Keystone Added to I-74 Arch Bridge

I am usually writing about failed or rotting infrastructure. But not all stories are doom and gloom. Crowds come out to watch crews complete first I-74 bridge arch. The piece was installed May 5th.

The I-74 bridge across the Mississippi River between Illinois and Iowa is old, and in bad shape. To fix that 2 new spans are under construction. True-arch, basket-handle bridges are being built just upstream of the existing bridges. They will carry 4 lanes in each direction.

The bridge joins Bettendorf, Iowa and Moline, Illinois, and is pretty much right in the middle of The Quad Cities region. The other 2 cities are Rock Island, Illinois and Davenport, Iowa. The first span of the existing bridge was built in 1935. A second bridge built to the same design was added in 1961. It is handling almost twice the number of vehicles the design called for, and it is NOT up to interstate highway standards.

While on a tour at the base of the bridge in Bettendorf in May 2012, U.S. Transportation Secretary Ray LaHood said that, in comparison with other bridges that he has seen in other states, the current I-74 Bridge is one of the worst he’s seen.

The keystone, or center piece of the arch, of the first span was put in place during the first week in May. A 100,000 pound chunk of steel. raised about 200 feet in the air. The video at the news story linked at the top of this post is about 2 minutes long, and is not too annoying. Other videos will play after the first video if you take no action.

This is a short video, about 1 minute, from April showing the stage of construction just prior to the keystone being placed. You can see the temporary towers and cables supporting the arch as it is built, and get a feeling for the size and the design. It isn’t my favorite video, but at a minute, it seems to capture what is important. There are more videos, and they are easy enough to find, that are in the 5-6 minute range, taken anytime from January through Easter, if you’re interested in more detailed views of the construction.

You can find an artist’s rendering of the new design at this link.

There is a longer video of the process of getting the keystone in place, but it is 45 minutes, or more, and not particularly interesting. I can’t really recommend it, but I include if for completeness.

Infrastructure Problems

A number of infrastructure problems have come to light due to all the rain.

News Flash: Chicago’s Lower Waker Drive is close to the level of the river. (That’s one of the reasons there is an Upper Waker Drive.) Chicago Weather: Recent Storms Break May Record For Rainfall.

Flooding also overwhelmed Lower Wacker Drive, prompting Fire Department crews to use inflatable boats to help rescue at least six homeless people who were left stranded Sunday night.

The flooding on Lower Wacker Drive also has left Willis Tower without power since early Monday morning, after a ComEd substation was knocked out. Crews were still working to pump out floodwater from the basement of the iconic skyscraper on Tuesday. ComEd said they are not yet able to estimate when power will be restored.

Cars parked in the sub-streets have been destroyed by flooding.

Willis Tower (previously known as Sears Tower) is still without electricity, though it should be restored over the weekend.

Another dam is in danger of failing. This one in Virginia. More than a dozen homes in Roanoke being evacuated due to potential dam failure.

Roanoke City officials say that the Spring Valley Dam located near Lake Dr. is in danger of failing, which would cause flooding in the area surrounding the dam.

The video at the link seems to show the outflow from the spillway. Definitely a potential to cause erosion, and the level of the lake behind the dam is in danger of overtopping the weir. It may have overtopped the weir briefly, but there is no sign of erosion.

Joliet, IL has also had trouble with flooding. Joliet’s Route 53 Closed, Road Damaged From Floods.

That part of Route 53 through Joliet is actually the old Route 66 through that part of the country. So that infrastructure is probably as old as the photos make it look. And viaducts always have problems with flooding. It is easier to dig out a trench for the road, than to build a hill for the train. They always flood, and occasionally a semitrailer will get stuck under the railroad bridge. (Don’t rely on Google Maps to tell you where Route 66 is. They are confused, though you could search for Route 66 raceway in Joliet.)

There are other stories of drownings, and flooding, but not so much tied to infrastructure.

2nd Dam Breached

The Sanford Dam, downstream from Edenville, breached. 2 Michigan dams breached, thousands evacuated amid flooding.

The evacuations include the towns of Edenville, Sanford and parts of the city of Midland, which has 42,000 people, according to Selina Tisdale, spokeswoman for Midland County.

Water in Midland is expected to be about 9 feet deep.

The Sanford Dam, which was built in 1925, received a fair condition rating.

This story say the Edenville dam was built in 1924, which differs from what I say in the Wiki. Anyway the previous post on these dams is at this link.

Edenville Dam Collapse

It was apparently not a surprise to some people that the dam was in danger. Feds revoked failed Edenville dam’s license in 2018 over inability to handle big floods.

Federal regulators in 2018 revoked the hydro-power generating license for the collapsed Edenville Dam in Midland and Gladwin counties, citing years of failure by the dam’s owners to address safety problems — especially the dam’s ability to withstand a major flood.

The Edenville Dam ruptured Tuesday after heavy rains

There is a short video, 35 seconds or so, at the link above that shows the extent of the flooding.

