Lateral Pile Analysis: Episode 9 - Driven Piles vs Bored Piles (Design Note)

Driven Piles vs Bored Piles (Design Note)

 When I was working on one of my early projects in BC, I still remember comparing the axial capacity of a driven pile and a drilled shaft in the same granular layer. Same beta method. Same soil. Same geometry.
The result was that:
the driven pile capacity was almost double.

But then it made perfect sense.

Driving densifies granular soils, increases effective stresses, and creates a tighter interface.
Drilling does the opposite. It releases stresses, relaxes the material, and even if you clean the hole perfectly, the soil around the shaft was disturbed before you poured the concrete.

This is why axial pile design concepts must always follow the construction method.
Driven vs bored is not a minor detail.
It can change the design by a factor.

But here is the twist that many do not expect:

This difference does not exist in lateral pile analysis.

Whether the pile is driven or bored, the software still uses the same p-y curve concept.
Full contact is assumed.
No densification, no relaxation, no construction effects.
The soil springs do not know how the pile got into the ground.

Some researchers propose adjusting the soil resistance for driven piles, but in practice, most engineers—and most software—treat both piles the same for lateral capacity.

So in axial analysis, driven and bored piles live in two different worlds.

In lateral analysis, they live in the same one.

Just a thought worth sharing.