Back in the mid-70's when the bridge was new, my friends and I were in high school and we'd drive up to that bridge, drinking or drunk, climb the fence then walk out on the bridge structure (under the roadway). We'd crawl inside the large square or rectangular hollow beams and poke our heads out the bottom holes and look down hundreds of feet to the rocky ground and river below. Sometimes we'd drop rocks but carrying a good size rock was a lot of work. None of us ever fell, I don't know how. In fact, I don't know how I survived my teen years.
From one engineer (electrical) to another, it’s both interesting and refreshing to listen to another engineer’s discipline. Keep up the excellent work.
There were 4 engineers riding in a car across the desert, an electrical engineer, a mechanical engineer, a chemical engineer and a software engineer. The car suddenly died and they drifted to the side of the road. The electrical engineer said, "we must have lost spark". The mechanical engineer said, "we must have thrown a rod". The chemical engineer said, "we must have bad gas". Then after a moment of silence the three looked at the software engineer who said, "maybe if we all get out of the car and get back in again it will start".
as a former shipfitter, I can tell you that you cannot weld hardened steel without gradual preheating, and then gradually cooling. The weld will crack and break if you don't do this. Those cracks in your T-1 steel happened because the proper weld procedure was ignored. So you have lots of hidden issues.
Amazing how the old wooden railroad bridges and trusses are still intact today.. back in the day, the railroad would take taker trains full of creosote and soak the tracks and bridges to control weeds and rot of the ties and bridges… what is worse??? The creosote or a bridge falling with millions of tons of very hazardous materials?
@@artmosley3337 yep, more of the same. Prioritizing some form of idealism, now so often some type of wokeness, over what makes perfect sense. Creosot works great...
@@gereshare6659 btw.. ya know that 55k acres that just burned up yesterday.. and is still burning.. I bet you a dollar a few of those trees would have worked better… and maybe the selected harvest of trees (people think they live forever.. 50-75 years and most start to rot.. NYC Central Park has a huge amount of trees that are hollow.. one fell on a woman.. huge lawsuit… but the trees that were used as timbers in the construction of Venice are 700+ years old… because they are totally submerged in water… the biggest environmental disaster ever was allowing Environmental Scientists to make decisions or recommendations.. replanting trees is the best solution to everything.. id start with the west coast and replant Red Woods and replace San Francisco
As a welder/fabricator I used to repair earth moving equipment, that used T-1 steel, or wear plate similar to it, as it's structure. It surprises me as others have stated, that it was used for bridges. It is great for it's wear resistance and has a very high tensile strength. Preheat and post heating of the welding process are very important. Another factor to keep in mind as I was told where I worked was the huge differential between the tensile strength of the plate versus the strength of the weld rods I used. If I remember correctly, the highest strength rods I used were called 9596 which had a tensile strength of 86 000 versus the 110 000-130 000 of T-1 type steel. This causes the welds to bear more stress because the welds will yield earlier under load versus the plate itself. This rod I used was supposed to be more ductile, than 7018 to help with that, but I just used to try to keep in mind the difference, and tried to account for it by making my welds larger to help compensate.
@@ssaraccoii Structural bolts have advanced further than Grade 5 and Grade 8 bolts. The current A325 bolts have a lowerish tensile strength, but are much more ductile (stretchable) than Grade 5, and particularly Grade 8 which are pretty brittle.
I also used T1 as a wear surface on front end loaders operating on a paved surface. I was instructed to use "low hydrogen" rod. Now I know why I was frequently welding up cracks...
In the early 70's when this steel came into use, the shop I was working in made sure anyone welding the higher strength steels was qualified and using the qualified procedures. That meant that we used a lot of gas to heat up the sections prior to welding and a lot of gas for a slow cool. We used 9018 electrodes and, later, 1118. Mostly ran 5/32 and 3/16 lo-hy kept in heated ovens. The containers we took to the weld itself were insulated and we were not allowed to use from a container that had cooled enough to to handle with the bare hand. Joints were cleaned to TIG ready and maintained that way. In later years I learned that a lot of shops didn't really maintain the lo-hy nature of the situation for electrodes or plates. So no surprise the cracking. I had the great fortune of working for some folks who knew the trade and had actually studied the metalurgy! I'm 76 now and I'm just ashamed of the practices used in the trade.... Keep up the good work!! We weren't building bridges but other stuff for equipment and buildings.
In the shipyard, it was HY80 steel used for high repeated stress areas like bows, rudders, etc. Submarines use HY80 too. Welding to a rudder post casting was a real nuisance. We used electric heating pads to heat the steel to 130 degrees. stick welded it, then gradually allowed it to cool over several days. Being a shipfitter, we had to slightly bend the over an inch thick already curved plate sections with hydraulic jacks to make them fit. And yes we broke lots of jacks :)> The shipyards have huge hydraulic hammers/ presses to bend steel to "about" the right curvature & etc. We had to force the steel the rest of the way until it actually "fit."
@@michaelcurtis-cdot8978 I hear you, but iron bridge was made when there weren’t iron bridges. Unless someone made a brass one there weren’t any metal bridges before that?
As a steel inspector early in my career, I witnessed column cracking at splice welds at the base of a high-rise in Boston. I asked the "experts" why they didn't maintain Interpass temps during the welding. That was the problem. Don't trust experts, do your homework. If working on a bridge, ensure the welding procedures matches the materials being used and check the operator's quals are AWS D1.1.5.
My dad used to laugh every time he heard the term “expert” used to describe person’s experience. His definition of “expert “ was a former drip under pressure. I laugh when I hear the description of a “blue Ribbon Panel” did the panel participants all get 4H Blue Ribbons.
@@jimpawa5793 It's popular these days to claim that there are no experts and one opinion is as good as any other, but that's not even close to true. There are people who have spent the years of study and years of experience it takes to be an expert. Sometimes experts make mistakes, but it's always better than guessing. Uninformed people sometimes make the correct decisions, but their reasoning will always be wrong.
@@jeffrey1312Experts are truly the only experts that qualified experts… according to the experts. Also… The same experts claim Men can get pregnant and give birth. 🤣
In my early years in construction I spent a few years on a rock crushing operation. We used a lot of T-1 steel plate to line chutes that washed gravel or crushed rock would pass through. T-1 plate was known as an “abrasion resistant” material far outlasting regular mild steel material. At the time we never really had to consider its brittleness. I’m really surprised to learn it was used in structural applications on major bridges…..
Very interesting, thank you! I am starting to research all of the other applications for this steel. I understand it was also used in building construction.
As a state and city licensed welder In NYC for 45 years I can tell you many welders do not adhere to proper welding techniques due to time constraints given to them. Many steel erectors would not allow the time spent as it is time-consuming and costly. You have to keep the welding rods in a heated oven. You have to clean the steel before welding. Most important with large welds preheat and post-heat are very important. The winter is extremely important when post-heating a weld and bringing the temp down to natural environment temp. slowly. Sometimes people. are to impatient and do not fully understand welding. It is about how many tons of Iron per day or floors can be erected. T1 steel from my memory you could use a 7018 up to 3/4" best to use an 8018 or 9018 as it has a higher structural component. Heat the rods is key. Love your channel very interesting information.
11018 is even better...and the rods are only allowed to be left out of the 250 degree f oven for 30 minutes for code work, then they get rebaked at 750 degrees for 30 minutes and can be used again.....they are allowed two rebakes....
@@thelaxman59 I still wonder when the requirement for keeping the welding rods in an oven started. 45 year ago is surprisingly after the discovery of hydrogen embrittlement, which happened in the 1970s.
@@johnhaller5851 I went through welding school with my Union Ironworkers Local 40 NYC structural union. I know in 1980 I had heaters for rods back then. I also took a welding test for the Indian Point Nuclear Power Plant. That test was much harder than the state and city tests.I know on most all the jobs we had rod heaters some small and portable some large stay in place. We would go to the large one and take out enough to fill the small box to take it to our welding points. The heating of the rods and large weld points was drilled into us. An apprentice would help with post-heating and temp control if you don't you would have cracked welds.I got away from welding at a young age as I finished school to get my riggers license and it helped me become a super. I would put up and take down many rigs in NYC. You had to have someone with a rigger's license on site. I love it and miss it every day. Great men and great job.
I've driven across that bridge when I was working in Sacramento in the early 2000s. It's a beautiful bridge. It goes over the North Folk American River
As a teenager, my friends and I used to climb over onto the catwalk and go out to the west side colum. Go down the ladder and sit on the colum and drink. Got a lot of memories of this bridge. Still go there from time to time. Unfortunately, alot of people have taken thier life at this bridge. There are inspirational signs, notes all along the bridge to try to help those who might go there to end their life. It a major landmark for the area. Hopefully any repairs will be minor.
@@TeddyRumble I don't see it this way. The bridge is now there and has been there for decades. Just leave it alone. Whether or not the Auburn Dam is built. Dismantling it would be a backward move.
Casey Jones- Thank you for your efforts to bring clarity to the often obscure questions regarding the details of engineering. CALTRANS has been aware of Fracture Critical bridges for quite a while. But the issues of T-1 steel have only recently been addressed by NDT and special inspection teams. Avoiding catastrophic failure in these aging bridges requires focusing on the most critical aspects of the structure. The information in your videos really helps everyone understand the true nature of the problem. This cannot be done by the general media to any degree required.
Thank you. That was one of the reasons why I started this channel as I found general media sources to be really lacking when covering things of a technical nature.
Our careers have traveled different paths for sure, but the goals we have appear to be quite similar. Flood Control, Transportation and Infrastructure Development can be accomplished with great success and also experience unforeseen and costly failures. Your efforts to bring greater clarity to both sides of this story with the thought of avoiding the avoidable is greatly appreciated. It’s important that the engineering community understand the value of this type of review. Learning from the experience of others is the easiest way to learn for most engineers, not from just your own mistakes.
Video of the 1994 Northridge Earthquake in the Los Angeles area and the many steel moment-resisting frame structures that experienced unexpected brittle damage to their beam-to-column connections might be interesting.