The details on the dam…

The Edenville Dam is a 6,600-foot [1.25 miles or just over 2 kilometers] earthen embankment up to 54.5 feet in height, spanning both the Tittabawassee and Tobacco Rivers in Midland and Gladwin counties. The dam creates a 2,600-acre reservoir known as Wixom Lake, with a gross storage capacity of about 40,000 acre-feet [4.934×107 cubic meters] of water and a 49-mile-long shoreline when full. The dam was equipped with two, 2.4 megawatt turbine generators and was licensed for hydro-power generation in 1998.

According to the Wiki, the dam was completed in 1925. So probably there were both design and maintenance issues with a dam that old.

Apparently they had been trying for 14 years to get some safety concerns addressed, before they finally revoked the license.

So with no ability to generate power, were the turbines just closed off, and not able to help drain the lake? It doesn’t say anywhere that I can find. And in any event, the dam seems to have been designed only to handle about 50% of the “probable maximum flood.” Which is apparently what they got. Water in that quantity over the spillway caused erosion of the earthen structure, and we see the result.

And while politicians are busy doing all the things that are popular today, like art in the park, and funding cultural centers, or whatever, infrastructure is left to crumble.

A 2018 report card on Michigan dams by the state chapter of the American Society of Civil Engineers found that while the state had improved its D-grade from the society’s 2009 report card, it still had persistent issues.

“There are approximately 2,600 dams in Michigan, of which about two-thirds are older than their typical 50-year design life. In the next five years, about 80 percent of Michigan’s dams will be over 50 years old,” their report stated.

There were 19 high-hazard dams in unsatisfactory or poor condition in Michigan in 2018, ranking 20th among the 45 states and Puerto Rico for which The Associated Press obtained condition assessments.

This won’t be the last dam to fail, or even the last one in Michigan. And I doubt politicians even think about infrastructure.

Nothing lasts forever. And an earthen dam built in 1925 is going to need some maintenance, and maybe even some improvements, and eventually it will need to be replaced. The “What could go wrong?” attitude has got to stop.

There is fairly good video of the breached dam at this link. It is only 35 seconds or so, but part of the video is a clear view of the breach in the dam from an airplane. Not the best video. (People hold your phones horizontal, when taking videos!) but it is clear. There are a few seconds at the end that show the breach from the shore.

Nanfang’ao Bridge Collapse

This bridge was constructed in 1996 in Taiwan. It was intended to last 50 years. On October 1st of last year, at 09:30, it collapsed killing 6 people and injuring 12 more.

Click on the image for a large view.

Rust never sleeps. Rust damage a potential factor in Nanfang’ao Bridge collapse: TTSB

An investigation into the collapse of Nanfang’ao Bridge in Yilan County last year found corrosion in several of the bridge’s steel cables, while the impact of other factors, including road construction projects and overloading, is still being studied

Five of 13 suspenders gave way, causing the arch to fall on one end, and the roadway to fracture.

This is not the first bridge failure in which overloading might be a factor. Bridges are not designed to hold infinite weight. And just because you need to drive across a bridge with your cargo, doesn’t mean that you should. And even if you make it across, doesn’t mean you haven’t damaged the structure so that it will fall tomorrow.

However, we can’t say definitively that was the cause.

The day before the bridge collapsed, the area was hit by Typhoon Mitag, and struck by a 3.8 magnitude earthquake at 13:54 in the early morning before the collapse.[3][19][20] However, MAA Consultants are not able to determine the actual cause as the crucial broken parts of the structure have yet to be recovered.

A typhoon, an earthquake, and a bridge collapse all in 2 days time.

Back to the article linked at the top…

Larger questions surrounding the bridge’s collapse, including the possibility of improper construction and the extent of the rust damage, require further investigation, the TTSB said.

A picture of the bridge before the collapse can be found at this link.

3-year-old Dam Fails

People in both Uzbekistan and Kazakhstan had to be evacuated. 70,000 Evacuated After Breach in Uzbek Dam, Investigation Into Failure Launched.

The dam failed on May 1st. It appears there was adequate warning to get everyone evacuated, as no deaths have been reported.

The dam and reservoir were completed just three years ago, suggesting that the failure was the result of either design or construction flaws. It will be interesting to watch who ends up with the blame for the dam’s failure. The project’s construction was begun under the presidency of Islam Karimov, in 2010, but it was overseen by Mirziyoyev, who served as prime minister from 2003 to 2016.

I doubt this will get much coverage in the English-language press, since there isn’t A) anyway to blame President Trump, and B) no one died.

May 9, 1980: MV Summit Venture Hits Sunshine Skyway Bridge

I usually do posts about failed infrastructure on Sunday, but since we have an anniversary today… The Skyway bridge collapsed 40 years ago. Here’s how we’re remembering the tragedy. That is a collection of links to things about the collapse. Interviews with people who worked search and rescue, information about the trial of the pilot, and a few other links.

Saturday marks 40 years since the 19,734-ton Summit Venture freighter slammed into the old Skyway bridge. Six cars, a truck and a Greyhound bus plummeted 150 feet into the choppy waters of Tampa Bay below. Thirty-five died.

A two-lane bridge opened in 1954. A second structure, similar to the first opened in 1959 making the crossing 4 lanes, connecting the south end of Pinellas County with the north end of Manatee County.

