📖Signed copies of my book, Engineering in Plain Sight, are back on sale! store.practical.engineering/ 🌌Get Nebula using my link for 40% off an annual subscription: go.nebula.tv/Practical-Engineering
Would you do a video on the emergency replacement of the Crown Point Bridge between New York and Vermont? Your viewers might be interested in what it takes to replace a major bridge in a hurry - about 2 years from finding that fatal defect to opening the new structure! A quick search didn't find anything.
Hey Grady, Australian Engineer here - when I was doing some post grad studies at QUT in Brisbane Australia in the late 80s I heard an interesting story about bridge loading that I was reminded about by a couple of Road Guy Rob's remarks. In the middle of Brisbane is the Victoria Bridge that crosses the Brisbane River. If you go onto the Wikipedia page and read through the details you will notice that is says there were signs in 1943 that the bridge was buckling due to increased loads. Those loads included trams - what you Americans call trolley cars and they are heavy. The story I was told was that it was university engineering students who discovered the buckling issues. As part of their practical work they were sent down to measure the deflection of the road deck when there were no trams and it was fully loaded with stationary trams which happens just from traffic lights activating. For years the university professors brushed aside the findings as just "student errors." They were sort of close enough but not too concerning. It was just dismissed as a "learning thing." Eventually one professor noticed that all these apparent errors were actually consistent so to check if there was something wrong with what the students were fundamentally doing he went and did the measurements himself and found that the students were actually accurate and that the bridge was deflecting an alarming amount when it was fully loaded with trams full of people. I'd like to say that I can verify the story I was told but can't. However the details on Wikipedia do NOT contradict it either and in particular note that the number of trams were restricted, which was exactly what I was told circa 1989. FYI - I am actually an aerospace engineer who did his degree in America (U of Illinois). In 2016 I had this odd little consulting job into Australia's energy sector which has major structural issues. I have since found that many other nations have similar issues and that the energy issues are PART OF the much larger INFRASTUCTURE ISSUES that include bridges. There is a 2014 (I think) 60 minutes titled "America’s Crumbling Infrastructure" that highlights "The Portal Bridge" that crosses the Hackensack River. Go check out that story and where its now at. I can't give you too many details as I can no longer see that episode of 60M here in Oz, but I believe they said that America has over 30,000 bridges that need major repairs, major upgrades or outright replacement. Its all part of this fundamental issue with keeping society functioning WHICH WE ARE NOT DOING WELL. I have traced this problem (as in Root Cause Analysis) back to ECONOMISTS. There was a revolution in the 1970s with Ronald Reagan introducing the world to Reaganomics. Hos contemporary Margret Thatcher gave the Brits Thatcherism while we called it Economic rationalism. One of its key concepts was that the private sector does everything better and therefore everything should be privatised. The problem is that infrastructure does NOT exist to make money it exists so that everyone else can make money. This is a concept that economists do NOT understand at all because they are trained to believe that everything must make money. Its also why they cut maintenance budgets everywhere they go because maintenance is a cost NOT a profit. This has resulted from the complete failure of economics education programs to teach how engineered systems work and is why we have so many issues with energy, water, roads, bridges,... etc. I will be in the Steve Keen & Friends podcast in the next few weeks to talk about this and some other things.
Grady, I studied vessel-bridge collision for my Masters and PhD under Dr. Gary Consolazio at the University of Florida. This topic is also my professional specialty as a practicing engineer. From that perspective, I wanted to let you know you did a excellent job explaining the topic and the AASHTO code requirements. I came into this video expecting to have comments or corrections, simply because the topic is esoteric and fairly complicated. But no, you have clearly done your research. Great job, and thank you for what you do. Daniel G.
as a specialist, what do you think of the lack of tugs to guide the dali past the bridge? iirc, there WERE tugs guiding the dali out of port; but they left some ways BEFORE dali reached the bridge... imagine if they just stayed along for just 15-30mins longer, they could've avoided the disaster. what size ships should have a mandatory requirement of tugs-past-bridge? how much would that cost? why didn't baltimore have that requirement?
@@alveolate No, they couldn't. They ran some simulations on one of the few ship simulators and the simulation found that you needed bigger tugs than they used and they needed to be attached to the ship to counter the wind and current. The forces involved are huge.
Sir, I have but two questions for you: 1. Does AASHTO also cover railway bridges, like the Big Bayou Canot Bridge that was struck by a lost bardge that caused the deadly derailment of Amtrak's Sunset Limited. It's the collision where the bridge sustained damage enough to the structure and tracks, but held up. The damage to the tracks caused the train (traveling at high speed) to launch off the tracks completely, crashing into the waterway below. 2. Did you get your PhD and can we call you "Doctor" instead of "Mister"? (Old Big Bang Theory joke.)
The extra research someone like me (not an engineer at all just kinda nerdy) won’t notice often doesn’t get the recognition it deserves for channels like this. Glad to see his hard work being appreciated by experts and common folk alike!
7:20 oh my god i never realised it's called a collision as in a co-llision because it's two things crashing into each other, and a-llision when it's one thing crashing into something stationary...
Technically the division is al-lision, not a-llision, and col-lision instead of co-llision: these are from the latin prefixes con- (together) and ad- (at (!)/to/into), but got assimilated due to the l at the beginning of "laedere" (compare pronouncing "conlision" and "collision"). In Latin, conlido and collido are both valid, but only one of them made it into English And I'm glad I'm not the only one to get excited about etymologies of words I'd never thought about before :)
@@hadinossanosam4459 yeah I was sure the exact history would be different but in my defense I'm a computers and stats guy not an English and history guy lol, but thanks for letting me know! I secretly love histories of language, it's really interesting to see what words cropped up where and why and what became popular, it's like a fossil record but for culture
Road Guy Rob is among the most underrated channels. The guy basically works for minimum wage for his daytime job and makes videos for pocketchange in his spare time. His content really should be capable of supporting him as a career. I highly recommend people binge watching anything in his archive that they're curious about. Skip the livestreams unless you're super nerdy, they're a lot content dense and is more just hangin' out with Rob.
@@cwtrainlook lol I normally would agree with you. But rob has 150k subs, to practical having 3.7 million. This, is one of the very rare times, something actually IS underrated.
I learned some years ago that the best definition of a truss is "it supports loads with math instead of mass" they are great for cheap light support systems, and that is why building roofs and floors are made out of trusses. the drawback is that if you compromise any component of a truss, there is usually no redundancy to prevent failure. thus the logical way to prevent catastrophic failure of truss bridges is to avoid collisions; rather than to try to reinforce them to survive collisions.
@@appa609 yes, you can build one so it is completely redundant. then it will weigh and cost twice as much, or actually more, since it has to support more of itself, as well. not an idea the bean counters will like, even if it does substantially increase the safety margin.
Grady, thank you for collabbing with Rob, he deserves way more attention than he gets. I am also not surprised that you are the first "big" youtuber to do so, as you have consistently shown yourself to be a kind and generous person. Thanks for being such a good example.
Rob is as big as Practical Engineering. Grady obviously considers him an equal, and did the collab to boost his _own_ channel. Why would you think otherwise?
Regarding Tugs, "What's Going on with Shipping" pointed out that much above 4 knots, tugs really can't do much to alter the path of a large ship anyway - there's simply too much inertia. Now you could force the ships to go slower and use tugs near the bridge, but this is a lot of extra cost and time on every single transit - for something that only occurred due to some sort of failure on the ship. His focus has been on identifying the root cause of the ship losing power in the first place, as there are many other locations such a failure could cause similar problems.
This could have been entirely prevented with escorts. The fact that the pilots act like the shipping companies money is their own is the problem. Their egos took down that bridge.
@@Jpwarner88 yes it could but it would cost extra money, and it is basically useless over 4knots on large ships. Not a single company will pay for tug escorts if it isn't required. A no sense example would be you paying a construction worker to show you the way when they are working on the road. He can't do anything if you for some reason lost control of the car. Even at walking speed the car is going 4+knots and he is the escort. In comparison.
@@gabrielarrhenius6252 I don't know how much it is to have required escorts for ships over a certain size. But I imagine it's a lot cheaper to require that then replace an entire bridge, and the economic cost of lost maritime trade for the duration of time it takes to replace the bridge.
@@LevaniaMeyano That is true, but how big is the chance that a boat big enough would actually crash into the bridge? That is the question. As long as it isn't required at all ports/bridges so will the boats take other ports/waterways as long as it becomes cheaper and gives bigger profits for the company, since it is them who decide. The requirement of having escorts will just make the companies choose another port if possible. You know all those height restrictions/warnings on bridges over roads, would most people choose to have an escort which they need to pay for when going under it for the chance that something happens which puts the traffic to a stop under that bridge. And if that was required would people choose that road if they absolutely didn't need to? Will you choose the road with a toll if you can take another which do not have a toll and the time difference is minimal?
When I saw the thumbnail for this, I thought it was probably one of your videos. Then I saw it was Grady, and... then I saw the shoutout, and was pleased. :)
I went to a great deal of effort trying to explain this math to people who were convinced that a ship at a slow speed didn't seem to be that big a deal impacting the bridge. I compared it to an average freight train to give people a reference for the energy. People could associate a freight train at 60 miles per hour with being an incredible amount of force, but they couldn't realize without the mathematics that it was only a tiny fraction of a percentage of the amount of energy of this vessel hitting the bridge. Physics is not intuitive, but it is inescapable.
It also has to do with reduced mass. A container ship coasting at 5 mph may have a lot of kinetic energy, but in an impact with a human only a minuscule fraction of that energy will be transferred. It may make your nose bleed, but it would not be very dangerous. Meanwhile, a train going 60 mph will transfer a lot more energy to the human despite having much less kinetic energy than the ship. For structures that are heavier than the ship or effectively immovable on the other hand the picture flips, and suddenly the fact that the ship is n times more massive than the train matters again.
@@appa609a fully loaded freight train weighs at most about 50 million pounds, this ship weighs 232 million when fully loaded even with the huge speed difference in this hypothetical the ship is putting out like 32.5x as much force from the impact and that's if the entire energy from the train hit all at once which isn't how train crashes happen cause the cars behind the lead spread out when their energy is applied
Kinetic energy can increase by either increasing an objects velocity, mass, or both. The amount of inertia these ships have is beyond many people's comprehension. It's beyond me and I would say that I have above-average experience in math/science and heavy industry.
@@daleolson3506 their findings are not used to assign guilt they are used to inform policy change. The thorough process is a benefit and the time it takes does a not pose a major concern to the purpose of what they do.
@@petermgruhn they are independent because they are under the executive branch but are not under any executive department and are largely outside of presidential control. They get to operate independent of any political or corporate motive and just do the one task they were made to do without fear of reprisal.
@@daleolson3506Then fund them. You can’t get accurate, reliable work done quickly unless you’re willing to pay for the increased staffing that will require. We are at the business end of 50+ years of methodical defunding of our government agencies, all of which now struggle with woefully inadequate staffing. Then people complain they don’t move quickly enough and call to further cut their funding. Which, of course, only makes them work even slower.
As a total non-engineer person (meaning as a person who knows close to zero about engineering and, turns out, grammar), It took me a few goes but I finally understand most of what was covered in this video and I must say - WHAT AN AMAZING JOB at making it soooooooo understandable and accessible for non-engineers x
Uniform is a uniform. Thinking of it maybe people in camo uniforms like the military are more often ordered to wear high visibility jackets and such, since by default they are very much not very visible.
He does NOT want to be seen or stand out, but on that day he has to by law. He does not like being at work, he likes to be in the forest, killing animals.