I live in the area and it's interesting to see that no mention of hydrogen embrittlement is the issue they're looking for when inspecting the Foresthill Bridge. They also don't mention the type of steel and it's ability to fracture at the welds if not welded properly. All we're seeing in the news is "they're inspecting the bridge".
Hydrogen embrittlement is an issue for all high strength steels. I have a welding textbook that notes under-bead cracking being an issue for naval gun mounts in WWII, but it's likely been an issue for as long as arc welding has existed. The biggest cause is the presence of moisture during welding, even just absorbed into the flux from the humidity in the air. There are ways around it, but you have to do stuff like keep electrodes in an oven to keep them dry enough.
Thanks for the useful information. I'm just an amateur at welding and have realized that there's a lot of experience involved making a good weld, but I stick to welding simple unimportant things where the quality of the weld isn't critical. I have also discovered that stick welding aluminum isn't an easy thing to do even under ideal conditions.
Ah, interesting! I was wondering where the heck the hydrogen came from, I’ve typically only heard about in the context of hydrogen pressure-containment vessels. Thanks for the info!
I took an introductory course on material science in about 1980. The book for the course was written in 1970 (the process for introducing new material into engineering curriculums is very slow). There was no mention of hydrogen embrittlement, only that welding could cause thermal damage such as overaging, over tempering, or annealing. One wonders when they discovered the actual cause of the under-bead cracking. The class might have mentioned hydrogen embrittlement, but I don't remember the lectures. Welding was covered in one paragraph of a 545 page book. When was that welding textbook originally written, and the latest revision made, just curious? I'm guessing electron microscopes needed to be sufficiently developed to understand the how, even if experimentation could have developed methods to avoid hydrogen embrittlement earlier than the understanding.
I dont know what the US is like but over here the problem is bridges built 50-60 years ago were designed to last 30-40 years and so have been replaced 20 years ago...but obviously they were never replaced. This is not just a bridge problem, lots of buildings and roads were also built on the cheap because they were supposed to only last 30 years and then replaced, yet somehow people "forgot" about the replacing part.
That is a far too common issue. And instead of replacing the worn out, poorly maintained bridges many DOTs are spending inordinate sums of money try to rehabilitate these old bridges instead of replacing them.
@@CaseyJones-Engineeryeah, just how politics goes, I guess. Meanwhile we have Victorian rail bridges built of thick slabs of mild steel riveted together and they are still going with just routine maintenance because they're so over-engineered. Unfortunately if a cheap, temporary option is available, that's what the people in charge will go with. I honestly don't know what the solution is, it's human nature but it is very frustrating.
@@PartanBreeThe railroad bridges were over-engineered partly because steam locomotives are so much heavier than any cargo. This allows a certain amount of deterioration to be left unfixed. Some of the railroad bridges leading into the CNW terminal (now Ogilvie Station) in Chicago have suffered a lot. The station opened in 1911, so I'm guessing that's when the bridges were originally built.
California has 10 more bridges constructed with T-1 Steel and are not giving up much information regarding the presence of these bridges and actions to replace or strengthen them. There will be another catastrophic bridge failure and then we will be hearing the politicians here sending their "thoughts and prayers" in response. It is a pathetic mess.
@@CaseyJones-Engineer Thanks Casey. My attempt ended up in a maze of bureaucracy. I have no knowledge about where to take my search. I think it is important we get this information to TV news outlets that perform local investigations and reports about these public safety issues. Inspections and Reports: If no one is pushing them and educating/alerting the public, then the State gets to set their own timeline.
We cross the East Liverpool bridge fairly frequently, and had to use the long detour when it was shut down. 1.5 miles west of this bridge is a fairly light 1905 built suspension bridge, still in use. It was built for lighter loads, so has a 10 ton limit. Street view is from 2019, and shows a crew inspecting the suspension cables.
I remember when Foresthill Bridge was built, we used to go watch in awe. I remember the day the news told us that 3 guys fell into a net and died anyway because the net tore.... I was about 10 and lived in Auburn, CA back in 1972 & 1973 etc.
I remember back in 1963 my welding class professor claiming that T-1 was a danger and that the preheat requirement was a crutch for postheating the weld. I never worked as a welding engineer, but still remember his comments.
Yes true .... welding with out preheating and post welding changes the Structure of the Steel Crystals ... There is so so much that goes into the design and actual frabrication of Welded joints ... Ref: AME Welding Manual ... The old Hot Riveting System is one that spreads loading around joints and are still in structures standing today where Modern welded ones have long Failed 😮😮😮😮😮
@@henrynelson9285 This appears to confirm that my hypothesis that hydrogen embrittlement wasn't really a thing in the 1960s. That's not to say that proper heat treatment wasn't an issue, but it wasn't the only one.
@@johnhaller5851 Hydrogen embrittlement is always a problem. It's just worse in high strength steels. USS pedaled T-1 as a weldable 100k steel as compared to A36 at 35k yield. It' wasn't appreciated that it took a lot more care to weld.
I was a little kid growing up in Telluride, CO, when the bridges over US 50 were built. We would look up as we were traveling on the road below. Once opened and before there was any water below we were in awe of how high up we were. Later we would go fishing there. Things sure change.
The alternate route down hwy 49, through the confluence and up the other side is amazing! If you have all day and love extremely twisty mountain roads 🤣🤣
Thanks for the straight up and indepth review of these projects. We have many problems throughout our infastructure due to age, environmental, or incompetence and no one wants to talk about them until they have to. Then is cover butts mode and no real information comes out.
I remember a Sacramento Bee article about this bridge back when it was being constructed that claimed the reinforced concrete support pillars were designed so that the waters of the reservoir would help support the weight. I have never heard anything about that since.
I lived in Auburn & a couple years in Foresthill. Thankfully in this case, there is a road from one side of the canyon to the other, (much slower of course than a nice straight bridge) , but better than being cut off!
For the curious, 13 million in 1973 for the Foresthill Bridge is 65 million in 2011, so, pretty much the same cost to retrofit the bridge as it cost to build it in the first place, since its construction started in 1971. And 13 million in 1973 is 92 million today, but I bet it would cost many times that amount to build that bridge today.
Thank you. I agree, this could be a $1 billion replacement project, although they could save a lot of money if they were able to reuse the foundations.
@@TeddyRumble If the Demmunists stay in power, you're right. They'll see to it that the Auburn (or any other dam) never sees reality. But then, neither Deukmeijian, Pete Wilson nor Schwarzenegger ever did anything to my knowledge to ensure the Dam's construction either.
My dad was an Engineering Tech for Omaha District starting in 1958, spending his entire career at Oahe. You are correct, they spent half the time riffing and the other half shipping talent out to other districts. Dad was routinely sent to places like Estes Park when their dams gave out, or were about to.
I used to inspect Oahe Dam in the late 80's. I heard a story that the old timers would take bowling balls and roll them down the long concrete spillway. Apparently they would bounce so high that they would shatter before reaching the end of the spillway!
@@CaseyJones-Engineer I learned to ride a bicycle on the generator floor. In the 1970s the kids of the Corps personnel pretty much had a free run of the powerhouse. Most of us lived in the same neighborhood in town that had been built for government personnel housing in the early 1950s. I was somewhat special, as Dad had an office in both the powerhouse and the outlet works. I knew all the old techs and maintenance staff, plus the operators and administrators. As late as the mid-1980s my non-Corps friends and I would ride or bike out to Oahe and give tours of all the places they couldn't go on the official tours. Dad was an interim project manager at Oahe for about a year and a half. He would have liked to run it permanently until retirement, but they wouldn't boost his GS level because he was still six credit hours short of his degree at Purdue from 30 years before. He has been gone for 13 years now, but Mom is still living and the last of the Federal personnel still residing in the housing project (even alive for that matter). I think she's also the only remaining resident of those who bought their home at the GSA sale in 1967. After 9/11 they moved all the admin at Oahe to a separate building and caged up the powerhouse. I can't get within a city block of it now unless I register for a tour at the visitor center on the hill. Sad.
I used to live in Placer county. Until now, the biggest issue with the bridge was jumpers. Sacramento has flooded many, many times. The levees give way or are over topped each time.
Hi I love your videos and I would like to request that you do a video on highway 20 east of Nevada City. They ‘straightened ‘ some sections and where they did some of their cuts, not properly shored up and washouts started
A recent fan of your videos as I had been researching the ranchos palos verdes landslide in LA, you make very informative content and I hope you continue to do so. As an engineer, your opinions and ability to communicate the information is both valuable and, as you had mentioned, not something you get from more typical commercial media outlets. TH-cam is an amazing thing! I'd recommend throwing any drone footage you might purchase up on stock video sites if allowed by your agreement with the videographer, as it may allow some additional income so you can make more. You never know when that footage might come in handy for someone else. I think your last video the drone pilot you hired delivered the footage in LOG, which is common within the media industry so that you have more control of the color and visual look of the final video by retaining data in the highlights and shadows of the footage. If you ask them they might be able to deliver a rec.709 LUT for you to apply to the footage for a more saturated and visually appealing color grade by default, or you don't know how to do that you can ask them to deliver in non-log color by default. Cheers!
Thank you so much! I am a newbie when it comes to the drone footage so I really appreciate your comments. I also like the idea of offering up the footage on stock sites. Great suggestions!!
Thanks, Casey. Very good presentation and I certainly remember that stunt when the Corvette went off that bridge! I wonder if anyone told the producers about the issues with the steel…. Hopefully the inspections and remediation plans will be ahead of any problems. Keep up hype good work and let us know. 👏👍🏻
Thanks very much. I will be interested to see if this inspection results in the discovery of any cracks in the steel? I will stay with this story and do future updates.
When you showed the image of the repair steel plates for the Colorado bridge, it made me wonder about the weight of those. I know that a lot of safety factors go into the design of bridges, but do you think that the additional weight will be an issue for the foundations?
