LATimes: Serious design, construction and maintenance defects doomed Oroville Dam, report says
New Article: A Failure Investigative Analysis Engineer reported his independent findings to the LA Times on the Oroville Spillway failure. Essentially, stating the same findings here: The weak points in the slabs from the drain emplacement upward into the slab causing thinning. He came to the same identical conclusions posted here on FR.
What is of great heartburn is the DWR spokesperson's commentary-> “We anticipate that their findings will be of interest to dam owners around the world,” Mellon said. “Their investigation is open-ended, and they have a great deal of complex information to analyze. The forensics team is expected to give DWR a plan and schedule soon.”
- - end DWR comment.
Why this is "heartburn" is that dam owners around the world already know what caused Oroville's spillway failure. The free flowing information of blueprints, photos, and discussion on engineering forums have revealed the design flaws, the continual patching, and the "jetting" waterflows from the sidewall drains. It is somewhat irritating to repeatedly state (spokesperson) that "findings will be of interest to dam owners around the world". Honestly, a reporter should go and ask what other dam owners around the world think. DWR would likely not appreciate what would be said (may include outright dismissal of DWR's commentary to even wry humor).
- - Engineer commentary Clips:
"The slab is 15 inches thick in most places, but the pipe is 6 inches in diameter and the bell housing at the end of the pipe is 10.4 inches in diameter, meaning that over the pipe the slab was just 4 to 6 inches thick — not much better than a common sidewalk, Bea said."…"“The spillway failed at its weakest point,” he said."
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"The drains play an important function in protecting the spillway. Massive amounts of water move through the ground underneath the spillway, exerting tremendous uplifting force, known as hydraulic jacking"…...“It would disintegrate like potato chips under these hydraulic forces,” Bea said. But even if the drains were working properly, they would not have prevented the failure, Bea said."
- -
BTW- Error in the Article: Their reference of about a third of the way down the spillway (incorrect)… should be about 2/3 of the way down the spillway or 1/3 of the way up the spillway…There are other errors in translation in this article regarding bars between the slabs. This may have been due to a communication understanding between what the engineer stated and what the reporter translated.
Serious design, construction and maintenance defects doomed Oroville Dam, report says
DWR Excoriated by Failure Engineering Expert - 78 page Prelim Failure Analysis Report extensively details flaws, issues, and culpability
Full report here: Well worth the read. Excellent work (note: a notable number of pictures w/ notes & graphics I created & posted on FRrepublic made it to the report, with insightful markups of his analysis. I don't mind - that is what I was hoping for - getting the word out. Thank you Robert Bea !. & GOOD JOB to ALL CONTRIBUTORS/POSTERS!!!!).
Very, very damaging to DWR as nothing is left untouched. However this report is good news for the public as Robert Bea reveals exactly what the public needed to hear on this failure, including the implications regarding all of the other DWR managed facilities.
I wonder if DWR spokespeople will now change their standard PR response of "other dam owners around the world" will be interested in DWR's findings?
note: Blue underlining of report pages, my emphasis.
Report finds serious design, construction and maintenance defects at Oroville Dam emergency spillway
