Posted on 02/12/2017 4:26:47 PM PST by janetjanet998
Edited on 02/12/2017 9:33:58 PM PST by Admin Moderator. [history]
The Oroville Dam is the highest in the nation.
” after the chute failure”
Oh!
Never mind.
I think so. A lot of aggregate is on hand already. It just needs to be classified. Truck in the Portland cement, and you're in business.
It is fairly straight forward to deduce the blacked out sections. Using a matrix of known issues, and what is excluded (via non-discussion elsewhere, thus the "blacked out" areas), a person may construct the missing pieces.
Big Failure Admission: Initial "spall defect" & then Stagnation Pressure "hydraulic jacking" lifted up & busted the slab at the failure region.
Main Spillway: One point was inferred to the risk of the time schedule (i.e. getting an option completed in time). They "blacked out" the concerns of "cavitation damage" from the high velocity flow in the rough RCC surface. Thus, smoothing layers were to be a priority to integrate.
Upper Main Spillway: They blacked out the information on the poor state of the substructure to the slabs. This information ties to the urgency to completely replace the upper spillway.
Emergency Spillway: There is a concern regarding the stability of the Large Concrete Ogee Weir. They blacked out a proposal to address this stability with layers of re-inforcement at the base, but there is a problem with forces peeling the re-inforcement away. The "blacking out" of this section was more of keeping this "flaw" state of the Emergency Spillway from being public (PR issue). The later report came to the acceptable conclusion of the massive RCC buttressing. (first report discussions talked about drilling anchors through the massive monolith Ogee Weirs - showed their concerns of "stability").
Another key point to the Emergency Spillway is that the current fixes are described for 30,000+ cfs (temporary until the full upgrade). This 30,000+ cfs rate is suspiciously aligned with the current rate of the main spillway. This could infer that they plan on depending on the Emergency Spillway to insure the May to November construction schedule. Nature may have the last say on what happens to an uncontrolled increase over 30,000+ cfs (when the main spillway is shut off & an unexpected meltoff occurs).
Critical Schedule: Construction window stated as May to November. As the spillway is limited to 35,000 cfs, inferred by the Target "slippage" from 40K to 50K cfs, there is a race with nature on whether the reservoir can be maintained from a predictable & manageable inflow (i.e. not having to use the main spillway). The report(s) do not state if the window can shrink to June to November, but there is a cutoff to construction options. (Emergency Spillway usage dependency comes to the forefront to meet these windows).
Very Surprised: No hint at all regarding the replacement of the Anchor Tendons on the FCO gate structure. DWR must be placing all of their eggs in the basket on the Dissipation Wave Testing of the Anchor rods (they are still waiting for the analysis data - delayed to Sept 2017).
Drains: Much discussion of doing drains properly. Reveals the "flawed" design of the current spillway. They also required "water stops" at the seams. Another "flaw" contributor to "hydraulic jacking".
Overall, I believe all of these issues have been covered in upthread discussions. It is ironic the blacked out areas are considered something someone may want to "attack". I believe the only "attack" that was of concern was from criticism.
The final design of the rebuild may forgo underslab drainage altogether, and rely upon sealing to prevent water infiltration.
please send me an email address so i can send the Google Document link. i do not know how to post the link on FreeRepublic.
i worked for NASA Ames...Complex Systems Group. my assignment was to provide consulting expertise on System Risk Assessment that addressed human and organizational uncertainties. during that assignment, while i was in Houston with NASA, the Columbia Space shuttle was ‘brought back’. my work was then focused by NASA to helping with their investigation of the reasons for the crash of the Columbia shuttle. i was part of the NASA internal investigation group. in the end, a primary ‘root cause’ (there were many) was traced to a mantra that the head of the Johnson Space Center had issued:”Better, Faster, Cheaper.”NASA could accurately measure Faster and Better. they could not accurately measure Better. The thermal insulation tiles on the leading edges of the wings proved not to be ‘robust’...they were intolerant of damage from things like foam that was breaking off of the launch vehicle. all known before they received the photographs from space of the missing tiles. tiles had been missing before. so they decided to ‘bring the bird back home.’
much of this experience re-surfaced at Oroville in early February of this year.
Well, there’s removal of the old spillway to be done.
Looks like they think they can make it.
(Liked this remark:”It was pointed out that excavation of the chute foundation to place a thicker slab would require careful blasting. “).
Yeah, wanta watch your blasting... next to a dam!
Interesting that using Moonbeam Canyon is the fall back position to cover the case of the lower portion of the MS not being complete by Nov 1.
Use the temporary email address of cavie46650@mypacks.net
Since the ES weir was full nearly to the top with water and it’s unclear exactly how that water entered, what’s the point of keeping the weir? Did the water penetrate a seam? Did it enter from beneath the weir?
Why bother buttressing a weir defective in so many ways? It’s not clear how or even if it’s anchored, or what the condition of the rock beneath it is, and it leaks.
Why not build a new weir using RCC or other modern technology, and key & anchor it to competent rock? Get rid of the ambiguities and the defects. Remove the junk weir, inspect the rock, and build a decent weir.
I suspect the leaking seams were from various cracks in these concrete monoliths at the mid to upper height levels of the concrete. They were built with a 4ft shell layer of enriched concrete. Penetrating water in the "build" seam layers are likely where the linear cracks exist that allowed water to seep into the base concrete.
