Emergency: California’s Oroville Dam Spillway Near Failure, Evacuations Ordered

Breitbart ^ | Feb 12, 2017 | Joel B. Pollak1

[janetjanet998]

The California Department of Water Resources issued a sudden evacuation order shortly before 5 p.m. Sunday for residents near the Oroville Dam in northern California, warning that the dam’s emergency spillway would fail in the next 60 minutes.

The Oroville Dam is the highest in the nation.

[EarthResearcher333]

Board worried - DWR keeping this from the public - "failing" anchor tendon scenario (engineers working on)

This is being kept from the public. No news stories on this. Not even a peep in the "rebuild" press conference in addressing a potential serious issue - DWR engineers are quietly calculating how much damage the spillway could be weakened by "snapped" anchor tendons (they don't know right now i.e. tendons snapped and/or loss of tension). Here is an April 8, 2016 letter to FERC from DWR regarding this matter. DWR is keeping anchor tendon history related information (report data) as CEII secret.

The Board of DWR is concerned, even expecting the failure of Anchor Tendons within the Radial Trunnion Gate Structure. As of this moment, they don't have the results back from Dispersal Wave Testing and do not know if any of them have failed. They performed Dispersal Wave Injection tests in late 2016, but the parent company contracted for this (FDH-Velocitel) has not been able to compare the waveform refraction/reflection data to a sample 40ft long "test" anchor rod in the lab. DWR has requested a delay in the report back to FERC until late in 2017 until they can get a reference model built properly. The first steel rod manufactured for this lab test bed reference came back with problems. They are in the process of re-doing another reference steel anchor rod. More later.

Board worried - DWR keeping this from the public - "failing" anchor tendon scenario anticipation (engineering analysis of). Letter to FERC on the affairs of the 50 year old, end-of-life, anchor tendons & anticipation of "breakages" and "loss of tensile tension".

[jpal]

Thanks for the pictures and the diagram of the radial gates. That really helps clear up the issues that you’re bringing to our attention.

Intuitively, I would think the trunnion pins would be more of an concern then the anchors that hold it in place being as it’s an exposed moving part where the stress is concentrated versus the anchors which are encapsulated, static, and where is the stress is distributed. However, your documentation shows otherwise. It is greatly appreciated that you’re willing to share your expertise within this forum.

Perhaps this is why DWR indicated that they would be upgrading the FCO.
They can bury this work in with everything else and hope that no one will notice, or be allowed to do to security reasons. I still don’t see how they can work on the FCO until they can use Hyatt alone to get and keep the water level down below the gates, unless they’re planning on building a cofferdam, which would be quite an undertaking and in itself.

[EarthResearcher333]

2012 Thermolito Plant Fire - DWR incident report to FERC

Hi Jpal, Since you mentioned this item in upthread posting - I found the official DWR's report to FERC on the thermolito fire incident. I've seen pictures of the control room with the electronic panels completely toasted. The official incident report had narrowed down the suspected source to be in the control room. I've dealt with spontaneous fires erupting from dielectric breakdown in capacitors (electronics). In some type of capacitors, the stored energy density is enough to trigger thermal ignition temperatures high enough to ignite and sustain progressive fire in the FR4 circuit boards.

These fires occurred even though the designs are UL certified. Technically, UL certification is to "contain" a fire within an enclosure via a "flaming drip test". But, the Thermolito Power Control room was operating in an automatic "un-manned" condition when the fire broke out. Alarms went off at 6:50am. It burned for a good time before someone arrived on scene (40 min later) & observed smoke coming from the building. The CO2 fire suppression system had discharged, but it failed to put the fire out. A number of attempts by Fire Crews (CAL FIRE & other districts) to put the fire out during the day were unsuccessful so they just "sprinkler" dosed the area until overnight (i.e. until it burned itself out the next day).