Dutchie here. We design our water defense for 1 in 1000 to 10000 year events, depending on failure mode and related things. It's pretty recent that we first needed the Maeslandtkeering, which is several decades old, and is one of those structures.
You're talking about the change of a (massive) flood, not the change of a large container ship hitting Maeslandkeering. When it is retracted, this is possible that a vessel hits the barriers. As long the keering is open, ships are allowed to enter the port, which is why it is an automated system. However take the following scenario: There is a very high tide and a MSC containership wants to enter the port to ride out the storm, meanwhile while is is approaching the keering the condition is met to start closing the keering, the container ship is told not to enter the port, but the captain ignores this instruction, and while the keering is closing it hits one of the barriers. Now, of course the change of this happening is very slim, but you cannot rule it out. However when they designed the keering they accepted that the change of such a scenario happening has such a low probability, they opted not to create a backup system for when the maeslandkeering fails for whatever reason. Based on the costs to create such a backup, they accepted this risk. However when a scenario as above does happen, people will get their pitchforks and demand blood from those who thought is was a acceptable risk. This is how it always goes...
@@2Fast4Mellow Well a few things you should know, the Maeslandkeering closes off the Nieuwe Waterweg, and that waterbody is not really used for large water traffic (although there are cruise ships visiting the port of Rotterdam). All the major cargo traffic travels to the Europoort via the Calandchannel below it which has no barriers towards the sea. The majority of the traffic is river barge and or coastal vessels. That and the fact if only closed for real like 3 or 4 times in it's life time, and if it is, it will be in extreme weather conditions making it something else than 'just a tuesday'. I hope you also realize what a superhighway the Channel is? There is no ship able to even approach withing 200 km without being in contact with the international authorities, let alone allowed to enter the Eurogeul and Maasgeul (60 km into sea) without a pilot on board (large vessels get a pilot onboard even 75 km out, way before reaching the Eurogeul). Nothing is impossible, but your example is probably a lot less plausible as you think it is.
@@derrickmcadoo3804 pretty poor attempt at a terrorist attack. Given there are huge chemical storage tanks right near the water, beside the giant coal storage area, very poor indeed. But you go ahead and put your foil hat on and believe whatever you want to believe.
@18:10 - another important note: While 2016 gave us the Panamax expansion which allowed large container ships like Dali to be practical, bulk freight ships in the 100 kiloton range have been around since the 1970s. This event could have happened at any point since the construction of this bridge, it was just more likely to be a coal, petrochemical, or grain freighter.
WHew, can you imagine just how much worse it would have been a bulk oil carrier? At least those 'containers' were.. well... 'contained' for the most part.
I really liked the way you explored risk and risk management in this, it would be super cool to have a whole video on risk based engineering, and breakdown risk control measure into engineering controls (like islands or putting piles on land) and administrative controls, like speed limits in channels, local port captains and tug boats! I work a lot in risk management engineering and sometimes it's hard to explain to other engineers the concepts behind risk based decisions and acceptable risk levels. Great work!
Fronts of the envelope are usually not used because they already have text on them, and on the back you only have to deal with the edges of the folder-over paper. But if you animate an envelope, you can create an envelope without text on the font (and then don't even have to deal with the paper edges getting in the way).
Nice to see a bike lane on the Long Beach bridge. Sad to see that it doesn't go anywhere. There's a difference between bike infrastructure and meaningful bike infrastructure. People use their car to get from point A to point B. I'd like to use my bike to do the same, but so much bike infrastructure goes from a point where nobody is to a point nobody wants to go to. Off topic I know, but Rob did talk about the bike lane, and covered how it was gated on one end, thereby rending it from potential usefulness to a point nobody wants to go to. That leads to feelings of money wasted as the bike path won't get used very much.
Seems like a lack of joined up planning between architects/engineers/city planners. I'd design a bridge with a bike lane because it should have one, but what it joins up with is Not My Department
@@RobertMilesAI true, and they did say the bridge over in LA is old. If it gets replaced, I bet it has a bike lane. Maybe then the Long Beach bridge gate can open?
For around a decade, the UK's Warrington Cycle Campaign ran a "Facility of the Month" feature, showcasing over a hundred examples of "excellence" in bicycle infrastructure design, such as cycle lanes that start / stop in random places, very narrow cycle lanes, shared or side-by-side footways + cycleways where the cycle part is either interrupted by sign poles or street furniture, has restricted headroom due to overhead signs, ends abruptly at a fence etc. Often, councils will take grants for installing bicycle facilities, but then "local authority logic" comes into play and the resulting infrastructure isn't fit for purpose (cue lots of Angry People In Local Newspapers moaning that cyclists aren't using the news infrastructure, and what a waste of money it was).
@@SDSBBQs i grew up around the Baltimore area. Was wild waking up in the morning to find your partner's commute to work takes 40 minutes (assuming 0 traffic) more now.
Grady, I am a naval architect and marine engineer who spent my career working for oil company marine operations. I was involved with everything from the design and construction of tankers to oil spill response. In fact, our tankers docked at berths 78, 118, and 121 in Long Beach, requiring passage under, or docking next to the Gerald Desmond Bridge. A major point in the discussion of the ability to predict the size of ships when the Francis Scott Key Bridge was built is not valid. We operated three classes of tankers, all built at the Bethlehem Bethlehem Steel Sparrows Point Shipyard, where the Francis Scott Key Bridge is being taken for recycling. The ships were built from the late 1960s to the early 1980s. The tankers were 70,000 DWT, 120,000 DWT, and 265,000 DWT. The fendering and dolphins around bridge piers can be designed not only to guide ships away from the piers but they can be designed to ensure in an allision the ship suffers the damage. I can attest to this, having had to direct the installation of temporary patches covering holes after an allision. One of our tankers hit the Carquinez Bridge. There were two holes, one 10' × 100' and the other 10' × 200'. The bridge had the wooden fendering destroyed and suffered minor damage to the concrete. As for the loss of ship's power, it will be interesting to see the NTSB's findings on the loss of power and inability to regain to regain power. It will also be interesting to find if they tried the main engine in reverse, to stop the ship, or start it going ahead in an attempt to regain steerage. Bob
Dali was definitely slowing down, i believe she was at 8 knots before losing power and according to Grady at 5 knots when it hit the pillar. But as you know it takes a good bit to slow those big ships down. I'm looking forward to see the report as well!
I spent my entire life in Baltimore with an interest in local history. I saw that bridge everyday in my travels around and can remember the first time that my father took me on a ride over the new bridge. Until this accident, I knew Dali as an Italian painter, who's works included "The Broken Bridge and The Dream." I knew that Francis Scott Key was a founding member of the American Bible Society. I knew Pelosi's dad packed up The Dream on "The Exodus" and sent it sailing in 1947. I witnessed the day that they brought in the new cranes to the port that had inches of clearance under the bridge. My question is caused by coincidence - it is not everyday that a ship crash takes down an entire bridge and it's owner claims on it's website of it's incentives to create better ports for bigger vessels with larger shipments to arrive. It seems that bridge was in the way of their progress. That day felt like 9/11 all over again. The collapse happened and no matter what people see, they will only pay attention to what the news tells them. Baltimore burned down in 1904 because of one discarded cigarette - that too was just an accident. Much love from Baltimore - I can't wait to see how this story ends.
I agree, Robert; I've seen the Dolphins on the replacement Florida bridge after its collision, and those things could probably handle the Dali no problem. I'd imagine that had the Francis have similar Dolphins installed, the bridge would probably still be standing. Brady is generally right though; cost and likelihood are two things engineers have to calculate, and back when this bridge was built, ships like the Dali didn't even exist.
@@TheEDFLegacy Engineers run the numbers and make presentations to "officials" who then decide if the benefit sufficiently outweighs the risk to ensure their own reelection. Engineers have tried to stop a number of ill-fated things only to be overruled by management or agency agendas.
I am curious how does a ship like that suffer such a total loss of power? That is should there not be multiple independent generators. I am thinking like how on a jet airliner each engine and the APU turns its own generator and hydraulic pump and so as long as you have one of them you have full electrical power and hydraulic power and the systems tend to be independent so a loss of one does not mean a loss of the others.
when the notre dame cathedral burned down they used the laser scans and recreation of the cathedral from one of the assassin's creed games to help rebuild it
It was somewhat the same with Assassins Creed Unity, Ubisoft gave it out for free after the Notre Dame fire for people to be able to see their detailed digital version, probably the only time Ubisoft have done something positive.
I loved that Grady waited before making a video on this. Really shows he’s engineer first, content creator second, by waiting to acquire in-depth analysis and information.
Nice to see the Road Guy adding some content to the video. Thanks for the colab. He has a great channel and goes into great detail on all things road and traffic with wit and knowledge. "What's Going on With Shipping" has been detailing the maritime side of things with some good channel suggestions as well. He's a good follow.
Seeing nearly a million views on this video and 3.76 million subscribers to your channel gives me a warm fuzzy feeling. Congrats on your success Grady.
I doubt the idea is that it should not fail. Its likely more about reducing how catastrophic that failure is. It may include failsafe/safety measures for bridge and people (evac routes et so), figuring out how the bridge might be designed to collapse in a more safe manner (like crumple zones in cars), etc
Yeah those are insane ships.... People that think a bridge is "too weak" or "should not have fallen so easily" really haven't seen a massive ship before. They can dwarf a city block of multi story factories as you approach them, they are massive. A bridge is like a toothpick.
@@KakaCarrotCakeVideos then you'll need multiple thick pillars and that will increase cost significantly all that for somthing that will not happen again for atleast 50yrs
@@Shubham_Bahiratthey recently dredged it allowing larger ships to pass and travel closer to the piers. Safety should have been included in the budget for the 50 year old bridge.
@@bighammer3464 It seems to me that it doesn't matter how many cars were on the bridge at the the time the police blocked it; it would take about the same time for all the cars to exit the bridge whether the police had stopped entering traffic during the day or the night.
@@Curt_Sampson didn't he say in the video that the police closed the bridge too late for all the cars to get off the bridge? I'm pretty sure there were cars on the bridge when it collapsed. It's reasonable to assume that there would have been more cars during the day.
Thank you for this video! As a maritime historian with a background in safety issues, the historical development of risk management, and port history this was such a treat and helps me explain these phenomena to people.
In Germany, the Autobahn bridge between Cologne and Leverkusen is being rebuilt. The bridge spans the Rhine river. There was no accident, but the bridge could no longer carry the load. The passage was closed to vans and trucks, and light cars were only allowed to pass slowly over the old bridge. In addition to the old bridge, the new bridge has now been completed. Trucks are allowed to pass through these again. Now the old bridge is being torn down and a second bridge is being built next to it. From the original 4 narrow lanes, the two new bridges will offer 6 wide lanes.
