I am going to pour a bridge deck to a private home. (my own) There is an exsisting bridge that I am just pouring a new road surface on. What is the rule about rebar ties? I am using #4 bar in an 8 X 8 pattern on 2″ chairs spaced 4′ on center with 6″ of concrete. I am using 6″ bag ties and a twister to complete the connection. Do I have to tie every place where two bars cross?
Thanks
Dave
Replies
Why not?
Spheramid Enterprises Architectural Woodworks
There is no cure for stupid. R. White.
Because I have to make 1000 connections! and I can't see that a twisted wire connection between 2 pieces of #4 bar adds any strength to the slab, all they do as far as I can see is keep the spacing correct.
Edited 6/18/2006 5:03 pm ET by Cletrac
tie the perimeter 100 percent and stagger tie the inside of the mat also tie every chair to the mat
Ya getting inspected prior to the pour?
Them guys like to make it up as they go in your specific area, for a reason..might be siesmic, might be subsoil, might be because they can.
I'd tie it, if it were me. There is a power version that is not hand cranked and there are plastic clips that do the TEE intersections, from a standing height, no bending over.
IMO, the chairs are the most important part, even fibered conc wont perform as well if the bar is on the grade gravel or remesh that gets all stomped on.
I have heard that the fibered don't need remesh, I say BS to that. Rebar is for someting else, and not being connected and then tromped or wheeled over is just sloppy work, again, IMO.
I'd hate to have atruck sitting there on the clock and MR.BilInsp tell ya to start tying..while the load gets hot.
Spheramid Enterprises Architectural Woodworks
There is no cure for stupid. R. White.
No inspection, no permit. The bridge was built in 55 after the first washed out in the flood. There are 4 12" 31 pound I beams with 1/4 steel strip laid edge to edge across the span then a section of open bridge decking spans from one side to the other with the decking poured full of concrete. There has been no shifting and there are no cracks. I did have a structural engineer do the calculations and I am way over what is required for the span and according to the concrete gods my "beam" is over reinforced which is the way I like it. The actual span is only 8 feet by 16 feet wide. The slab I am pouring is 32 feel long to be sure to go beyond the abutments.
Your call then huh?
Spheramid Enterprises Architectural Woodworks
There is no cure for stupid. R. White.
Sphere
I am looking for and forward to more pics of your homestead.
Get me up to speed on the progress. last pic seen was driveway gravel and dog
Hope your well love your post. In one post pic I noticed a slick laying on a bench
I've got a sister to it here in my shop, leverage is a wonderful thing.
MikeL (sweeper)
Will do. Moving along, slowly, but moving.
Spheramid Enterprises Architectural Woodworks
There is no cure for stupid. R. White.
Did someone do the engineering that says the bridge will hold up the load you are adding?
On This Old House they showed some plastic clips that are used to hold rebar in place. Nice product.
Tie the rebar crosspoints 24"OC. The perimeter every cross point.
At rebar 8"OC, that's every third one.
But ya gotta stagger the ties to insure that all rebars are tied.
Take the first row of ties one in from the perimeter, tie #1 cross point, #4, #7, etc. The second row, tie #2, #5, #8, etc. Third row 6, 9, 12.
See the pattern?
the rebar ties does nothing for strength. all they do is hold rebar in place. so do you have to tie each one, no. will the inspector make you tie each one, yes. but as long as the rebar doent move, that all that needed.
BB
SoCal Civil inspectors require ties @24"OC. That's stout enough to pick up 20x20 mats of #4 12"OC with 2 straps.
The Foremen wanted every crosspoint tied with double wire where we were climbing over the wall mats like ladders.SamT
Yep.
We were always told "if you tie it,... you climb it"
Having a couple of tie wires break and a bar or two slip as you're monkeying around on a wall full of rebar is 6.5 pucker, even if you are tied off and have your fall arrest gear cinched up tight. We use to use spool wire and a figure eight tie both ways on large walls. Twist ties were only used on flat work because they can slip on the vertical to horizontal tie points.
Course the guy I worked for was a civil engineer, so everything we did was way over the top even for commercial work.
Dave
Well it seems we have gone from how to tie rebar on a bridge deck to something about climbing a rebar wall.
Yesterday we laid out and tied off 120 pieces of #4 bar on a 14 x 32 slab / bridge deck. With 4 of us working we placed the steel and tied it off in about 5 hours. We tied everything around the perimeter and every other cross point in the field as best we could. With 3 people doing the actual tieing we had places where one persons pattern didn't match with the other so we had a bunch of places were every cross point was tied. Today we poured 9 yards of 3500 psi concrete in about 2 1/2 hours.
Thanks for the input.
Dave