Electronics, wires, plastics, etc can burn as a fuel source IF there is an oxygen supply. I've worked on designs that automatically "trip" and blow a fuse to limit fire damage triggering. It is amazing the energy that capacitors can store. (even the lithium-ion battery fire issues of laptops & hover boards - defect mitigation, via design in quality & statistical process control [SPC] is absolutely critical if you push the limits of dielectrics & anode/cathode designs). However, there is nothing like having a backup where a person is able to immediately shut things down when you first smell the unique odor of burning electronics (you will never forget that smell).

[abb]

http://www.cement.org/concrete-basics/paving/roller-compacted-concrete-(rcc)

Roller-compacted concrete, or RCC, takes its name from the construction method used to build it. It’s placed with conventional or high-density asphalt paving equipment,then compacted with rollers.

Roller-compacted concrete has the same basic ingredient as conventional concrete: cement, water, and aggregates, such as gravel or crushed stone.

But unlike conventional concrete, it’s a drier mix—stiff enough to be compacted by vibratory rollers. Typically, RCC is constructed without joints. It needs neither forms nor finishing, nor does it contain dowels or steel reinforcing.

[mad_as_he$$]

Here is a brief overview of what they did at Folsom.

http://sanfrancisco.cbslocal.com/2017/02/19/oroville-folsom-tale-dams-illustrates-challenge-old-infrastructure/

[WildHighlander57]

http://www.freerepublic.com/focus/f-news/3524221/posts?page=2840#2840

Thanks for the info!

Anytime officials make info secret on a case like this, they are hiding something.

Not. Good.

[meyer]

IIRC, the Thermolite fire is the reason that the River release valves are not being used presently. They were taken out of commission recently to upgrade the fire suppression system.

[meyer]

Thanks. I’m envisioning RCC as a sort of man-made “bedrock” that will be used as a base for the spillway.

[Jim W N]

Wow, you bring up a good point about structures like the Golden Gate Bridge.

Don’t want to get too far off the Orville Dam topic here, but do you guys have any idea of the assessment of how long the Golden Gate Bridge is built to withstand the continual tension since it was built in the 30’s?

[abb]

http://www.cat.com/en_US/products/new/equipment/compactors/tandem-vibratory-rollers.html

[abb]

Here’s an informative site.

http://www.rollercompacted.org/production.html

[abb]

https://www.youtube.com/watch?v=CbNW0jibEU8

Rollcon, Inc. Roller Compacted Concrete Promotional Video

[abb]

https://www.youtube.com/watch?v=LVYYf05A2ZA

RCC mixer

[abb]

[abb]

[meyer]

Thanks for filling me in on the concrete. No pun intended...

I don’t like that they’re going to remove and replace portions of the upper chute. I mean, for this year, maybe they can get by if it’s not suffered from the recent past releases, but in the long run, it ought to get replaced also. Maybe next year or 2019.

[abb]

Note the RCC buttress for the ogee weir emergency spill way. Wonder if they got scared it may tip over?

[meyer]

Honestly, I didn’t think tipping was a problem. But undermining would be, though I thought the quick-fix rifraf and concrete would hold for a while.

Apparently, they saw differently (and that’s one reason I’m not in charge of this type of operation).

From the looks of the drawing, they’d have to dig up some of what they just laid down.

[abb]

I imagine they’ll just lay it atop the rock/slurry work. I want to see how they start out with the RCC to fill in the rough spots. Might be tough maneuvering the vibrating rollers until they get some smooth places to work with.

Back when I was doing some paving of yards for sawmill log storage back in the 80s, RCC was a new thing. First place I ever saw anything about it was at the 1984 New Orleans Worlds Fair. Someone had a booth with literature.

I can see how it could be very economical in some applications. No forms, no reinforcing. Lots of concrete in a short period of time.

[Repeal The 17th]

I do not understand, can not picture in my mind, how they
can apply RCC in the plunge pool (AKA Moonbeam’s Canyon).
How do you put in a layer of RCC and then compact it
(rinse and repeat) into a deep crevasse like that?
Apply a layer of RCC and then lower a compacter into the hole?

It is also not going to be easy to use RCC on the uneven
surface of the emergency spillway overflow area.

I hope we get pictures/videos when the plan comes together.