And have you considered an investigation of the new - cable stayed - San Francisco/Oakland Bay Bridge? It was designed to be un-repairable, and CalTrans specified bolts that its own design standards prohibit for use in a marine environment. These bolts began fracturing and cannot be replaced due to the bridge design. They were also used, at the bottom of the Bay, to anchor the tower to its foundation. There are many articles in the San Francisco Chronicle.
I vaguely recall the threaded rods to anchor the structure were cast in concrete, and were susceptible to hydrogen embrittlement because of the way they were hot dipped galvanized. I don’t recall if any had HE cracks. I also recall a fastener company Dyson being involved, and they’re a big name in industrial fasteners. 10 years ago, this was big news. I would be interested to see a follow up on this.
If i understand correctly, the reason why the auburn dam was cancelled was because far more landslides than expected occurred behind boulder/hoover dam as it filled, leading to substantial concerns about how stable the land under the cities of auburn and foresthill might be as the reservoir filled. Also, if foresthill bridge is condemned, I doubt it would be replaced since it would be much cheaper to improve the road that runs through auburn SRA. The bridge was only needed because the alternate road would have been submerged
Much appreciated. I grew up in the counties of Placer and Sacramento and remember well he influx of hopeful construction workers coming to build the ill-fated Auburn Dam. I used to climb the hill from the fork of the American River below up to the undergirding of the bridge with my son and watch hang gliders take off from it. I still cross it occasionally to visit friends in Foresthill and my current employer, Wellspace Health, staffs the suicide prevention operators who answer the phones placed along both sides of the bridge (as of February, 2024, there have been 102 suicides from the bridge).
I'm not an engineer, nor do I play one on TV. But I have built a lot of stuff out there in our big wide world, so I've seen a thing or two. One thing I have discovered, is that paper doesn't care! Paper will just lay there and let any idiot make marks on it, and they usually do. One of the biggest problems I find on nearly every project, is the design engineers failure to adequately address Point Load Transfer. When I look at those extremely heavy duty repair plates- I see an incoming pile of problems likely in some combination or other to cause failure. 1st, how about all those holes that need to be drilled through the existing steel. Turning those webbed members into Swiss cheese isn't going to help -> 2nd, All that additional weight! You will sequentially potentially overload each point load to the next point load and so on down line. Those connections are already designed to supposedly adequate minimums taking into account, weight, moment, and shear, to name a few. I suspect it's theoretically possible to add enough weight to reverse the Tension/Compression role of a given member. Trusses work because every member has a role with every other member. Fail any member (or it's connection point) and the whole thing fails. Thanks Casey for bringing these issues to light. I recently got a camper, so I think I will avoid this bridge, just to be on the safe side.
I don't think swiss cheese is the problem. With the correct clamping force, the new plates will pick up the load. My concern is the transitions. If the stiffness of a structure doesn't transition gradually, that's another mechanism for developing cracks. Those plates look to end somewhat abruptly. One way to transition better is to taper the height of the plate towards the ends. Another way to transition better is to use a stack of several plates with each new plate added being shorter than the one underneath.
@@CaseyJones-Engineer Do you think it's a short term solution? Quoting Red Green, "This is only temporary, unless it works." Do you think they're going to find the money for a new bridge if the patch works?
@@major__kongA great point! And in fact, some of the plates I have seen are actually stacked just like you mentioned. I too have concerns about drilling all these holes in the web of the existing girders. If this T-1 steel is already prone to cracking, couldn’t drilling cause more micro cracks? The other concern is creating areas for the environment to attack the integrity of the structure. Looking at the history of steel bridge failures, joints between gussets, hangars and plates secured by bolts are one of the leading causes and why inspections focus so heavily on them. I, too, think replacement would be better than retrofit, however I am not a fan of of this national campaign to replace everything with bulky concrete monoliths. We are underestimating steel and overestimating concrete in my estimation. 😉
I'm no engineer, but it sounds like every single welded joint will need to be reinforced, whether or not it shows any signs of cracking. And if this T1 steel has any tendency to crack at places other than at welds, patching an unstable structure would be wasted money. Davidmiller6010 makes other good points about drill holes weakening the girders, and that the added weight could exceed the bridge's designed capacity.
My daughter and I lived in Foresthill for several years and I thought often about the consequences of flying off the bridge on virtually every trip to my business in Sacramento (daily). Although I was a private pilot and owned my airplane, I would have occasional bouts of acrophobia while flying. The flap over the building of Auburn dam was really intense. The need for additional flood protection plus the need for increased water storage were strong arguments for it's construction but this was in the heyday of the environmental movements. Even though an alternative plan made a lot of sense, a flood control dam ( a dam that had a big hole in it to limit the flow of water to 100,000 CFS) to match what the downstream water system could manage. Also, this was the era when we learned what El Nino was, very heavy rainfall and those levees were really stressed to the limit. My office was within walking distance of one, it felt very jelly like to stand on it!
@@desertdenizen6428 Thank you. I understand that they're going to raise Folsom dam 3.5 feet to provide extra flood protection. I'll look more into that story.
They knew about this potential problem as soon as that bridge in Minneapolis fell, because the Foresthill Bridge has a similar design. Caltrans is currently doing a major inspection using the latest tools and may do repairs as needed. But unlike the bridge in Minneapolis, they haven't made changes to increase the load on the bridge, so I don't expect much in the way of serious structural wear.
When the cover plates are bolted into place, doesn't that move the stress load to the points just past the band-aid plate? Thus creating a new weak spot that will need to be ultrasonically inspected in a few years.
Our local bridge on the interstate is almost 110 years old. None of that fancy-pants high strength steel to worry about here! It is going to collapse the old fashion way.
I was just thinking about the Jennings Randolph Bridge when you mentioned it. I can see that bridge from my house. Another incident was the I-79 bridge over the Ohio River at Coraopolis PA which developed a large crack in bitterly cold weather in 1979.
That failure did occur at a weld. But I don't think that it was a hydrogen enbridlement. At the time it was related to the type of weld that was used. (I think the process was primarily related to the type of shielding used during welding. The shielding is what makes me think that is was a different failure type.) I don't remember if they determine if the welding process was a bad process or if the process wasn't accurately followed. It would be interesting to see a comparison video of the I-79 failure and these recent failures since they are all related to weld failures.
@@erniecolussy1705 I remember watching a show on WQED about the area bridges that started with a story about the crack. They interviewed the towboat captain who spotted and reported the crack, preventing a collapse. The segment also included how that welding process was new at the time, but was eventually banned from bridge construction due to weakening the surrounding steel. The show also included an interview with the iron worker who was trapped on the old Brady Street bridge and how a surgeon had to be brought to the bridge to amputate his leg so they could get him down after the bridge, which was being weakened so they could implode it, settled and trapped him.
I have not used a lot of T-1 steel. All my welds were done using flux-cored wire. There have been no issues with cracking on 30-year-old weldments. It seems to me that the issue is not the steel. Rather it is the welding procedure. Perhaps you should do a video focusing on the currently recognized proper welding parameters and how the welding was done when the bridges were constructed. Maybe a welding engineer might do a collaboration with you. I'm going out on a limb here and guessing that Kawasaki might have used wire in prefabricating the Foresthill Bridge, which may be less prone to embrittlement.
Check out the Glade Creek Bridge (a.k.a Phill G McDonald Memorial Bridge) on I-64 near Beckley, WV. The highest bridge on the Interstate system, it is a near carbon copy of the Foresthill Bridge and was closed by WVDOT for over a month this summer due to cracks. It was built in 1988 so it’s not the same T-1 butt weld issue, but it’s an uncanny coincidence nonetheless.
Can you look into the multi million dollar bridge in Sacramento they just built, but was constructed so poorly that they are talking about tearing the entire bridge down, by the way great work on this auburn video as well, thanks for all the info.
The location of the Auburn dam was also a poor one. The western foothills of the Sierra include a couple of major faults that run parallel to the range's strike. The fault zones often are marked by roughly north-south oriented valleys. Empounding large amounts of water can inject fluid into the faults triggering earthquakes. But, politicians and bureaucrats looking at those valleys have frequently concluded they were ideal locations to impound water.
I was working as a driver and trapped for 6 hours in downtown Roseville during the flood of ‘86. Did the floods of 1996 help validate or show places where more work was needed?
Interesting you worked on levees in Sacramento. Enjoying your content and Palo Verdres land slide and explanation. I am down in Coronado, San Diego, and San Diego shares a sewage treatment plant with Mexico along the border along the Tijuana River. The sewage treatment plant requires a 1/2 billion in repair, deferred maintenance from US and Mexico. The beaches can not be used due to the contamination. I pass this along as similar to Palo Verdes, is the investment for the sewage treatment in the interest of the City as a whole? This may be a political discussion, however your coverage of Palo Verdes prompted a discussion in the back of my mind. Thank you for that. Historically, the sewer treatment plant has always been a problem. Another "infrastructure" failure. I am retired civil engineer and tell friends this is a matter of priorites, don't give up hope. My takeaway is, after 60 years, or two generations, the "infrastructure" is failing. We need to reset our priorities. Just a general thought prompted by your discussions.
Thank you. I am very concerned about the insufficient investments being made in infrastructure these days. Also there seems to be an incentive to negligent maintenance and repairs until a crisis is reached and the Feds are expected to pick uo the tab at that point.
Just for clarification, have other bridges experienced T-1 steel beam/girder fractures like the I-40 bridge? The other examples you mentioned seem to all be weld failures due to HE. My though here goes to the potential breadth of the problems; i.e. weld failures can be corrected and monitored forward, however if the base T-1 steel is the source of the failures then the problem is much broader with greater potential, perhaps probability, for catastrpoic failures. Thanks for sharing your expertise and valuable insights as an engineer.
All materials have problems with cracks, some more, some less; all materials contain cracks straight from the factory, that's why bridges are subject to inspection. The problem with welds is that they change the properties of the metal they're done on and their quality is highly dependent on the skill of the individual performing them. I don't think these problems, as far as they're related to the base steel, are really a defect of the material so much as these bridges are nearing end of life.