On Friday May 9th, 1980 at 7:33 in the morning, the vessel MV Summit Venture, in fog and rain, struck one of the supports of the southbound lanes of the Sunshine Skyway, causing about 1200 feet of the bridge to fall 150 feet into the water. 35 people died. Cars, trucks and a Greyhound bus fell into the water that day. Most died of blunt-force trauma. Some drowned. One man survived when his truck landed on the deck of the Summit Venture before falling into the water.

This video documents the official recording of the MAYDAY call between MV Summit Venture and the US Coast Guard base in St Petersburg. A few other ships are heard as well. Photos are of the aftermath.

The new bridge corrects the design flaw of the original bridge, in that any vessel straying off course is going to impact something substantial before it impacts the bridge structure itself. I hope they got it right.

The new bridge has the following stats:

  • total length 1219.60 m (if you include the causeway, it s 6.7km)
  • main span 366.75 m
  • clearance below main span 55m

As I write this, there is not much coverage of the anniversary outside of Florida. I guess that’s to be expected.

The video after the break is of the new bridge.

Continue reading

Preparing for an Earthquake in the SF Bay Area

Not that people will prepare. Being prepared for a disaster is apparently “uncomfortable.” Or something. We Can Outsmart Disaster: The HayWired scenario.

So what would happen if a major earthquake hit the Hayward Fault, in the San Francisco Bay? That is the question this scenario was designed to answer, and to communicate.

The HayWired scenario depicts a scientifically realistic earthquake sequence, and its cascading impacts, that all starts with a magnitude 7 earthquake on the Hayward Fault. The scenario emphasizes understanding impacts from modern society’s lifeline interdependencies and reliance on the Internet.

The .gov tries to understand what would happen if the big one ever hit in the San Francisco Bay Area. But it is only ever as good as what people will do for themselves and people resist preparing. Because to think about what bad things might happen is uncomfortable.

The Hayward fault runs through some of the more populated portions of the SF Bay Area. If a major earthquake hits (when a major quake hits?) it will be a nightmare. 5 million people could be impacted. Water could be cut to more than 2 million people. (Bets on whether or not those 2 million people have ANY water supply on hand?)

Lack of water means lack of sanitation. Lack of sanitation means problems like cholera and dysentery. And death by dehydration.

The USGS produced a movie about the HayWired study. You can find that video (less than 6 minutes) at this link.

There is also a site dedicated to how to prepare in the face of this certainty. Outsmart Disaster. A major quake occurs on this fault every 100 to 220 years. The last quake was 150 years ago. Not that people will prepare, because it is someone else’s responsibility to take care of me. Or something.

Disruption is immense. As many as 22,000 people could be trapped in elevators.

More people will be trapped in collapsed buildings. Fires, compounded by lack of water will be everywhere.

So do you think people will take heed of this? Probably not.

There are documents on Engineering Implications, and general service disruptions.

The service disruptions are of most interest to this post. Lifeline Infrastructure and Collocation Exposure to the HayWired Earthquake Scenario—A Summary of Hazards and Potential Service Disruptions.

BART stations and train yards will take longer (a few years) than highway bridges (as long as 10 months) to restore in the most heavily impacted areas

Three airports, a seaport, an oil refinery and a water treatment plant are at risk due to liquefaction. Oil and gas pipelines and communications cables are at risk.

Restoring water supply to all areas could take 6 months. How would you survive without city water for months on end? Could you?

Dam Inspections Do Not Equal Safety

The dam in question got good safety reviews right up until the day it failed. Toddbrook dam collapse | ‘Closing gap between compliance and safety’ must be priority.

First a review of what happened.

On 1 August 2019, a single slab of the dam’s spillway chute collapsed into a large void that had formed underneath, and a brown slurry could be seen discharging from under slabs (which had also failed and lifted) further down the spillway chute. During the day the void enlarged, and more slabs collapsed, risking the integrity of the dam. A full-scale emergency was declared, and, as a precaution, 1,500 people were evacuated from the town of Whaley Bridge immediately downstream of the 25,000m3 Toddbrook Reservoir.

I haven’t read the complete report, but the summary isn’t surprising. The design of the spillway, which was built 100 years ago, and redone in some way in the 1970s, wouldn’t meet design standards today. The concrete in the spillway was too thin, reinforcing was inadequate, there was no under-spillway drainage, etc.

But the problem – to my mind – is the maintenance. Even though they got good reports from the inspections, and had NEVER had a safety violation, it’s clear that something was wrong.

The reports adds: “Maintenance over the years had been intermittent with extensive plant growth in cracks and joints for prolonged periods, suggesting open passageways to the embankment beneath. Generally, the slab concrete remained sound but there was honeycombing and/or deterioration at some joints, some missing chute plums, some cracking and evidence of significant prior plant roots through joints and in some cases through slabs.”

For a more complete review of what happened, see It Isn’t Only The USA That Has Been Ignoring Infrastructure. There is a video from Blancoliro that covers details of the dam and the emergency response, which included a helicopter from the Royal Air Force.

