OT: shop-made concrete form anchors

[rimcanyon]

Bill, your description is quite clear & extra details are useful.

I could use single walers with hairpins by drilling the walers for the snap ties or by using a 2x4 block along with the waler.

The only bulkheads I have to deal with are at locations where the wall is 3' tall, so I suspect that a plywood panel screwed to the form studs will be adequate.

I was surprised that only one base plate gets attached to the footings, but if the ties do their work that should be adequate. Along with deadmen and braces to support the wall...

Putting the inside wall up first has advantages in addition to the access due to the cut. It makes the electrical work a lot simpler and simplifies the rebar installation since you can see what you are doing.

-Dave

 

[Navigator7]

I pump concrete for a living. It's my business.

Walls are poured every day and snap ties are just part of the deal.

There are many different types of wall systems that work.

I think your efforts to get a cheaper wall by redesigning a snap tie is not time wisely spent.

Searching Ebay and buying snap ties cheaper might be a solution?

To me....the cheapest way to build a concrete wall is to use quality materials and build it right the first time.

I work with pros and homes owners.......and the pros know better. You can't cheat physics.

Homeowners scrimp on whalers, bracing, plywood thickness, footings........,,,,and I make a lot of money pumping the same wall twice.

Shop smart, build stout.

Edit...I might have misread....you're looking to replace the wedges that hold the snap tie?
Naw.....it's a system. Stick with the system or risk doing the wall twice.

When your job goes south, the RM plant doesn't care, the RM drivers don't care, the pumper doesn't care,,,,and you have just made everybody's job harder and you still have to pay.

You don't want to sitting there thinking...I should have gone with the steel wedges......Or mebbie lignum vitae?

 

[Charles Dolan]

Dave,

I have sent you a sketch by email. I am damned if I can ever get images up by myself but if you can and wish to you might like to post it for the benefit of others.

Charles.

 

[rimcanyon]

Charles, glad to post a link to your superb sketch. I have often wished I could create a freehand drawing this nice. However, I don't own a copy of an editor for Adobe pdf format, so I am unable to modify the image and rotate it 90 degrees counterclockwise.
I also could not figure out how to get a pdf image to show up in the body of this post. The best I can do is provide a link:

form work

-Dave

 

[PeteM]

Dave - You've probably already checked this, but might be worth a mention: check with your inspector or engineer before using the 3/4 ply for a shear wall. At one point in an addition, I was told that too stiff a shear wall would increase the likelihood of failure at the sill plate in an earthquake. However, that was for a 2-3 story structure.

 

[LOU'S CUE'S]

SNAPTIE SYSTEM - MASCO.NET | MASONS SUPPLY COMPANY | OREGON & WASHINGTON

check out the jahns-a

3/4 ply, single 2x4 waler, no nails. rotating, slotted eccentric tightens the clamp to the snap ties.

prob can rent these ??

 

[Robert Campbell Jr.]

Dave, Bill Simmons has it right.

I started to respond to your quest for suppliers, then TFPace beat me to it. I usually used HUB.

Single walers; if used, only the top row. There is a stamped support bracket available to counter against the whaler but your 2X4 block will work just as well. Just start a nail in the hairpin hole, (angle the hairpin a little if the hole doesn't have wood behind it) it simply holds the hairpin in place, the mud will tighten it against the whaler.

Bottom whaler as close to the bottom as practical, second up a foot and third 18", third, 24". Your forms can extend a bit above the last whaler. This for five feet or a little more.

A common misconception is that only thick walls need strong whaler support. Not true, the pressure is determined by wall height, added thickness adds little more pressure. A pin hole, 1" up, in a one foot tall can, one gallon or one hundred gallons, pisses out to the same distance

A vibrator will make a better pour BUT YOU CAN BLOW UP THE FORMS with a vibrator.

As you form up the walls, always keep in mind that the forms must be removed and concrete shrinks. In a narrow U- shape with a single form, build the form an 1-1/2" short, nail a 2 X 4 flush with the face of the plywood, with 16 duplex nails from the form end stud, out to added stud. Latter, just pull the nails and remove as 2 pieces.

