appreciated because the effects are slow. As I understand it, soil would not occur as prolifically as it does without this effect breaking up rock.

Just one of the many extraordinary properties of water that allows life to flourish.

Reply to  Zig Zag Wanderer
October 24, 2019 7:46 am

In many parts of the US (e.g. NYS) you also have to add in the negative impact of salting those bridges during freezing conditions.

Craig from Oz
October 23, 2019 7:16 pm

From new Scientist;

“Hussam Mahmoud at Colorado State University and his colleague…”

This ‘colleague’ is Susan Palu, and according to a bit of casual research on the interwebs not only has a master’s degree in civil engineering, but is also the LEAD AUTHOR of this paper.

Well done New Scientist. Not only do you manage to fill your pages with fluff pieces filled with IF and MAY, but you do so while Mansplaining. Well done. It takes a special something to successfully offend both the rational and the woke within the same article, but you seem to have pulled it off. High five.

October 23, 2019 7:16 pm

One wonders if they allowed for the extra load of ants crossing the bridges, it is in the same magnitude of factor.

Reed Coray
Reply to  LdB
October 23, 2019 7:49 pm

Only if the ants march in-step. I want money for a study on how to train ants to cross-bridges out-of-step.

Mike Smith
October 23, 2019 7:17 pm

I spent time as a government employed scientist studying bridges specifically including the thermal issues.

We do have a problem but it has absolutely nothing to do with climate change. The issues arise because we’ve done a great job of deferring if not skipping the maintenance that was envisioned at design time.

We will see structural failures unless we catch up on the backlog of maintenance work. But once again, it has nothing to do with “climate change” or CO2.

October 23, 2019 7:17 pm

Interestingly the study authors appear to have used average rather than peak minimum and maximum temperatures applied to a bridge with dysfunctional expansion gaps, to predict when each bridge will exceed its structural design tolerances.

The temperatures that have been warming are the night time minimums. link That means the daily maximum temperatures which would cause the most expansion aren’t a big problem. Also, the diurnal delta T is decreased. In other words, even if average temperatures continue to increase, bridges may be under less stress rather than more.

Joel O'Bryan
October 23, 2019 7:25 pm

Just alarmist nonsense. States have bridge inspection programs. Palu and Mahmoud obviously are academics who do not have CE experience in the professional world outside of academia.

Dr. Hussam N. Mahmoud has zero non-academic professional experience in structural CE and his CV indicates no attempts towards attaining his PE certification with actual professional work outside academia. His main accomplishments are securing grants. Hence, he is like Mark Jacobs. He can make any nonsensical claim regarding Climate Change impacts and not worry about ethics if he were a PE.

Ms. Susan Palu was a recent MS grad from his structural lab program.

And as noted above by Steve Case, the authors wrote:
“if civic authorities don’t properly clean clogged bridge expansion gaps, “

Why don’t Palu and Mahmoud just come out and say, “If state highway dept professional engineers fail to ensure that bridges under their assigned responsibility are inspected and properly maintained by mnx crews … then bad shit will happen.

Because that is effectively what they are claiming: Don’t do your job as a PE, things fail and people die. Well Duh!
Of course Dr. Mahmoud will never have to worry about that as an academic CE.

John Dowser
Reply to  Joel O'Bryan
October 23, 2019 10:40 pm

One element is missing from your reasonable reply: inspection and maintenance would be normally scheduled and calculated based on existing average numbers. If these numbers would shift in any significant way, it can still be interesting for inspectors to base any recommendations on. Underneath the alarmist feeling, the numbers can still be helpful for planning and calculating cost of maintenance over the lifetime of a structure.

Jeff Alberts
Reply to  John Dowser
October 24, 2019 8:23 am

“inspection and maintenance would be normally scheduled and calculated based on existing average numbers. If these numbers would shift in any significant way, it can still be interesting for inspectors to base any recommendations on.”

One would first have to show that slight warming is specifically bad for expansion joints of various types. And one would have to show that slight warming is actually occurring in the region of any particular bridge. Global warming isn’t global.

Joel O'Bryan
Reply to  Jeff Alberts
October 24, 2019 1:41 pm

Warming or not, in cold weather the state and county highway depts routinely send out the spreader trucks to sand the bridges and overpasses during the winter months.
So irregardless of CC, Springtime maintenance of expansion joints is necessary. Road and highway maintenance supervisors must schedule the plan for the maintenance and inspections. Those depts will have to bring in the big air compressor carts and maintenance crews to blow- out and remove the debris in the joints and repair the seals as necessary. Every spring time.