DWR has "blacked out" information on discussion revealing any of the Ogee Weir "flaws", other than a non-blacked out section discussing a way to drill & anchor the Weir to the footing rock (was just a passing "idea" that was abandoned). The discussion then evolved and became the new proposed concept design using massive buttressing with RCC.
At least they can control the integrity of the RCC Buttress construction, thus the envelope of the RCC will secure the "flaws" of shear & anchoring.
Their decisions are "triage" driven. It is the best choice given the time and circumstances.
I'm confident that there is discussion of improving the seal at the front side rock, called a "grout curtain". Their current drilling at the front of the ES will determine what they will need to do to seal off any "piping" channels under the Weir.
I will give the BOC credit. They are driving the issues & specifications to be met correctly.
Thank you for the reply. I lost track of whether it was anchored or not. It seems to me that the existing weir serves no purpose, the buttress does the work.
I guess this is a bigger issue of intellectual dishonesty than I thought. Par for the course in this “best of all possible worlds” as Pangloss would say.
Interestingly, even though I know who you are and the quality of your mind, I don’t know your name. And if the lack of attribution to you doesn’t bother you, ok by me.
TW
http://www.latimes.com/local/lanow/la-me-oroville-spillway-20170424-story.html
Water under Oroville spillway probably caused February collapse, state consultants say
Bettina Boxall
4/24/17
Official reports released Monday say the catastrophic damage to Oroville Dam’s main spillway probably stemmed from swift water flows under the concrete chute, which was cracked and of uneven thickness.
The observations, contained in consultants’ reports prepared for the state Department of Water Resources, echo much of an independent assessment made for UC Berkeley’s Center for Catastrophic Risk Management.
An official verdict on the cause is not due until the fall, when a separate forensics team investigating the February spillway break will submit its report.
But a Board of Consultants reviewing the state’s repair plans noted several problems with the spillway’s original design and construction.
snip
http://www.sacbee.com/news/politics-government/capitol-alert/article146429894.html
April 25, 2017 12:01 AM
Fixing Oroville Dam will cost hundreds of millions. Who should pay the bill?
By Jim Miller
jmiller@sacbee.com
The damage has been done and the repair contract awarded. Yet more than two months after damaged spillways at the Oroville Dam prompted authorities to order the evacuation of 188,000 people, the question of who will ultimately pay the bill remains murky.
How much will be the responsibility of homeowners, businesses, farmers and other customers of the more than two dozen local and regional agencies that contract with the State Water Project? The 700-mile network of canals, pipelines and lakes, including Lake Oroville, brings water mostly from Northern California to parts of the San Francisco Bay Area, Central Valley and Southern California.
What will be the cost to state taxpayers, who have approved billions of dollars in borrowing to pay for flood prevention and dam-related work, most of which has already been spoken for? Will the federal government have a role after the Trump administration’s recent approval of $274 million to cover emergency repair costs from mid-February through May?
snip
New pictures have been added showing, among other things, debris removal on the lake side of the main spillway gates.
Oops, forgot the link...
The professor has initiated contact.. in apology (a new report will be created on the attribution). In his communication, an altruistic motivation was revealed, on his part for all of his work. I picked up these insights: he has been doing this as a personal project with minimal resources. His altruistic motivation is driven from the same in my part. We've both been through failure dynamics that have affected lives.
The benefits of the report have become even more fruitful as fresh press articles - essentially are confirming (and stating this in their articles) the report's findings against the newly released BOC documents by DWR. The public, the press, and even the engineers will move forward for the better, although in the shadow of the current crisis & its pre-crisis evolvement.
All of this, I believe, is mainly due to the collective efforts of postings & discussions here, the other forum(s), and especially due to the the work & expertise by the professor. The "heat" applied by the combined work, and well directed & correct analysis report with sharp wording of culpability/truths, essentially forced DWR to relent and release the BOC documents (although some sentences/paragraphs were redacted).
Crane with gripper attachment used to extract Logs and Wood debris collecting at the Spillway Inlet. Waterflow directed this floating debris and has been threatening to be pulled-in and flow through the Radial Gate Inlet structure when reservoir levels drop to the concrete curved Gate Inlet Chutes. This could cause damage to the Radial Gate metal skin plates in addition to the risk of debris jamming in the Radial Gate side seams. The force of a passed through log, then "jumping" from the outlet tail "fins" could also risk an unwanted impact on the spillway concrete chute. Good idea to eliminate these risks. Not sure "item"….I suspect the normal floating log boom is either damaged or may be unable to handle the volume and size of the logs in recent runoffs.
DWR is emplacing three large concrete pipes in the channel carved by the first emergency spillway flow near the junction at the Feather River. A large earthen bridge has been in use for the excavation process to deposit the river dredged materials. These concrete pipes will allow a volume of waterflow to pass under the rebuild of the earthen bridge. Not sure if the combined flow volume capacity of these pipes are intended for the spill volume in a potential temporary re-use of the spillway (i.e. enough for 30,000 cfs as noted in the recent BOC reports?).
Existing earthen bridge excavated to emplace 3 large concrete pipes. Pipes in the channel eroded by the first emergency spillway flow. Channel dubbed "Oregon Gulch". Bridge facilitates access for reconstruction work & to massive debris pile side of the bridge.
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