Cory6188 From United States of America, joined Feb 2004, 2686 posts, RR: 6 Posted (8 years 3 months 1 week 4 days 3 hours ago) and read 2217 times:
I was reading the thread about the logic (or lack thereof) of rebuilding New Orleans in the same spot that exists right now, and it got me thinking. I have a beach house on Long Beach Island, NJ, a barrier island off the southeast coast connected by a causeway to the rest of the state. Any new home built today on the island must be built on pilings. There are still many older homes that are only a few feet above ground level, but all of the new ones are 6 feet off the ground, if not higher.
While clearly, Long Beach Island isn't New Orleans by any stretch of the imagination, is it even a possibility to do something like that?
For any of you who don't know what a house on pilings looks like, here's a pic (sorry for the tiny size):
As you can see, if there was any flooding, the only thing that might have to be replaced is the stairs - as long as the pilings remain securely anchored in the ground, the house is totally sound.
BHMBAGLOCK From United States of America, joined Jul 2005, 2698 posts, RR: 5 Reply 3, posted (8 years 3 months 1 week 4 days ago) and read 2184 times:
This could be viable in NO if you could get around the fact that there is no way to maintain the historical architecture of the city for a house built in this way.
However, in less protected areas like coastal MS and parts of AL it wouldn't do any good. For example, take a house at 10 ft MSL and then throw a 30 ft storm surge like in Gulfport/Biloxi. This typical situation would require 20 ft pilings which is a lot more than the 6 ft -12 ft typical for this type of construction. The bracing requirements to stabilize the pilings under a coastal windload would be prohibitively expensive.
Mikey711MN From United States of America, joined Nov 2003, 1381 posts, RR: 8 Reply 4, posted (8 years 3 months 1 week 3 days 22 hours ago) and read 2171 times:
Also on the note of expense, the mobilization of the pile-driver is often the driving cost in determining the economy of pile-supported structures. That is, the number of piles (typically quantified in feet of piling driven) tends to be dwarfed by the equipment needed to do the work on the site.
Is it a solution? Sure. There are plenty that a civil engineer could apply. But the economics of many of them just aren't feasible, and I'm afraid putting entire neighborhoods essentially on stilts is an example of one of them.
Cory6188 From United States of America, joined Feb 2004, 2686 posts, RR: 6 Reply 7, posted (8 years 3 months 1 week 3 days 16 hours ago) and read 2140 times:
Quoting Mikey711MN (Reply 4): But the economics of many of them just aren't feasible, and I'm afraid putting entire neighborhoods essentially on stilts is an example of one of them.
If it's feasible in NJ, I don't see why it isn't possible in New Orleans. At least 50% of the houses on Long Beach Island are now on pilings, and that number is only growing as old houses are knocked down and new ones are built. If for some reason the whole island was built that way I read in an island newspaper that the local governments predict that by 2020, all of the buildings on the island will be above sea level. It's not exactly a hard process - pilings are driven into the ground, and the house is built on them using the pilings as a foundation. Actually, the pilings can be put in the ground faster than concrete blocks can.
Cptkrell From United States of America, joined Sep 2001, 2861 posts, RR: 13 Reply 8, posted (8 years 3 months 1 week 3 days 15 hours ago) and read 2129 times:
Pilotsmoe wrote; "It's NJ. No hurricanes here."
Guess you don't remember the flooding that Hurricane Floyd brought to NJ? Probably don't remember the NJ close calls from Gloria in '85 and Bob in '91 or the devastating floods of Agnes in '72, either?
On the issue of pilings, I wonder if the outdated gambling laws in LA requiring the casinos to be "floating" will be readdressed in the future. Some of these structures are monsters but are still no match for Mother Nature as seen how some were swept away and deposted inland atop other structures seemingly quite easily. Regards...Jack
Mikey711MN From United States of America, joined Nov 2003, 1381 posts, RR: 8 Reply 9, posted (8 years 3 months 1 week 3 days 14 hours ago) and read 2108 times:
Cory, with all due respect, I'm fully aware of how piled foundations are constructed. But what is economical in Long Beach Island, NJ is not necessarily so in New Orleans, LA despite the relative need being the same. To that end, economics of construction is usually dictated by results found in a quantified cost-benefit analysis, and therein lies the difference.
Having checked out a handful of websites about Long Beach Island--not having been there myself--I would argue that it probably enjoys a higher median real estate value than New Orleans ($87,000 IIRC from some random news report I've seen in the last few days), which is a good metric in the "benefit" category. Therefore, if LBI's real estate values are, say, double that of New Orleans, there is that much more padding, if you will, to determine whether a construction method is feasible.
Now I have no hard data on houses constructed on piles, but if it costs $100,000 to build it where this house will only realize a value of $87,000 in New Orleans and $170,000 in Long Beach Island, it is clear that constructing in New Orleans with this method is, again, uneconomical.
There are certainly other variables, Cory, that dictate economical construction, but again, the key point that I'm trying to make is that either ignoring those other factors or flatly disregarding the disparity in realized benefits between the two situations, you are prone to make some invalid conclusions about construction economy.