The major source of the debris these authors talk about is mainly coming from applied sand during the winter months to bridges and overpasses for obvious traffic safety reasons.

Deborah Beachboard
October 23, 2019 7:40 pm

Sounds like poor maintenance to me….but by all means blame it on Climate Change!

Mike Smith
Reply to  Deborah Beachboard
October 24, 2019 6:58 am

It’s a great strategy perfected by Jerry Brown of California.

Mark H
October 23, 2019 7:41 pm

Sounds to me like they sat down and thought “how can we get funding to do this boring study on bridge failures”. They came up with the “bright” idea of tacking “Climate Change” onto the title and into the abstract, and voila, the magical fount of funding was opened to them.

Maybe I’m cynical, I prefer to think of it as realistic.

Reply to  Mark H
October 23, 2019 8:53 pm

Actually, I was thinking along the same lines, albeit not as cynically framed. Assume that the motives of the study writers are actually noble. “aaieeeeeee!!!, Climate change!!’ allows them to get funding, and it may also get more response in solving the MAINTENANCE PROBLEMS with bridges.

Jeff Alberts
Reply to  John Sanford
October 24, 2019 8:24 am

“aaieeeeeee!!!, Climate change!!’


Sceptical lefty
Reply to  Mark H
October 23, 2019 10:27 pm

“The power of accurate observation is commonly called cynicism by those who haven’t got it.”

Reed Coray
October 23, 2019 7:46 pm

Another ridiculous attribution of global warming to a potential problem. Well, let’s cross that bridge when we come to it.

October 23, 2019 8:10 pm

Isn’t it a good thing, that global warming is creating jobs.

Checking bridges, repairing bridges, and making new bridges.

Some people are never happy.

P.S. You might want to check these videos, to see whether there were any bridge failures during warming events that occurred from 1880 to 2019.

I recommend that you look at February 1903. There was a major warming event over most of Russia. And I am almost positive that some of their bridges collapsed.

Clary of Oz
Reply to  Sheldon Walker
October 23, 2019 8:30 pm

Russian bridges need to get permission before they collapse

Chris Hanley
October 23, 2019 8:43 pm

Based on a study of bridges (within NY State) as the av. T has increased (+5.0F /Cent.) the bridge failure rate per year has declined:
comment image
(W Cook 2014).
If the trend continues it looks as though increasing temperatures will make bridge structures stronger, or the trend could reverse at some point at which we will have reached the ideal temperature for bridge structural integrity and durability.

Reply to  Chris Hanley
October 23, 2019 10:07 pm

A bridge optimum!

Tim Whittle
October 23, 2019 9:21 pm

Aaaaaand the bridge failure in Italy had NOTHING to do with expansion joints, and everything to do with poor design and lack of maintenance.

October 23, 2019 10:07 pm

Is there a single shred of evidence that more bridges fail in warm weather than in cold weather ? I’m thinking NOT, the reason being that the last bridge failure I recall actually was due to cold causing the structure to shrink off one of its supports that was intended to allow for thermal expansion and contraction.

Reply to  DMacKenzie
October 24, 2019 4:24 pm

A-ha! Climate-change™!

Patrick MJD
October 23, 2019 10:09 pm

Tower bridge in London is over 130 years old. Richmond bridge in London was completed in 1777, over 240 years ago. Both are still standing and in use. Was that due to construction, materials used or maintenance?

Jeff Alberts
Reply to  Patrick MJD
October 24, 2019 8:27 am


October 23, 2019 11:36 pm

If true, this has nothing to do with climate change. Instead it has everything to do with government failing to perform necessary maintenance due to short-sighted political leadership.

October 23, 2019 11:37 pm

If any bridge fails just due to clogged expansion joints on hot days then all I can say is it was …

“Build down to a price, not up to an adequate specification.”

October 23, 2019 11:39 pm

Here’s a story about a bridge that failed 42 days!!!! after opening.

All it takes is the low bidder….