Dams and Earthquakes

Not a winning combination. Feds Order Anderson Reservoir to be Emptied.

It should be no surprise that this dam is in California.

A 2009 study concluded the possibility that a 6.6M earthquake with an epicenter right at the dam or a 7.2M one up to a mile away, could cause dam failure due to liquefaction.

Here’s a short video of what soil liquefaction looks like after an earthquake. That isn’t something you want to happen to dam, that has the potential to flood a populated area.

Despite that study, the reservoir stayed full until another study, in 2019, showed what a wall of water would do if the dam collapsed with that much water behind it. The dam has been kept at 58% capacity since then, but now the feds want it drained.

Another result of the [2009] study was the inception of the Anderson Dam Seismic Retrofit Project costing about $550 million to strengthen the dam against a strong earthquake, however a “complicated and time consuming” process including securing a number of permits amidst changing state and federal regulations has delayed the project for over a decade.

So here’s a piece of infrastructure, that is somewhat critical to the water supply of the San Francisco Bay Area, that they have been trying to repair for nearly 20 years. Yet they can’t make any progress because of regulators. And they don’t say it, but I’m sure there are environmental suits involved over getting the dam removed.

There is a quote, which I won’t find, that compares our society with Italy in the dark ages. We are surrounded by all these things built by previous generations, and we’re unable to reproduce them, or even maintain them. Soon, we won’t even understand them.

They Were Told to Stay Off the Bridge

But that is hard so they ignore the signs and warnings. UPDATE: SDOT still working on solutions for both West Seattle Bridges.

When this bridge collapses, people will be shocked and appalled. And it will collapse, soon. The cracks are apparent. (Click the link above for a photo of the cracks.)

Low bridge seeing 15,000 cars a day despite signs restricting access

It is supposed to be limited to freight and buses. But that would be inconvenient.

“The West Seattle High-Rise Bridge was originally designed for 3 lanes of travel in each direction. As Seattle grew, the bridge grew to 3 westbound lanes and 4 eastbound lanes. This added traffic, combined with the increase in size and weight of commercial and transit vehicles, has only compounded the long-term maintenance challenges posed by the bridge. Further, 80 percent of the bridge load is dead load, meaning deterioration is possible even when all traffic is removed.”

As a side note, the average weight of cars and trucks grew by some 900 pounds per vehicle between 1987 and 2020.

High dead load. Increasing live load. Cracks that are visible in the structure. People ignoring the signs restricting access. I wonder if anyone is running a pool on when the bridge will collapse.

Another Dam Failed on Friday

Not much information, but there didn’t seem to be much danger of loss of life when the failure occurred. Flash flooding possible in Putnam, White Counties after dam failure.

Flash flooding is possible Friday evening in areas below Perdue Farms in southeast Putnam County and northeast White County after an [earthen] dam failed Friday afternoon.

As for the edit above, they said “earthing” which is apparently a quack medicine fad, and not a type of dam. But then professional journalists can’t be expected to know these kinds of things.

Tennessee would generally make me think TVA, but this doesn’t sound like that somehow. And I can’t find information to say, one way or another, but I would think that a TVA dam would be named.

There are 2 interesting photos of the breach at the article linked at the top of this post.

There are a lot of small dams all over the place holding back small lakes that were created for various purposes. If you search your county’s website, you might even find one or 2 near you. Probably under emergency management planning or something similar.

Are We Ignoring Infrastructure Problems?

There are many dams in America that are in danger of failing for one reason or another. Let’s look at 2.

First up, a simple problem with a dam in Ohio, could have bad consequences. Goose carcass causes clogged drain at Cattle Dam.

A dead goose was blocking the primary outlet of a dam in Ohio. This caused water to flow over the weir, and that caused erosion. The city tried to remove the goose, and failed and hired a contractor, who was successful. But there are still problems.

The erosion downstream of the weir has continued and has started to undercut the grouted section stone slope protection adjacent to the weir thereby increasing risk of dam failure.

It is one of the many dams in America where no one is quite sure who owns it.

So is a dead goose (or other creature) causing problems common or uncommon?

Then there are the many dams that have been ignored. This one is in the news. ‘We’re gambling every day:’ Lake Conestee dam remains a flooding and environmental risk.

This dam has been in poor condition for quite a while. The last inspection was in 2019.

The inspection also noted:

  • Seepage
  • Deterioration
  • Trash and woody debris

In addition to the problems with the dam, toxic debris is known to be behind the dam (the result of upstream problems). If the dam were to fail, that toxicity would be released downstream causing a whole host of problems.

They have plans to build a new dam, 10 feet downstream from the old one, which is supposed to be complete by 2022, but they haven’t even acquired all of the land they need. So who knows.

If it were to fail, it would be catastrophic, [Conestee Foundation Executive Director Dave] Hargett said.

All the toxic sediment the dam is holding back would make its way down the Reedy River and into Boyd Mill Pond and Lake Greenwood — which provides water for Greenwood and Laurens counties.

“If we lost the dam, it wouldn’t just be an environmental catastrophe, it would be an economic catastrophe,” Hargett said.

Yet they don’t seem to be moving too quickly getting funding, or the land needed.

