Weep hole in existing wall

[lahpe65]

I am involved in a project where we are backfilling against an existing below grade wall. There is a street adjacent to this wall that must be maintained. This wall has been in place for 50+ years. I have been told to add weep holes to the existing wall prior to backfilling against it. I am hesitant to agree to this. There have been no drainage issues and I am afraid that by adding these weepholes we would be changing the make-up of the soil on the street side of the existing wall. Possibly causing additional settlement/movement on the wall as the structure above is demolished. Any thoughts?

 

[wallguy]

lahpe65

If I have the right picture, the reason for adding the weep holes would be to alevate the possiblity of hydrostatic pressure in the future behind your backfill. If you were to capture any water coming through the wall because of the weep holes by using a type of chimney drain and exiting it out into a storm water pipe somewhere or directly into the street you could solve both issues. Does that make sense?

 

[DRC1]

If after backfilling both sides of the wall will be below grade, I don't see the reason or the weepholes.

 

[lahpe65]

That was my thought. But it has been requested that I add them to my detail.

 

[BigH]

lahpe65 - assuming that there will be some fill elevation differnce in your wall (not a buried wall), if you are going to add weepholes, please detail them! I've not run into any weepholes that were actually detailed (10 years of work in China, Laos and India). And, nobody pays much attention other than lip to them. One structural guy suggested to me, though, that the weepholes should point up rather than down. Reason? Hard to push coarse sand or gravel up a weephole. Doesn't have to be steep, just a bit. And, it won't made a damn bit of difference to the design from a hydrostatic point of view - in a practical way!

 

[lahpe65]

Buried wall is a good way to explain the situation. We are buryng the wall. Thanks for the tip on the weephole.