
Optimizing Driven Pile Foundations
Design-build and remote PDA testing By John C. Ryan, Ph.D., P.Eng., Ryan Structural Engineers, LLC Sharpening the proverbial pencilIt's a familiar saying, and in an engineering office it may sound like this: “Four per cent overstress ... maybe I can sharpen the pencil and make it work.” Despite the fact that a given balance between load and resistance cannot be “made to work,” there is some insight that this euphemism provides. In reality, deeper understanding of a problem is being sought with the intent of removing uncertainty. As engineers, we are inherently and appropriately risk averse. If we have not personally proven or maintained control of an idea from inception to completion, we become skeptical of it. In practice, this tends result in unnecessary conservatism, particularly where often-disconnected design professionals have tangential or overlapping responsibility. Such is the case with driven piles. Much of the excessive conservatism that persists in the driven pile industry can be reduced significantly through a design method that treats the pile foundation as a performance specified component. Utilizing bid solicitations, which include pile design criteria and subsurface reports, foundation contractors, along with a driven-pile specialty engineer, can provide design-build solutions with pricing and schedule to be evaluated for best value. Further, by incorporating remote dynamic pile testing within the scope of the design-build team, the most optimized foundation and installation schedule can be achieved. If the pile specialty engineer and contractor team are engaged from concept through design and certification, the pencil is always sharp with respect to foundation design.