What people not from this area need to understand are some small details about the German Autobahn Network. As with for example the Interstates in the US, this is the Network of the major roads for long haul traffic. Now traffic wise, besides having our own share of inland traffic, due to its size and position within Europe, some of the major transit routes unavoidably go across Germany. Lets say anything comming from Asia to the Port of Rotterdam in the Netherlands, the largest Port in Europe, or the second largest, Antwerps in Belgium going about anywhere in Europe will go across Germany in some way. Third largest Port is Hamburg in Germany by the way, creating its own share of traffic. Anything comming from the West, from Belgium or the Netherlands, or comming from Hamburg up north will more or less have to go through Northrhine-Westfalia, where mentioned bridge is located. Being the state with the highest and densest population in Germany (about a fifth of people in Germany live in this one of 16 states) and anything from Cologne through Leverkusen up north across the "Ruhrgebiet" being more or less one huge Metropolitan area along the river Rhine and Autobahnen being used for commuter traffic as well, anyone likely can imagine what is going on here. Traffic from Antwerps from example may meet the network just south of cologne, while traffic from Roterdam will hit the northern Rhur Area. But imagine the network around Cologne, including Leverkusen Next to it, being more or less the main hub for that traffic plus trafffic comming from Hamburg, to go south along the western border towards France and Switzerland, Southeast towards Munich to get to Austria, Tchechia and everything behind those, or just up north and northeast, Hamburg, Berlin, Denmark, Poland... So impact on traffic in case of any construction sides or unforeseen events like accidents around here is hard to wrap your head around. There are of course parallel routes, but those mostly are smaller sections of the Autobahn network with less lanes and thus a lot less capacity. I think the most undisturbed from those factors way to get Cargo up to Cologn and further down South along the Rhine is actually loading onto Barges in Rotterdam and shipping along the Rhine.
@@eriklarson9137 Some people do, but feel free to skip ahead. I am fully aware, that in comments some peoples span of attention doesn´t go further than maybe three sentences. Others enjoy a more detailed addition. Some indeed do not care or want to read longer texts. No issues about that. If someone is interested in reading and getting something out of it fine. If someone doesn´t care, fine as well. after all this is just a comments section not more and not less..
Not relevant but since this is RUclips and not a strictly moderated forum we can write it anyway 😂 It's far from the only BAB bridge in Germany being rebuilt. A ton of them were originally built in the 30's (!) and can't handle the load anymore. There is one near me and the traffic going across that is insane.
It's really fun watching this channel because I started watching before college and am now slowly understanding more and more of what is said. I just finished a grueling study grind for a statistics midterm and when you said "if you are familiar with a normal distribution" I went "don't Even get me started". It was really cool to hear about the application of a normal distraction as it relates to the probability overlayed on the bridge like that. It was extremely pertain to my current education.
“Back of the envelope physics” … and then writes in the front of the envelope. I mean, I don’t care, but for a few seconds all I could pay attention to was that being the front of the envelope, and then I saw the Practical Engineering stamp, hey can I buy Practical Engineering stamps? I’d buy those. Oh right where were we? F = ma ok …
As someone from Baltimore that has crossed that bridge many many times, what a great video! Thank you so much for taking the time to put this together and giving us something positive to consider with the loss of such a great historic bridge and loss of life. I have appreciated your content for quite some time. I was pleasantly surprised to see your take on this incident that hits so close to home. Prayers to the families of those affected.
Channel recommendation about this topic: “Casey Jones - Professional Engineer”. He is a bridge engineer and has very insightful commentary on this kind of thing. “What Is Going On With Shipping” is also great and handles the maritime side of things.
Sal from "What's Going on with Shipping" was the first person I looked to for the maritime side, which is why the bridge collapsed. Unresolved power failure alarms before the Dali left the dock? Tracking of course and speed? Currents, tides ebbing or flowing? How ships' systems work? Sal's videos answer lots of these questions. The questions about the power failure will be determined by the NTSB.
Well done Grady. As a former Civil Engineer I've gotten a lot of questions from friends and family as to how something like this can happen with such disastrous effects. I will certainly direct those asking to your video as you very clearly explain all the factors that must be considered and weighed when designing such a structure. Thanks!
I feel like a lot of people dont understand or respect the fact that everything we use on a daily basis has some kind of risk factor that was approved by a comitee of people. That's a lot of what engineering is.
Also, as a utility worker, that has to foul railroad tracks often, i can say that any time a train is en route past our work zone, there is a clear order of operations that has to take place. 1st of all, we have a flagger, who places a restricted zone within a large area of our work zone, often up to 20 miles each way of our scope of work. This means that any train engineer who approaches that zone needs to radio, not only the tower, but also the flagger to get clearance to traverse that zone, often times at slower speeds too. This alows the flagger to activate our chain of egress operations, which are clearly written down and agreed upon by all workers that at any point throughout the day may be located in the rr row. This order of operations is determined based upon the type of work you are doing in the row. It will clearly state where equipment, and personnel need to get to, and how they get there, should a train need to move through the restricted area. And if at any point during the day, your scope of work changes, work stops, and a meeting is held to determine if changes to the egress plan need to take place. Believe me, it sucks to have to be so meticulous, it often lessens the amount of work that can get done in a given time, especially when your on a major trunk line, where you can have 15 or 20 trains or hyrail vehicles a day. But it ensures that rail workers, utility workers, car motorist at at-grade crossings, train conductors, and train passengers all go home to their families. Perhaps we should have a similar order of operations plan in place when working on high port traffic waterways. If they had, those construction workers would still be going home to their families. Im not putting blame on the crew managers or the companies that had them there, these things are often unimaginable.......until they happen. I would just like it if this horrendous loss of life could lead to better practices.
Are you suggesting having all traffic stop on a bridge before a vessel goes under the bridge? The only cause of problem to the workers as I understand it was the whole bridge collapsing. Honestly they were almost certainly at much higher risk from passing drivers.
Not necessarily vehicle traffic, as that can maybe be cleared out quickly. But the guy dangling from a harness painting pillars, he can't get off that bridge quickly. So if more constant communication is held between the port authorities and the work crew, then perhaps the guy dangling could get to a more egress ready position before a large vessel rolls through, incase something did happen
@glennmcgurrin8397 also, cars are the number one danger on any construction project located adjacent to a roadway, your never going to get rid of that hazard, all you can do is put buffers between you and vehicles
One of my favorite memories is a University open day lecture, “Bridge that gap,” which explained the different types of bridges and their respective advantages and factors influencing relative costs. Fascinating.
Glad to see our new bridge in your video. It was a real headache dealing with the years of construction, but it makes the crossing easier and safer for all. Take care.
Truly appreciate this video. I've traveled the Key Bridge probably a million times in my lifetime, as I lived in Baltimore for over 20 yrs., and it breaks my heart to see this happen. A dear friend of mine worked at Sparrows Point for over 50 yrs. Unfortunately, he is no longer with us, but if he was, the devastation for him would be immeasurable. Your presentation and description of things is very clear and precise, you are a very good speaker. I'm not an engineer by any means but am always intrigued on how things work and the thought process that goes behind their creation. I watched your video on Every Kind of Bridge Explained......and had no idea there were so many bridges just in the US, not to mention other countries. I'm sure there are plenty more you didn't mention as well. Thanks again for a very informative video. Even when Baltimore rebuilds a new bridge, 695 in this location will never be the same. ❤
as soon as the bridge collapse I was immediately looking forward to see how you and road guy rob would cover the event, mind was blown when you collaborated on this video, hope you do more in the future!
I'm a bridge engineer who works for a firm in Baltimore. This video was a good explanation of the history and methodology of bridge design without getting too much into the fine detail. The general public really lacks a true understanding of the necessity for probability and statistics in bridge design. They cannot comprehend the magnitude of funding required to "design a bridge for the apocalypse". It's not a few grand more. It's not double the price. It's tens to hundreds of times the price of what we currently design. And with signature bridges like these in the video easily exceeding $1B to construct, it's easy to see how unaffordable apocalypse design really is. We don't have the money to spend $100B on every one of these bridges. No amount of money in the world could pay for that level of design. There are over 560k bridges in the United States, and 60% of them are over water. Many of the 560k bridges are in need of major repair or replacement. Although the vast majority of that 560k are much smaller and simpler bridges, it's still too costly to spare no expense in design. You always must design with a balance of risk and safety. I also just wanted to clarify robs discussion about load ratings of bridges. First, load rating a bridge is a routine procedure. It's done every time a new bridge is built as well as periodically throughout the bridges life, especially if the bridge is deteriorating or doesn't meet current code. As to meeting code, Rob noted that the bridge didn't rate for any design trucks, but he really should have clarified this statement. A "design truck" in bridge engineering terminology is a theoretical load. Current AASHTO LRFD bridge design code specifies HL-93 design loading, which is a combination of a theoretical fully loaded truck (HS-20 truck) AND a fully loaded lane of other vehicles acting simultaneously. Back when that old bridge was built, LRFD code didn't exist. The older code, called AASHTO standard specifications, called for a theoretical truck OR fully loaded lane. Furthermore, the weight of the theoretical truck has increased over time, so it may have been less than the current HS-20 truck back when that bridge was originally designed. My point to all this is to say that a bridge failing a load rating analysis says nothing about the condition of the bridge. Bridges fail load ratings all the time due to being older bridges that were designed to the older code. And a bridge failing to rate also doesn't make it unsafe. It just means that it may need to have a weight restriction and/or lane restriction for trucks. Any unusually heavy trucks will require a permit to cross the bridge anyway, and it is determined well in advance if those permit trucks are allowed over the bridge or if they need a detour. The driver will know this before he even leaves site with his load.
just to respond to your first paragraph about how expensive it would be to build stronger bridges and protections; A simple solution is 4 parts (1) the costs to reinforce the bridge dolphins or whatevers, should be paid by the people involved in building these monster-sized ships. (from the designers, engineers and owners ). (2) All ships this big and operated in "tight spaces" (subjective) should be aided by tugs as insurance - again paid by the responsible parties mentioned above (deo). (3) the entire crew of these ships should be certified and tested periodically. (4) the ship's power trains and generators and backups should be inspected prior to every time traveled to "tight spaces". All of these costs should come from the $billions profits directly and indirectly to the "owners". NOT CONSUMERS!
Again, your comments here show the lack of understanding by the general public. There is no justification for an international shipping company to fund transportation infrastructure in the US. It's not their bridge. It's not their land or waters. It's not their jurisdiction. Even if we attempted to force them to pay, whatever law we create would be unenforceable internationally. The best we could hope for is coordination of safety standards with the origin country. We only have the power to control how these ships navigate our waterways, and we already do this by mandating the use of tugboat or by requiring a US captain navigate the ship through the channel. The latter is what is done in the Baltimore port. As for practical solutions to avoid a disaster like this, we already have them well established. My original comment was only to rebuff the idea of 'designing for an apocalypse'. I did not get into standard design practices used today, which include the use of dolphins and fenders. Those channel devices are routinely used in new bridges over navigation channels, and they will most certainly be employed in the replacement of the Key bridge. Several other bridges in Baltimore already have these devices in place. I've inspected several of them. I would bet money that MdTA (the agency that owns the Key bridge) will be looking to outfit the remainder of their bridges with these devices to avoid another disaster. The Bay Bridge is likely their highest priority. Fortunately MdTA is fairly proactive, so I don't doubt they will do something.
@@rfehr613i think the general public usually assumes the engineers know what they’re doing and therefore should not have to be familiar with bridge design principles, unless they themselves are engineers. Seems fairly reasonable to me
There's a price on your head. About $10M to be specific. I think that's the value the federal government uses for the value of a human life when designing regulations and making recommendations like the NTSB does to the FAA. If the NTSB had their way, everything would be built for Armageddon because they don't have to pay for it.
7:00 - Even if you DO get an engineer to explain why a massive ship slamming into a bridge pier can cause the bridge to collapse, you still get insane conspiracy theorists arguing that there's no way it could happen. Social media was filled with them right afterwards.
@@kaiserruhsam More along the lines of "there's no way that a ship can cause a bridge collapse. Bridges are massive! This was clearly a deep state plan! That's why there were construction workers on the bridge - they were there to help bring it down!"
We didn't even need social media to spin conspiracy theories. Fox was on it right off, hyping for views by acting like ghost chasers "could it be this wild scenario? you decide" smh
Grady, your practical thoughts at the end of the video are very insightful, kind and truthful about humans and how to look at probabilities. Very wise. Thx.
