From: John Cuccia 

On Fri, 16 Dec 2005 22:21:58 -0800, Jeff Shultz
 wrote:

>> I don't care where it comes from.  If the feds are going to fill a hole
>> with money, I'd rather it be the hole that the Corps of Engineers dug in
>> South Louisiana, not the one Bush is still digging in Iraq.
>
>The Corps of Engineers dug? You apparently haven't heard the latest - they
>pulled up some of that "shallow" seawall and discovered it
was planted to
>the correct depth after all.

I've been following this story very closely indeed, Jeff, as you might
imagine.  First, it's a floodwall, not a seawall. second, what pulling the
pile did was eliminate construction malefeasance as a factor in the
failure, placing the onus squarely on the designers.  That is,
unfortunately, what passes for good news in New Orleans these days.

The independent engineers (from LSU, UC- Berkeley and the ASCE) studying
the design and failure indicated early on that even if the sheet piles were
driven to their 17-feet below sea level design depth it wasn't sufficient,
*given the soil data available when the walls were designed*.   The Corps
themselves now say the sheet piles should
be driven considerably deeper to meet their own nominal design criteria.

Here's a quick excerpt from an Times-Picayune article dated 10/28. Sorry,
but it's not online anymore
==============
-- The jumble of different types of weak, porous soils that were
layered at the levee location should have raised more alarms among
engineers because it meant water could travel through the material, setting
up conditions allowing it to move easily. The effect was like icing between
layers of a sponge cake; it would take even less water pressure from the
side for layers to move, threatening any vertical structures -- like a
floodwall -- embedded within it.

-- The sheet piling used to support the floodwall's concrete top was
driven to a depth of 17 feet, while the canal bottom was 18.5 feet deep.
That meant water from the canal could easily migrate through the porous
soils beneath the sheet pilings, further eroding the passive support system
engineers counted on.

-- The levee walls were built atop "spoil banks" that had been dredged
from the canals when they were dug in the late 1800s and early 1900s, and
when they were later deepened. That meant some of the support for the piles
and the concrete cap were made up of a mix of the same weak soil found
below them.

-- Attaching a concrete top to the sheet piles in weak soils further
reduced the margin of safety because it created a joint requiring even more
support. Using only sheet pilings would have been safer, the team said.

The team emphasized that while driving a single layer of sheet pile 50 or
60 feet deep to harder, less porous sands would have provided more support,
the single-wall design still might not provide the factor of safety needed
to withstand a Category 4 or stronger hurricane.
======================

Note that the Corps now says they will either drive sheet pile to a depth
of 57 feet or install batter piles to resist water pressure.

>They are also trying to decide who the heck was actually responsible for
>maintenance - it's starting to look like it was a bunch of NOLA political
>hacks... who didn't actually realize it.

Yep, NOLA hacks plus state hacks plus federal hacks:
http://federaltimes.com/index2.php?S=1414092
In preparation for the Senate Homeland Security and Governmental Affairs
Committee hearing, Jamey Huey, former president of the Orleans Levee
District Board of Commissioners, told staff that levee inspections by the
Army Corps of Engineers, the Louisiana Transportation Department, and the
levee district were largely ceremonial.

“They normally meet and get some beignets and coffee in the morning and get
to the buses and the colonel and the brass is all dressed up. You have
commissioners. They have some news cameras following you around and all of
this stuff. And you have your little beignets, and then you . . . go and do
the tourist and . . . you nave a nice lunch somewhere or whatever. They
have this stop-off thing or whatever. And that’s what the inspections are
all about,” according to a transcript of the interview.

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