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.
I believe Kiewit is planning on a crane "move and place out-of-the-spillway" of the crane's disassembled components outside of the spillway just to expedite the spillway "clear out" process and insure "Quality Control" in eliminating any chance of damage infliction on the many fresh "curing" patches to get to the gates.
Keep in mind, DWR is also sensitive to and likely looking at the "Public Relations" viewpoint of this Nov 1 stated completion deadline.
Even though its been stated that slab seam work, drains, and other minor tasks are still to be done, the Media may jump on the issue of this deadline if there is any major equipment and/or materials distributed in the spillway.
The prior drone footage photo capture shows the "staging" of a bull dozer, roller compactor, and a tracked dump truck, that drove on sheets of wood panels, to a point near a large crane next to the spillway. This reveals that Kiewit will "lift" these out by crane even though they could theoretically bring in flat bed tractor trailer units. (but then this would not be too wise to risk "stressing" the curing of the fresh pour concrete work to get to the gates).
Always choose the highest Quality Control option. Don't risk any margin of uncertainty in the process.
----- DWR Statement: (emphasis mine)
An aerial view of the Lake Oroville spillways recovery site in Butte County, California. The California Department of Water Resources (DWR) met its November 1, 2017 goal of replacing the lower chute and sections of the upper chute of the flood control spillway and placing roller-compacted concrete in the erosion area, allowing the flood control spillway to handle flows of 100,000 cubic feet per second for the coming winter season. Construction will continue after the November 1 milestone, focusing on site cleanup and the completion of the emergency spillway’s underground secant pile wall. During the second phase of construction in 2018, DWR will place additional structural concrete on the flood control spillway and complete the emergency spillway buttress and splashpad. Photo taken November 01, 2017.
---- end Statement
Yet to be removed from the spillway: Large Crane, RCC compactor head Excavator, Sidewall panels, 10 large concrete "barriers" at RCC lower transition slab, concrete coverings, miscellaneous scaffolding and equipment. Notice the "gathering" for a photo-op at the Aerator Transition Slab.
My mistake. I noticed the width of the vehicle after posting that it could drive out.
Never believe the government’s self-assessment.
Not a problem...Gave me an excuse to see what the track width was on these big machines.
Without Kiewit's expertise, project/materials management, coordination, workforce leveraging, engineering skills, and talent, I do not believe that DWR could have accomplished this feat if DWR tried to fill these roles as the prime contractor. In essence, Kiewit "carried" DWR through this.
So the question becomes will they have to use the spillway this year or not...
1) I believe that more often then not most years they DO NOT need to use the spillway
2) lets look at lake levels now 693 feet last year at this time it was 737....so far less then an inch of rain has fallen at the DAM while last year at this time 5.25 inches(of course more in the MTS)...a wet 7-10 days ahead however starting now..
3) the lake level bottom out at 725 feet last year on NOV 30 despite 8.28 inches of rain season to date at the DAM..the outflow was about what it is now 3-4000cfs outflow
4) in the middle of a very wet winter and average outflow of 3-4000cfs season to date from the power plants the spillway was used for the first time last year on Jan 13th when the lake hit 851 feet..the total precip to date at that point was 24.4 inches
I suspect when the lake gets to a certain elevation they will increase the outflow from the power plants from the typical 3-4000cfs well before the lake hits 850 feet and they have to use the spillway..
so odds are unless this season is very wet similar to last season they will NOT have to use the spillway this year...and if they do it will likely be later then last year...
of course, in the end, it all depends on mother nature
I have no reason not to trust Kiewit, but I think we all have reason to not trust DWR and its self-assessments.
For instance, whose “deadline”? Certainly not the deadline of the residents of Oroville and others in jeopardy below the dam. Their “deadline” is for DWR to make the dam safe before the reservoir fills up this winter. DWR hasn’t met that deadline as far as I can tell.
“Without Kiewit’s expertise, project/materials management, coordination, workforce leveraging, engineering skills, and talent, I do not believe that DWR could have accomplished this feat if DWR tried to fill these roles as the prime contractor. In essence, Kiewit “carried” DWR through this.”
Amen.