The crack shown at 2:40 is not 'at the weld' it is on the edge of the HAZ (heat affected zone). if the weld area had been pre-heated to around 200-220°C at the time of welding it would not have happened. It is there due to rapid conductive cooling around the weld inducing micro cracking that precipitate embrittlement much earlier than would be the case with correct management of welding procedures. Retired Engineering Professor at a top British University.
You may have mentioned it elsewhere but it would help for there to be another explanation of what is different with the t1 steel that makes it susceptible to these issues. Why was t1 used in the first place.
I look at this as a generally positive story. They are actively preventing future failures. Yes, the inspection are an inconvenience and costly. But they are easly and cheap compared to failures.
I'm curious, why did the cracking in T-1 girders occur in the I-40 Hernando Desoto bridge girders where the attachment used is bolts instead of welding? If preheating and cooling procedures T-1 welding were not used, then the failures in the bridges are in part due to the civil engineering firm by not monitoring the construction company's welding procedures.
Usually the HAZ [Heat Effected Zone] next to the weld is the area to fail......as the weld metal is usually stronger than the material, but due to stress in that area, it will fail first, if the proper rod and technique are used....... one thing to remember, a weld is cast steel......not wrought steel like the members being joined.......so grain structure is very different......cheers from Florida, Paul
I had telescoping crane boom extensions made from T1 plate in the 1980s. No butt welds were involved. I did study the data sheets and the welder did too. He used a very high tensile rod. Did my own design calculations. I did lots of lifts at the limit of capacity. No problems. I can see the butt welds in a tension member would be a real worry. Nightmare.
The added dead load of those gusset plates to the three piers is a factor worth mentioning. Visually, they already appear less than robust. How is something that tall and spindly withstand an earthquake? As always, I enjoyed your presentation. Thank you.
1970s + A588 Weathering Steel + High Mast Lighting Towers + Deicing Salts Can you imagine what went wrong? Not only was it very brittle but it never stopped rusting. They sent men up the towers to drill the cracks everytime they relamped. Used it in overhead sign supports too until one fell off a bridge into a car. Pack rust in that case. Hard lessons to learn. Hot dipped does pretty well. Not sure why we don't see it in bridge superstructures. It only lasts 30 years but so does coating and confinement for painting onsite is very complicated and expensive, especially over water. Galvanize + Zinc anodes if necessary. We can hot dip all of our guardrail but beams are too expensive? Or are there technical reasons?
Is it possible you examine GATE 8 in the Oroville Dam? It has a giant crack in the concrete yet the DSOD claims there’s nothing to worry about. Thanks.
I live near Memphis. Losing the Hernando Desoto bridge was a huge deal around here. While it should have never gotten as far as it did without being noticed. TDOT and ARDOT did an amazing job in the response and some how got the bridge fixed and ropened in about 3 months. This situation further aggravated the supply chain crisis back then from covid and other global logistical disruptions. We really need to get ahead of these old bridges before someone gets hurt.
You might be interested in the recent collapse of the Carola bridge (Carolabrücke in German) in Dresden, Germany that might become a problem during the expected flooding next week.
It bears mentioning that these bridges are about 40-60 years old. They should last 100 years but most have also gotten much heavier use than originally predicted.
Would you please post a video of the (recent long repairs) to Benjamin Fitzpatrick Bridge in Tallassee AL. It's 143 ft tall & 1738 ft long crossing the Tallapoosa River.
If they find cracks and install the reinforcing plates, I wonder if they will allow the bolts holes to be hydraulically punched instead of requiring them to be drilled?
I love the Foresthill bridge; it provides quick access to some of the most beautiful parts of my county. But if there is any chance of structural issues, I can take a detour (is the good old Yankee Jim's bridge any safer?).
@@CaseyJones-Engineer Ditto. Ruined many blanks because I didn't anneal or quench properly. Made some blades so brittle they are like trying to sharpen obsidian. Thanks
I went to that bridge with a friend about 1995 and he dropped a bowling ball size rock from the bridge, when it splashed in the river a person moved away from the splash. Never drop things from that high, you cannot see people below. Also wise to not hang out under the bridge, should be warning signs about people dropping objects from the bridge underneath it.
5:38 - Anecdotal Story: I was told by a local that the ridge top properties in the area were sold in the 60's and 70's as _"future lake front properties."_. The cancellation of the Auburn Dam changed all that. The Auburn Confluence area has lots to do and I recommend _carpooling_ to it and enjoying it!
Question.....I live in auburn and am extremely familiar with forresthill Bridge. I walk under it to get to my favorite swimming hole and drive over it to see friends. We have extreme weather as summer cooks us and winter near forresthill brings snow. My Question is would temperature fluctuations also threaten the steels strength or cause that particular flaw to deteriorate more? After watching your video I won't be using that Bridge anytime soon!! Sidenote walking below the bridge is deafening, sounds like large booms of thunder as each car passes over.
This is a VERY high bridge. I have driven over it a lot, and even (foolishly) flew under it (in my ultralight --- well, maybe even more than once --- but that was long ago)... I have a difficult time agreeing with it having 20,000 cars/day over it. There is traffic, but not very much in my opinion. I would have a hard time getting up the nerve to haul the magnaflux equipment out to xray the welds --- just looking down gives me pause --- it would take a looong time to reach the bottom if one were to slip..... But thanks for the information --- I might reconsider the next time I need to drive across it and decide there are other things I should be doing.
Would love for you to dig into how the cost of 6 million dollars for a small team of guys to test welds is arrived at. We could do a lot more repairs if the costs weren’t thru the roof
It doesn't seem to me that it should be an enormous surprise that lightweight steel-truss bridges that are more than 50 years old are going to need repairs and that a bunch of them are going to need replaced. Did they think they would last forever?
So I gather they stopped using T1 steel for bridges. What type of steel replaced it, and what type of steel is currently in use for bridge construction?
They’ve been repairing the Sherman Minton bridge for 15 or so years now. The govt had announced that it will all be done some time this fall. I’m doubtful.
I guess the lesson here is that to avoid hugely expensive repairs in the future, build it properly in the first place, not necessarily with the lowest bidder.
So since I know little to nothing… question 1- what sort of steel is the SF bridge made of? Question 2- Does the SF bridge have any welds at all or is it all rivets? Question 3- is welding cheaper than riveting?
The Zilwaukee Bridge in Michigan might be an interesting case study. The 8,000 foot, 8-lane bridge (4 in each direction) carries I-75/US-23 over the Saginaw River. It's my understanding that it has a few interesting things about it 1) It has needed significant retrofitting and became a money-pit for MDOT. 2) It was built higher than what it needed to be to support river traffic that never ended up happening 3) It's hollow inside. en.wikipedia.org/wiki/Zilwaukee_Bridge
Back in the mid-70's when the bridge was new, my friends and I were in high school and we'd drive up to that bridge, drinking or drunk, climb the fence then walk out on the bridge structure (under the roadway). We'd crawl inside the large square or rectangular hollow beams and poke our heads out the bottom holes and look down hundreds of feet to the rocky ground and river below. Sometimes we'd drop rocks but carrying a good size rock was a lot of work. None of us ever fell, I don't know how. In fact, I don't know how I survived my teen years.
Ive seen a few bowling balls fall off it!🙃👍
From one engineer (electrical) to another, it’s both interesting and refreshing to listen to another engineer’s discipline. Keep up the excellent work.
Thank you, I appreciate it!
There were 4 engineers riding in a car across the desert, an electrical engineer, a mechanical engineer, a chemical engineer and a software engineer. The car suddenly died and they drifted to the side of the road. The electrical engineer said, "we must have lost spark". The mechanical engineer said, "we must have thrown a rod". The chemical engineer said, "we must have bad gas". Then after a moment of silence the three looked at the software engineer who said, "maybe if we all get out of the car and get back in again it will start".
@@motofunk1 This needs a gillion more up votes. This is factual and well reasoned. 👍 🙄
@@motofunk1 🤣
as a former shipfitter, I can tell you that you cannot weld hardened steel without gradual preheating, and then gradually cooling. The weld will crack and break if you don't do this. Those cracks in your T-1 steel happened because the proper weld procedure was ignored. So you have lots of hidden issues.
Thank you. I suspect that many of these T-1 bridges will simply have to be replaced rather than trying to remediate them.
Amazing how the old wooden railroad bridges and trusses are still intact today.. back in the day, the railroad would take taker trains full of creosote and soak the tracks and bridges to control weeds and rot of the ties and bridges… what is worse??? The creosote or a bridge falling with millions of tons of very hazardous materials?
@@artmosley3337 yep, more of the same. Prioritizing some form of idealism, now so often some type of wokeness, over what makes perfect sense. Creosot works great...
@@gereshare6659 btw.. ya know that 55k acres that just burned up yesterday.. and is still burning.. I bet you a dollar a few of those trees would have worked better… and maybe the selected harvest of trees (people think they live forever.. 50-75 years and most start to rot.. NYC Central Park has a huge amount of trees that are hollow.. one fell on a woman.. huge lawsuit… but the trees that were used as timbers in the construction of Venice are 700+ years old… because they are totally submerged in water… the biggest environmental disaster ever was allowing Environmental Scientists to make decisions or recommendations.. replanting trees is the best solution to everything.. id start with the west coast and replant Red Woods and replace San Francisco
I thought I read ‘former shoplifter’ since it’s so common to see that term in the news here in CA. 😂
As a welder/fabricator I used to repair earth moving equipment, that used T-1 steel, or wear plate similar to it, as it's structure. It surprises me as others have stated, that it was used for bridges. It is great for it's wear resistance and has a very high tensile strength. Preheat and post heating of the welding process are very important. Another factor to keep in mind as I was told where I worked was the huge differential between the tensile strength of the plate versus the strength of the weld rods I used. If I remember correctly, the highest strength rods I used were called 9596 which had a tensile strength of 86 000 versus the 110 000-130 000 of T-1 type steel. This causes the welds to bear more stress because the welds will yield earlier under load versus the plate itself. This rod I used was supposed to be more ductile, than 7018 to help with that, but I just used to try to keep in mind the difference, and tried to account for it by making my welds larger to help compensate.
