Brick wall for flood protection

[publiuss]

I'm not an engineer so forgive me. I am considering buying a house in a flood zone in S. Louisiana and am trying to figure out a way to block floodwaters with an acceptable asthetic presentation. My idea, a brick faced concrete filled wall. Build 2 brick walls parallel 16-18in. apart 1 brick thick and fill with concrete 4-5ft. tall. Will it work. will the brick withstand the weight of the poured concrete and how deep in the ground should I start the first layer of brick? Wall example- XXXXBRICK WALLXXXXXX
XXXXCONCRETEXXXXXXXX
XXXXBRICK WALLXXXXXX
Many thanks.

 

[Ryb01]

Before purchasing your home, take some time to do some homework on the property. Since this home is in a flood zone, there's bound to be a history of past flood events. What were the flood elevations of these flood events? How frequent? How long did the water stay elevatated, etc?

Constructing a wall to prevent the flooding seems like a logical idea. However, there is a couple of things you will need to do prior to constructing the wall.

1) Set up a preliminary meeting with FEMA and other govering agencies to determine whether such a structure is permitted within the flood plain and also discuss other permitting requirements.

2)Obtain a professional engineering firm which can design this wall for you. The engineering firm should have specialty divisions in water resources and structural design. You may also have to aquire expertise from a geotechnical engineer for footing designs.

Hope this helps.

 

[publiuss]

Thank you ryb01, those are very good points.

 

[cvg]

construct the concrete wall first and then attach the brick facing afterwards. For design of floodwalls you might review the following book:

Publication Number: EM 1110-2-2502
Title: Engineering and Design - Retaining and Flood Walls

http://140.194.76.129/publications/eng-manuals/em1110-2-2502/entire.pdf

 

[chicopee]

Why would you buy a house in a flood plain of all places in Louisiana?

 

[publiuss]

Don't really want to, but you really don't have a choice in some areas. Pretty much everything South of I-10 is a flood zone.

 

[TDAA]

If you are going to try and "block" floodwaters from getting to the house, the first thing I would think of is where to put the stairs up and over the wall, or the ramp to drive your car over it. Short of that, you will need a sealed gate of some kind.

 

[dicksewerrat]

Jack up the house?

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[stormboy]

don't forget to make allowance for water from within the wall to egress or be safely stored during flooding. Remember the joke about the brick wall around new zealand and the aussie says to the genie: 'now fill it with water'...
Also you may have an issue with making flooding conditions worse for other people/land parcels because you are introducing an object which will deflect flows and displace a considerable volume of floodwaters ('loss of flood storage') I don''t know what US rules are like but over here in AU the golden rule is 'don't make it worse for anyone else'. It would help to know the nature of the flooding to decide whether you are best to direct fast flows away, keep rising water out, or raise the house above both. Look for existing flood studies of sufficient resolution to give you depths, velocities, rates of rise and recession, duration of flooding, extent of flooding. A problem like this generally speaking has no cheap and easy solution. Data on flood behaviour is a good place to start scoping the problem.

 

[gibfrog]

I would follow dicksewerrat's advice. Raise the house above the flood level. The higher the better. You can have a garage and storage under your house if you raise it ~8'. 4-5 Feet of fill is almost a "no brainer" Think majestic steps leading to a front entrance way feature with columns.
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A flood wall has 2 basic issues. 1 - It must be strong enough to hold back the flood water. No big deal, gravity retaining walls are well understood. Your flood wall may also need some kind of membrane. Just some more money. You will need some kind of ramp for vehicular access over the wall, unless you park outside the wall or have a water-tight gate. Think ~10:1 slopes and maybe 10'-20' flat at the top. Just more money. 2a - You must not flood yourself from a downpour or seepage. When a hurricane hits, it also brings maybe 16" of rain and knocks out the power. (Melbourne FL got 30" of rain from tropical storm Fay on 8-20-2008) Think gasoline powered pump to remove the rainwater. Your wall may be holding back the flood water, but it can seep under the wall. The rate will depend upon your soil and the water depth. I seem to remember that they installed deep sheet pilings/coffer dams under the rebuilt flood walls in LA. Again think gasoline powered pump.

Of course, FEMA must approve this. To the best of my knowledge, they do not approve flood proofing of "living" spaces. They require the finished floor to be at or above the 100 year base flood elevation.







Clifford H Laubstein
FL PE 58662