Rubble stone foundation underpinning project planning (overview)
Rubble stone foundation underpinning project planning (overview)
(OP)
Please bear with me, as I have never managed an underpinning project before. My goals today are to obtain/confirm the high level steps so I may ask more detailed/accurate questions later.
Here is my outline of tasks:
1. Define depth required to accommodate future use
2. Survey site
2.1. Existing Foundation
2.1.1. What about it?
2.2. Building in general
2.2.1. What about it?
2.3. Soil?
2.4. Anything else?
3. Draft plan & sequence activities
4. Construction
What am I missing or have wrong?
Here is my outline of tasks:
1. Define depth required to accommodate future use
2. Survey site
2.1. Existing Foundation
2.1.1. What about it?
2.2. Building in general
2.2.1. What about it?
2.3. Soil?
2.4. Anything else?
3. Draft plan & sequence activities
4. Construction
What am I missing or have wrong?





RE: Rubble stone foundation underpinning project planning (overview)
RE: Rubble stone foundation underpinning project planning (overview)
RE: Rubble stone foundation underpinning project planning (overview)
Read the underpinning chapters in books by Winterkorn & Fang, Robert Ratay, and Alan McNabb.
www.PeirceEngineering.com
RE: Rubble stone foundation underpinning project planning (overview)
Monitoring the building elevations may be needed to be sure nothing settles in the process.
A guarantee from the contractor to be sure his work does the job.
Who draws up the plans for the work? Is that person insured for errors and omissions?
RE: Rubble stone foundation underpinning project planning (overview)
Michael.
Timing has a lot to do with the outcome of a rain dance.
RE: Rubble stone foundation underpinning project planning (overview)
RE: Rubble stone foundation underpinning project planning (overview)
Rubble stone foundation underpinning project to provide deeper basement
Project specific #'s in []
1. Define interior depth required to accommodate future use [11' 4"]
2. Survey site
2.1. Soil conditions
2.1.1. Type [clay]
2.1.2. Frost line @ X [2' 6"]
2.1.3. What else?
2.2. Existing Foundation
2.2.1. Height [6']
2.2.2. Depth below grade [4']
2.2.3. Wall boundaries [2 exterior, 1 party]
2.2.4. Re-grouting? How to determine?
2.2.5. What else?
2.3. Building in general
2.3.1. Pre-construction survey
2.3.1.1. Water issues? [receives water from party wall when rains]
2.3.1.2. What else?
2.3.2. What about it?
2.4. Anything else?
3. Draft plan & sequence activities
3.1. Pit size
3.2. Lateral support
4. Construction
4.1. Monitoring
4.1.1. Elevations for settling
4.1.2. Anything else?
RE: Rubble stone foundation underpinning project planning (overview)
RE: Rubble stone foundation underpinning project planning (overview)
Well, in constructing the blocks of underpinning concrete how are you tying them together? How is load transferred down to the underpinning?
A common way is to drive re-rods into the earth alongside and below to the next block zones. This makes digging difficult for the neighboring blocks,but not impossible if the rods can be bent and then straightened.
Once the concrete is hardened and partly filling the cavity, we have then rammed a stiff mortar into the void between the concrete below and what ever is above. You might even use an expanding grout to get some load transfer.
If you really want to transfer a decent load, you could install a form of screw jack there to pick up the load before raming in the stiff mortar..
You do know about how concrete will shrink as related to water content, right?
So you see, lacking an experienced person on the job, a good treatise on different forms of underpinning might be a good investment.
RE: Rubble stone foundation underpinning project planning (overview)
I worked for a national, design-build underpinning company and now continue to design major underpinniing jobs for qualified contractors. I have designed and constructed several hundred underpinning jobs. I never used dowels or reinforcing steel in underpinning piers, never used non-shrink or expanding grout for dry packing, and never needed to use a jack to transfer loads to the piers. Most of a pier's concrete shrinkage occurs before the pier is dry packed and there is insignificant shrinkage in 2 or 3 inches of dry pack. Properly installed dry packing can transfer load to an underpinning pier. I have used keyways between underpinning piers but only when forced to by one local structural engineer.
www.PeirceEngineering.com
RE: Rubble stone foundation underpinning project planning (overview)
All I can say is with much fewer jobs, that's the way I did it.
RE: Rubble stone foundation underpinning project planning (overview)
www.PeirceEngineering.com