So will this be another entry at Damfailures.org? Who knows?

Ignore Weight Limits at Your Own Peril

A suspension bridge collapsed on Monday, November 18, 2019, dumping cars into the River Tarn, north of Toulouse, France.

Because politicians the world over can’t be bothered to maintain/upgrade our infrastructure.

Of course if you ignore the limits, that doesn’t mean that other people can’t end up dying as well. Girl, 15, in her mother’s car and a truck driver are killed after suspension bridge collapses in France, sweeping away their vehicles. They pay for your mistakes.

At least one truck and a two cars were seen plunging into the Tarn River below, said eyewitness Eric Bonnin, who owns a restaurant overlooking the bridge, around 20 miles north of Toulouse.

‘I’m in deep shock, it’s horrible to think about it,’ he said. ‘I’d just opened the kitchen door, when I heard a huge noise, like an explosion.

‘I thought a plane had broken the sound barrier. I looked out the window and shouted ‘Oh no, the bridge has broken!’

Local reports indicated that the truck was substantially over the weight limit of the bridge.

When the “authorities” post a limit about what is the maximum, safe vehicle weight that a bridge can hold, they are not trying to make your life difficult; they are trying to save your life. But that doesn’t stop people from ignoring warnings.

The BBC had this to say: France bridge collapse: 50-tonne lorry ‘probably caused accident.

The bridge – 155m long and almost 7m wide – dates back to 1931 and was described by Mr Oget as a “very important crossing point” in the region.

The safe limit on the bridge was about 19 tonnes. So the truck in question was more than 100% above the safe limit. What would you expect under those conditions? And even if he had driven across that bridge before, it clearly was not safe to do so.

Eric Oget, mayor of Mirepoix-sur-Tarn, has suggested warnings about the bridge’s weight restriction – displayed at either side of the crossing – might have been ignored by drivers.

A video of the aftermath can be found at this link.

After the Genoa, Italy bridge collapse, in 2018, France commissioned a survey of bridges. The report called for substantial investments in the infrastructure of France.

“Unfortunately what happened illustrates what we said in the report, which is that the state of our bridges poses a real danger,” Senator Herve Maure, who oversaw the audit, told AFP.

If that happened in America, the driver’s heirs, the company he worked for, and maybe the manufacturer of the truck in question would be sued. Not sure what happened in France after the fact. I can find no information on plans to replace the bridge in question.

The Devil is in the Details – St. Francis Dam Collapse

It was 92 years ago today.

This week we get an extra story of engineering failure courtesy of EBL. The St. Francis Dam Disaster. This is the worst US civil engineering failure of the 20th Century.

The St. Francis Dam, was a curved, concrete gravity dam about 40 miles from Los Angeles. It was constructed between 1924 and 1926 and it failed March 12-13, 1928. 400 people died and property damage was estimated to be $7 million, in 1928 dollars.

Click thru the link above for a short video (about 6 and a half minutes) on the dam, the need for water in Los Angeles and William Mulholland, the man who oversaw construction of the dam, some links to info on the dam, and a musical-interlude-video, “St. Francis Dam Disaster” by Frank Black and the Catholics. (Yes, that Frank Black, AKA Black Francis.)

For more details, we can consult Damfailures.org – Case Study: St. Francis Dam (California, 1928).

While the dam’s upstream face exhibited a nearly vertical profile, the downstream side was equipped with a stair step design that resulted in base and crest thicknesses of 175 and 16 feet, respectively. The main structure reached a height of 205 feet and spanned 700 feet along its curvilinear crest.

It was supposed to impound a 1-year-supply of water for the City of Los Angeles.

I suppose I should not be shocked that one part of the design was changed, while the impacts of that change were not accounted for. It is not the first time I’ve run across that, and the opinion of the folks in charge is usually (always?) the same; it is never feasible to start over, even though (as in this case) you should start over. Or at least make some major changes.

Multiple instances of poor judgment by Mulholland and several of his subordinates significantly contributed to the cause of the failure of St. Francis Dam. Plans for the dam were based upon those previously prepared by Mulholland for the Mulholland Dam with little regard for site-specific investigations. When these plans were finalized and after construction began, the height of the dam was raised by ten feet on two separate occasions in order to provide additional reservoir storage needed to sustain the growing community surrounding the dam. Although these modifications increased the dam’s height by twenty feet, no changes were made to its base width. As a result, the intended safety margin for structural stability decreased significantly. Mulholland’s team recognized this effect, however the engineering analysis, acquiring of additional materials, and extended construction time to properly mitigate the height increase were considered to be too costly to the project and to those stakeholders who were financially invested in the completion and operation of the dam.

Those damn engineers and their numbers. Don’t they know how much it costs to build a dam? And it’s only a little higher. What could go wrong?

Of course I’m sure that none of the those financial stakeholders lost lives or property when the dam succumbed to uplift failure.

It isn’t clear that accounting for the changes in height would have saved this dam, because underlying aspects of the geology had been ignored. It was considered another detail, not worth worrying about, and besides we built dams like this before and they are fine. Or something.

