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| Science & Technology |
| Floodwall's shallow pilings called 'design flaw' |
| 2005-10-24 |
| New Orleans -- When the Army Corps of Engineers started to design a floodwall on the 17th Street Canal here in the early 1980s, deep probes found what geologists viewed as a potentially weak layer of peat soil about 15 feet below sea level in the area where the wall collapsed during Hurricane Katrina. Yet in building the wall, Corps officials acknowledge that they did not drive the steel pilings -- the main anchors for the structure -- any deeper than 17 feet. Several outside engineers who have examined the designs say the decision not to hammer the pilings deeper and into firmer ground left the support for the floodwall dangerously dependent on soil that could easily have washed out under the immense pressure from the floodwater. And members of a team of experts from the National Science Foundation say it now seems likely that this simple failure probably led to the collapse of the walls on the 17th Street and London Avenue canals, which flooded the main parts of the city. Corps investigators say they have just started going through 235 boxes of the agency's records that could shed more light on why the engineers believed the design was safe. And outside investigators say they would like to examine more of the records before deciding what caused the break. Robert Bea, an engineering professor at UC Berkeley who has examined the soil data for the National Science Foundation, said the decision not to drive the piling deeper was "a design flaw." He said he and others in his group believed it was the most likely reason that the floodwaters broke through, shoving parts of the walls and the earthen levees beneath them as far as 35 feet into nearby neighborhoods. Walter Baumy, the chief engineer for the Corps' New Orleans district, said, however, that the problem was "a little more complicated than just saying that there's a 5-foot-deep layer of peat in there." "What's probably more important is, how did we account for it in the design?" Baumy said. "Or did we properly address it?" He added, "We need to step back and review our design and see if it was done properly at that time." The teams from the National Science Foundation and the American Society of Civil Engineers visited the breach sites and plan to release a preliminary report in early November. |
| Posted by:Steve |
| #14 my RetainPro program doesn't have a setting for "politics trumps physics".... sorry |
| Posted by: Frank G 2005-10-24 22:48 |
| #13 Frank---it was not a bug, but a feature. As long as the water did not rise up on the levee, it was fine and served the city well. If there was no global warming, the piling would never have been overstressed and failed. So it was Bush's fault because he did not sign Kyoto. QED |
| Posted by: Alaska Paul 2005-10-24 22:37 |
| #12 yep |
| Posted by: Frank G 2005-10-24 20:28 |
| #11 "dependent on soil that could easily have washed out under the immense pressure from the floodwater" I hate journalists. They don't seem to understand the basics of anything. The water pressure at the base is determined solely by the water depth at the base. There was no "immense" pressure -- just a few more feet of water and a very crappy piling design. |
| Posted by: Darrell 2005-10-24 20:01 |
| #10 I'm fairly sure the Army Corps of Engineers is funded and managed at a federal level. Yes. But it's called 'going native'. |
| Posted by: Pappy 2005-10-24 19:32 |
| #9 Corps are career beauracrats that let their interns do the shit work like levee studies. They likes um build bridges, and let the underlings do everything else. EP |
| Posted by: ElvisHasLeftTheBuilding 2005-10-24 18:39 |
| #8 these wall types are pretty easy to design, given adequate soil info. Any competent private firm can do them (and the few gov't offices incapable of doing the design would normally contract out the work). Heads should roll...... |
| Posted by: Frank G 2005-10-24 16:20 |
| #7 My take as well, .com. back in 1986 I did some architectural work for the Corps. There was NO oversite as far as I could see. The regional manager was as far as it went and that only for the larger projects. Lots of civilians working for them as well. |
| Posted by: Deacon Blues 2005-10-24 15:48 |
| #6 Woops, I was still a-typin' when one of our notable resident CE's posted. Thanks, Frank, heh. |
| Posted by: .com 2005-10-24 13:05 |
| #5 It was my experience, quite by accident, to come to know the Corpse of Engineers as a fairly autonomous collection of regional specialists. Sure, they deferred to HQ on many things, I guess, but when it came to their area of expertise, such as those who ran the LA & Miss River fiefdom(s), they were not seriously challenged when they put forth a plan in their district. Consider the monumental task of auditing every single project in the country. No HQ could've checked all of the engineering specs, reviewed the plans in depth, or, assuming the project proposals even contained sufficient detail to do so, thoroughly verified the plan was without error. Additionally, consider that congressional funding of such plans was usually project-specific. The Corpse, as a whole, received admin funding for HQ and to maintain staff throughout the system, but local politicians pushed for specific funding of their pet projects and such funds were earmarked, accordingly. So was the Corpse district responsible for LA (Miss River, NO levee system, et al) quasi-independent? You fucking bet it was. And it was the envy of the entire Corpse, too, for it received the mostest for the longest. And now the tab comes due. NO was only hit with a Cat 2-3 level storm and, until the levee failed, it looked like it would manage to wiggle out of yet another brush with reality. But it did fail, and so the bright white light of Blame finally begins to pinpoint some of the culprits who played the game. Most certainly, the LA politicians will throw anyone, anyone at all, to the dogs to save their own hides. The Corpse is both culpable and convenient. I just happen to think that engineering allows for specific determinations, y'know - the hard fact thingys we hear about on occasion, being all scientific and everything, so yep, thar be blame here. So I'm thinking they will burn. Right, wrong, or indifferent - they will get a major measure. Such is my take. |
| Posted by: .com 2005-10-24 13:03 |
| #4 basic engineering 101: piles have to have adequate side or bottom bearing against stable soil or they don't work. Licenses should be pulled and jobs lost - this was an entirely forseeable failure |
| Posted by: Frank G 2005-10-24 12:55 |
| #3 Phil raises a good issue that I have often wondered about. The Army Corps of Engineers seems to this civilian like it often doesn't have a lot to do with the Army and that there's probably two parts to it, one that actually does build bridges and fortifications for combat troops and one that acts as a service organization to curry favor with congresscritters by doing pet projects, some of which may actually be beneficial, to help improve the critters chances of reelection and the Army appropriations chances of passage. But it sure does seem like the Corps of Engineers is a lot more involved in the internal workings of the country than the Posse Comitatus Act allows :-). |
| Posted by: Unaviting Whomotch1171 2005-10-24 11:41 |
| #2 .com, I'm fairly sure the Army Corps of Engineers is funded and managed at a federal level. (Although I thought that particular canal was designed by the New Orleans Levee Board. I've lost track of which levees are the responsibility of which agency over the years). |
| Posted by: Phil 2005-10-24 11:30 |
| #1 The Army Corpse of Engineers in LA is just Nooooooo. Say it ain't so. "We need to step back and review our design and see if it was done properly at that time." Or you could admit, along with all of the other LA institutions that have lobbied since Adam for Federal handouts, that you are no different from the rest of the bloody political pork project assholes there and nobody in LA really gave a shit and so happily wasted untold billions of tax $ largesse heaped upon your sorry asses for generations to design and address an engineering problem that could be solved by almost any competent CE with .1% of what's been thrown your way. Then commit seppuku. |
| Posted by: .com 2005-10-24 10:55 |