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Long concrete driveway Chuck 11-15-2006
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Posted by Chuck on November 15, 2006, 4:29 pm
On Wed, 15 Nov 2006 18:03:55 +0000, Bob Morrison wrote:

<snip>
> I'd probably go no less than 9 feet minimum to allow for the occasional
> small truck or delivery van.
>
Alright, 9 feet wide sounds reasonable.

<snip>
>
> End of pour cold joints can be 100 feet apart or so. This kind of joint
> will be full depth and will have a shear key and some oiled dowels to
> transfer shear across the joint. Crack control joints should be every 12
> to 15 feet. These joints are usually tooled or sawcut and are 1" deep.
>
Researching a bit I've found some details described here concerning shear
keys and oiled dowels in addition to how to make various connections
between pours. Do you think an oiled dowel joint would be sufficient?
http://www.usace.army.mil/publications//////////armytm/tm5-822-5/chap15.pdf

> For hand mixed concrete you will probably not be able to pour more than
> 9'x 14' in a day. So, it won't be necessary to cut crack control
> joints, but you will need some method for transferring shear between one
> day's pour and the next.
>
From work we've done in the past, your estimate(9'x14'x5"= 52.5cft) seems
reasonable but I've got to figure out a way to do much more.
Otherwise(according to my calculations) it will take 38 days to pour the
slabs alone. The plan is to start at the top and work our way down
because materials can be dropped at the top and it's easier to move them
downhill than up. Also it's going to help if at least some people can use
the top portion of the road before the lower section is able to be driven
upon.

> For compaction of subgrade, use a loaded dump truck or other heavy
> vehicle. For compaction of gravel base see if you can rent a Jumping
> Jack. If not then you can run the heavy truck over the gravel and use
> hand compaction methods for as needed.
>
If a heavy truck were to be used for compaction, how deep of a gravel bed
do I want(and what size gravel should be used?) As for actually
compacting the gravel, I'm curious how that works. Are the rocks really
getting pressed together tighter or are they being pressed into the
topsoil?? Sorry for asking such basic questions but from what I
gather this stage is crucial to the longevity of the drive and I'm
pretty fuzzy on it's function in general. I also worry about water
undermining the entire road if it seeps below the slab in places such as
the uncovered center section. Is this a legitimate concern?

Thanks,
Chuck

Posted by Bob Morrison on November 15, 2006, 7:11 pm
In a previous post Chuck wrote...
> Researching a bit I've found some details described here concerning shear
> keys and oiled dowels in addition to how to make various connections
> between pours. Do you think an oiled dowel joint would be sufficient?
> http://www.usace.army.mil/publications//////////armytm/tm5-822-5/chap15.pdf

For light traffic an oiled dowel w/o shear key is probably okay.
>
> > For hand mixed concrete you will probably not be able to pour more than
> > 9'x 14' in a day. So, it won't be necessary to cut crack control
> > joints, but you will need some method for transferring shear between one
> > day's pour and the next.
> >
> From work we've done in the past, your estimate(9'x14'x5"= 52.5cft) seems
> reasonable but I've got to figure out a way to do much more.
> Otherwise(according to my calculations) it will take 38 days to pour the
> slabs alone. The plan is to start at the top and work our way down
> because materials can be dropped at the top and it's easier to move them
> downhill than up. Also it's going to help if at least some people can use
> the top portion of the road before the lower section is able to be driven
> upon.
>
> > For compaction of subgrade, use a loaded dump truck or other heavy
> > vehicle. For compaction of gravel base see if you can rent a Jumping
> > Jack. If not then you can run the heavy truck over the gravel and use
> > hand compaction methods for as needed.
> >
> If a heavy truck were to be used for compaction, how deep of a gravel bed
> do I want(and what size gravel should be used?) As for actually
> compacting the gravel, I'm curious how that works. Are the rocks really
> getting pressed together tighter or are they being pressed into the
> topsoil?? Sorry for asking such basic questions but from what I
> gather this stage is crucial to the longevity of the drive and I'm
> pretty fuzzy on it's function in general. I also worry about water
> undermining the entire road if it seeps below the slab in places such as
> the uncovered center section. Is this a legitimate concern?

You want to end up with 6" of compacted thickness. I usually recommend
3/4" minus crushed rock. If you are concerned about pushing the gravel
into soft soil then use a geotextile between the gravel and soil.
Otherwise, compact the soil first then apply and compact the gravel layer.

The gravel layer is intended to be free-draining. Water should pass
through it. You could excavate a deeper section in the middle of the an
install a "french" drain, but given the slope of the driveway I don't
think water will be of much concern as long as you have drainage ditches.

