Masonry Dowels Spec Interpretation.

[Greatone76]

I'm watching a contractor layout masonry dowels that go from the foundation into the masonry. I have standard 2 cell blocks. I want to see them layout the 16 inch lengths of the blocks then measure in 4 inches from the ends of the block to aim for the middle of the cells of the block. Using this layout method I have dowels that are more than 2 inches off that mark. I want to use the ACI 530 bar placement tolerance of +\-2 inch in the length of the wall to say that there layout doesn't meet the specs/code. I keep getting push back that as long as they end up in cells we are ok. I keep pointing out they are really tight to cell walls and some seem to me to be in the webs. I am aware of the 1/2 inch and 1/4 inch off the cells requirement based on grout, but I would like to see them in the middle as much as possible. Am I right to use my center of cell layout not meeting the spec or do I have to find 2 bars that are farther that the 2 inch tolerance and or rebar too close to cell walls? How do you apply the masonry spec in relation to masonry dowels?

 

[CELinOttawa]

It is unforunately not a hard and fast rule, but I do agree with you. The spec is hard and fast, but open to interpretation. Once they are able to find a P.Eng. to say it is okay, you're going to be having more trouble than it is worth.

If you are not comfortable signing off on a structure, then you fight. Period. If that is the case, you must be COMPLETELY FIRM with the contractor and leave them feeling no "give". The least bit of weakness and they will walk all over you.

If you need the placement because of cantilever or other moment resistance, fight fight fight. If this is just truly shear dowels and their location is less critical, tell them you want to see the placement before core filling. If any are too close to the walls (violation of Smin is enough, they don't have to touch to be no good), then it will be time for remove and make good, or remedial actions. That is usually enough to make an honest builder fly right.

 

[JAV72]

CEL is right. If you need them in the center tell them that is where they need to be for the wall to perform. I'd suggest bar positioners but they probably won't like either. Also look at the contract documents...surely they show the bars centered (if that was the intent) and that would give you your strongest leverage.

 

[DaveAtkins]

Since you are asking about bar layout PARALLEL to the wall, as long as there is adequate grout cover, I see no problem with what the contractor has done.

DaveAtkins

 

[Greatone76]

Dave that is the conclusion I came to but I was looking for a definitive way to call the layout not acceptable prior to having to wait for wall layout and blocks. Moving rebar prior to placing the wall is a lot easier then the fights over fixes and all the mess that will come about when they don't have them placed correctly.

 

[dhengr]

Greatone76:
Today, many tape measures have 16" o/c markings for the really dumb contractors who don’t know how to add. Then, they should stretch/provide a line and measure from the first rod, once they have properly located that w.r.t. the type of block being used. They should not be just stabbing them into the wet conc., they should be tied in place before the conc. is poured. You could have them provide clean-outs at every rod so you can inspect/reject the rods before grouting. You could tell them that you don’t care about the size of the head joints, but you do want the rods within some dia./tolerance of the center of the cores. And, he can explain his ugly block laying to the Owner and the Arch., because all you care about the structural aspects of the wall, even though he doesn’t care about spending a few more seconds to do his job right.

 

[CELinOttawa]

I keep pointing out [that the dowels] are really tight to cell walls and some seem to me to be in the webs.

There is everything wrong with this. Such poor layout should not be permitted, and often results in bars have have the CMU scrap its way into position. The mortar (or concrete, depends on where you are building) MUST be able to fully surround the bar and bond with the inner face of the block (shell and frog).

No debate; If your facts were accurate, this is simply no good a la "Contractor go correct and make good all bar layout works to ensure bars are place centrally to the CMU void after pour."