They didn’t use bolting, or metal technology hadn’t advanced to the capability to manufacture Grade 5-Grade 8 bolts?
"tink!" the sound every welder hates
@@ssaraccoii Structural bolts have advanced further than Grade 5 and Grade 8 bolts. The current A325 bolts have a lowerish tensile strength, but are much more ductile (stretchable) than Grade 5, and particularly Grade 8 which are pretty brittle.
11018 rods exist too...9596 is for repairing leaf springs and scraper blades not bridges/
I also used T1 as a wear surface on front end loaders operating on a paved surface. I was instructed to use "low hydrogen" rod. Now I know why I was frequently welding up cracks...
In the early 70's when this steel came into use, the shop I was working in made sure anyone welding the higher strength steels was qualified and using the qualified procedures. That meant that we used a lot of gas to heat up the sections prior to welding and a lot of gas for a slow cool. We used 9018 electrodes and, later, 1118. Mostly ran 5/32 and 3/16 lo-hy kept in heated ovens. The containers we took to the weld itself were insulated and we were not allowed to use from a container that had cooled enough to to handle with the bare hand. Joints were cleaned to TIG ready and maintained that way. In later years I learned that a lot of shops didn't really maintain the lo-hy nature of the situation for electrodes or plates. So no surprise the cracking. I had the great fortune of working for some folks who knew the trade and had actually studied the metalurgy!
I'm 76 now and I'm just ashamed of the practices used in the trade....
Keep up the good work!! We weren't building bridges but other stuff for equipment and buildings.
Ironbridge is still up near telford. Since then we seemed to have pushed our luck on steel structures.
In the shipyard, it was HY80 steel used for high repeated stress areas like bows, rudders, etc. Submarines use HY80 too. Welding to a rudder post casting was a real nuisance. We used electric heating pads to heat the steel to 130 degrees. stick welded it, then gradually allowed it to cool over several days. Being a shipfitter, we had to slightly bend the over an inch thick already curved plate sections with hydraulic jacks to make them fit. And yes we broke lots of jacks :)> The shipyards have huge hydraulic hammers/ presses to bend steel to "about" the right curvature & etc. We had to force the steel the rest of the way until it actually "fit."
This steel came into use in bridge construction in 1959. Standards weren't in place back then to deal with T-! Steel.
@@teamidris Largely because it is in compression, not tension.
@@michaelcurtis-cdot8978 I hear you, but iron bridge was made when there weren’t iron bridges. Unless someone made a brass one there weren’t any metal bridges before that?
As a steel inspector early in my career, I witnessed column cracking at splice welds at the base of a high-rise in Boston. I asked the "experts" why they didn't maintain Interpass temps during the welding. That was the problem. Don't trust experts, do your homework.
If working on a bridge, ensure the welding procedures matches the materials being used and check the operator's quals are AWS D1.1.5.
T1 is used in crane and machine booms buckets and as you say must be welded as per AWS spec.
If done properly amazing strength durability.
My dad used to laugh every time he heard the term “expert” used to describe person’s experience. His definition of “expert “ was a former drip under pressure.
I laugh when I hear the description of a “blue Ribbon Panel” did the panel participants all get 4H Blue Ribbons.
@@jimpawa5793 It's popular these days to claim that there are no experts and one opinion is as good as any other, but that's not even close to true. There are people who have spent the years of study and years of experience it takes to be an expert. Sometimes experts make mistakes, but it's always better than guessing. Uninformed people sometimes make the correct decisions, but their reasoning will always be wrong.
@@jeffrey1312Experts are truly the only experts that qualified experts… according to the experts.
Also… The same experts claim Men can get pregnant and give birth. 🤣
@@jimpawa5793 Or did they drink too much Pabst Blue Ribbon Beer?!
Dig deep 👍🏾
You are doing a public service for us all - thank you.
In my early years in construction I spent a few years on a rock crushing operation. We used a lot of T-1 steel plate to line chutes that washed gravel or crushed rock would pass through. T-1 plate was known as an “abrasion resistant” material far outlasting regular mild steel material. At the time we never really had to consider its brittleness. I’m really surprised to learn it was used in structural applications on major bridges…..
Very interesting, thank you! I am starting to research all of the other applications for this steel. I understand it was also used in building construction.
Starting to really enjoy this channel…useful info and I learn something every time…
Wow, thank you!
As a state and city licensed welder In NYC for 45 years I can tell you many welders do not adhere to proper welding techniques due to time constraints given to them. Many steel erectors would not allow the time spent as it is time-consuming and costly. You have to keep the welding rods in a heated oven. You have to clean the steel before welding. Most important with large welds preheat and post-heat are very important. The winter is extremely important when post-heating a weld and bringing the temp down to natural environment temp. slowly. Sometimes people. are to impatient and do not fully understand welding. It is about how many tons of Iron per day or floors can be erected. T1 steel from my memory you could use a 7018 up to 3/4" best to use an 8018 or 9018 as it has a higher structural component. Heat the rods is key.
Love your channel very interesting information.
It really makes you wonder if the problem extends beyond just T1 welds. Casey, do the non-T1 welded bridges undergo more than just visual inspection?
11018 is even better...and the rods are only allowed to be left out of the 250 degree f oven for 30 minutes for code work, then they get rebaked at 750 degrees for 30 minutes and can be used again.....they are allowed two rebakes....
@@thelaxman59 I still wonder when the requirement for keeping the welding rods in an oven started. 45 year ago is surprisingly after the discovery of hydrogen embrittlement, which happened in the 1970s.
@@johnhaller5851 I went through welding school with my Union Ironworkers Local 40 NYC structural union. I know in 1980 I had heaters for rods back then. I also took a welding test for the Indian Point Nuclear Power Plant. That test was much harder than the state and city tests.I know on most all the jobs we had rod heaters some small and portable some large stay in place. We would go to the large one and take out enough to fill the small box to take it to our welding points. The heating of the rods and large weld points
was drilled into us. An apprentice would help with post-heating and temp control if you don't you would have cracked welds.I got away from welding at a young age as I finished school to get my riggers license and it helped me become a super. I would put up and take down many rigs in NYC. You had to have someone with a rigger's license on site.
I love it and miss it every day. Great men and great job.
@@Zupdood2 I agree
I've driven across that bridge when I was working in Sacramento in the early 2000s. It's a beautiful bridge. It goes over the North Folk American River
It's so high because the Auburn dam was to be built.
As a teenager, my friends and I used to climb over onto the catwalk and go out to the west side colum. Go down the ladder and sit on the colum and drink. Got a lot of memories of this bridge. Still go there from time to time.
Unfortunately, alot of people have taken thier life at this bridge. There are inspirational signs, notes all along the bridge to try to help those who might go there to end their life.
It a major landmark for the area. Hopefully any repairs will be minor.
@@TheLionsDen72 The bridge needs to be torn down. No need for it since Auburn dam will sadly never be built.
@@TeddyRumble I don't see it this way. The bridge is now there and has been there for decades. Just leave it alone. Whether or not the Auburn Dam is built. Dismantling it would be a backward move.
@@TeddyRumble How else are you going to go to Forestville? The other route is a crazy winding road many times longer.
Casey Jones-
Thank you for your efforts to bring clarity to the often obscure questions regarding the details of engineering.
CALTRANS has been aware of Fracture Critical bridges for quite a while. But the issues of T-1 steel have only recently been addressed by NDT and special inspection teams.
Avoiding catastrophic failure in these aging bridges requires focusing on the most critical aspects of the structure. The information in your videos really helps everyone understand the true nature of the problem. This cannot be done by the general media to any degree required.
Thank you. That was one of the reasons why I started this channel as I found general media sources to be really lacking when covering things of a technical nature.
Our careers have traveled different paths for sure, but the goals we have appear to be quite similar. Flood Control, Transportation and Infrastructure Development can be accomplished with great success and also experience unforeseen and costly failures.
Your efforts to bring greater clarity to both sides of this story with the thought of avoiding the avoidable is greatly appreciated.
It’s important that the engineering community understand the value of this type of review. Learning from the experience of others is the easiest way to learn for most engineers, not from just your own mistakes.
Video of the 1994 Northridge Earthquake in the Los Angeles area and the many steel moment-resisting frame structures that experienced unexpected brittle damage to their beam-to-column connections might be interesting.
I live in the area and it's interesting to see that no mention of hydrogen embrittlement is the issue they're looking for when inspecting the Foresthill Bridge. They also don't mention the type of steel and it's ability to fracture at the welds if not welded properly. All we're seeing in the news is "they're inspecting the bridge".
Yep I noticed that as well 😬.
Another great video. Keep up the good work
Thanks, will do!
I live near the Sherman Minton. Didn't know it was the first one to have cracks. Nice video.
Hydrogen embrittlement is an issue for all high strength steels. I have a welding textbook that notes under-bead cracking being an issue for naval gun mounts in WWII, but it's likely been an issue for as long as arc welding has existed. The biggest cause is the presence of moisture during welding, even just absorbed into the flux from the humidity in the air. There are ways around it, but you have to do stuff like keep electrodes in an oven to keep them dry enough.
Thanks for the useful information.
I'm just an amateur at welding and have realized that there's a lot of experience involved making a good weld, but I stick to welding simple unimportant things where the quality of the weld isn't critical. I have also discovered that stick welding aluminum isn't an easy thing to do even under ideal conditions.
Ah, interesting! I was wondering where the heck the hydrogen came from, I’ve typically only heard about in the context of hydrogen pressure-containment vessels. Thanks for the info!
I took an introductory course on material science in about 1980. The book for the course was written in 1970 (the process for introducing new material into engineering curriculums is very slow). There was no mention of hydrogen embrittlement, only that welding could cause thermal damage such as overaging, over tempering, or annealing. One wonders when they discovered the actual cause of the under-bead cracking. The class might have mentioned hydrogen embrittlement, but I don't remember the lectures. Welding was covered in one paragraph of a 545 page book.