Reply to  Yooper
October 24, 2019 6:09 am

For those who want “the rest of the story”, here’s a good link to the failure analysis reports about what (really) happened to the Nipigon Bridge:

This quote is from the Associate Engineering Executive Summary:
“8. Passage of heavy but legal trucks over the bridge, combined with the out-of-parallel bearing condition arising from the installation methods, would be sufficient to cause permanent deformations (plastic strains) in bolts from changing uplift reactions and axial forces in the critical bolts at the north-west bearing. Overload permits issued by MTO indicate that just under ninety trucks over 60 tonnes (the weight of a code design truck) potentially crossed the bridge. The passage of these vehicles would be sufficient to contribute to the accumulation of low-cycle fatigue fractures of the bolts. The number of heavy trucks crossing the bridge is similar in magnitude to the number of crack propagation cycles seen in the striations on the fracture surface of some of the bolts.”

Carl Friis-Hansen
October 24, 2019 12:15 am

Poor maintenance due to Climate Change happens in Siberia too:
Or would it be due to Russia now officially will have nothing to do with Climate Change, apart from reporting CO₂ contributions for the plants’ well being.

Ben Vorlich
October 24, 2019 12:16 am

Extreme weather events have always destroyed man-made structures. It started when people started building things and didn’t get the design right or take into account hom extreme a weather event could be. Add poor maintenance and failure is inevitable.

Moderately Cross of East Anglia
October 24, 2019 1:03 am

I wonder if any Roman bridges or aqueducts failed because of warmer temperatures/climate change. There must be money available for this crucial matter (yawn) to be studied.

Michael Ozanne
October 24, 2019 1:53 am

Did they do some actual fieldwork to estimate the proportion of steel bridges where the gaps aren’t being adequately maintained?

Carl Friis-Hansen
Reply to  Michael Ozanne
October 24, 2019 2:23 am

On German motorway bridges the maintenance crew regularly clean the expansion gab, check for loose bolts and fractures. All issues are photographed and documented. You know “Ordning mus sein!”

son of mulder
October 24, 2019 2:40 am

Here in the UK train rails used to buckle in hot weather. The design was changed which significantly reduced such failures. In very hot countries are they better at maintenance or are their bridges designed differently? Or maybe in the UK climate change has reduced to amount of rail buckling.

October 24, 2019 3:10 am

I propose an alternative title: “Poor maintenance could cause bridges affected by severe weather to collapse”.

Peter Quinby
October 24, 2019 3:45 am

Not entirely relevant to the thread, but :
“I have seen plenty of software systems fail because the hardware capacity estimates were based on average load rather than peak load.” Well, non-IBM mainframe systems anyway. Those may go slow but you rarely if ever get collapse. Whereas Unix variants, Windows, etc…….

October 24, 2019 4:48 am

One doesn’t need “climate change” to collapse bridges that are poorly maintained.

This is just a falsifiable hypothesis fallacy trap article so they can point and say “there, see see!”

October 24, 2019 5:35 am

Cause of Bridge collapse: (A) Climate change. (B) Poor maintenance. I choose (B) every time!

Patrick MJD
Reply to  Derek Wood
October 24, 2019 5:50 am

There is C, poor design based on assumptions, Tacoma Narrows for example.

October 24, 2019 6:03 am

Sheesh. Poorly maintained bridges cause poorly maintained bridges to collapse. Did they not take into account winter and summer temperature differences?

October 24, 2019 7:02 am

The famous “Pont du Gard” built in France 2000 years from now is in an excellent condition and presents no clues of next nor remote collapse risks.

October 24, 2019 7:45 am

So what would the extra expansion length of a bridge be (in mm) if the climate was 1/2 degree warmer?

Are we really to expect that this increase is significant? Anyone with a few rough numbers?


Reply to  ralfellis
October 24, 2019 9:07 am

Coefficient of expansion of steel is 12 millionths of a meter per meter length per degree C warmed, as a first approximation, but that doesn’t mean that a bridge will grow that much. You have to consider stress strain relationship, geometry of structural members, and curvature of bridge deck as well.

Kerry Eubanks
October 24, 2019 8:19 am

Wouldn’t you just love to read some of the grant applications for such obviously BS studies? Of all the ones reviewed on this site and others, the claims in this one are among the most farcial.

October 24, 2019 9:13 am

This is otherwise known as Democrats infrastructure stimulus spending 2.0

Just be careful what you wish for. The last Shovel Ready deal of Obama was reshuffled to give highways only 5 percent of the windfall stimulus. Even Obama could not help but chuckle over that ruse.

michael hart
October 24, 2019 9:29 am

Alternatively, just send an engineering bloke to take an afternoon looking at such important structural features of the bridge once a decade. Disaster averted.