Extracting from fluid flow dynamics...these photos reveal key features of the Aerator air injection design. The spillway water flow will "fall" in a curve from the upper lip as the flow has a given inertial velocity. This forms a lower pressure cavity region at the face of the vertical lip. Using this low pressure formation, the placement of an "air vent" at this low pressure area facilitates a volume of air to be drawn into the crease region or the face region of the vertical step.
This natural energy powered arrangement is formed as the air vent is part of a hollow box concrete column. The column is the inlet to the air. Not sure from he shadows of the concrete inlet if column has an internal taper to the "box" outline into the smaller area of the "air vent". This is important to insure a clean laminar airflow while avoiding a resonant pulsation effect. A non-tapered "bottom" design could resonate a bit like a church organ pipe and hinder the intended maximum airflow injection & pressure. Overall, a simple and elegant design. If it does resonate with "pulsations", the acoustics of this may be interesting, but not amusing to the nearby homeowners to the dam.
Another feature is observed in a special pour of "rough surface" concrete at the sidewall at the Aerator lip. This "rough surface" will induce a turbulence to the sidewall surface water flow - most likely to prevent vortices from forming at the post drop lip sidewall. This is a similar effect type of design used in aircraft wings where little metal tabs are spaced along a section of the wing to keep the airflow from separating from the wing's surface (forming oscillatory vortices and destabilizing lift/control/efficiency).
The main goal of an Aerator design is to inject as much air bubbles as efficiently as possible without creating disruptive oscillatory conditions, pulsations, or vortices. It will be interesting to see how far the air penetrates in the crease region to the center regions of the spillway.
Note: Answer on the "large crane" in the spillway - DWR revealed in a recent press update that Kiewit will disassemble the crane in the spillway and truck out the crane components through the Gates. No mention of the "trucking out timeframe" considering the curing of the fresh patchwork on the Upper Spillway. It's possible that plates may laid down to drive over any "patches" still in any sensitive curing window from any tire weight distribution. I guess DWR is not as concerned now about PR of getting the crane out quickly.
Crane lifting out Small Excavator - Nov 1. Note the custom "rough surface" concrete on the sidewall at the Aerator transition slab - plus the Aerator "Air Injection" vent at the RCC level.
Closer view of the custom "rough surface" concrete and the lighting shadows revealing the "Air Injection" vent at the sidewall lip of the Aerator lift. Air will be pulled into and underneath the "curved fall" of the spillway waterflow. Hollow "box column" allows a volume of Air to flow down into this vent via "differential pressure" formation.
Thanks for this. Interesting observations and analysis. I was wondering the purpose of the prefab concrete structures. A very simple design. “No moving parts” is a good thing!
I have followed this thread from the beginning but don’t know if this live cam has been mentioned. The top left is a live video on the top of the spillway which switches from the spillway to the area of the emergency spillway. You can see the crane we have been talking about with people near it. It turned a little from when I started watching this mourning. They just laid the boom down.
The one on the left gives several views from the bottom. Saturday it was raining enough to see some water flowing off the bottom.
http://www.disclosuremedia.net/oro/cams.php
enjoy , BVB
Hi BVB, Thanks for the link. DWR recently noted that the crane in the spillway was going to be disassembled and the pieces trucked out through the gates. I'll bet the workers would prefer the nice dry weather they've had until recently (for this task).
Images from a video where US Navy MH53 large helicopters are doing emergency drops of material to mitigate the erosion of the destroyed spillway. Hurricane Maria caused the dam to overflow into its designed overflow emergency spillway.
The photos reveal the extent of the erosion and the movement of sections of the back section of the earthen dam from the destabilizing erosion after the concrete spillway fell apart. Emergency Repair work is being coordinated by on-site US Army Corps of Engineers.
Youtube of repairwork: https://www.youtube.com/watch?v=l9IZtnZ-4-I
https://www.youtube.com/watch?v=l9IZtnZ-4-I Navy MH53's placing barriers down for emergency stop-gap repair to the broken and eroded spillway at Guajataca Dam in Puerto Rico.
Concrete drop zone to enact repairs to mitigate further erosion of the backside overflow spillway.
Navy MH53 lifting new concrete barrier to drop into erosion area of spillway at Guajataca Dam in Puerto Rico. Rows of concrete barriers set up on the road for sequential lift-drop cycles.
