When motorists take to San Francisco�s new $1-billion Presidio Parkway in late 2013, they won�t see some of the massive foundation piles placed deep into ground below. But they will feel the support of some of the largest cast-in-drilled-hole piles currently in use.
�The biggest challenge on this job from the beginning was a requirement to use 12-ft-diameter piles and [insert them with] very limited vibration because of historic buildings in the Presidio,� says Peter Faust, project manager for San Francisco-based Malcolm Drilling Co. �This meant we couldn�t use a pile driver with an impact hammer.