Although opinions vary, more recent and more thorough investigations assign the ultimate failure mode to weakening of the left abutment foundation rock due to the saturated condition created by the reservoir which essentially re-activated a large landslide that combined with a destabilizing uplift force on the main dam caused failure to initiate at the dam’s left end. In quick succession as catastrophic failure was occurring at the left end, the maximum height section tilted and rotated which destabilized the right end of the main dam causing catastrophic failure at the right end as well.

Mulholland was entrusted with the dam’s design and construction, not because he was a brilliant engineer, but because he was well known for having completed other water projects for Los Angeles. This is also not the first time that “reputation” was used to substitute for “engineering qualifications.” And so the dam looked like a previous dam he had built, that was in a geologically different area. Details.

Small changes in the details can destroy a project. This is not a lesson we learned in 1928 – because it has come back again and again. I doubt that the powers-that-be, or the media talking heads know that even now. I mean, they can’t divide 500 by 327.

Maintenance On A Bridge

Øresund BridgeBecause (as I’ve said before) everything needs maintenance. So here’s the story of a bridge that is getting exactly that. Iconic Øresund Bridge Linking Denmark & Sweden Gets A 13-Year Paint Job.

Click the image for a larger view and more details, and links to more images – via the Wiki. The image is from a airplane taking off from the nearby airport.

The Øresund Bridge is a tourist destination, based on a television show.

Two cops—one Swede, one Dane—investigate a crime in which the victims were placed across the international border on the Øresund Bridge. Broadcast in more than 100 countries, the tense Scandinavian thriller The Bridge made its namesake an unlikely international tourist attraction.

The bridge is in part an under-slung truss bridge, with one of the spans being suspended. The top level is a roadway, the truss level (lower) also carries a railway. This makes maintenance a bit of a challenge.

The bridge is 7,845 meters long, the longest span is 490 meters long, and the lower part of the truss is 57 meters above the water. So quite a bridge.

While the bridge is starting to show its age, the project is about much more than just its looks. The new paint is an important part of maintaining the steel structure, according to project manager, Johan Nord: “The top layer of the five-layer painting system will wear out within the next 10 years, so we have to apply a new top layer to be able to maintain the lower levels, which protect the steel from corrosion,” he told The Guardian.

Everything requires maintenance, and steel in close proximity to salt water, needs a complete coating. “Rust never sleeps.”

Everything Needs Maintenance – The Morandi Bridge Collapse

Morandi Bridge, Genoa, ItalyEverything Needs Maintenance. What caused the Genoa bridge collapse – and the end of an Italian national myth? The image is of the bridge, before the collapse. (Click the image, for a larger view, and background info. Image by Davide Papalini)

Construction was from 1963 through 1967. It collapsed on August 14th, 2018.

43 people died. 600 people were made homeless.

The day in question was a stormy, summer day.

By 11.30am, the rain was so heavy that visibility had fallen dramatically. Videos captured by security cameras show vehicles slowing down as they crossed Morandi Bridge, which grew progressively more enveloped in a grey mist.

A few minutes later, a 200-metre section of the bridge collapsed, including one of its three supporting towers.

Click the link at the top of this post for an image of the bridge after the collapse.

Reinforced concrete deck, and pre-stressed concrete wrapping the cables of what otherwise looked like a typical suspension bridge. (Think Brooklyn Bridge.) But maintenance of the bridge wasn’t a high priority thing.

A documentary found problems in the 1990s. Riccardo Morandi, the designer, created a list of things to-do to prolong the life of the bridge. Nothing was done.

Aside from the lack of maintenance, there was an increase in the load on the bridge, which is probably a message for engineers, that things should be overbuilt, because you don’t know what the future will bring.

Little, however, was done, and by 1992 the trademark concrete cables were heavily corroded. The company that managed the bridge, Autostrade per l’Italia – then owned by the state – decided to add extra new cables around the corroded ones, rather than replace them. It also neglected to retrofit the remaining two sets.

That led to the collapse on the stormy August morning.

About a year later, the remains of the bridge were demolished. See Genoa’s Morandi Bridge demolished in dramatic explosion. (Explosive demolition is always a fascinating video!)

So why did the bridge collapse?

Instead, it was probably simple neglect that felled the bridge. In April 2018, Autostrade – now a private company – finally decided there was no more time to waste, and issued a tender offer to retrofit the bridge. The repairs were supposed to start last autumn.

“They waited 25 years and then the bridge collapsed. This is how things go in Italy – you start something and you never finish it,” says Saggio.

Today, the new bridge is under construction and it is supposed to be done this year. The replacement bridge was designed by Genoa native Renzo Piano, and is a little more than half complete. Construction of Renzo Piano-designed Genoa Bridge reaches milestone. (There is a video at that link with English subtitles.) The last of the piers have been completed, and the bridge deck is about 550 meters long, just over half of its finished length of 1067 meters. You can find some info on the design at the following link. Renzo Piano unveils design for new Genoa bridge following disaster. It is supposed to be complete in late spring or summer of this year. Let’s hope this one lasts longer.

