|
Architecture and Design - Building design/construction and related topics.
|
|
|
|
If you were Registered and logged in, you could reply and use other advanced thread options
|
Posted by Kris Krieger on August 21, 2007, 7:17 pm
I have a question. We've all seen and heard the stories about wooden
houses being lifted off their foundations byu flood waters.
What I'm wondering is this. Are houses/other buildings of concrete
construction (block, o\poured, whatever) part of the foundation? IOW, are
the outer walls "fused" so to speak to the concrete foundation, and as
such, how water-tight are they, or how water-tight *could* they be...?
What I'm wonderin is whether it's possible to pour walls and foundation to
be one unit, or even, if the foundation could be poured such tat it would
come partway up and the framing would go inside of it, and then the
exterior sheathing etc. would go on top or perhaps even over it...?
Just how water-tight could a place be made?
Links would be great, as well as any info or thoughts on htis. I'm just
trying to think whetehr there are better ways of coping with flooding, than
having stick-houses that jsut sort of sit on top of a concrete pad. IT
seems like ther ehas got to be a better way, so I'm jsut wondering.
Thanks In Advance!
- K.
|
|
Posted by Edgar on August 21, 2007, 8:20 pm
>I have a question. We've all seen and heard the stories about wooden
> houses being lifted off their foundations byu flood waters.
>
> What I'm wondering is this. Are houses/other buildings of concrete
> construction (block, o\poured, whatever) part of the foundation? IOW, are
> the outer walls "fused" so to speak to the concrete foundation, and as
> such, how water-tight are they, or how water-tight *could* they be...?
>
>
> What I'm wonderin is whether it's possible to pour walls and foundation to
> be one unit, or even, if the foundation could be poured such tat it would
> come partway up and the framing would go inside of it, and then the
> exterior sheathing etc. would go on top or perhaps even over it...?
>
> Just how water-tight could a place be made?
>
> Links would be great, as well as any info or thoughts on htis. I'm just
> trying to think whetehr there are better ways of coping with flooding,
> than
> having stick-houses that jsut sort of sit on top of a concrete pad. IT
> seems like ther ehas got to be a better way, so I'm jsut wondering.
>
> Thanks In Advance!
>
> - K.
In some places, even full concrete buildings won't save them, such as New
Orleans. I found this image interesting:
http://en.wikipedia.org/wiki/Image:New_Orleans_Levee_System.svg
Normally, anchors are embedded into the concrete slab when it is poured, and
these anchors are used to attach stick built walls. In a pure concrete
building, it is basically like one monolithic structure, if we are referring
to cast in place, or similarly concrete block. The slab and/or footings are
poured first, and let dry, with rebar coming out where the concrete walls
will be. With concrete blocks, the blocks are formed as a wall with the
rebar coming through the middle, and then the middle cavities are filled to
form more or less a monolithic structure. Large buildings such as my old
architecture building, are poured in layers, beginning with the foundation,
all the usual rebar goes through the structure, but the forms are attached
directly to the concrete for the next layer and then the attachments are cut
off (in the case of our building you could see a pattern of metal rebar
looking pieces on the exterior walls where the forms were attached). Each
layer is poured onto the next, and these basically fuse to the one below it
to make one giant monolithic structure. But as far as I know, concrete is
porous and not very water tight. I don't know too much about water and
concrete personally so I'll leave that to others.
--
Edgar
--
Posted via a free Usenet account from http://www.teranews.com
|
|
Posted by Kris Krieger on August 22, 2007, 1:36 am
>>I have a question. We've all seen and heard the stories about wooden
>> houses being lifted off their foundations byu flood waters.
>>
>> What I'm wondering is this. Are houses/other buildings of concrete
>> construction (block, o\poured, whatever) part of the foundation?
>> IOW, are the outer walls "fused" so to speak to the concrete
>> foundation, and as such, how water-tight are they, or how water-tight
>> *could* they be...?
