Existing - New basement wall connection 3

[COEngineeer]

I need to connect a new wall into existing wall. The thing is I am connecting it it in the middle of the wall span. How do I know that dowel epoxied 6" into the existing at 16" o.c. is good enough to make the combined wall as one unit (instead of a hinge point in the middle). My new wall is going to be reinforced 16" o.c. both directions. How do I figure out the development length of the epoxied #5 rebar?

 

[csd72]

COEngineer,

What type of masonry, thickness, wall support configuration?

What are the supports at the sides, top and bottom? Can you make it span the other way?

Need to know more before we can give you any decent advice.

csd

 

[COEngineeer]

8' tall existing concrete wall spanning about 20' (soil only on one side). Then at 20' the wall dropped to only 3' tall with framed wall for about 5 feet. (so the total length is 25 ft). We are going to build concrete wall instead of framed wall at that 5 feet section and it will filled with soil on the other side. Pretty much we are moving a garage door on the other side of the garage so the wall has to be all concrete because we need it for the driveway. The garage floor framing will sit on top of this wall.

 

[csd72]

A few comments:

Check your footings.

If this is a cantilever wall then you may only have reinforcement on the outside face, no help for spanning.

If it is only 3' high, it would be a much better job (and probably cheaper) to demolish the 3' of wall and build a new full height wall.

Would recommend hilti HIT RE500 for reinforcement bonding, they have charts that give required depth for full development.

CMU may be cheaper than concrete in this case, particularly if there is no other concrete work on site.

Regards

csd

 

[PackerFan]

Since I may be an engineer with a well known adhesive anchor mfg, I will note the following. If you want to develop the rebar using principals of anchor theory (concrete breakout or bond failure), use the depth noted in the mfg's tables. However, if you want to have the rebar develop as a lap splice and have the new rebar transfer the load into the existing rebar, you will want to embed the rebar into the existing slab to the lengths in ACI 318 Chapter 12 using the epoxy/adhesive. If you have a certain red and black 2006 Product Technical Guide, take a look at page 83 for a short explanation of this.

 

[DaveAtkins]

PackerFan is exactly right. Embedding the new bars into the existing wall 6" or 8" will only develop the new bars--the bars in the existing wall will not be developed. You should tear down the 3" of existing wall and pour a full height wall.

DaveAtkins

 

[haynewp]

Why do you need full moment transfer? Can you design the new wall as cantilevered and have pin connection to the existing wall?