I-85 Bridge Collapse in Atlanta

On March 30, 2017 a large fire, apparently set, (though arson charges were dropped) under a section of I-85 in Atlanta resulted in the collapse of part of one of the major freeways through Atlanta. 7 things we know now about the I-85 bridge collapse. (There is a nice – short – video at the link. More videos will play if you don’t stop them.)

If you’ve ever driven through Atlanta, well you know; traffic is bad. And if you haven’t driven through Atlanta, you probably can’t appreciate how bad traffic can be when everything is fine. After this fire, everything was not fine.

A large amount of plastic was stored under the bridge. It was ignited, and the fire damaged the steel in the bridge.

When The Atlanta Journal-Constitution’s reporters investigated what exactly happened under the bridge and why the materials were stored there, the newspaper found security at the site was lacking and determined that officials don’t really know what’s stored under other bridges around the state.

Not what you would call “good management.”

After a massive rebuilding effort the bridge opened in May of 2017. Restoring what passes for normal in the Atlanta commuting environment. That is a pretty Herculean effort by the standards of today. I am sure it helped that it was a completely ordinary highway bridge.

According to police, the flames ignited in a state-owned storage area under I-85 northbound just south of Ga. 400.

Stored there were high-density polyethylene pipes, which are commonly used in the transportation industry for cabling and fiber optic wire networks.

This isn’t a marquee bridge, like The Tacoma Narrows Bridge or The Silver Bridge, that collapsed in a dramatic fashion and killed lots of people. It is a low-key bridge of the kind that millions of people drive over every week. And it is a reminder that even the small bridges, when they fall, can make life miserable for a lot of people. It isn’t just the marquee bridges that need inspection, maintenance and repair. And talk about not managing infrastructure, if you can’t say, what is stored where, and it turns out that what is stored can bring down that infrastructure, then I think there is a problem. If you don’t know what you have stored where, how do you know what you need to order? Maybe you just keep ordering more stuff, after all, it isn’t your money being wasted. I don’t think it would be much different in any other state, aside from Georgia, and I don’t expect the situation has gotten much better.

Not managing infrastructure is not the way to ensure that infrastructure lasts. But not managing anything seems to be the way of government.

What Happens When Engineers Don’t Consider Geology?

More accurately, “What happens when engineers make assumptions about the operating environment of whatever they are designing?” because the failures aren’t just about dams or bridges. Why do software engineers continue to build in back-doors to their systems in an era where hackers attack everything? Why do companies sell devices with an embedded computer, and there is no mechanism to upgrade the operating system, or the updates are not checked for authentication? Because they assumed it would be OK. “What could go wrong?” As a sentence in the English language, it ranks with “Hold my beer.”

While looking for an infrastructure failure this week, there were several candidates. Dams built in the early 1900s that failed due to lack of maintenance, or because of record rainfall, which caused a new mode of the structure to be stressed. (In at least one case, both issues were involved.) But I finally settled on an example where the fault lay in the geology, and the fact that the people designing the dam, didn’t take enough of that geology into account before designing the dam. Or in this case, dike, Quail Creek Dike to be specific. (Unclear on the difference between dam and dike, see this link.)

This structure was built in 1984, the associated main dam was completed in 1985 and that is when the reservoir was filled. The dike failed catastrophically on January 1, 1989, though the failure started before then. Quail Creek Dike (Utah, 1989).

The Quail Creek Dike was designed as a 1,980 foot long, 78 foot high zoned earthfill structure.

The lake impounded 40,000 acre-feet (4.934×10^7 cubic meters) of water for irrigation, and as a municipal water supply. As the reservoir filled in 1986, seepage was detected in the downstream toe. It reached 6 cubic feet per second (and then some) by the time grouting was contracted and begun. When grouting was complete, seepage was reduced to 0.3 cubic feet per second. That was 1986. In 1987, a sinkhole was detected downstream of the dike, and more grouting was performed. Seepage in April of 1988, when the grouting stopped was 1 cubic foot per second.

The summer of 1988 was when things started to go wrong, in a big way. More seepage. More grouting. When grout wasn’t helping they brought in 100 cubic yards of concrete and “large amounts” of filler. In September the seepage had been reduced to 0.8 cfs.

Then on December 31st, things went from bad to catastrophe.

“Cloudy” seepage was observed on the morning of December 31. People worked through the day to try and stop it.

By 10:30 PM, the seepage flow rate had reached 70 cfs [about 2 cubic meters per second] and the flow direction had changed from vertical to horizontal with a growing hole at the downstream toe. Unable to control the flow, personnel and equipment were moved to safe locations and a downstream evacuation was ordered. Between 11:00 and 11:30 PM, a wedge 50 feet wide and 25 feet high suddenly dropped several feet, blocking flow temporarily until flow resumed and began removing the collapsed material. Erosion continued toward the reservoir until at 12:30 AM on January 1, 1989, Quail Creek Dike failed, releasing an estimated 25,000 acre-feet [3.084×10^7 cubic meters] of water into the Virgin River and downstream flood plain; the result of a breach 300 feet wide and some 80 to 90 feet deep.

While no life was lost, the damage was about $12 million (in 1989 dollars). Homes, apartments, businesses, roads, bridges, farm animals and agricultural equipment were all lost.

