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Underground garage "basement"?

jeeptj19992001 said:
The slab is not supporting anything.
framed over the slab, framing is supported by the foundation walls.
Thinking of filling in the access door in the back of the house and filling it all in with flowable fill.
Click to expand...
So it's normal rooms now, not a garage, and has a wooden floor above the steel/concrete?
Why fill in a perfectly good basement?
 
subybaja said:
So it's normal rooms now, not a garage, and has a wooden floor above the steel/concrete?
Why fill in a perfectly good basement?
Click to expand...
Cause the slab will fall in someday.
The decking has rusted away in many place and i am afraid it will fall in someday.
Its a low headroom storage area.
Gets damp in summer, that is why everything is rusted.
 
M92PV4U said:
:homer: There is a possibility of it caving in before he even gets the structure installed. Around here you aren't digging a 6' pit without it caving in. Unless you drill dewatering wells.
Click to expand...

Around here it's a solid coin toss what kind of soil you hit but after the first foot you'll know what kind of soil you're dealing with and what you gotta do to make the project work.
:laughing:
M92PV4U said:
Sandy.
Click to expand...
That picture looks like where I grew up. The only thing I miss is how easy it was to dig by hand there.
 
jeeptj19992001 said:
When my house was built in 64, they put storage under the garage.
Steel beams.
48 " oc with steel decking on top.
Concrete finshed slab.
Waiting for it cave in some day.
The decking is all rusted out.
1000006369.jpg
1000006368.jpg
1000006367.jpg

Not the smartest idea.
There are rooms about now.
The slab is not supporting anything.
framed over the slab, framing is supported by the foundation walls.
Thinking of filling in the access door in the back of the house and filling it all in with flowable fill.
Click to expand...
the decking itself doesn't add much strength
 
jeeptj19992001 said:
When my house was built in 64, they put storage under the garage.
Steel beams.
48 " oc with steel decking on top.
Concrete finshed slab.
Waiting for it cave in some day.
The decking is all rusted out.
1000006369.jpg
1000006368.jpg
1000006367.jpg

Not the smartest idea.
There are rooms about now.
The slab is not supporting anything.
framed over the slab, framing is supported by the foundation walls.
Thinking of filling in the access door in the back of the house and filling it all in with flowable fill.
Click to expand...

even with those big i beams it might still cave? how is that possible? ttying to understand
 
jeeptj19992001 said:
When my house was built in 64, they put storage under the garage.
Steel beams.
48 " oc with steel decking on top.
Concrete finshed slab.
Waiting for it cave in some day.
The decking is all rusted out.
1000006369.jpg
1000006368.jpg
1000006367.jpg

Not the smartest idea.
There are rooms about now.
The slab is not supporting anything.
framed over the slab, framing is supported by the foundation walls.
Thinking of filling in the access door in the back of the house and filling it all in with flowable fill.
Click to expand...


That's a long ways from rusting out.


You could get crazy and actually paint it if you want to stop the rust...:flipoff2:


Pan deck and concrete is holding up lots of buildings. You just don't realize how often you're walking on that exact same thing.
 
Chevy_man said:
2 kinds of concrete, 1 has cracks, 1 is going to crack :flipoff2:
Click to expand...
9/10 sections of my 100yo sidewalk are still fine and that's with tree roots heaving them up and me parking cars on them. Control joints, good compaction and not building on top of shitty organic soils or sand go a long way.
 
At my place I am on solid rock. The development that went in about a 1/2 mile away had to have blasting crews for everything. Just vertical rock pits. 1.5 miles away in town its old river bed and you can did for days with no end in site. That said its river rock and gravel so the sides constantly cave in.
 
jeeptj19992001 said:
The concrete slab is cracking as well.
Click to expand...
Cracks aren't a problem and not a sign of slab failure, chunks coming loose is a sign of failure. Concrete shrinks from the time it's poured till the day it's ripped out, causes tension in the slab matrix and those turn into cracks eventually. Add some ventilation fans to that space and squirt some rusty metal primer on the underside of the deck. It'll last another 30yrs, I've seen parking garages that look way worse
 
sides a hundred yards of flowable fill ain't gonna support that at all, you'll still have a couple feet of void space under the slab unless you tear the slab out to get it all in there


but hey, we all do that thing where we imagine up a problem that doesn't exist and then go to inordinate lengths to solve it when it wasn't in need of touching to begin with
just look at my retarded house thread for mine
 
ironman_gq said:
Cracks aren't a problem and not a sign of slab failure, chunks coming loose is a sign of failure. Concrete shrinks from the time it's poured till the day it's ripped out, causes tension in the slab matrix and those turn into cracks eventually. Add some ventilation fans to that space and squirt some rusty metal primer on the underside of the deck. It'll last another 30yrs, I've seen parking garages that look way worse
Click to expand...