Happy Thanksgiving, ER333,
Have you retired this thread? I see you began to follow progress on the Puerto Rico dam repair.
Thank you for following the Oroville project to completion of phase 1. Perhaps we can look forward to a rainy season in which the dam functions normally and the folks living below the dam are safe.
The Westerner
Happy Thanksgiving,
I’m waiting for the new events to unfold. Of particular, the release of the Independent Forensics Team final report.
First, thank you to KCBurke and the many other Freepers who contributed to the historical record contained here. And thanks to Jim and John Robinson for hosting this document.
“I’m waiting for the new events to unfold. Of particular, the release of the Independent Forensics Team final report.”
Do you think the “Independent” Forensics report will be objective? Will they have read this thread I wonder?
I’m not an engineer so cannot understand much of what has been posted by you and the other experts here. What I did retain is:
1) the implication of the wet patch on the side of the dam, and
2) the malfunctioning gate 7(?), and
3) the shocking non-replacement of all piezometers (sp).
Stunning discoveries made thanks to the dogged work of journalists, honest scientists and our Freeper community.
The big picture I’ve gleaned is that Oroville Dam is crucial to the water supply of agriculture in California’s Central Valley because it supplies water to the aqueduct running from North to South. And also that the dam was built to supply the growing Los Angeles basin in the 60’s.
If this dam is breached, it will be a catastrophe worse than any other America has suffered. That is what I have learned from this thread. The loss to life of people and livestock, farms, cities from Sacramento to the SF Bay and South to Southern California could take down California’s economy (one of the largest in the world, I believe). When Freepers outside the Great State of California make flippant comments that it ought to be destroyed, they have no idea that a breach of the Oroville Dam will have consequences to their own precious lives as well JimRob and his family in Fresno. ER333, I hope I’m wrong, but as a layman, this is what I’ve concluded from a diligent reading of this thread.
May rational forces prevail on the DWS and Jerry Brown’s government there so that all of California’s great water project is governed by objective scientists once again. Finally, kudos to Kiewet Engineering Contractors for a job professionally done. We await the Forensic Report.
IN a potential blow to PR, news of hairline cracks have been discovered on the new massive main spillway concrete. CCRM expert Prof Bea says that "cracking in high-strength reinforced concrete structures is never expected."
DWR swiftly notified FERC of the cracking in the spillway concrete. For now, until more information is provided, the "sources" to this situation rest upon DWR and FERC.
Another potential hit to PR: Information pieces from the IFT findings were revealed by DWR's chief engineer Jeanne Kuttel on the original design deficiencies of the main spillway. Noted is the comment of "low-quality rocks".
However, the original Final Geology report noted the highly erosion prone substructure areas were in fact "clay". Many images of Kiewit workers extracting this "clay" during the new spillway construction reveal a "conflict" with the usage of the term "low-quality rocks".
"In fact, the independent forensic team points to several physical causes for the erosion (in February)," she said. "Thin concrete overlying the drains, a drainage system with deficiencies, a single layer of nominal reinforcement and shallow anchorages and low-quality rocks."
----Article clips:
Earlier this week, the Associated Press first reported that small cracks have appeared in the brand-new concrete spillway.
University of California, Berkeley, civil engineering professor Robert Bea said cracking in high-strength reinforced concrete structures is never expected.
Kiewit project director Jeff Petersen said this kind of cracking does occur in projects of this size as the concrete dries.
"It's important to understand that it's physical property of the concrete during the curing process to shrink slightly, which leads to internal stresses and therefore is normal for concrete to crack to relieve the stress," he said. "These hairline cracks do not in any way affect the structural integrity of the spillway."
….
DWR chief engineer Jeanne Kuttel said the agency promptly notified the Federal Energy Regulatory Commission about the hairline cracks. The agency will be monitoring the cracks through the rainy season and next year's construction season.
"When DWR noticed the hairline cracks in the newly reconstructed slab, we proactively notified FERC that we were putting together a monitoring program and following up on that," she said.
--- end clips more at link
DWR: Hairline cracks in Oroville spillway normal in massive concrete projects
http://www.sacbee.com/news/state/california/water-and-drought/article186945568.html
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