Use Concrete Pier in Residential Soldier Pile? 1

[JoshH726]

For a small residential soldier pile design (wall height is 6ft) at a site that is all sand, is there any benefit in not providing a concrete base extending the depth of the required pile embedment rather than using just a wide flange or h-pile? Thanks in advance

 

[BUGGAR]

Unless you are driving the piles into the soils, you need the concrete to adequately restrain the base of your piles. The benefits of not using the concrete are that you will meet someone new - your neighbor's attorney.

 

[PEinc]

For drilled-in soldier beams, lean mix, low strength concrete or low strength flowable fill are often used to backfill the entire drill hole after placement of the soldier beam. If using stronger concrete, it should be carefully placed only around the soldier beam toe with the rest of the drill hole (above the embedded portion of the beam) being filled with the low strength concrete or flowable fill.

http://www.PeirceEngineering.com

 

[jayrod12]

PEinc, care to clarify why you shouldn't provide high-strength concrete for the entire fill depth?

 

[PEinc]

The purpose of the fill above the toe embedment of drilled-in soldier beams is to replace the soil around and behind the soldier beams. Since these walls are intended to be built from the top down, as lagging is installed, you want material around the soldier beams that will not fall out each time you excavate another 4 or 5 foot lift to install the lagging. Also, the material around the soldier beams should not be so hard that you need to spend great time, effort, and money to remove enough fill so that the lagging can be placed. Therefore, for drilled-in soldier beams, the drill holes should be backfilled with low strength, cementitious material which can be easily removed (with shovels and or small, hand-held, pneumatic or electric chippers or clay spades) just behind the front flange of the soldier beams and the material will stay in place around the remaining portion of each soldier beam. Therefore, you haven't disturbed the soil arching action between the beams and the soldier beams will have proper bearing behind them so that they will not push back excessively when you install tieback anchors or pre-load any steel bracing. By low strength, I am talking about a maximum of 100 to 200 psi compressive strength. If the drill holes are filled with uncompacted soil or gravel, there is a good probability that this material will fall out during excavation. Compaction down inside a deep drill hole is not practical or economical compared to the cost of using low strength concrete or flowable fill.

http://www.PeirceEngineering.com

 

[jayrod12]

Thanks,

Makes sense, the few I've seen around here they've not done any backfilling above the top of the plug. They just excavate down and go at the lagging.