This is among my favorite videos you've ever produced and the two person perspective here really did a great job of creating speculative content that was still grounded and not reaching. I really appreciate the content the quality of this video thanks to both of you
As a seafarer myself and in Engineering Department of the ship, there are tons of backup machinery in case something fails. I'm talking about 2 pumps each for Lubrication, Fuel, Hydraulics, Air system and Cooling Water (Fresh water and Sea water), and each machinery has 2, meaning Generators and Main Propulsion have their own set of 2. Also all of those machinery have corresponding backup (Auxiliary) pumps which means even if 2 pumps fails (or the power fails) there's still smaller pumps capable of running the ship. There's also an Emergency Generator beside 3 Main Generators (really big ones) so an engine failure on 3 will still able to run the ship as all non-essential machineries like AC and normal lights are off to lower the load. Basically a ship is capable of sailing on Emergency Generator alone if worst comes to worst, theoretically. Now onto inspections, there are 3 port authorities that are somewhat infamous for how strict they are in the world, US Port Authority, Australia's AMSA, and Chinese Port authorities (they're getting stricter every year) not to mention EU countires and Port Authorities. To prepare for going to Port in US alone will cost the ship tons of drills, testing of machineries and cleaning. I'm talking about a month of preparation with minimum of 2 weeks, basically lot of overtime for all crew to test and drill for emergency (these authorities are no joke for us!) as failing for inspection means lots of trouble and more overtime for us to rectify said troubles. Overall my point is, it takes a lot, I mean a lot to cripple a ship. You need to be a bad Engineer to disregard all maintenance operation and it will still take months prior to this incident to f up the ship. I know nobody is perfect and those shipping companies that does wihtheld supplies for ship maintenance and crew living ain't gonna go to these 3 countries (US, Australia and China) and EU in the first place since it will cost them tons with their little budget and low profit and one peep of a seafarer about their living condition and these companies are now under special spotlight every time. They'll be going to more convenient deals that will not give them much trouble with convenient countries, and even then a skeleton ship is still susceptible to ITF (International Transport Workers' Federation) raid and charges, basically a seafarer police that will force companies to treat us better as well as making the ship more safer. TL;DR - It takes a lot to cripple a ship with bad machineries and poor company policies, my conclusion is, a cyber attack is easier way to cripple a perfectly good ship undergoing regular inspection of US Port Authorities and maybe other good Port Authorities. Also I heard Synergy is a somewhat good company.
The "no tug" requirement is a competitive one - if a port requires tugs, the ship captain or operator will go to a port that does not require tugs. So ports do not require tugs to maintain their competitiveness.
Here in Hampton Roads Virginia (Norfolk), we have tunnels and the Navy made it clear that there would be no more bridges leading to the base and shipyards, but Grady is right, consider the cost of tunnels versus bridges and the politicians will always say they need money for other things. It's a tough trade off. Thanks for another great video that even an old pharmacist can understand!
At the risk of replying to a joke... the utility poles are nigh invisible in the dark, while the bridge is coated in street lights. I'd wager they're much more likely to get bumped into.
those power lines are new. only installed in the past couple years, so they may have had higher standards about collisions/protection. previously there were power lines under the water in that area. police even stopped traffic at times during installation as to not have distracted drivers on the bridge while helicopters ran the power lines.
You’re going to be surprised of how many 20 meter bike lanes that start from nowhere and end up nowhere too are in Kyiv. The Mayor of this city (vitaliy klichko) is just a crazy gangster doing nothing practical, but everything for money laundering and corruption.
@@appa609 That's what the quote means. Anyone can break the bank to construct a bridge that will last. IT takes an engineer how to safely cut costs so that the bridge is in a constant state of barely standing.
@@dhawthorne1634 A well engineered bridge is not generally "barely standing" it fulfills all project requirements including regulations on structural FOS. A typical road bridge might be capable of holding 3x the maximum design load.
Excellent job as usual explaining a complex subject so that us non engineers can understand it. I like the twofer part of including Road Guy Rob with his perspective too.
Great as always, Grady. Thanks for looping Rob in. Something I just thought about, maybe an idea for a future episode ... What are the relative advantages for cable-stayed over suspension or truss bridges? I can think of several, but I'm not a CE, so there are probably more issues (cost, span, height, etc.) that play into that decision.
Structural engineer here. At a high level, cable-stayed bridges are generally more economical than truss and suspension bridges for medium-length spans, which is why it seems like every new large bridge being built is cable-stayed. One of the reasons for this is that cable-stayed bridges are "balanced" on the piers, so you can construct them by building the piers first and then extending the bridge deck out from the piers in both directions. However, cable-stayed bridges are not a good design for short spans and long spans. Some eyeball math says the main span of the Gerald Desmond bridge in this video is on the shorter end of what's economical with a cable-stayed design.
I think in this case the advantage of a cable-stay bridge is the combination of span and boot-strap ability. I.e. the cable-stay bridge design makes it easy for the bridge to be used to build the bridge. So there would be minimum disruption to the shipping channel.
Hi Grady! Excellent video on the subject. You're right that assist Tugs were not required in Baltimore for the ship transit under the bridge, but if they were, the ship would have needed to be moving at only 2-3 knots instead of 8 knots (like the Dali before it dropped its anchor)) for the tugs to have any hope of guiding such an enormous vessel in the event of a total power loss. As I'm sure you know, the mass of that beasty is astornomical, so each additional knot of speed greatly increases the inertia, and the tugs (even the big ones) only have just enough power to gently nudge such a large ship in any direction, so they would all need to be moving rather slowly for the limited power of the tugs to have enough time to actually have an effect on the ship, once it starts going awry. Incidentally, assist tugs cost $$$ and that increases shipping costs. I'm sure you agree. Just pointing this out for non-boat-nerds.
To be fair, it really is time, and the horizontal speed of the escorted vessel, that are more the important factors here from a mathematics perspective. Then possible lateral currents (or wind) acting on the vessel and when that might start acting on the vessel are also key. I can't speak to the maneuverability of the tugs with the 5-knot forward speed though.
A few years ago a truck driver (40 tonnes 70 mph) near Pariis hit the pillar of a freeway bidge. It was the first time that a vehicule had brought down a bridge, closing both directions. The driver is no more. A 100,000 ton ship hitting a bridge is the same. No mystery.
Last I heard, thanks to Sal Mercogliano's excellent "What's Going On With Shipping?" channel, is they're expecting the main channel in Baltimore to be reopened by the end of May. A portion of the main channel has already been reopened, with a 5-knot speed limit, wind-speed restrictions...and tugs must be attached to ships fore and aft while transiting the channel (not just escorting them). The salvage and recovery operation is truly enormous. Lots of practical engineering going on there!
Layman's Terms: Bridges are designed to resist vertical pressures, not horizontal pressures. That is why earthquakes take down bridges... because of the lateral movement.
📖Signed copies of my book, Engineering in Plain Sight, are back on sale! store.practical.engineering/
🌌Get Nebula using my link for 40% off an annual subscription: go.nebula.tv/Practical-Engineering
All the mainstream media is worried about now is this f'in flotilla!!! What's wrong with shipping
Love your videos
Would you do a video on the emergency replacement of the Crown Point Bridge between New York and Vermont? Your viewers might be interested in what it takes to replace a major bridge in a hurry - about 2 years from finding that fatal defect to opening the new structure!
A quick search didn't find anything.
@@Idkidkidk716 Same!
Hey Grady,
Australian Engineer here - when I was doing some post grad studies at QUT in Brisbane Australia in the late 80s I heard an interesting story about bridge loading that I was reminded about by a couple of Road Guy Rob's remarks.
In the middle of Brisbane is the Victoria Bridge that crosses the Brisbane River. If you go onto the Wikipedia page and read through the details you will notice that is says there were signs in 1943 that the bridge was buckling due to increased loads. Those loads included trams - what you Americans call trolley cars and they are heavy.
The story I was told was that it was university engineering students who discovered the buckling issues. As part of their practical work they were sent down to measure the deflection of the road deck when there were no trams and it was fully loaded with stationary trams which happens just from traffic lights activating.
For years the university professors brushed aside the findings as just "student errors." They were sort of close enough but not too concerning. It was just dismissed as a "learning thing." Eventually one professor noticed that all these apparent errors were actually consistent so to check if there was something wrong with what the students were fundamentally doing he went and did the measurements himself and found that the students were actually accurate and that the bridge was deflecting an alarming amount when it was fully loaded with trams full of people.
I'd like to say that I can verify the story I was told but can't.
However the details on Wikipedia do NOT contradict it either and in particular note that the number of trams were restricted, which was exactly what I was told circa 1989.
FYI - I am actually an aerospace engineer who did his degree in America (U of Illinois). In 2016 I had this odd little consulting job into Australia's energy sector which has major structural issues. I have since found that many other nations have similar issues and that the energy issues are PART OF the much larger INFRASTUCTURE ISSUES that include bridges.
There is a 2014 (I think) 60 minutes titled "America’s Crumbling Infrastructure" that highlights "The Portal Bridge" that crosses the Hackensack River. Go check out that story and where its now at. I can't give you too many details as I can no longer see that episode of 60M here in Oz, but I believe they said that America has over 30,000 bridges that need major repairs, major upgrades or outright replacement.
Its all part of this fundamental issue with keeping society functioning WHICH WE ARE NOT DOING WELL. I have traced this problem (as in Root Cause Analysis) back to ECONOMISTS. There was a revolution in the 1970s with Ronald Reagan introducing the world to Reaganomics. Hos contemporary Margret Thatcher gave the Brits Thatcherism while we called it Economic rationalism. One of its key concepts was that the private sector does everything better and therefore everything should be privatised.
The problem is that infrastructure does NOT exist to make money it exists so that everyone else can make money. This is a concept that economists do NOT understand at all because they are trained to believe that everything must make money. Its also why they cut maintenance budgets everywhere they go because maintenance is a cost NOT a profit. This has resulted from the complete failure of economics education programs to teach how engineered systems work and is why we have so many issues with energy, water, roads, bridges,... etc.
I will be in the Steve Keen & Friends podcast in the next few weeks to talk about this and some other things.
Grady,
I studied vessel-bridge collision for my Masters and PhD under Dr. Gary Consolazio at the University of Florida. This topic is also my professional specialty as a practicing engineer. From that perspective, I wanted to let you know you did a excellent job explaining the topic and the AASHTO code requirements. I came into this video expecting to have comments or corrections, simply because the topic is esoteric and fairly complicated. But no, you have clearly done your research. Great job, and thank you for what you do.
Daniel G.
This is about the best reply a technical youtuber can ever get - thank you very much for giving it to Grady, and the rest of us too! :)
as a specialist, what do you think of the lack of tugs to guide the dali past the bridge? iirc, there WERE tugs guiding the dali out of port; but they left some ways BEFORE dali reached the bridge... imagine if they just stayed along for just 15-30mins longer, they could've avoided the disaster.
what size ships should have a mandatory requirement of tugs-past-bridge? how much would that cost? why didn't baltimore have that requirement?
@@alveolate No, they couldn't. They ran some simulations on one of the few ship simulators and the simulation found that you needed bigger tugs than they used and they needed to be attached to the ship to counter the wind and current. The forces involved are huge.
Sir, I have but two questions for you:
1. Does AASHTO also cover railway bridges, like the Big Bayou Canot Bridge that was struck by a lost bardge that caused the deadly derailment of Amtrak's Sunset Limited. It's the collision where the bridge sustained damage enough to the structure and tracks, but held up. The damage to the tracks caused the train (traveling at high speed) to launch off the tracks completely, crashing into the waterway below.
