Driven Battered Concrete Piles for Lateral Bracing

[WaterfrontPE]

Hi all,

A number of bulkhead projects I have seen recently (particularly residential) utilize a concrete pile and panel system (in the style of a soldier pile wall) for shoreline stabilization. Instead of anchors or deadmen, they are utilizing concrete piles driven on a positive batter as a brace. The whole system is tied together with a concrete cap. (Note: this is not in a high-seismic area).

Some of the design guidance I have found on this seems to indicate that the horizontal reaction force transferred to the top of the batter pile can be resolved into an axial load for analysis, based upon the batter angle. The lateral load would then be balanced by the lateral components of skin friction and end bearing, dictating the pile length.

My concern with this methodology is that it treats it as a pure compression pile and does not consider the flexure in the pile. For deeper waters/higher walls with longer unbraced lengths, this can be very significant. What is the proper method to resolve the horizontal reaction at the head of the pile into axial/transverse loads on the pile, and how does this influence uplift/overturning of the whole vertical pile/panel/batter pile/cap system?

Any thoughts on this are welcome. Photo below to illustrate the type of wall to which I am referring.
Thanks

 

[r13]

This arrangement is similar to truss system under combined axial and lateral load, the pile are capable of resist axial compression and uplift by design. I've difficulty to picture the battered pile in bending.

 

[SlideRuleEra]

WaterfrontPE - Resolve the horizontal force applied to the batter pile into axial and lateral components (see my sketch). Axial component causes batter pile compression, lateral component causes batter pile bending.

Plumb piles will tend to resist some of the horizontal force by bending, but the batter piles should resist the majority of horizontal force.

http://www.SlideRuleEra.net

 

[r13]

This is the truss action mentioned before.

 

[chicopee]

Wouldn't you have a partial steel bending reinforcement on those concrete piles?

 

[r13]

The piles are designed as column, which should be able to resist incidental bending moment.