Levees in New Orleans 13

[livingston]

After Hurricane Katrina hit Lousiana, more destruction is occurring because of levee failures around the city. Does this mean the factor of safety was too low, they were old, what? They seem to be failing at the purpose for which they were designed. Please explain.

 

[unclesyd]

Kinda discounting the original source here is a point really bears looking into. Just another problem that was allowed to exist apparently with no real concern.

http://ktla.trb.com/news/local/la-na-levee1oct01,0,4363200.story?coll=ktla-news-1

Here is the American Society of Civil Engineers Investigation Team.

http://www.asce.org/static/hurricane/team.cfm

Another disquieting situation is the lack of off the self plans for repair or remediation of existing levees. I heard two statements that they were working on conceptual ideas for repair or replacement. I could see this situation existing for an earthquake hitting NO, but not something that was inevitable.

 

[jmw]

Time for "N'orleans" pizza a la "Veniziana"?

http://calvin.st-andrews.ac.uk/external_relations/news_article.cfm?reference=300

JMW

http://www.ViscoAnalyser.com

 

[BitTwiddler]

A new cause has been reported for the flooding of New Orleans:

"Much of the city flooded not because water rushed over the tops of levees, but because two of the storm barriers that ring New Orleans actually shifted and then collapsed, a team of independent engineers said Friday.

The preliminary analysis contradicts initial reports by the U.S. Army Corps of Engineers, which said water may have pushed over the top of the levees, eroding the earthen embankments that support the flood walls."

http://news.yahoo.com/s/ap/20051008...bsbRNes0NUE;_ylu=X3oDMTA3MjBwMWtkBHNlYwM3MTg-

 

[nola]

as mentioned in the yahoo news article pasted in an earlier post it does seem that some of the failures were not due to overtopping. the levees along the london ave canal seem to have failed due to design flaws associated with the underlying shallow geology in the area. under 10 -15 ft of deltaic muds upon which the levees were constructed lies a 35 ft. thick barrier island sand deposit that extends from the new orleans area westward to alabama. the canals were excavated to a 10 ft depth. current velocites in these canals during times of heavy rains when the city pumps were pumping rainwater into the lake had the velocities high enough to scour the canal channel floor down to the sand deposits. the sand is a clean sand relatively free of clays and silts and therfore has a high permeability underneath the levee. as water rose and pressure increased on the levees the piping through the sands allowed for boils to form and eventually undermine the levee. evidence of this is the high volume of sand and marine shell material that formed splay deposits into the neighborhood at each of the london ave breaches. also vines and other vegetation remain along the tops of the floodwalls. there are also sections of levee that have been moved back about 10 feet and vertically about 8 ft and still retain their grassy crowns giving validity to the undermining and heave theory. i was at one of the breaches yesterday and the usace was installing monitoring wells along the levee to determine if there is any connectivity between the canal and the underlying sand deposits. there are various groups conducting forensic type investigations into these failures so it will be interesting to see what comes of this.

 

[jmw]

Thanks Nola and welcome to Eng-tips.

JMW

http://www.ViscoAnalyser.com

 

[BitTwiddler]

Evil has triumphed again in the US Senate.

From USA Today:

Ground hasn't been broken yet, but the infamous "bridge to nowhere" that would connect Ketchikan, Alaska, to an offshore island where only 50 people live, appears to be indestructible. The highway bill allots $223 million for that project and $229 million for another boondoggle bridge near Anchorage. Coburn wanted to withdraw funds for the bridges and shift $75 million to rebuild a Louisiana bridge damaged by Hurricane Katrina. It should be a no-brainer that the needs of the devastated Gulf Coast are greater.

Sen. Ted Stevens (R-Alaska), was personally insulted, however. Alaska, which ranks No. 1 in per capita federal spending, was being unjustly singled out, he argued. The 37-year Senate veteran threatened to resign and "be taken out of here on a stretcher" if the Senate killed off perhaps the most egregious example of wasteful spending in the massive highway bill.

Senators were so moved by Stevens' sense of outrage - or the idea that their own pet projects could be next - that they voted 82-15 to keep funding the bridges. The Senate also refused to defund a $500,000 sculpture park in Seattle and $950,000 for a Nebraska museum parking facility.

Those wasteful projects are only a few of the 6,371 "earmarks" legislators pushed into the transportation bill alone.

http://news.yahoo.com/s/usatoday/20...3wIfnWs0NUE;_ylu=X3oDMTA3YWFzYnA2BHNlYwM3NDI-

Why on Earth would any bright young American want to become a civil engineer? Would any sane person want to waste his or her time catering to the whims of these clowns?

There are over 200 lawyers and zero engineers in the 108th Congress. It shows.

Americans should expect more civil engineering disasters such as New Orleans for the rest of this century.

 

[bradphillips]

BitTwiddler for Congress!!!