Development Length with Dilled and Epoxyed Rebar
Development Length with Dilled and Epoxyed Rebar
(OP)
I am currently working on a project that is requiring an existing mat foundation to be extended to accommodate the new loading and revised column locations. The mat extension will be the same thickness as the existing foundation. The existing foundation has sufficient reinforcement for the modified stresses, and we can reinforce the extension as needed. At the concrete interface I am planning on drilling and epoxying rebar into the existing concrete and extending it into the new concrete and provide a class "B" lap length. This will allow for the transfer of the moment and shear between the two faces. The existing rebar is finished with a standard 180 degree hook. While the drilled and epoxyed rebar will be developed at the interface, my question is how deep should I extend the drilled rebar into the existing mat to ensure that it is developed with the existing rebar. Should I extend the doweled rebar equal to Concrete Cover + Ldh (hook development length) + embedment for epoxy anchoring, or is it sufficient to dowel it just the recommended embedment depth? Any thoughts would be appreciated.






RE: Development Length with Dilled and Epoxyed Rebar
Personally, I would not skimp on the dowel length, regardless of any complaints by the contractor. It's your a$$, not his.
Mike McCann
MMC Engineering
RE: Development Length with Dilled and Epoxyed Rebar
I would call you for the concrete to be removed at the ends of the slab. Then you can have the new bars tied to the exitsting bars and pour the two pieces together.
Might be easier/cheaper than drilling and epoxying a bunch of bars. Plus, you would get a much more controlled final product.
RE: Development Length with Dilled and Epoxyed Rebar
RE: Development Length with Dilled and Epoxyed Rebar
RE: Development Length with Dilled and Epoxyed Rebar
It would also be a good idea to call the anchor company. I sometimes call Hilti.
RE: Development Length with Dilled and Epoxyed Rebar
he is trying to transfer moment as such he needs to get the forces from the doweled bar in to the existing reinforcing. just epoxying a bar to some nominal depth without considering the existing bar, will only provide a moment connection to the end of the dowel bar at attempts to take the moment.
How could you do anything so vicious? It was easy my dear, don't forget I spent two years as a building contractor. - Priscilla Presley & Ricardo Montalban
RE: Development Length with Dilled and Epoxyed Rebar
DaveAtkins
RE: Development Length with Dilled and Epoxyed Rebar
was meant to say:
"will only provide a moment connection to the end of the dowel bar as the concrete attempts to take the moment without reinforcing."
How could you do anything so vicious? It was easy my dear, don't forget I spent two years as a building contractor. - Priscilla Presley & Ricardo Montalban
RE: Development Length with Dilled and Epoxyed Rebar