Shoring with backfill

[lahpe65]

I am proposingto use sloped backfill to provide lateral reinforcement to a concrete basement wall . The building is being demolished but portions of the basement wall have to remain in place as the floor above is removed. Has anyone done anything similar. Also, any methods of placement and compaction suggestions are appreciated.

 

[jdonville]

lahpe65,

I am concerned that you will not have the room to place the soil in a controlled manner. I think you should not plan on having any compaction.

Per standard practice, you will need to calculate the passive resistance taking into account the slope of the material (Coulomb Kp). You should probably also discount the passive contribution from the top foot or two of the soil against the wall (similar to sheet pile wall design).

If you can achieve compaction, there was a good thread recently that dicussed the effect of compaction on lateral wall loads.

Jeff


Jeffrey T. Donville, PE
TTL Associates, Inc.

http://www.ttlassoc.com

 

[DRC1]

Using slopes for lateral shoring is difficult in that a slope develops little passive pressure unless the berm is fairly wide. Also, if you are putting this on a concrete floor, I would check sliding. The difficulties of getting the material in, wetting it and compacting would seem to make the operation somewhat challenging. I would consider temporary struts from wall to wall or rakers from the wall to the floor secured by epoxy bolts.

 

[lahpe65]

Thanks for the input. I should explain that this is actually a large area and only 2 walls are below grade. Exterior grade of the building slopes. Therefore, some of the walls are below this grade. I have called for braced shoring, but the owner would like the option of using the backfill as shoring. I am restricting the amount of above grade wall demolition that can be done behind the shoring. The contractor does have very open access to the inside of the wall so I can create a large berm and demolish a portion of the concrete floor to help with sliding.