So what caused a dam/dike to fail only 5 years from its construction? QUAIL CREEK INVESTIGATION OFFERS LESSONS FOR FUTURE.

The fault lay in the geology of the foundation, and the lack of study of the same. The engineers drilled 10 cores to sample the bedrock. And it looked good, but there were large vertical cracks in the rock running perpendicular to the dike.

The failure of the dike was caused by significant seepage beneath the dike because the bedrock was badly fractured in places. That weakness apparently was not discovered by engineers who originally planned the dam.The panel of outside experts who examined the dike failure refrained from pointing fingers, but several of them clearly felt that not enough was done in checking out the bedrock at the start of construction.

This is not to say that engineers and designers were careless. The bedrock fractures were a vertical type that are hard to detect, even when some drilling is done. Yet vertical cracks were visible in the bedrock both upstream and downstream from the dam site.

The task force investigating the dike disaster said that “foundation exploration was not designed or complete enough to fully detect seepage problems . . .”

What’s that old saying about “When you assume…?

It seems that once they scraped away overburden and reached bedrock, engineers assumed that it was safe enough to build a dam on. Many times, when things go wrong, the problem can be traced back to some kind of assumption.

The dike was rebuilt out of roller-compacted concrete.

This is of course not a new lesson. But it is one that bears repeating. What are you assuming to be true? “He who thinks he knows, doesn’t know. He who knows that he doesn’t know, knows.” That probably has some ancient origin, but I first heard it in a Joseph Campbell lecture many years ago.

There was a Mars lander that was lost because one of the subcontractors assumed that the data coming from the control module was in feet-per-second and not meters-per-second. I can’t begin to tell you how many software systems I have had to take apart and put back together because of assumptions programmers made about the underlying architecture.

How many people today make assumptions about what hackers can decode and what they can’t, or what constitutes decent security, or what F*c*book is doing with all their data?

Assumptions are fine, when the only thing that goes wrong is the new version of Candy Crush is delayed, and it is not so fine when dams collapse and destroy people’s homes and lives.

So What Happens When Engineers Get It Wrong?

Folsom Dam Spillway-gate Failure – 17 July 1995. The design for the gate didn’t account for corrosion over time. Folsom Dam (California, 1995). And it doesn’t help matters that they dropped the ball on maintenance. (The dam looked fine right up until the point of failure.)

Actually this is more a case engineers not taking time and the elements into account. Steel rusts.

The reservoir was at full capacity on the day in question, and so one of the spillway gates was opened to draw down the water levels. Should have been just another day…

As the radial gate was raised water began flowing down the spillway chute as designed. It was not until the gate opening reached approximately 2.4 feet that the operator felt an “unusual vibration” accompanied by harsh grinding noises. No more than five seconds passed between the time the vibrations and sounds began and when the operator turned to look at the gate. The radial gate swung completely open releasing approximately 40,000 cfs.

While 40,000 cubic-feet per second is a lot of water, it is only about 1/3 of the amount of flow that the Folsom Dam spillway and downstream dams were engineered to handle. So proper setting of other spillway gates in the downstream dams avoided over-topping of those dams. It could have been so much worse.

So. What happened to the gate that failed?

The forensic report documenting the failure of the Folsom Dam gate revealed the cause of the malfunction to be excessive friction at the 32-inch diameter trunnion pin, or pivoting mechanism. Unaccounted for in the gate design, this friction was caused by the corrosion of the pin over time. Due to the additional friction forces, the loads experienced by the trunnion pin caused increased loading in the gate struts and braces of the gate.

It caused enough increase in the loads to cause a failure of one of the diagonal braces. If you look at the photos that accompany the link above, it appears that one whole side of the gate tore free from its pivot resulting in uncontrolled release of water. About 40 percent of the reservoir was drained before the water level was below that of the gate in question.

Repairs cost 20 million dollars.

So the design of a steel dam-gate was done in by corrosion that wasn’t accounted for in the initial design. (“Rust never sleeps.”) The truly sad thing is that they seem to acknowledge that they were ignoring maintenance, because everything “looked fine.”

A renewed focus was placed on maintenance and monitoring of radial gates, many of which were retrofitted to strengthen struts and bracing and ensure sufficient lubrication.

In other words, this was probably avoidable, had they been managing the infrastructure.

Stuff needs maintenance. When 2 bits of metal are supposed to move relative to one another, like this trunnion pin, lubrication is required. And when you are designing something with a life-span that is expected to be decades, you should consider the impacts of the elements. Why is it that time again, this stuff gets ignored? Because the the dam looked fine, right up until the point that if failed.

A part of me doesn’t want to include this video, but hey… “Rust never sleeps,” was a saying around the docks that got repeated a lot. Because it’s true. “Water always wins,” was another.

That is the “Out of the Blue” version of “My My, Hey Hey” by Canadian singer-songwriter Neil Young and the American band Crazy Horse from the album Rust Never Sleeps. For a harder-edged version see the “Into the Black” version. I’m not sure I ever liked either version. One is too clean, and one is too distorted. Needs some middle ground.