When was that welding textbook originally written, and the latest revision made, just curious? I'm guessing electron microscopes needed to be sufficiently developed to understand the how, even if experimentation could have developed methods to avoid hydrogen embrittlement earlier than the understanding.
@@DaveEtchells Just be aware that now with low carbon emissions there are experiments ongoing using hydrogen gas to make steel.
Yes I have an electrode oven.
Also we put rods in refrigerator for days took moisture out.
As just an 'everyday'-kind of citizen, I thank you for these very interesting and informative presentations!
I dont know what the US is like but over here the problem is bridges built 50-60 years ago were designed to last 30-40 years and so have been replaced 20 years ago...but obviously they were never replaced. This is not just a bridge problem, lots of buildings and roads were also built on the cheap because they were supposed to only last 30 years and then replaced, yet somehow people "forgot" about the replacing part.
That is a far too common issue. And instead of replacing the worn out, poorly maintained bridges many DOTs are spending inordinate sums of money try to rehabilitate these old bridges instead of replacing them.
@@CaseyJones-Engineeryeah, just how politics goes, I guess. Meanwhile we have Victorian rail bridges built of thick slabs of mild steel riveted together and they are still going with just routine maintenance because they're so over-engineered. Unfortunately if a cheap, temporary option is available, that's what the people in charge will go with. I honestly don't know what the solution is, it's human nature but it is very frustrating.
The vehicle weight going up and overall traffic numbers often also exceed the design loads.
@@PartanBreeThe railroad bridges were over-engineered partly because steam locomotives are so much heavier than any cargo. This allows a certain amount of deterioration to be left unfixed. Some of the railroad bridges leading into the CNW terminal (now Ogilvie Station) in Chicago have suffered a lot. The station opened in 1911, so I'm guessing that's when the bridges were originally built.
@@PartanBree
Where is 'over here', Partan?
California has 10 more bridges constructed with T-1 Steel and are not giving up much information regarding the presence of these bridges and actions to replace or strengthen them. There will be another catastrophic bridge failure and then we will be hearing the politicians here sending their "thoughts and prayers" in response. It is a pathetic mess.
I'll see what I can do about getting a list of those bridges. I wonder why California is so far behind on their inspections?
@@CaseyJones-Engineer Thanks Casey. My attempt ended up in a maze of bureaucracy. I have no knowledge about where to take my search. I think it is important we get this information to TV news outlets that perform local investigations and reports about these public safety issues.
Inspections and Reports: If no one is pushing them and educating/alerting the public, then the State gets to set their own timeline.
Where are the 5 in Missouri?
@@CaseyJones-Engineer I would guess because inspections are expensive and the government official do not want to know the results.
@@scott_meyer I don't know. I will look into it.
OH!!! ... uh .. I live in Placer County. Wow! Am I glad I came across your channel.
Welcome!
We cross the East Liverpool bridge fairly frequently, and had to use the long detour when it was shut down. 1.5 miles west of this bridge is a fairly light 1905 built suspension bridge, still in use. It was built for lighter loads, so has a 10 ton limit. Street view is from 2019, and shows a crew inspecting the suspension cables.
When we were teenagers we would climb underneath this bridge and hang upside down on it and it was frickin scary looking down!
I remember when Foresthill Bridge was built, we used to go watch in awe. I remember the day the news told us that 3 guys fell into a net and died anyway because the net tore.... I was about 10 and lived in Auburn, CA back in 1972 & 1973 etc.
I remember back in 1963 my welding class professor claiming that T-1 was a danger and that the preheat requirement was a crutch for postheating the weld.
I never worked as a welding engineer, but still remember his comments.
Very interesting. Thank you!
Yes true .... welding with out preheating and post welding changes the Structure of the Steel Crystals ...
There is so so much that goes into the design and actual frabrication of Welded joints ...
Ref: AME Welding Manual ...
The old Hot Riveting System is one that spreads loading around joints and are still in structures standing today where Modern welded ones have long Failed 😮😮😮😮😮
@@josephcooksley3219
Interesting thought on the rivets.
@@henrynelson9285 This appears to confirm that my hypothesis that hydrogen embrittlement wasn't really a thing in the 1960s. That's not to say that proper heat treatment wasn't an issue, but it wasn't the only one.
@@johnhaller5851 Hydrogen embrittlement is always a problem.
It's just worse in high strength steels.
USS pedaled T-1 as a weldable 100k steel as compared to A36 at 35k yield.
It' wasn't appreciated that it took a lot more care to weld.
I was a little kid growing up in Telluride, CO, when the bridges over US 50 were built. We would look up as we were traveling on the road below. Once opened and before there was any water below we were in awe of how high up we were. Later we would go fishing there. Things sure change.
The alternate route down hwy 49, through the confluence and up the other side is amazing! If you have all day and love extremely twisty mountain roads 🤣🤣
Thanks for the straight up and indepth review of these projects. We have many problems throughout our infastructure due to age, environmental, or incompetence and no one wants to talk about them until they have to. Then is cover butts mode and no real information comes out.
I remember a Sacramento Bee article about this bridge back when it was being constructed that claimed the reinforced concrete support pillars were designed so that the waters of the reservoir would help support the weight. I have never heard anything about that since.
I would think that the columns are better off not being submerged from a corrosion potential standpoint of the reinforcing steel in the concrete.
I lived in Auburn & a couple years in Foresthill. Thankfully in this case, there is a road from one side of the canyon to the other, (much slower of course than a nice straight bridge) , but better than being cut off!
That is true, there is an option here.
For the curious, 13 million in 1973 for the Foresthill Bridge is 65 million in 2011, so, pretty much the same cost to retrofit the bridge as it cost to build it in the first place, since its construction started in 1971. And 13 million in 1973 is 92 million today, but I bet it would cost many times that amount to build that bridge today.
Thank you. I agree, this could be a $1 billion replacement project, although they could save a lot of money if they were able to reuse the foundations.
@@CaseyJones-Engineer Would 2024 environmental restrictions allow for a new bridge?
Auburn dam will never be built.
@@TeddyRumble If the Demmunists stay in power, you're right. They'll see to it that the Auburn (or any other dam) never sees reality. But then, neither Deukmeijian, Pete Wilson nor Schwarzenegger ever did anything to my knowledge to ensure the Dam's construction either.
My dad was an Engineering Tech for Omaha District starting in 1958, spending his entire career at Oahe. You are correct, they spent half the time riffing and the other half shipping talent out to other districts. Dad was routinely sent to places like Estes Park when their dams gave out, or were about to.
I used to inspect Oahe Dam in the late 80's. I heard a story that the old timers would take bowling balls and roll them down the long concrete spillway. Apparently they would bounce so high that they would shatter before reaching the end of the spillway!
@@CaseyJones-Engineer I learned to ride a bicycle on the generator floor. In the 1970s the kids of the Corps personnel pretty much had a free run of the powerhouse. Most of us lived in the same neighborhood in town that had been built for government personnel housing in the early 1950s.
I was somewhat special, as Dad had an office in both the powerhouse and the outlet works. I knew all the old techs and maintenance staff, plus the operators and administrators.
As late as the mid-1980s my non-Corps friends and I would ride or bike out to Oahe and give tours of all the places they couldn't go on the official tours.
Dad was an interim project manager at Oahe for about a year and a half. He would have liked to run it permanently until retirement, but they wouldn't boost his GS level because he was still six credit hours short of his degree at Purdue from 30 years before. He has been gone for 13 years now, but Mom is still living and the last of the Federal personnel still residing in the housing project (even alive for that matter). I think she's also the only remaining resident of those who bought their home at the GSA sale in 1967.
After 9/11 they moved all the admin at Oahe to a separate building and caged up the powerhouse. I can't get within a city block of it now unless I register for a tour at the visitor center on the hill. Sad.
I used to live in Placer county.
Until now, the biggest issue with the bridge was jumpers.
Sacramento has flooded many, many times.
The levees give way or are over topped each time.
Hi
I love your videos and I would like to request that you do a video on highway 20 east of Nevada City. They ‘straightened ‘ some sections and where they did some of their cuts, not properly shored up and washouts started
A recent fan of your videos as I had been researching the ranchos palos verdes landslide in LA, you make very informative content and I hope you continue to do so. As an engineer, your opinions and ability to communicate the information is both valuable and, as you had mentioned, not something you get from more typical commercial media outlets. TH-cam is an amazing thing! I'd recommend throwing any drone footage you might purchase up on stock video sites if allowed by your agreement with the videographer, as it may allow some additional income so you can make more. You never know when that footage might come in handy for someone else. I think your last video the drone pilot you hired delivered the footage in LOG, which is common within the media industry so that you have more control of the color and visual look of the final video by retaining data in the highlights and shadows of the footage. If you ask them they might be able to deliver a rec.709 LUT for you to apply to the footage for a more saturated and visually appealing color grade by default, or you don't know how to do that you can ask them to deliver in non-log color by default. Cheers!
Thank you so much! I am a newbie when it comes to the drone footage so I really appreciate your comments. I also like the idea of offering up the footage on stock sites. Great suggestions!!
Thanks, Casey. Very good presentation and I certainly remember that stunt when the Corvette went off that bridge! I wonder if anyone told the producers about the issues with the steel….
Hopefully the inspections and remediation plans will be ahead of any problems. Keep up hype good work and let us know. 👏👍🏻
Thanks very much. I will be interested to see if this inspection results in the discovery of any cracks in the steel? I will stay with this story and do future updates.
it wasn’t Fast and Furious but it was Vin Diesel in XXX.
When you showed the image of the repair steel plates for the Colorado bridge, it made me wonder about the weight of those.
I know that a lot of safety factors go into the design of bridges, but do you think that the additional weight will be an issue for the foundations?
Thanks!
Thank you so much!
And have you considered an investigation of the new - cable stayed - San Francisco/Oakland Bay Bridge? It was designed to be un-repairable, and CalTrans specified bolts that its own design standards prohibit for use in a marine environment. These bolts began fracturing and cannot be replaced due to the bridge design. They were also used, at the bottom of the Bay, to anchor the tower to its foundation.
