Project Summary

Modified helical (i.e. screw) piles are lightweight deep foundation elements that are screwed into the ground and efficiently generate geotechnical compressive and uplift resistance by mobilizing the shear strength of soil adjacent to helical plates that are welded to an extendable shaft. The addition of a novel collar vane increases the lateral and torsional resistance of this deep foundation element. Helical piles (HPs) are quick and simple to install, utilizing nonspecialized equipment that is ubiquitous in the United States construction industry, eliminating the need for a specialty contractor. Relative to conventional deep foundation alternatives, HP installation is relatively non-intrusive, less cumbersome, and appreciably less expensive. Lightweight transportation structures are often supported on costly conventional foundation systems that have only been advanced incrementally for decades. Savings that could arise from efficient design of these lightweight facilities may be applied elsewhere as available funding for transportation infrastructure continues to diminish. Moreover, these benefits may not be isolated to new lightweight transportation infrastructure, and benefits from this research may extend to other applications, including retrofits and upgrades to increase the capacity and extend the life of existing foundations required to support new or augmented structures.