2. Did you get your PhD and can we call you "Doctor" instead of "Mister"? (Old Big Bang Theory joke.)
The extra research someone like me (not an engineer at all just kinda nerdy) won’t notice often doesn’t get the recognition it deserves for channels like this. Glad to see his hard work being appreciated by experts and common folk alike!
7:20 oh my god i never realised it's called a collision as in a co-llision because it's two things crashing into each other, and a-llision when it's one thing crashing into something stationary...
Same! Learn something new everyday lol
Words are fun! Hope you get hundreds of likes on that insight! 😎✌️
I’m telling anyone who will listen and nobody I’ve talked to so far has even heard the word before
Technically the division is al-lision, not a-llision, and col-lision instead of co-llision: these are from the latin prefixes con- (together) and ad- (at (!)/to/into), but got assimilated due to the l at the beginning of "laedere" (compare pronouncing "conlision" and "collision"). In Latin, conlido and collido are both valid, but only one of them made it into English
And I'm glad I'm not the only one to get excited about etymologies of words I'd never thought about before :)
@@hadinossanosam4459 yeah I was sure the exact history would be different but in my defense I'm a computers and stats guy not an English and history guy lol, but thanks for letting me know! I secretly love histories of language, it's really interesting to see what words cropped up where and why and what became popular, it's like a fossil record but for culture
Road Guy Rob is among the most underrated channels. The guy basically works for minimum wage for his daytime job and makes videos for pocketchange in his spare time. His content really should be capable of supporting him as a career. I highly recommend people binge watching anything in his archive that they're curious about. Skip the livestreams unless you're super nerdy, they're a lot content dense and is more just hangin' out with Rob.
I subscribed based on your recommendation and will binge his videos after work. Thanks 😊
>underrated
" You keep using that word. I do not think it means what you think it means."
@@cwtrainlook lol I normally would agree with you. But rob has 150k subs, to practical having 3.7 million. This, is one of the very rare times, something actually IS underrated.
@@cwtraintho, I still wish RUclips could ban the word.
He definitely sets himself apart from other urban/transit RUclipsrs by doing interviews with transportation officials and going on scene.
I learned some years ago that the best definition of a truss is "it supports loads with math instead of mass" they are great for cheap light support systems, and that is why building roofs and floors are made out of trusses. the drawback is that if you compromise any component of a truss, there is usually no redundancy to prevent failure. thus the logical way to prevent catastrophic failure of truss bridges is to avoid collisions; rather than to try to reinforce them to survive collisions.
I think I will steal that for class.
@@petermgruhn go for it.
Love that phrase!
You can overdetermine a truss. Then a single element failure will not be catastrophic.
@@appa609 yes, you can build one so it is completely redundant. then it will weigh and cost twice as much, or actually more, since it has to support more of itself, as well. not an idea the bean counters will like, even if it does substantially increase the safety margin.
A two for one Practical Engineering AND Road Guy Rob video?!? What did we do to deserve such a treat!?
Collab of the year
I didn't even know about Rob. Gonna take a look at his channel.
This is the third video in the past week that's had combined RUclipsrs.
"What is this? A crossover episode?!" -Mr. Peanutbutter
@@bartsanders1553eh if your 12 years old he might be entertaining lol
Grady, thank you for collabbing with Rob, he deserves way more attention than he gets. I am also not surprised that you are the first "big" youtuber to do so, as you have consistently shown yourself to be a kind and generous person. Thanks for being such a good example.
I thought Not Just BIkes did a colab with him?
@aidanlevy2841 Not Just Bikes is such an insufferable ahole.
@aidenlevy2841 I'm not aware of one? In fact, I'd be surprised if he had, I seem to recall that NJB having put Rob on blast once.
Rob is as big as Practical Engineering. Grady obviously considers him an equal, and did the collab to boost his _own_ channel. Why would you think otherwise?
Regarding Tugs, "What's Going on with Shipping" pointed out that much above 4 knots, tugs really can't do much to alter the path of a large ship anyway - there's simply too much inertia. Now you could force the ships to go slower and use tugs near the bridge, but this is a lot of extra cost and time on every single transit - for something that only occurred due to some sort of failure on the ship.
His focus has been on identifying the root cause of the ship losing power in the first place, as there are many other locations such a failure could cause similar problems.
This could have been entirely prevented with escorts. The fact that the pilots act like the shipping companies money is their own is the problem. Their egos took down that bridge.
@@Jpwarner88Ah so you want a compromise between the ship going through alone, and the ship being pulled by tugboats.
@@Jpwarner88 yes it could but it would cost extra money, and it is basically useless over 4knots on large ships. Not a single company will pay for tug escorts if it isn't required. A no sense example would be you paying a construction worker to show you the way when they are working on the road. He can't do anything if you for some reason lost control of the car. Even at walking speed the car is going 4+knots and he is the escort. In comparison.
@@gabrielarrhenius6252 I don't know how much it is to have required escorts for ships over a certain size. But I imagine it's a lot cheaper to require that then replace an entire bridge, and the economic cost of lost maritime trade for the duration of time it takes to replace the bridge.
@@LevaniaMeyano That is true, but how big is the chance that a boat big enough would actually crash into the bridge? That is the question. As long as it isn't required at all ports/bridges so will the boats take other ports/waterways as long as it becomes cheaper and gives bigger profits for the company, since it is them who decide. The requirement of having escorts will just make the companies choose another port if possible. You know all those height restrictions/warnings on bridges over roads, would most people choose to have an escort which they need to pay for when going under it for the chance that something happens which puts the traffic to a stop under that bridge. And if that was required would people choose that road if they absolutely didn't need to? Will you choose the road with a toll if you can take another which do not have a toll and the time difference is minimal?
... the new bike path just ends at a gate...
Yeah, that tracks with my bike riding experiences
Just one more lane bro
Thanks for the shout out!
When I saw the thumbnail for this, I thought it was probably one of your videos. Then I saw it was Grady, and... then I saw the shoutout, and was pleased. :)
I went to a great deal of effort trying to explain this math to people who were convinced that a ship at a slow speed didn't seem to be that big a deal impacting the bridge. I compared it to an average freight train to give people a reference for the energy. People could associate a freight train at 60 miles per hour with being an incredible amount of force, but they couldn't realize without the mathematics that it was only a tiny fraction of a percentage of the amount of energy of this vessel hitting the bridge.
Physics is not intuitive, but it is inescapable.
It also has to do with reduced mass. A container ship coasting at 5 mph may have a lot of kinetic energy, but in an impact with a human only a minuscule fraction of that energy will be transferred. It may make your nose bleed, but it would not be very dangerous. Meanwhile, a train going 60 mph will transfer a lot more energy to the human despite having much less kinetic energy than the ship. For structures that are heavier than the ship or effectively immovable on the other hand the picture flips, and suddenly the fact that the ship is n times more massive than the train matters again.
Trains are bigger than you think. Some freight trains at 60 mph would have significantly more energy than this ship.
@@appa609a fully loaded freight train weighs at most about 50 million pounds, this ship weighs 232 million when fully loaded even with the huge speed difference in this hypothetical the ship is putting out like 32.5x as much force from the impact and that's if the entire energy from the train hit all at once which isn't how train crashes happen cause the cars behind the lead spread out when their energy is applied
Kinetic energy can increase by either increasing an objects velocity, mass, or both.
The amount of inertia these ships have is beyond many people's comprehension. It's beyond me and I would say that I have above-average experience in math/science and heavy industry.
The NTSB is one of the most pure and principled government agencies out there. They do one job and they do it incredibly thoroughly.
It takes them way too long,and there have been many questions after some of there later findings.
I thought it odd that he used the term "independent government agency".
@@daleolson3506 their findings are not used to assign guilt they are used to inform policy change. The thorough process is a benefit and the time it takes does a not pose a major concern to the purpose of what they do.
@@petermgruhn they are independent because they are under the executive branch but are not under any executive department and are largely outside of presidential control. They get to operate independent of any political or corporate motive and just do the one task they were made to do without fear of reprisal.
@@daleolson3506Then fund them.
You can’t get accurate, reliable work done quickly unless you’re willing to pay for the increased staffing that will require.
We are at the business end of 50+ years of methodical defunding of our government agencies, all of which now struggle with woefully inadequate staffing. Then people complain they don’t move quickly enough and call to further cut their funding.
Which, of course, only makes them work even slower.
As a total non-engineer person (meaning as a person who knows close to zero about engineering and, turns out, grammar), It took me a few goes but I finally understand most of what was covered in this video and I must say - WHAT AN AMAZING JOB at making it soooooooo understandable and accessible for non-engineers x
6:55 I always smile when I see people in camouflage and high-vis jackets. Like, do you want to be seen or not?! 😂
Yes.
Uniform is a uniform. Thinking of it maybe people in camo uniforms like the military are more often ordered to wear high visibility jackets and such, since by default they are very much not very visible.
It's like when Harry Potter put on the invisibility cloak for the first time, only his head was showing.
He does NOT want to be seen or stand out, but on that day he has to by law. He does not like being at work, he likes to be in the forest, killing animals.
It's like a mullet hairdo - business in the front, party in the back.
Dutchie here. We design our water defense for 1 in 1000 to 10000 year events, depending on failure mode and related things. It's pretty recent that we first needed the Maeslandtkeering, which is several decades old, and is one of those structures.
You're talking about the change of a (massive) flood, not the change of a large container ship hitting Maeslandkeering. When it is retracted, this is possible that a vessel hits the barriers.
As long the keering is open, ships are allowed to enter the port, which is why it is an automated system. However take the following scenario: There is a very high tide and a MSC containership wants to enter the port to ride out the storm, meanwhile while is is approaching the keering the condition is met to start closing the keering, the container ship is told not to enter the port, but the captain ignores this instruction, and while the keering is closing it hits one of the barriers.
Now, of course the change of this happening is very slim, but you cannot rule it out. However when they designed the keering they accepted that the change of such a scenario happening has such a low probability, they opted not to create a backup system for when the maeslandkeering fails for whatever reason. Based on the costs to create such a backup, they accepted this risk. However when a scenario as above does happen, people will get their pitchforks and demand blood from those who thought is was a acceptable risk. This is how it always goes...
@@2Fast4Mellow Well a few things you should know, the Maeslandkeering closes off the Nieuwe Waterweg, and that waterbody is not really used for large water traffic (although there are cruise ships visiting the port of Rotterdam). All the major cargo traffic travels to the Europoort via the Calandchannel below it which has no barriers towards the sea. The majority of the traffic is river barge and or coastal vessels. That and the fact if only closed for real like 3 or 4 times in it's life time, and if it is, it will be in extreme weather conditions making it something else than 'just a tuesday'.
I hope you also realize what a superhighway the Channel is? There is no ship able to even approach withing 200 km without being in contact with the international authorities, let alone allowed to enter the Eurogeul and Maasgeul (60 km into sea) without a pilot on board (large vessels get a pilot onboard even 75 km out, way before reaching the Eurogeul).
Nothing is impossible, but your example is probably a lot less plausible as you think it is.
This was a terrorist attack. Intentional. The question is, why did the media assure us it wasn't a blatant attack?
@@derrickmcadoo3804mainly because it wasn’t an intentional attack.
@@derrickmcadoo3804 pretty poor attempt at a terrorist attack. Given there are huge chemical storage tanks right near the water, beside the giant coal storage area, very poor indeed.
But you go ahead and put your foil hat on and believe whatever you want to believe.