Hold your end studs in an 1/8" or so, the 16 duplex nails you use to nail two of them together, will pull the plywood edges tightly together. Get 'um right before you give that nail it's last couple of hits. Takes a helper watching the face and pulling panels into alignment. Start at bottom and work up.

Yes, the snap ties will locate the floating outside forms just fine.

A 16d nail on the backside of electrical boxes, to lock a loop of tie wire, that feeds through a hole in the face form, will allow you to tighten the box in place. A little tricky to feed the wire through the form as you close it up, so leave the wire long. Masking tape over holes will help to keep out slurry. Best is to stuff with wadded paper or scrap styrofoam.

Oh yeah, there is a slotted tool that is designed to break snap ties but I prefer a piece of 1/2" water pipe. Place end against plastic plug and bend back and forth. Just grabbing the tie and bending, will sometimes cause it to break beyond the face of the wall, not good.

Have fun, Bob

 

[rimcanyon]

check with your inspector or engineer before using the 3/4 ply for a shear wall.

Pete, I had not heard that before! When we built the house 15 years ago that was not a factor, is this a relatively recent change to the code? We used 10' 2x6's for studs (20' studs for the two story part of the house).

-Dave

 

[rimcanyon]

Robert,
thanks for the suggestions. Most of the elect. boxes are on the inside walls so mounting them should not be a problem, but I had been wondering how I was going to fish for the one or two that are on the outside face. Good idea.

We finished the foundation trenches this weekend & started bending rebar; now it makes my wallet sore to see the size of the dirt piles and think about all that concrete. 30" footings 12" deep for 130 feet = 325 cu. feet = 12 yds. & 2400 ft. of rebar (almost 1/2 mile!)...

The walls will take another 400 cu. ft = 15 yds.

I have a couple of questions relating to the stepped foundations:

the foundation has several 12" or 18" steps. We've tried to make these steps at 4', 8' or 12' intervals to make it easier to form. The rebar in the foundation follows the steps (five 1/2" continuous, spaced 5" apart, with cross ties & verticals every 16", as well as a 30" dowel for the slab every 30"). This is a whole lot of bending, to put it mildly. I welded up a tool out of steel pipe shaped like a T with a slot along one side to slip over the rebar (I used a double layer of pipe welded at the ends), and it works pretty well to make the more complicated bends, but there must be better ways to do it.

Also there are spots (like where one wall butts up to another), where we end up with lots of rebar tied together. We're staggering the splice joints in straight runs, should we do something similar here (such as have 3 of the 5 rebar from the other wall splice left, and two of them splice right)? We're using a 30" overlap in both the straight runs and in the wall junctions. I was sort of surprised that rebar overlaps weren't covered in the structural engineering details; they required about everything else.

-Dave

 

[PeteM]

Dave -- I'm not sure of the code status. This was an informal discussion with the structural engineer (who was doing the calcs for my 2 story home shop / office a few years back). I asked about sheathing the inside of my crawl space with the 3/4 ply left from my forms. His comment was that it might be too stiff and cause the above-mentioned failure in a quake -- and that I should use 1/2" ply and Simpson connectors to bolt the crawl space from the sill to the first story. My home sits on hill and is about 40' high at the high point, so there'd be a lot happening up above in a quake.

 

[Bill Simmons]

I think your lap spices are a bit bigger than required. I can not remember but I don't think code has any requirements greater than 40*D or twenty inches and it could be much less. Cal Trans specs in grade 40 half inch bars require 30*D or 15 inches. I would ask your building department or engineer for the lab requirement.

I would not try to put more than one bend in each piece of rebar. This simplifies the bending. I have a manual cutter bender that can turn that out pretty fast but will make you sweat doing it. You can make ells up using two pieces of pipe by sliding your bar into a stationary piece of pipe and bending the bar using another piece of pipe or the tool that you fabricated. I suspect you are trying to make up bars with multiple bends to follow the steps. This is not required and really complicates the bending.

At wall intersections, I would turn every other bar opposite directions but this is assuming a single mat of steel.