>>
>>
>> What I'm wonderin is whether it's possible to pour walls and
>> foundation to be one unit, or even, if the foundation could be poured
>> such tat it would come partway up and the framing would go inside of
>> it, and then the exterior sheathing etc. would go on top or perhaps
>> even over it...?
>>
>> Just how water-tight could a place be made?
>>
>> Links would be great, as well as any info or thoughts on htis. I'm
>> just trying to think whetehr there are better ways of coping with
>> flooding, than
>> having stick-houses that jsut sort of sit on top of a concrete pad.
>> IT seems like ther ehas got to be a better way, so I'm jsut
>> wondering.
>>
>> Thanks In Advance!
>>
>> - K.
>
> In some places, even full concrete buildings won't save them, such as
> New Orleans. I found this image interesting:
>
> http://en.wikipedia.org/wiki/Image:New_Orleans_Levee_System.svg
Well, that is a more extreme situation than I'm thinking of. I'm
wondering whether somethign could be at all water-resistant, and to what
extent. TO whit, if, say, 4 inches of water built up on a property, is
there a structure that could resist that. Well, aside from building high
;) I'm not talking about serious flood plains, such as South-East
Houston...
>
> Normally, anchors are embedded into the concrete slab when it is
> poured, and these anchors are used to attach stick built walls. In a
> pure concrete building, it is basically like one monolithic structure,
> if we are referring to cast in place, or similarly concrete block.
> The slab and/or footings are poured first, and let dry, with rebar
> coming out where the concrete walls will be. With concrete blocks,
> the blocks are formed as a wall with the rebar coming through the
> middle, and then the middle cavities are filled to form more or less a
> monolithic structure. Large buildings such as my old architecture
> building, are poured in layers, beginning with the foundation, all the
> usual rebar goes through the structure, but the forms are attached
> directly to the concrete for the next layer and then the attachments
> are cut off (in the case of our building you could see a pattern of
> metal rebar looking pieces on the exterior walls where the forms were
> attached). Each layer is poured onto the next, and these basically
> fuse to the one below it to make one giant monolithic structure. But
> as far as I know, concrete is porous and not very water tight. I
> don't know too much about water and concrete personally so I'll leave
> that to others.
>
Well, it sound like a *sturdy* structure would result, which isn't a bad
thing. Porosity - hmmm. I have to think about that - although it makes
me wonder why dams don;t leak like seives...?
I've just been looking at all the flood reports this week (well, all
Summer, actually) and this question popped into my mind.
|
|
Posted by EDS on August 21, 2007, 10:16 pm
> "Kris Krieger"> wrote
>>I have a question. We've all seen and heard the stories about wooden
>> houses being lifted off their foundations byu flood waters.
>>
>> What I'm wondering is this. Are houses/other buildings of concrete
>> construction (block, o\poured, whatever) part of the foundation? IOW,
>> are
>> the outer walls "fused" so to speak to the concrete foundation, and as
>> such, how water-tight are they, or how water-tight *could* they be...?
>>
>>
>> What I'm wonderin is whether it's possible to pour walls and foundation
>> to
>> be one unit, or even, if the foundation could be poured such tat it would
>> come partway up and the framing would go inside of it, and then the
>> exterior sheathing etc. would go on top or perhaps even over it...?
>>
>> Just how water-tight could a place be made?
>>
>> Links would be great, as well as any info or thoughts on htis. I'm just
>> trying to think whetehr there are better ways of coping with flooding,
>> than
>> having stick-houses that jsut sort of sit on top of a concrete pad. IT
>> seems like ther ehas got to be a better way, so I'm jsut wondering.
>
> Yes, and no.
> In FL a CBS house on a monolithic footing is about as *bonded* as it gets.
> You have to have a *break* in the system otherwise it become almost
> impossible to build.
> Monolithic footings are footings that are poured at the same time as the
> slab and it all cures as one piece of solid concrete.
> Around the perimeter of the slab 4' long dowel rods (5/8" d. reinf. rods)
> protrude up from the footing and the concrete blocks are laid around these
> rods with the rods going up inside the block cores.