@18:10 - another important note: While 2016 gave us the Panamax expansion which allowed large container ships like Dali to be practical, bulk freight ships in the 100 kiloton range have been around since the 1970s. This event could have happened at any point since the construction of this bridge, it was just more likely to be a coal, petrochemical, or grain freighter.
WHew, can you imagine just how much worse it would have been a bulk oil carrier? At least those 'containers' were.. well... 'contained' for the most part.
@@mikefochtman7164Baltimore Grain Party. What a mess that would be!
@@phantomkate6maybe it ferments and turns to a superior drink than tea?
I really liked the way you explored risk and risk management in this, it would be super cool to have a whole video on risk based engineering, and breakdown risk control measure into engineering controls (like islands or putting piles on land) and administrative controls, like speed limits in channels, local port captains and tug boats! I work a lot in risk management engineering and sometimes it's hard to explain to other engineers the concepts behind risk based decisions and acceptable risk levels. Great work!
Awesome collab with @RoadGuyRob!! I love that guy!!
15:40 Grady: “Back of the envelope”
Animator: Here’s the front of an envelope!
😆
To be fair, "back of the envelope" is such a common expression in engineering that it's kind of divorced from the original, literal meaning.
@@NicholasMati and yet, to be fair, envelopes do have backs and fronts.
I don't know why that wasn't caught in production. It's so much the kind of nerdy detail that people who watch this channel would notice.
Fronts of the envelope are usually not used because they already have text on them, and on the back you only have to deal with the edges of the folder-over paper. But if you animate an envelope, you can create an envelope without text on the font (and then don't even have to deal with the paper edges getting in the way).
Nice to see a bike lane on the Long Beach bridge. Sad to see that it doesn't go anywhere. There's a difference between bike infrastructure and meaningful bike infrastructure. People use their car to get from point A to point B. I'd like to use my bike to do the same, but so much bike infrastructure goes from a point where nobody is to a point nobody wants to go to. Off topic I know, but Rob did talk about the bike lane, and covered how it was gated on one end, thereby rending it from potential usefulness to a point nobody wants to go to. That leads to feelings of money wasted as the bike path won't get used very much.
Seems like a lack of joined up planning between architects/engineers/city planners. I'd design a bridge with a bike lane because it should have one, but what it joins up with is Not My Department
They should have built it somewhere else.
@@RobertMilesAI true, and they did say the bridge over in LA is old. If it gets replaced, I bet it has a bike lane. Maybe then the Long Beach bridge gate can open?
For around a decade, the UK's Warrington Cycle Campaign ran a "Facility of the Month" feature, showcasing over a hundred examples of "excellence" in bicycle infrastructure design, such as cycle lanes that start / stop in random places, very narrow cycle lanes, shared or side-by-side footways + cycleways where the cycle part is either interrupted by sign poles or street furniture, has restricted headroom due to overhead signs, ends abruptly at a fence etc.
Often, councils will take grants for installing bicycle facilities, but then "local authority logic" comes into play and the resulting infrastructure isn't fit for purpose (cue lots of Angry People In Local Newspapers moaning that cyclists aren't using the news infrastructure, and what a waste of money it was).
Come to Seattle!
As a Baltimore City resident and a fan of your channel I have been waiting for this video! Thanks you did NOT disappoint!
Hey Hon!!
@@ms.donaldson2533 I see what you did there... Truth be told I pronounced the T... I just live here I am not FROM here.
@@SDSBBQs i grew up around the Baltimore area. Was wild waking up in the morning to find your partner's commute to work takes 40 minutes (assuming 0 traffic) more now.
same!
As a recent viewer of The Wire, I couldn't help but imagine Frank Sobotka rolling in his grave when I heard the news.
I very much appreciate efficient, clear, concise scripts. Well done Grady and Rob. You pack in so much explanation (and humour) with no wasted words.
Grady,
I am a naval architect and marine engineer who spent my career working for oil company marine operations. I was involved with everything from the design and construction of tankers to oil spill response. In fact, our tankers docked at berths 78, 118, and 121 in Long Beach, requiring passage under, or docking next to the Gerald Desmond Bridge.
A major point in the discussion of the ability to predict the size of ships when the Francis Scott Key Bridge was built is not valid. We operated three classes of tankers, all built at the Bethlehem Bethlehem Steel Sparrows Point Shipyard, where the Francis Scott Key Bridge is being taken for recycling. The ships were built from the late 1960s to the early 1980s. The tankers were 70,000 DWT, 120,000 DWT, and 265,000 DWT.
The fendering and dolphins around bridge piers can be designed not only to guide ships away from the piers but they can be designed to ensure in an allision the ship suffers the damage. I can attest to this, having had to direct the installation of temporary patches covering holes after an allision. One of our tankers hit the Carquinez Bridge. There were two holes, one 10' × 100' and the other 10' × 200'. The bridge had the wooden fendering destroyed and suffered minor damage to the concrete.
As for the loss of ship's power, it will be interesting to see the NTSB's findings on the loss of power and inability to regain to regain power. It will also be interesting to find if they tried the main engine in reverse, to stop the ship, or start it going ahead in an attempt to regain steerage.
Bob
Dali was definitely slowing down, i believe she was at 8 knots before losing power and according to Grady at 5 knots when it hit the pillar.
But as you know it takes a good bit to slow those big ships down.
I'm looking forward to see the report as well!
I spent my entire life in Baltimore with an interest in local history. I saw that bridge everyday in my travels around and can remember the first time that my father took me on a ride over the new bridge.
Until this accident, I knew Dali as an Italian painter, who's works included "The Broken Bridge and The Dream." I knew that Francis Scott Key was a founding member of the American Bible Society. I knew Pelosi's dad packed up The Dream on "The Exodus" and sent it sailing in 1947. I witnessed the day that they brought in the new cranes to the port that had inches of clearance under the bridge.
My question is caused by coincidence -
it is not everyday that a ship crash takes down an entire bridge and it's owner claims on it's website of it's incentives to create better ports for bigger vessels with larger shipments to arrive. It seems that bridge was in the way of their progress. That day felt like 9/11 all over again. The collapse happened and no matter what people see, they will only pay attention to what the news tells them.
Baltimore burned down in 1904 because of one discarded cigarette - that too was just an accident.
Much love from Baltimore - I can't wait to see how this story ends.
I agree, Robert; I've seen the Dolphins on the replacement Florida bridge after its collision, and those things could probably handle the Dali no problem. I'd imagine that had the Francis have similar Dolphins installed, the bridge would probably still be standing.
Brady is generally right though; cost and likelihood are two things engineers have to calculate, and back when this bridge was built, ships like the Dali didn't even exist.
@@TheEDFLegacy Engineers run the numbers and make presentations to "officials" who then decide if the benefit sufficiently outweighs the risk to ensure their own reelection. Engineers have tried to stop a number of ill-fated things only to be overruled by management or agency agendas.
I am curious how does a ship like that suffer such a total loss of power? That is should there not be multiple independent generators. I am thinking like how on a jet airliner each engine and the APU turns its own generator and hydraulic pump and so as long as you have one of them you have full electrical power and hydraulic power and the systems tend to be independent so a loss of one does not mean a loss of the others.
3:06 well this just opened up a whole new reason for video game preservation. theres actual history there
when the notre dame cathedral burned down they used the laser scans and recreation of the cathedral from one of the assassin's creed games to help rebuild it
It was somewhat the same with Assassins Creed Unity, Ubisoft gave it out for free after the Notre Dame fire for people to be able to see their detailed digital version, probably the only time Ubisoft have done something positive.
Ubisoft giveth, Ubisoft taketh
They need to add the ability to pilot container ships on the next gta
If anyone reading this hasn't been to the "stop killing games" website, I suggest you do it now if you're interested in the topic
I loved that Grady waited before making a video on this. Really shows he’s engineer first, content creator second, by waiting to acquire in-depth analysis and information.
Nice to see the Road Guy adding some content to the video. Thanks for the colab. He has a great channel and goes into great detail on all things road and traffic with wit and knowledge. "What's Going on With Shipping" has been detailing the maritime side of things with some good channel suggestions as well. He's a good follow.
Seeing nearly a million views on this video and 3.76 million subscribers to your channel gives me a warm fuzzy feeling. Congrats on your success Grady.
Honestly the thought that any structure should be able to withstand a direct hit by a ship that large is absurd to me.
I doubt the idea is that it should not fail. Its likely more about reducing how catastrophic that failure is. It may include failsafe/safety measures for bridge and people (evac routes et so), figuring out how the bridge might be designed to collapse in a more safe manner (like crumple zones in cars), etc
Yeah those are insane ships.... People that think a bridge is "too weak" or "should not have fallen so easily" really haven't seen a massive ship before. They can dwarf a city block of multi story factories as you approach them, they are massive. A bridge is like a toothpick.
They should build protective pillars, so if the ship drifts it hits the dummy pillar instead of the main pillars.
@@KakaCarrotCakeVideos then you'll need multiple thick pillars and that will increase cost significantly all that for somthing that will not happen again for atleast 50yrs
@@Shubham_Bahiratthey recently dredged it allowing larger ships to pass and travel closer to the piers. Safety should have been included in the budget for the 50 year old bridge.
Single-digit casualties for such a spectacular disaster still amazes me. The early warning system and those cops turned out to be the real heroes.
Tards tossing hero around. No wonder you country failed.
What about the fact that everyone was asleep at the time. The earth spinning is the real hero
@@bighammer3464 It seems to me that it doesn't matter how many cars were on the bridge at the the time the police blocked it; it would take about the same time for all the cars to exit the bridge whether the police had stopped entering traffic during the day or the night.
Don't let @derrickmcadoo3804 hear you say that. They'll tell you how it was actually a devious terrorist attack and the media is lying to you.
@@Curt_Sampson didn't he say in the video that the police closed the bridge too late for all the cars to get off the bridge? I'm pretty sure there were cars on the bridge when it collapsed. It's reasonable to assume that there would have been more cars during the day.
Thank you for this video! As a maritime historian with a background in safety issues, the historical development of risk management, and port history this was such a treat and helps me explain these phenomena to people.
20:19 I didn't know Calvin's dad was right about how engineers test bridges
True, he was an architect so really should know
@@markedis5902are equating architects to engineers? That will not earn you much goodwill in the company of either lol
Calvin's dad was a patent attorney.
@@brighamshamrell4524 I can confirm this
Man...Rob and Grady make for one awesome team! I enjoy the energy dynamic that exists between the two!
In Germany, the Autobahn bridge between Cologne and Leverkusen is being rebuilt. The bridge spans the Rhine river.
There was no accident, but the bridge could no longer carry the load. The passage was closed to vans and trucks, and light cars were only allowed to pass slowly over the old bridge.
In addition to the old bridge, the new bridge has now been completed. Trucks are allowed to pass through these again.
Now the old bridge is being torn down and a second bridge is being built next to it. From the original 4 narrow lanes, the two new bridges will offer 6 wide lanes.
What people not from this area need to understand are some small details about the German Autobahn Network.
As with for example the Interstates in the US, this is the Network of the major roads for long haul traffic.
Now traffic wise, besides having our own share of inland traffic, due to its size and position within Europe, some of the major transit routes unavoidably go across Germany.
Lets say anything comming from Asia to the Port of Rotterdam in the Netherlands, the largest Port in Europe, or the second largest, Antwerps in Belgium going about anywhere in Europe will go across Germany in some way. Third largest Port is Hamburg in Germany by the way, creating its own share of traffic.