--
Bob Morrison, PE, SE
R L Morrison Engineering Co
Structural & Civil Engineering
Poulsbo WA
bob at rlmorrisonengr dot com

Posted by Chuck on November 15, 2006, 10:38 pm
On Thu, 16 Nov 2006 00:11:24 +0000, Bob Morrison wrote:

<snip>
>
> For light traffic an oiled dowel w/o shear key is probably okay.
>
Would it take much extra effort or cost much more to make dowel joints
with shear keys at the end of each day? Is anything special used to
separate the old and new pours or do I just place the new pour up against
the old with oil on the (painted?) dowels side of the new pour?
<snip>
>
> You want to end up with 6" of compacted thickness. I usually recommend
> 3/4" minus crushed rock. If you are concerned about pushing the gravel
> into soft soil then use a geotextile between the gravel and soil.
> Otherwise, compact the soil first then apply and compact the gravel
> layer.
>
> The gravel layer is intended to be free-draining. Water should pass
> through it. You could excavate a deeper section in the middle of the an
> install a "french" drain, but given the slope of the driveway I don't
> think water will be of much concern as long as you have drainage
> ditches.
>
The drainage ditch will only be on one side at a time but along the entire
length of roadway and I'll need to switch it from the uphill side to the
downhill side at about the halfway point which I figure means a bridge.
How thick should the two 3.5' wide sections be in order to support an
occasional truck for a span of 3 feet over air? And if you don't mind me
asking, how much reinforcement will be needed there as well?

Bob, thanks for all your help! You've already made a significant
difference in the project.

--
Chuck

Posted by Bob Morrison on November 16, 2006, 10:58 am
In a previous post Chuck wrote...
> >
> Would it take much extra effort or cost much more to make dowel joints
> with shear keys at the end of each day? Is anything special used to
> separate the old and new pours or do I just place the new pour up against
> the old with oil on the (painted?) dowels side of the new pour?
>
Since you are going to be making lots of these joints you may wish to buy
preformed metal shear keys with holes punched for the dowels. Something
like these.

http://tinyurl.com/y2kz9m

Or perhaps you can get a local welder to make up something.

Here's a link describing how joints in concrete should work:

http://tinyurl.com/y2rsxe

> The drainage ditch will only be on one side at a time but along the entire
> length of roadway and I'll need to switch it from the uphill side to the
> downhill side at about the halfway point which I figure means a bridge.
> How thick should the two 3.5' wide sections be in order to support an
> occasional truck for a span of 3 feet over air? And if you don't mind me
> asking, how much reinforcement will be needed there as well?

Think about using a plastic or metal culvert (or culverts) instead of
making a bridge. They should be buried with at least 12 inches of
gravel/dirt cover below the bottom of the concrete.

--
Bob Morrison, PE, SE
R L Morrison Engineering Co
Structural & Civil Engineering
Poulsbo WA
bob at rlmorrisonengr dot com

Posted by Chuck on November 17, 2006, 12:09 am
On Thu, 16 Nov 2006 15:58:50 +0000, Bob Morrison wrote:

> In a previous post Chuck wrote...
>> >
>> Would it take much extra effort or cost much more to make dowel joints
>> with shear keys at the end of each day? Is anything special used to
>> separate the old and new pours or do I just place the new pour up
>> against the old with oil on the (painted?) dowels side of the new pour?
>>
> Since you are going to be making lots of these joints you may wish to
> buy preformed metal shear keys with holes punched for the dowels.
> Something like these.
>
> http://tinyurl.com/y2kz9m
>
> Or perhaps you can get a local welder to make up something.
>
Well, we have a welder as one of the group of 5 taking on this challenge
and I'm pretty sure he has access to material so I'll ask if he can weld
up two short 3.5' keys and drill holes in them for dowels. From the link
you sent I can see that the dowels are pretty substantial but I can't find
a size. How large should they be if I have a 6" slab with shear key?

<snip>
>
> Think about using a plastic or metal culvert (or culverts) instead of
> making a bridge. They should be buried with at least 12 inches of
> gravel/dirt cover below the bottom of the concrete.
>
OK, I'll have to think about a design to keep the culvert clean because
the last effort(12 years ago and super shoddy construction) had a 14"
galvanized culvert which filled up solid due to rocky debris getting stuck
in it when it rained hard. If I can pull it out and reuse it I'd be set,
but so far I haven't come up with any real imaginative plan to do that.
Best I have is lots of guys with picks and some rope. ;) But then that
might just be what it takes.

I'm creating a materials list now and have a specific question pertaining
to concrete mixture. We use 42.5 kg sacks of Portland type 1 cement, 3/4"
minus crushed granite with clean & sharp sand. Do you(or anyone else
reading this thread) have a mixture recommendation for building a STRONG
6" slab using these materials?

Chuck

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