Phew, that was a close one.

Loren Wilson
October 24, 2019 9:30 am

The picture in the title is very misleading. This bridge collapsed because the barge hit it, not because of climate change. The captain passed out. Makes me not trust anything else in the article.

October 24, 2019 9:31 am

Well, now that math has been declared to be “oppressive,” we should expect that more bridges to collapse.

Jeff Labute
October 24, 2019 9:45 am

NOVA had an episode on why bridges collapse and did not touch on climate change at all. More about improper design and the belief that steel in concrete won’t rust and concrete doesn’t mind encasing steel under tension. Lots of old bridges have a poor design. I can’t see engineers siding with climate nut-bars on this. Concrete is cheaper than steel so it was used in the italian bridge. Hope they don’t bring in a rain and humidity tax.

Al Miller
October 24, 2019 10:51 am

OMG the stupid burns!! Old, poorly maintained infrastructure may collapse – due to hmmm, maybe being old and poorly maintained- no that’s too simple and won’t get funding- yes, Global warming apocalypse that’s it. Gotta go barf now.

Mike McHenry
October 24, 2019 11:39 am

It seems to me that the RCP 8.5 was written into the IPCC report to provide cover for academics who want to write impactful papers.
The lower Mississippi R. has got to be one of the moct extreme environments for bridges in the USA. Where are all the collapsing bridges?

October 24, 2019 12:06 pm

It ain’t the heat that could do in the bridges, it’s the delta heat. Think how good global warming could be for roadways, no more potholes due to freeze-thaw.

Alexander Vissers
October 24, 2019 1:54 pm

Poor maintenance may cause poorly maintained bridges to fail. Acts of god may cause poorly maintained bridges to fail.

Alexander Vissers
October 24, 2019 2:01 pm

In the Netherlands especially in Amsterdam we more and more frequently have to cool bridges, especially with tramway rails on them with the water below to be able to lift them for the reasons mentioned, expansion of metal in heat, so make sure to cool your bridges if necessary.

October 25, 2019 4:25 am

Just an idea – maintain the bridges properly?

October 25, 2019 8:16 am

Bridge engineer here. For a 20 – 30 m (60 – 90 foot) bridge span, which is typical for most overpasses and highway bridges, you’re usually dealing with 2.5 mm or so (1/16 – 1/8 inch) of temperature expansion/contraction that must be designed for. That comes from design codes, and should cover the extreme temperatures over the bridge life. And that will be on the high side since my climate of Alberta, Canada sees +30 to -30 Celsius in a typical year (also, pardon my use of metric, above).

So I haven’t run any numbers, but it’s really hard to believe that a few degrees of warming is going to max out one in four bridge expansion joints. If the temperature changed by 5 degrees Celsius in an RCP 100 scenario (why not go crazy), pretty basic math but if 60C of difference creates 2.5 mm of change in bridge span length then 5 / 60 x 2.5 mm = another 0.2 mm makes 2.7 mm expansion instead of 2.5 mm. If that’s going to fail one in four bridges then I’ve got a bridge to sell you.

Rudolf Huber
October 27, 2019 3:53 pm

My Lasagne tasted a bit stale this weekend. Must be Climate Change. My friend’s dog was very sleepy too – surely Climate Change. And there was the issue with my hair. Why don’t I have hair? The Climate – that’s it. Why didn’t I think of that? It’s so simple if one just puts his mind to it.

Johann Wundersamer
October 29, 2019 2:39 am

Utter Drivel.

“What caused the Genoa bridge collapse?

We’ve looked at what experts say might have caused the Morandi Bridge to fall down. The demolition of the Morandi bridge, which gave way on August 14 last year, sending dozens of vehicles plunging 50 metres to the ground below, began in February.

Jun 28, 2019

The concrete sections of the bridge were stretched together, biased.

It was not rust that brought the bridge to collapse. This bridge was very old, italia had to meet the EU requirements: the famous “black zero” in the budget balance

Such a bridge must be constantly observed

+ incl. Maintenance

There simply was no money left in the state’s balance sheet – the lira / €€ were reserved, urgent, to prevent the “mass extinction climate change”.


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