Anything comming from the West, from Belgium or the Netherlands, or comming from Hamburg up north will more or less have to go through Northrhine-Westfalia, where mentioned bridge is located. Being the state with the highest and densest population in Germany (about a fifth of people in Germany live in this one of 16 states) and anything from Cologne through Leverkusen up north across the "Ruhrgebiet" being more or less one huge Metropolitan area along the river Rhine and Autobahnen being used for commuter traffic as well, anyone likely can imagine what is going on here.
Traffic from Antwerps from example may meet the network just south of cologne, while traffic from Roterdam will hit the northern Rhur Area. But imagine the network around Cologne, including Leverkusen Next to it, being more or less the main hub for that traffic plus trafffic comming from Hamburg, to go south along the western border towards France and Switzerland, Southeast towards Munich to get to Austria, Tchechia and everything behind those, or just up north and northeast, Hamburg, Berlin, Denmark, Poland...
So impact on traffic in case of any construction sides or unforeseen events like accidents around here is hard to wrap your head around. There are of course parallel routes, but those mostly are smaller sections of the Autobahn network with less lanes and thus a lot less capacity.
I think the most undisturbed from those factors way to get Cargo up to Cologn and further down South along the Rhine is actually loading onto Barges in Rotterdam and shipping along the Rhine.
@@alexanderkupke920 Lol at thinking someone will read all of that.
@@eriklarson9137 Some people do, but feel free to skip ahead. I am fully aware, that in comments some peoples span of attention doesn´t go further than maybe three sentences. Others enjoy a more detailed addition. Some indeed do not care or want to read longer texts. No issues about that. If someone is interested in reading and getting something out of it fine. If someone doesn´t care, fine as well. after all this is just a comments section not more and not less..
Why is that relevant to the topic of the video?? I'm German too, but if everyone in the world states what things was built in their country ...
Not relevant but since this is RUclips and not a strictly moderated forum we can write it anyway 😂
It's far from the only BAB bridge in Germany being rebuilt. A ton of them were originally built in the 30's (!) and can't handle the load anymore. There is one near me and the traffic going across that is insane.
It's really fun watching this channel because I started watching before college and am now slowly understanding more and more of what is said. I just finished a grueling study grind for a statistics midterm and when you said "if you are familiar with a normal distribution" I went "don't Even get me started". It was really cool to hear about the application of a normal distraction as it relates to the probability overlayed on the bridge like that. It was extremely pertain to my current education.
Road Guy Rob!!! Hell yeah!!
Bridge engineer here (PE and SE too) and thoroughly enjoyed this video. Great job on explaining how risk is accounted for in design.
“Back of the envelope physics” … and then writes in the front of the envelope. I mean, I don’t care, but for a few seconds all I could pay attention to was that being the front of the envelope, and then I saw the Practical Engineering stamp, hey can I buy Practical Engineering stamps? I’d buy those. Oh right where were we? F = ma ok …
12:02 this telephoto shot is incredible, really puts the scale of the bridge into perspective.
15:40 Sir, that was the front of the envalope.
Adding to the love for @RoadGuyRob. Always entertaining and realistic about the engineering aspects of road design without taking a side.
As someone from Baltimore that has crossed that bridge many many times, what a great video! Thank you so much for taking the time to put this together and giving us something positive to consider with the loss of such a great historic bridge and loss of life. I have appreciated your content for quite some time. I was pleasantly surprised to see your take on this incident that hits so close to home. Prayers to the families of those affected.
I am not an engineer, yet I could grasp the impact of economic and engineering that goes into bridge & highway design. Thanks Grady & Rob. Well done!
Channel recommendation about this topic: “Casey Jones - Professional Engineer”. He is a bridge engineer and has very insightful commentary on this kind of thing. “What Is Going On With Shipping” is also great and handles the maritime side of things.
He was also a rail engineer, unfortunately he passed away on the job...
@@genuinecve I think we may talk about two different people.
Sal from "What's Going on with Shipping" was the first person I looked to for the maritime side, which is why the bridge collapsed. Unresolved power failure alarms before the Dali left the dock? Tracking of course and speed? Currents, tides ebbing or flowing? How ships' systems work? Sal's videos answer lots of these questions. The questions about the power failure will be determined by the NTSB.
And a hockey enthusiast.
Well done Grady. As a former Civil Engineer I've gotten a lot of questions from friends and family as to how something like this can happen with such disastrous effects. I will certainly direct those asking to your video as you very clearly explain all the factors that must be considered and weighed when designing such a structure. Thanks!
I feel like a lot of people dont understand or respect the fact that everything we use on a daily basis has some kind of risk factor that was approved by a comitee of people. That's a lot of what engineering is.
By far the best, most polished video from this channel yet! Great job!
Also, as a utility worker, that has to foul railroad tracks often, i can say that any time a train is en route past our work zone, there is a clear order of operations that has to take place. 1st of all, we have a flagger, who places a restricted zone within a large area of our work zone, often up to 20 miles each way of our scope of work. This means that any train engineer who approaches that zone needs to radio, not only the tower, but also the flagger to get clearance to traverse that zone, often times at slower speeds too. This alows the flagger to activate our chain of egress operations, which are clearly written down and agreed upon by all workers that at any point throughout the day may be located in the rr row. This order of operations is determined based upon the type of work you are doing in the row. It will clearly state where equipment, and personnel need to get to, and how they get there, should a train need to move through the restricted area. And if at any point during the day, your scope of work changes, work stops, and a meeting is held to determine if changes to the egress plan need to take place. Believe me, it sucks to have to be so meticulous, it often lessens the amount of work that can get done in a given time, especially when your on a major trunk line, where you can have 15 or 20 trains or hyrail vehicles a day. But it ensures that rail workers, utility workers, car motorist at at-grade crossings, train conductors, and train passengers all go home to their families. Perhaps we should have a similar order of operations plan in place when working on high port traffic waterways. If they had, those construction workers would still be going home to their families. Im not putting blame on the crew managers or the companies that had them there, these things are often unimaginable.......until they happen. I would just like it if this horrendous loss of life could lead to better practices.
Are you suggesting having all traffic stop on a bridge before a vessel goes under the bridge? The only cause of problem to the workers as I understand it was the whole bridge collapsing. Honestly they were almost certainly at much higher risk from passing drivers.
Not necessarily vehicle traffic, as that can maybe be cleared out quickly. But the guy dangling from a harness painting pillars, he can't get off that bridge quickly. So if more constant communication is held between the port authorities and the work crew, then perhaps the guy dangling could get to a more egress ready position before a large vessel rolls through, incase something did happen
@glennmcgurrin8397 also, cars are the number one danger on any construction project located adjacent to a roadway, your never going to get rid of that hazard, all you can do is put buffers between you and vehicles
Excellent point
One of my favorite memories is a University open day lecture, “Bridge that gap,” which explained the different types of bridges and their respective advantages and factors influencing relative costs. Fascinating.
Love what you do and always look forward to your videos Grady!
Glad to see our new bridge in your video. It was a real headache dealing with the years of construction, but it makes the crossing easier and safer for all. Take care.
that's a lot of pier pressure
Truly appreciate this video. I've traveled the Key Bridge probably a million times in my lifetime, as I lived in Baltimore for over 20 yrs., and it breaks my heart to see this happen. A dear friend of mine worked at Sparrows Point for over 50 yrs. Unfortunately, he is no longer with us, but if he was, the devastation for him would be immeasurable. Your presentation and description of things is very clear and precise, you are a very good speaker. I'm not an engineer by any means but am always intrigued on how things work and the thought process that goes behind their creation. I watched your video on Every Kind of Bridge Explained......and had no idea there were so many bridges just in the US, not to mention other countries. I'm sure there are plenty more you didn't mention as well. Thanks again for a very informative video. Even when Baltimore rebuilds a new bridge, 695 in this location will never be the same. ❤
as soon as the bridge collapse I was immediately looking forward to see how you and road guy rob would cover the event, mind was blown when you collaborated on this video, hope you do more in the future!
I could listen to Rob explain things for hours
Loved seeing Road Guy Rob here!
23:45 I DO ENJOY IT!!! And now the both of you together!!! This was an amazing video!!! Well done and thank you!!! 💚🤙
Omg!!!! Amazing video AND collab!!! 🙏👏
Retired maritime engineer here, excellent content. Thank you.
I'm a bridge engineer who works for a firm in Baltimore. This video was a good explanation of the history and methodology of bridge design without getting too much into the fine detail. The general public really lacks a true understanding of the necessity for probability and statistics in bridge design. They cannot comprehend the magnitude of funding required to "design a bridge for the apocalypse". It's not a few grand more. It's not double the price. It's tens to hundreds of times the price of what we currently design. And with signature bridges like these in the video easily exceeding $1B to construct, it's easy to see how unaffordable apocalypse design really is. We don't have the money to spend $100B on every one of these bridges. No amount of money in the world could pay for that level of design.
There are over 560k bridges in the United States, and 60% of them are over water. Many of the 560k bridges are in need of major repair or replacement. Although the vast majority of that 560k are much smaller and simpler bridges, it's still too costly to spare no expense in design. You always must design with a balance of risk and safety.
I also just wanted to clarify robs discussion about load ratings of bridges. First, load rating a bridge is a routine procedure. It's done every time a new bridge is built as well as periodically throughout the bridges life, especially if the bridge is deteriorating or doesn't meet current code. As to meeting code, Rob noted that the bridge didn't rate for any design trucks, but he really should have clarified this statement. A "design truck" in bridge engineering terminology is a theoretical load. Current AASHTO LRFD bridge design code specifies HL-93 design loading, which is a combination of a theoretical fully loaded truck (HS-20 truck) AND a fully loaded lane of other vehicles acting simultaneously. Back when that old bridge was built, LRFD code didn't exist. The older code, called AASHTO standard specifications, called for a theoretical truck OR fully loaded lane. Furthermore, the weight of the theoretical truck has increased over time, so it may have been less than the current HS-20 truck back when that bridge was originally designed. My point to all this is to say that a bridge failing a load rating analysis says nothing about the condition of the bridge. Bridges fail load ratings all the time due to being older bridges that were designed to the older code. And a bridge failing to rate also doesn't make it unsafe. It just means that it may need to have a weight restriction and/or lane restriction for trucks. Any unusually heavy trucks will require a permit to cross the bridge anyway, and it is determined well in advance if those permit trucks are allowed over the bridge or if they need a detour. The driver will know this before he even leaves site with his load.
just to respond to your first paragraph about how expensive it would be to build stronger bridges and protections; A simple solution is 4 parts (1) the costs to reinforce the bridge dolphins or whatevers, should be paid by the people involved in building these monster-sized ships. (from the designers, engineers and owners ). (2) All ships this big and operated in "tight spaces" (subjective) should be aided by tugs as insurance - again paid by the responsible parties mentioned above (deo). (3) the entire crew of these ships should be certified and tested periodically. (4) the ship's power trains and generators and backups should be inspected prior to every time traveled to "tight spaces". All of these costs should come from the $billions profits directly and indirectly to the "owners". NOT CONSUMERS!
Again, your comments here show the lack of understanding by the general public. There is no justification for an international shipping company to fund transportation infrastructure in the US. It's not their bridge. It's not their land or waters. It's not their jurisdiction. Even if we attempted to force them to pay, whatever law we create would be unenforceable internationally. The best we could hope for is coordination of safety standards with the origin country. We only have the power to control how these ships navigate our waterways, and we already do this by mandating the use of tugboat or by requiring a US captain navigate the ship through the channel. The latter is what is done in the Baltimore port.