how do those huge freeway bridges not crack?
 
fordguy said:
how do those huge freeway bridges not crack?
Click to expand...
They do, just not structural cracking as much. There's also about 150 pages of rules starting with the aggregate in the concrete to make sure they don't have structural cracks and they still fail. :flipoff2:
 
jeeptj19992001 said:
When my house was built in 64, they put storage under the garage.
Steel beams.
48 " oc with steel decking on top.
Concrete finshed slab.
Waiting for it cave in some day.
The decking is all rusted out.
1000006369.jpg
1000006368.jpg
1000006367.jpg

Not the smartest idea.
There are rooms about now.
The slab is not supporting anything.
framed over the slab, framing is supported by the foundation walls.
Thinking of filling in the access door in the back of the house and filling it all in with flowable fill.
Click to expand...
Those pans were just forms to hold the concrete during the placement. Should be rebar and the slab giving it all the strength. The pan is not considered when designing an elevated slab.
 
fordguy said:
how do those huge freeway bridges not crack?
Click to expand...

They do. They also typically have #6 or larger bar on 6-12" centers with 100% tie off. Then they use 6-8000psi concrete.

Your typical slab on grade will be #4 on 18-24" centers with 50% tie off. With 2500psi mud, maybe 3500psi if they're feeling fancy.
 
junkytj said:
Those pans were just forms to hold the concrete during the placement. Should be rebar and the slab giving it all the strength. The pan is not considered when designing an elevated slab.
Click to expand...
they do make decking that is engineered to be structural, but that normal B-deck really is not

you can easily tell because it has a bunch of little convolutions inside the corrugations to help with bonding to the concrete
but even that shit will specify bar inside it
 
[486] said:
they do make decking that is engineered to be structural, but that normal B-deck really is not

you can easily tell because it has a bunch of little convolutions inside the corrugations to help with bonding to the concrete
but even that shit will specify bar inside it
Click to expand...
The "convolutions" are actually venting to help with proper curing of the Structural Concrete above.
Concrete generates a SHITLOAD of heat as it cures. This is why there are curing processes for structural concrete, along with all the different admixtures, etc.

Current concrete technology is lightyears ahead of where it was just 20 years ago.
 
fordguy said:
say what? never noticed any heat when curing
Click to expand...
Yep
Its a chemical reaction....not going to get to 175 degrees, But 10 to15 degrees warmer.

You are also not laying on it asit cures, so you cannot tell it is getting warmer.

www.concreteideas.com

How Much Heat Does Concrete Produce While Setting?

How much heat does concrete produce while setting? Here's thorough description of why concrete gives off heat when it is curing and how much heat it gives off.
www.concreteideas.com
 
fordguy said:
say what? never noticed any heat when curing
Click to expand...
Depends on the mix design and area of placement. Slab on Grade, or footings against natural earth, you probably won't really notice it, but..........

Build a 1 cubic foot box and fill with concrete
Report back tomorrow

I've also heard that a cubic yard of concrete, poured as such, can take up to 30+ years to "fully" cure (design strength) at its core. Could be an Old Wive's Tail.

Another Tail I heard way back when was that when they demoed the supports (In the 80's??) for the bridges over the 110 Freeway (Arroyo Seco Parkway, completed 1941) in L.A. to build the elevated deck south of Downtown, there was still "green" concrete in some of them.
 
Bogus One said:
Another Tail I heard way back when was that when they demoed the supports (In the 80's??) for the bridges over the 110 Freeway (Arroyo Seco Parkway, completed 1941) in L.A. to build the elevated deck south of Downtown, there was still "green" concrete in some of them.
Click to expand...
bet the middle just got hot enough that it cured to a shitty strength and was chippy like 'couple days old' concrete
 
I was thinking something leeching in from the outside leaving the middle looking how it originally cured. But in LA heat related shit makes more sense. You know that shit sat in the sun as it cured.
 
Bogus One said:
Depends on the mix design and area of placement. Slab on Grade, or footings against natural earth, you probably won't really notice it, but..........

Build a 1 cubic foot box and fill with concrete
Report back tomorrow

I've also heard that a cubic yard of concrete, poured as such, can take up to 30+ years to "fully" cure (design strength) at its core. Could be an Old Wive's Tail.

Another Tail I heard way back when was that when they demoed the supports (In the 80's??) for the bridges over the 110 Freeway (Arroyo Seco Parkway, completed 1941) in L.A. to build the elevated deck south of Downtown, there was still "green" concrete in some of them.
Click to expand...
Concrete is always curing and never fully cures

www.forbes.com

Concrete Deforms Over Time - And Scientists Finally Know Why

It’s a mystery that has plagued scientists and engineers for decades, but UCLA researchers think they’ve cracked concrete’s creeping behavior.
www.forbes.com www.forbes.com
 
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