> 8' long rods are then dropped down from the top and tied to the dowel rods
> and the block cores are filled with concrete.
> Also, along the top of the block walls is whats called a concrete tiebeam,
> which is solid concrete with a series of horizontal reinf rods inside,
> which are tied to the vertical rods coming up through the block cores.
> What this sort of amounts to is one solid piece of masonry consisting of
> floor, footings, walls and tiebeam.
> Very strong, very heavy.
> Concrete and concrete blocks are porous and not waterproof.
> What actually makes the walls somewhat waterproof is the paint that goes
> on the outside of the walls.
>
> But anyways, door openings and windows are not waterproof so the whole
> thing becomes moot at a certain point.
>
> I designed a building on Fort Myers Beach where the requirements were that
> the building MUST be waterproof to a height of 8' above finished floor
> because of the structures orientation to an open body of salt water and
> the flood plane. Because this building had large areas of glass on the
> exterior walls all sorts of people had to get involved with it.
> One more thing, this building also had to NOT float.
> You see, whan you design a building to be watertight, when a tidal surge
> occurs the building will turn into a boat and try to float away.
>
>
3,000# Concrete is not watertight. 4,000# is much more watertight, but all
joints must be designed to include waterstops (6" wide ribbed vinyl or
rubber sheets) that must be lapped and heatsealed at the laps. An
interesting concrete system is Royal Building Systems from Canada, with pvc
forms that remain in place and form an impervious surface on both sides.
system is set up by sliding the plastic units together and installing rebar
as you go. I have a large carwash, detailing, and lube building going up
this summer.
If your building is not heavy enough to stay put during flooding, a thicker
slab will hold it down. I've seen up to 11' thick slabs, and commonly are 3'
in areas with high water tables. Underground fuel tanks usually have to have
a slab to hold them down.
EDS
|
|
Posted by Bob Morrison on August 22, 2007, 1:57 pm
In a previous post EDS wrote...
> 3,000# Concrete is not watertight. 4,000# is much more watertight, but all
> joints must be designed to include waterstops (6" wide ribbed vinyl or
> rubber sheets) that must be lapped and heatsealed at the laps. An
> interesting concrete system is Royal Building Systems from Canada, with pvc
> forms that remain in place and form an impervious surface on both sides.
> system is set up by sliding the plastic units together and installing rebar
> as you go. I have a large carwash, detailing, and lube building going up
> this summer.
> If your building is not heavy enough to stay put during flooding, a thicker
> slab will hold it down. I've seen up to 11' thick slabs, and commonly are 3'
> in areas with high water tables. Underground fuel tanks usually have to have
> a slab to hold them down.
>
Better yet is to use an integral waterproofer put in the mix. However,
any openings (windows and doors) will render the waterproof concrete moot.
It is simply not possible to build a waterproof house unless you design it
as a boat that will float when the water gets too high. This is the only
idea I've seen recently that has any merit.
--
Bob Morrison, PE, SE
R L Morrison Engineering Co
Structural & Civil Engineering
Poulsbo WA
bob at rlmorrisonengr dot com
|
Page 1 of 3 1 2 3 > last >>
| Similar Threads | Posted | | well well well... (not water) | February 11, 2008, 6:05 pm |
| OK folks, about well water... | January 21, 2007, 11:18 pm |
| Water Walls | July 30, 2007, 6:42 pm |
| Re: water in architecture | April 24, 2006, 12:02 pm |
| Re: water in architecture | April 24, 2006, 12:05 pm |
| Re: Concrete slab question | July 3, 2007, 4:09 am |
| New Cast Concrete Elements | September 7, 2007, 6:27 pm |
| Light transmitting concrete | November 1, 2007, 7:18 pm |
| Visited Falling Water Today... | July 29, 2007, 2:29 pm |
| Concrete Deck Overhang depth | May 17, 2007, 5:49 am |
|
|
|
Yahoo! 
Google 
Windows Live 
del.icio.us 
digg 
Netscape 
XML Sitemap