As for practical solutions to avoid a disaster like this, we already have them well established. My original comment was only to rebuff the idea of 'designing for an apocalypse'. I did not get into standard design practices used today, which include the use of dolphins and fenders. Those channel devices are routinely used in new bridges over navigation channels, and they will most certainly be employed in the replacement of the Key bridge. Several other bridges in Baltimore already have these devices in place. I've inspected several of them.
I would bet money that MdTA (the agency that owns the Key bridge) will be looking to outfit the remainder of their bridges with these devices to avoid another disaster. The Bay Bridge is likely their highest priority. Fortunately MdTA is fairly proactive, so I don't doubt they will do something.
@@rfehr613i think the general public usually assumes the engineers know what they’re doing and therefore should not have to be familiar with bridge design principles, unless they themselves are engineers. Seems fairly reasonable to me
@@russellg1473 you must be new to the internet ha ha. Everyone thinks they're an expert nowadays. I think that's how conspiracy theories are born 😆
There's a price on your head. About $10M to be specific. I think that's the value the federal government uses for the value of a human life when designing regulations and making recommendations like the NTSB does to the FAA. If the NTSB had their way, everything would be built for Armageddon because they don't have to pay for it.
7:00 - Even if you DO get an engineer to explain why a massive ship slamming into a bridge pier can cause the bridge to collapse, you still get insane conspiracy theorists arguing that there's no way it could happen. Social media was filled with them right afterwards.
there was no ship, the bridge just did that /s
@@kaiserruhsam More along the lines of "there's no way that a ship can cause a bridge collapse. Bridges are massive! This was clearly a deep state plan! That's why there were construction workers on the bridge - they were there to help bring it down!"
We didn't even need social media to spin conspiracy theories. Fox was on it right off, hyping for views by acting like ghost chasers "could it be this wild scenario? you decide" smh
This is one of the best documentary programs I watched on any platform. Thank you both!
My two favorite creators collab on a video???? We truly don’t deserve such good content ❤️
Grady, your practical thoughts at the end of the video are very insightful, kind and truthful about humans and how to look at probabilities. Very wise. Thx.
This is among my favorite videos you've ever produced and the two person perspective here really did a great job of creating speculative content that was still grounded and not reaching. I really appreciate the content the quality of this video thanks to both of you
As a seafarer myself and in Engineering Department of the ship, there are tons of backup machinery in case something fails. I'm talking about 2 pumps each for Lubrication, Fuel, Hydraulics, Air system and Cooling Water (Fresh water and Sea water), and each machinery has 2, meaning Generators and Main Propulsion have their own set of 2. Also all of those machinery have corresponding backup (Auxiliary) pumps which means even if 2 pumps fails (or the power fails) there's still smaller pumps capable of running the ship. There's also an Emergency Generator beside 3 Main Generators (really big ones) so an engine failure on 3 will still able to run the ship as all non-essential machineries like AC and normal lights are off to lower the load. Basically a ship is capable of sailing on Emergency Generator alone if worst comes to worst, theoretically.
Now onto inspections, there are 3 port authorities that are somewhat infamous for how strict they are in the world, US Port Authority, Australia's AMSA, and Chinese Port authorities (they're getting stricter every year) not to mention EU countires and Port Authorities. To prepare for going to Port in US alone will cost the ship tons of drills, testing of machineries and cleaning. I'm talking about a month of preparation with minimum of 2 weeks, basically lot of overtime for all crew to test and drill for emergency (these authorities are no joke for us!) as failing for inspection means lots of trouble and more overtime for us to rectify said troubles.
Overall my point is, it takes a lot, I mean a lot to cripple a ship. You need to be a bad Engineer to disregard all maintenance operation and it will still take months prior to this incident to f up the ship. I know nobody is perfect and those shipping companies that does wihtheld supplies for ship maintenance and crew living ain't gonna go to these 3 countries (US, Australia and China) and EU in the first place since it will cost them tons with their little budget and low profit and one peep of a seafarer about their living condition and these companies are now under special spotlight every time. They'll be going to more convenient deals that will not give them much trouble with convenient countries, and even then a skeleton ship is still susceptible to ITF (International Transport Workers' Federation) raid and charges, basically a seafarer police that will force companies to treat us better as well as making the ship more safer.
TL;DR - It takes a lot to cripple a ship with bad machineries and poor company policies, my conclusion is, a cyber attack is easier way to cripple a perfectly good ship undergoing regular inspection of US Port Authorities and maybe other good Port Authorities. Also I heard Synergy is a somewhat good company.
The "no tug" requirement is a competitive one - if a port requires tugs, the ship captain or operator will go to a port that does not require tugs. So ports do not require tugs to maintain their competitiveness.
Here in Hampton Roads Virginia (Norfolk), we have tunnels and the Navy made it clear that there would be no more bridges leading to the base and shipyards, but Grady is right, consider the cost of tunnels versus bridges and the politicians will always say they need money for other things. It's a tough trade off. Thanks for another great video that even an old pharmacist can understand!
7:20 technically a bridge is moving, you just have to push hard enough
i love this collab going on here, perfect execution and i couldnt have imagined a better youtube to be chosen for this topic.
15:24 the power lines had more protection than the bridge lol
At the risk of replying to a joke... the utility poles are nigh invisible in the dark, while the bridge is coated in street lights. I'd wager they're much more likely to get bumped into.
those power lines are new. only installed in the past couple years, so they may have had higher standards about collisions/protection. previously there were power lines under the water in that area. police even stopped traffic at times during installation as to not have distracted drivers on the bridge while helicopters ran the power lines.
two of my favourite RUclips content creators in the same video. loved it.
I didn't know Bill Burr was that interested in Civil Engineering.
it is such a delight seeing road guy rob here! his videos are some of the best on education youtube in my opinion
22:40 I'm "happy" to see that it's not just Italy that builds bike lanes that go nowhere
Dude you so dang Correct i am laughing my fanny off on what you said amd 100% true
At least yall got bike lanes
You’re going to be surprised of how many 20 meter bike lanes that start from nowhere and end up nowhere too are in Kyiv. The Mayor of this city (vitaliy klichko) is just a crazy gangster doing nothing practical, but everything for money laundering and corruption.
Love seeing a Road Guy Rob cameo. As others have said, his channel is super underrated and worth checking out!
the power lines near the bridge have fenders to protect against collisions but not the bridge itself
23:08 I like the extra attention for the bike section! I absolutely support the US working on its bike infrastructure.
"Anyone can design a bridge that will stand for 100 years. It takes an engineer to design a bridge that will barely stand for that time."
This is a misconception. The Engineer's goal is not to reduce redundancy it is to meet a list of goals including a budget and timeline.
@@appa609 That's what the quote means. Anyone can break the bank to construct a bridge that will last. IT takes an engineer how to safely cut costs so that the bridge is in a constant state of barely standing.
@@dhawthorne1634 A well engineered bridge is not generally "barely standing" it fulfills all project requirements including regulations on structural FOS. A typical road bridge might be capable of holding 3x the maximum design load.
Thank you for all of your explanations. There were excellent. I now fully understand the great complexities of designing a Bridge
Long Beach resident here. Another important fact about our bridges is the support pylons are on land so it's much less likely to suffer a collision.
Yes, that’s why Rob discussed that in the video…….
don't tell the ships about this... or it won't be long before one of em goes CHALLENGE ACCEPTED
Excellent job as usual explaining a complex subject so that us non engineers can understand it. I like the twofer part of including Road Guy Rob with his perspective too.
I love how they designed a pedestrian/bike path over the bridge that goes nowhere...
California moment
It'll go somewhere someday...
nice to see 2 you tubers working together for a good vid
I've driven on this bridge many times which makes it sad to see it go
Rob is phenomenal.
Great as always, Grady. Thanks for looping Rob in.
Something I just thought about, maybe an idea for a future episode ...
What are the relative advantages for cable-stayed over suspension or truss bridges? I can think of several, but I'm not a CE, so there are probably more issues (cost, span, height, etc.) that play into that decision.
Structural engineer here. At a high level, cable-stayed bridges are generally more economical than truss and suspension bridges for medium-length spans, which is why it seems like every new large bridge being built is cable-stayed.
One of the reasons for this is that cable-stayed bridges are "balanced" on the piers, so you can construct them by building the piers first and then extending the bridge deck out from the piers in both directions.
However, cable-stayed bridges are not a good design for short spans and long spans. Some eyeball math says the main span of the Gerald Desmond bridge in this video is on the shorter end of what's economical with a cable-stayed design.
@@louisvaught2495 Thanks!!
Also, they look cooler.
I think in this case the advantage of a cable-stay bridge is the combination of span and boot-strap ability. I.e. the cable-stay bridge design makes it easy for the bridge to be used to build the bridge. So there would be minimum disruption to the shipping channel.
I like this "reporter in the field" addition. Thank you for collaboration between the channels!
LOVE a good Road Guy Rob collab!
Road guy Rob was an amazing addition to this video, so well done
very cool to see a road guy bob feature
bridge guy bob
I had to skip through his segments.
Great collaboration between two of my favorite engineering channels!! Bravo!
Hi Grady!
Excellent video on the subject.
You're right that assist Tugs were not required in Baltimore for the ship transit under the bridge, but if they were, the ship would have needed to be moving at only 2-3 knots instead of 8 knots (like the Dali before it dropped its anchor)) for the tugs to have any hope of guiding such an enormous vessel in the event of a total power loss. As I'm sure you know, the mass of that beasty is astornomical, so each additional knot of speed greatly increases the inertia, and the tugs (even the big ones) only have just enough power to gently nudge such a large ship in any direction, so they would all need to be moving rather slowly for the limited power of the tugs to have enough time to actually have an effect on the ship, once it starts going awry. Incidentally, assist tugs cost $$$ and that increases shipping costs.
I'm sure you agree.
Just pointing this out for non-boat-nerds.
To be fair, it really is time, and the horizontal speed of the escorted vessel, that are more the important factors here from a mathematics perspective. Then possible lateral currents (or wind) acting on the vessel and when that might start acting on the vessel are also key. I can't speak to the maneuverability of the tugs with the 5-knot forward speed though.
I think this program is informative no fingerpointig and made easy to understand the engineering terms
This accident was so avoidable, it makes it an even bigger tragedy :(
He has an on site reporter now, this is getting out of Hand ! :) (Great cooperation!)
A few years ago a truck driver (40 tonnes 70 mph) near Pariis hit the pillar of a freeway bidge. It was the first time that a vehicule had brought down a bridge, closing both directions. The driver is no more. A 100,000 ton ship hitting a bridge is the same. No mystery.
Years ago a Porsche hit the side of a bridge near my old house at 120+ mph... It left a burnt stain on the bridge.
@@volvo09 And the driver? It's a funny old game innit!?
@@paulstewart6293 yeah, he wasn't as lucky as the bridge...
you have the right chemistry for this work and I glad for it. thank you.
15:40 - Brady talks about "Back of the envelope math", but proceeds to do all his math on the front of the envelope. 🤣
Last I heard, thanks to Sal Mercogliano's excellent "What's Going On With Shipping?" channel, is they're expecting the main channel in Baltimore to be reopened by the end of May. A portion of the main channel has already been reopened, with a 5-knot speed limit, wind-speed restrictions...and tugs must be attached to ships fore and aft while transiting the channel (not just escorting them).
The salvage and recovery operation is truly enormous. Lots of practical engineering going on there!
Layman's Terms: Bridges are designed to resist vertical pressures, not horizontal pressures. That is why earthquakes take down bridges... because of the lateral movement.
chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/www.fhwa.dot.gov/bridge/seismic/nhi130093.pdf