Abstract:
Continuous flight auger (CFA) piles have been used in the US and internationally but have not been used frequently in foundations of bridge structures in the United States, with AASHTO not addressing their design. Engineers at Pennoni Associates designed an alternate foundation as part of a Value Engineering Change Proposal for the MD 152 overpass replacement project, part of the I-95 northbound E-ZPass toll lane (ETL) expansion Project. CFA piles provided a viable alternative for the project due to their high production rate, low cost, and minimized noise and vibration. The alternative foundation sought to replace battered and plumb 10.75-inch micropiles with 18-inch diameter plumb CFA piles in a 160-feet long abutment footing and wingwalls. Installation of plumb CFA piles was the preferred alternative due to site and confined area restrictions due to an 108-inch water main located 45 feet east of the proposed abutment. An overview of the project and the geotechnical and structural design will be discussed from this innovative application.