There are many articles in the San Francisco Chronicle.
I vaguely recall the threaded rods to anchor the structure were cast in concrete, and were susceptible to hydrogen embrittlement because of the way they were hot dipped galvanized. I don’t recall if any had HE cracks. I also recall a fastener company Dyson being involved, and they’re a big name in industrial fasteners. 10 years ago, this was big news. I would be interested to see a follow up on this.
Regarding the inspection instructions, it seemed specific to butt welds on tension. Were fillet welds included too?
If i understand correctly, the reason why the auburn dam was cancelled was because far more landslides than expected occurred behind boulder/hoover dam as it filled, leading to substantial concerns about how stable the land under the cities of auburn and foresthill might be as the reservoir filled.
Also, if foresthill bridge is condemned, I doubt it would be replaced since it would be much cheaper to improve the road that runs through auburn SRA. The bridge was only needed because the alternate road would have been submerged
It was put to a vote and the Chicken Littles of the area got their way. Fools.
Much appreciated. I grew up in the counties of Placer and Sacramento and remember well he influx of hopeful construction workers coming to build the ill-fated Auburn Dam. I used to climb the hill from the fork of the American River below up to the undergirding of the bridge with my son and watch hang gliders take off from it. I still cross it occasionally to visit friends in Foresthill and my current employer, Wellspace Health, staffs the suicide prevention operators who answer the phones placed along both sides of the bridge (as of February, 2024, there have been 102 suicides from the bridge).
Suicide is a right. People need to remember that.
Cheers From your newest subscriber from California 😎
@@nilo70 Welcome aboard!
There are so many bridges in the USA that are 50 years old or older. The companies that do inspections will be busy forever.
I'm not an engineer, nor do I play one on TV. But I have built a lot of stuff out there in our big wide world, so I've seen a thing or two. One thing I have discovered, is that paper doesn't care! Paper will just lay there and let any idiot make marks on it, and they usually do. One of the biggest problems I find on nearly every project, is the design engineers failure to adequately address Point Load Transfer.
When I look at those extremely heavy duty repair plates- I see an incoming pile of problems likely in some combination or other to cause failure. 1st, how about all those holes that need to be drilled through the existing steel. Turning those webbed members into Swiss cheese isn't going to help -> 2nd, All that additional weight! You will sequentially potentially overload each point load to the next point load and so on down line. Those connections are already designed to supposedly adequate minimums taking into account, weight, moment, and shear, to name a few. I suspect it's theoretically possible to add enough weight to reverse the Tension/Compression role of a given member.
Trusses work because every member has a role with every other member. Fail any member (or it's connection point) and the whole thing fails.
Thanks Casey for bringing these issues to light. I recently got a camper, so I think I will avoid this bridge, just to be on the safe side.
Thank you. It certainly is a lot of extra steel. It strikes me as just a short term solution to what really should be a bridge replacement.
I don't think swiss cheese is the problem. With the correct clamping force, the new plates will pick up the load. My concern is the transitions. If the stiffness of a structure doesn't transition gradually, that's another mechanism for developing cracks. Those plates look to end somewhat abruptly. One way to transition better is to taper the height of the plate towards the ends. Another way to transition better is to use a stack of several plates with each new plate added being shorter than the one underneath.
@@CaseyJones-Engineer Do you think it's a short term solution? Quoting Red Green, "This is only temporary, unless it works." Do you think they're going to find the money for a new bridge if the patch works?
@@major__kongA great point! And in fact, some of the plates I have seen are actually stacked just like you mentioned. I too have concerns about drilling all these holes in the web of the existing girders. If this T-1 steel is already prone to cracking, couldn’t drilling cause more micro cracks? The other concern is creating areas for the environment to attack the integrity of the structure. Looking at the history of steel bridge failures, joints between gussets, hangars and plates secured by bolts are one of the leading causes and why inspections focus so heavily on them. I, too, think replacement would be better than retrofit, however I am not a fan of of this national campaign to replace everything with bulky concrete monoliths. We are underestimating steel and overestimating concrete in my estimation. 😉
I'm no engineer, but it sounds like every single welded joint will need to be reinforced, whether or not it shows any signs of cracking. And if this T1 steel has any tendency to crack at places other than at welds, patching an unstable structure would be wasted money. Davidmiller6010 makes other good points about drill holes weakening the girders, and that the added weight could exceed the bridge's designed capacity.
since you lived in Sac you are likely familiar with the FH Bridge, but it is beautiful and is a route into the lower gold country.
It certainly is beautiful. I worked on the foundation upgrades to Mormon Island Auxiliary Dam in the late 80's.
My daughter and I lived in Foresthill for several years and I thought often about the consequences of flying off the bridge on virtually every trip to my
business in Sacramento (daily). Although I was a private pilot and owned my airplane, I would have occasional bouts of acrophobia while flying. The flap
over the building of Auburn dam was really intense. The need for additional flood protection plus the need for increased water storage were strong
arguments for it's construction but this was in the heyday of the environmental movements. Even though an alternative plan made a lot of sense, a flood
control dam ( a dam that had a big hole in it to limit the flow of water to 100,000 CFS) to match what the downstream water system could manage. Also,
this was the era when we learned what El Nino was, very heavy rainfall and those levees were really stressed to the limit. My office was within walking
distance of one, it felt very jelly like to stand on it!
@@desertdenizen6428 Thank you. I understand that they're going to raise Folsom dam 3.5 feet to provide extra flood protection. I'll look more into that story.
The same "activists" that shut down the damn project got Rancho Seco Nuclear Powerplant shut down. And there are even more idiots here now.
They knew about this potential problem as soon as that bridge in Minneapolis fell, because the Foresthill Bridge has a similar design. Caltrans is currently doing a major inspection using the latest tools and may do repairs as needed. But unlike the bridge in Minneapolis, they haven't made changes to increase the load on the bridge, so I don't expect much in the way of serious structural wear.
When the cover plates are bolted into place, doesn't that move the stress load to the points just past the band-aid plate? Thus creating a new weak spot that will need to be ultrasonically inspected in a few years.
Our local bridge on the interstate is almost 110 years old. None of that fancy-pants high strength steel to worry about here! It is going to collapse the old fashion way.
I was just thinking about the Jennings Randolph Bridge when you mentioned it. I can see that bridge from my house.
Another incident was the I-79 bridge over the Ohio River at Coraopolis PA which developed a large crack in bitterly cold weather in 1979.
That failure did occur at a weld. But I don't think that it was a hydrogen enbridlement. At the time it was related to the type of weld that was used. (I think the process was primarily related to the type of shielding used during welding. The shielding is what makes me think that is was a different failure type.) I don't remember if they determine if the welding process was a bad process or if the process wasn't accurately followed.
It would be interesting to see a comparison video of the I-79 failure and these recent failures since they are all related to weld failures.
@@erniecolussy1705
Now that you mentioned this, I do remember hearing about a now-banned welding method that was new at the time
@@leehuff2330
I knew that it was related to the process. But I did realize that it was later band. Thank for the information.
@@erniecolussy1705
I remember watching a show on WQED about the area bridges that started with a story about the crack. They interviewed the towboat captain who spotted and reported the crack, preventing a collapse. The segment also included how that welding process was new at the time, but was eventually banned from bridge construction due to weakening the surrounding steel.
The show also included an interview with the iron worker who was trapped on the old Brady Street bridge and how a surgeon had to be brought to the bridge to amputate his leg so they could get him down after the bridge, which was being weakened so they could implode it, settled and trapped him.
I have not used a lot of T-1 steel. All my welds were done using flux-cored wire. There have been no issues with cracking on 30-year-old weldments. It seems to me that the issue is not the steel. Rather it is the welding procedure. Perhaps you should do a video focusing on the currently recognized proper welding parameters and how the welding was done when the bridges were constructed. Maybe a welding engineer might do a collaboration with you. I'm going out on a limb here and guessing that Kawasaki might have used wire in prefabricating the Foresthill Bridge, which may be less prone to embrittlement.
Check out the Glade Creek Bridge (a.k.a Phill G McDonald Memorial Bridge) on I-64 near Beckley, WV. The highest bridge on the Interstate system, it is a near carbon copy of the Foresthill Bridge and was closed by WVDOT for over a month this summer due to cracks. It was built in 1988 so it’s not the same T-1 butt weld issue, but it’s an uncanny coincidence nonetheless.
Every materials class professor needs to talk about this to their engineering students.
Can you look into the multi million dollar bridge in Sacramento they just built, but was constructed so poorly that they are talking about tearing the entire bridge down, by the way great work on this auburn video as well, thanks for all the info.
Thank you. I am starting to look at this situation and will follow up with a video.
@@CaseyJones-Engineer great thank you so much! Take care!
The location of the Auburn dam was also a poor one. The western foothills of the Sierra include a couple of major faults that run parallel to the range's strike. The fault zones often are marked by roughly north-south oriented valleys. Empounding large amounts of water can inject fluid into the faults triggering earthquakes. But, politicians and bureaucrats looking at those valleys have frequently concluded they were ideal locations to impound water.
I was working as a driver and trapped for 6 hours in downtown Roseville during the flood of ‘86. Did the floods of 1996 help validate or show places where more work was needed?
@@tfodthogtmfof7644 I'm not really sure about the details with the '96 floods. I have to do more checking.
Interesting you worked on levees in Sacramento. Enjoying your content and Palo Verdres land slide and explanation. I am down in Coronado, San Diego, and San Diego shares a sewage treatment plant with Mexico along the border along the Tijuana River. The sewage treatment plant requires a 1/2 billion in repair, deferred maintenance from US and Mexico. The beaches can not be used due to the contamination. I pass this along as similar to Palo Verdes, is the investment for the sewage treatment in the interest of the City as a whole? This may be a political discussion, however your coverage of Palo Verdes prompted a discussion in the back of my mind. Thank you for that.
