Foresthill Bridge in California - Another T-1 Mess?

In this video, I discuss what what is being done to determine if there are any cracks in the welds for structural steel members for this very tall bridge in Auburn, California. Due to FHWA requirements, many of these bridges are required to be inspected using highly intensive non-destructive test methods which will take approximately 6 to 9 months to complete at an estimated cost of $6.3 million. I will also discuss the background on the issues with this type of bridge steel, including past issues.

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[lewis]

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.

[joefin]

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.

[BadDadio]

From one engineer (electrical) to another, it’s both interesting and refreshing to listen to another engineer’s discipline. Keep up the excellent work.

[dpeter]

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.

[scottwall]

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.

[richardpark]

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.

[richardraef]

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…..

[BitwiseMobile]

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

[neilrusling-jezo]

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.

[thelaxman]

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.

[barryf]

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".

[kruelunusual]

Starting to really enjoy this channel…useful info and I learn something every time…

[williamlloyd]

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.

[sleepib]

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.

[henrynelson]

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.

[ross]

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.

[dgsantafedave]

When we were teenagers we would climb underneath this bridge and hang upside down on it and it was frickin scary looking down!

[jimw]

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.

[RonaldSimkin]

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.

[Yowzoe]

Dig deep 👍🏾
You are doing a public service for us all – thank you.