Historically, the sewer treatment plant has always been a problem. Another "infrastructure" failure. I am retired civil engineer and tell friends this is a matter of priorites, don't give up hope. My takeaway is, after 60 years, or two generations, the "infrastructure" is failing. We need to reset our priorities. Just a general thought prompted by your discussions.
Thank you. I am very concerned about the insufficient investments being made in infrastructure these days. Also there seems to be an incentive to negligent maintenance and repairs until a crisis is reached and the Feds are expected to pick uo the tab at that point.
@@CaseyJones-Engineer You are right about expecting the Feds to pick up the tab. Great reporting and enjoying your new back drop of tiles.
@@kenty2831 Thank you!
@@CaseyJones-EngineerSame taxpayer pocket. Just a different hand taking it (-;
I go hiking around there lot. Always wondered why that bridge was so freakishly tall lol.
Just for clarification, have other bridges experienced T-1 steel beam/girder fractures like the I-40 bridge? The other examples you mentioned seem to all be weld failures due to HE. My though here goes to the potential breadth of the problems; i.e. weld failures can be corrected and monitored forward, however if the base T-1 steel is the source of the failures then the problem is much broader with greater potential, perhaps probability, for catastrpoic failures. Thanks for sharing your expertise and valuable insights as an engineer.
All materials have problems with cracks, some more, some less; all materials contain cracks straight from the factory, that's why bridges are subject to inspection. The problem with welds is that they change the properties of the metal they're done on and their quality is highly dependent on the skill of the individual performing them.
I don't think these problems, as far as they're related to the base steel, are really a defect of the material so much as these bridges are nearing end of life.
@@Kandralla Thx very much for this clarification.
The crack shown at 2:40 is not 'at the weld' it is on the edge of the HAZ (heat affected zone). if the weld area had been pre-heated to around 200-220°C at the time of welding it would not have happened. It is there due to rapid conductive cooling around the weld inducing micro cracking that precipitate embrittlement much earlier than would be the case with correct management of welding procedures.
Retired Engineering Professor at a top British University.
You may have mentioned it elsewhere but it would help for there to be another explanation of what is different with the t1 steel that makes it susceptible to these issues. Why was t1 used in the first place.
A review of the recent bridge collapse in Dresden, Germany would be of interest.
I look at this as a generally positive story. They are actively preventing future failures. Yes, the inspection are an inconvenience and costly. But they are easly and cheap compared to failures.
Yes, I think you are right to point that out.
I literally drive across this bridge regularly and iv never even heard about any potential problems.
Except for Av Week and a couple of other sources, aviation news is NEVER reported correctly by the news services. You go guy. Fellow engineer.
Thanks a bunch Casey 🙏
Certainly!
I'm curious, why did the cracking in T-1 girders occur in the I-40 Hernando Desoto bridge girders where the attachment used is bolts instead of welding? If preheating and cooling procedures T-1 welding were not used, then the failures in the bridges are in part due to the civil engineering firm by not monitoring the construction company's welding procedures.
Usually the HAZ [Heat Effected Zone] next to the weld is the area to fail......as the weld metal is usually stronger than the material, but due to stress in that area, it will fail first, if the proper rod and technique are used.......
one thing to remember, a weld is cast steel......not wrought steel like the members being joined.......so grain structure is very different......cheers from Florida, Paul
I had telescoping crane boom extensions made from T1 plate in the 1980s. No butt welds were involved. I did study the data sheets and the welder did too. He used a very high tensile rod. Did my own design calculations. I did lots of lifts at the limit of capacity. No problems. I can see the butt welds in a tension member would be a real worry. Nightmare.
The added dead load of those gusset plates to the three piers is a factor worth mentioning. Visually, they already appear less than robust. How is something that tall and spindly withstand an earthquake? As always, I enjoyed your presentation. Thank you.
Some bridges look so scary I wouldn't wanna be on them even with a Casey Jones stamp of approval 😅
t1 is britle dont remember what we did to weld it but if its done wrong it will bust before you get the project bolted together
1970s + A588 Weathering Steel + High Mast Lighting Towers + Deicing Salts
Can you imagine what went wrong? Not only was it very brittle but it never stopped rusting. They sent men up the towers to drill the cracks everytime they relamped. Used it in overhead sign supports too until one fell off a bridge into a car. Pack rust in that case. Hard lessons to learn. Hot dipped does pretty well. Not sure why we don't see it in bridge superstructures. It only lasts 30 years but so does coating and confinement for painting onsite is very complicated and expensive, especially over water. Galvanize + Zinc anodes if necessary. We can hot dip all of our guardrail but beams are too expensive? Or are there technical reasons?
Is it possible you examine GATE 8 in the Oroville Dam? It has a giant crack in the concrete yet the DSOD claims there’s nothing to worry about. Thanks.
Thanks for calling that to my attention. I will look into it.
@@CaseyJones-Engineer This was covered by TH-camr 'Millie Kay'. I will look for her vid and link it here if I can.
I live near Memphis. Losing the Hernando Desoto bridge was a huge deal around here. While it should have never gotten as far as it did without being noticed. TDOT and ARDOT did an amazing job in the response and some how got the bridge fixed and ropened in about 3 months. This situation further aggravated the supply chain crisis back then from covid and other global logistical disruptions. We really need to get ahead of these old bridges before someone gets hurt.
You might be interested in the recent collapse of the Carola bridge (Carolabrücke in German) in Dresden, Germany that might become a problem during the expected flooding next week.
It bears mentioning that these bridges are about 40-60 years old. They should last 100 years but most have also gotten much heavier use than originally predicted.
Would you please post a video of the (recent long repairs) to Benjamin Fitzpatrick Bridge in Tallassee AL. It's 143 ft tall & 1738 ft long crossing the Tallapoosa River.
Whatever happened to shop welding with easy quality control, and field bolting, as a rule of thumb?
Very informative. 😊
Thank you!
If they find cracks and install the reinforcing plates, I wonder if they will allow the bolts holes to be hydraulically punched instead of requiring them to be drilled?
That is an interesting point. I would like to see more details about what they are planning.
I love the Foresthill bridge; it provides quick access to some of the most beautiful parts of my county. But if there is any chance of structural issues, I can take a detour (is the good old Yankee Jim's bridge any safer?).
Metallurgy is fascinating. From pocket knives to machine tools to steel structures; all require good engineering to succeed.
I agree. I have learned a lot by making several fixed blade knives!
@@CaseyJones-Engineer
Ditto. Ruined many blanks because I didn't anneal or quench properly. Made some blades so brittle they are like trying to sharpen obsidian. Thanks
I went to that bridge with a friend about 1995 and he dropped a bowling ball size rock from the bridge, when it splashed in the river a person moved away from the splash. Never drop things from that high, you cannot see people below. Also wise to not hang out under the bridge, should be warning signs about people dropping objects from the bridge underneath it.
5:38 - Anecdotal Story: I was told by a local that the ridge top properties in the area were sold in the 60's and 70's as _"future lake front properties."_. The cancellation of the Auburn Dam changed all that.
The Auburn Confluence area has lots to do and I recommend _carpooling_ to it and enjoying it!
Very interesting. Thanks.
Glad you enjoyed it
I would be interested to know how many welds have failed due to bridge movement and vibration vs the initial fabrication weld.
Question.....I live in auburn and am extremely familiar with forresthill Bridge. I walk under it to get to my favorite swimming hole and drive over it to see friends. We have extreme weather as summer cooks us and winter near forresthill brings snow. My Question is would temperature fluctuations also threaten the steels strength or cause that particular flaw to deteriorate more? After watching your video I won't be using that Bridge anytime soon!! Sidenote walking below the bridge is deafening, sounds like large booms of thunder as each car passes over.
Thanks Casey
T-1 sounds like Terminator One before he helped that kid. Deadly. I never heard of this before. Deadly, too.
This is a VERY high bridge. I have driven over it a lot, and even (foolishly) flew under it (in my ultralight --- well, maybe even more than once --- but that was long ago)... I have a difficult time agreeing with it having 20,000 cars/day over it. There is traffic, but not very much in my opinion. I would have a hard time getting up the nerve to haul the magnaflux equipment out to xray the welds --- just looking down gives me pause --- it would take a looong time to reach the bottom if one were to slip..... But thanks for the information --- I might reconsider the next time I need to drive across it and decide there are other things I should be doing.
Would love for you to dig into how the cost of 6 million dollars for a small team of guys to test welds is arrived at. We could do a lot more repairs if the costs weren’t thru the roof
It doesn't seem to me that it should be an enormous surprise that lightweight steel-truss bridges that are more than 50 years old are going to need repairs and that a bunch of them are going to need replaced. Did they think they would last forever?
So I gather they stopped using T1 steel for bridges. What type of steel replaced it, and what type of steel is currently in use for bridge construction?
I'd think since Kawasaki was involved there might be problems in Japan and many other locations. I wonder what might be happening elsewhere?
That is an excellent point. Although for this bridge no problems have been reported so far, but the inspections will take many months to complete.
They’ve been repairing the Sherman Minton bridge for 15 or so years now. The govt had announced that it will all be done some time this fall.
I’m doubtful.
That U.S. Route 50 bridge in Colorado lies on the run-up to Monarch Pass, doesn't it?
I guess the lesson here is that to avoid hugely expensive repairs in the future, build it properly in the first place, not necessarily with the lowest bidder.
So since I know little to nothing… question 1- what sort of steel is the SF bridge made of? Question 2- Does the SF bridge have any welds at all or is it all rivets? Question 3- is welding cheaper than riveting?
I'm confused. Is there a second bridge I can't see? Why else would there be a big red arrow in the thumbnail?
The Zilwaukee Bridge in Michigan might be an interesting case study. The 8,000 foot, 8-lane bridge (4 in each direction) carries I-75/US-23 over the Saginaw River. It's my understanding that it has a few interesting things about it 1) It has needed significant retrofitting and became a money-pit for MDOT. 2) It was built higher than what it needed to be to support river traffic that never ended up happening 3) It's hollow inside.
en.wikipedia.org/wiki/Zilwaukee_Bridge