Underpinning inherently involves high risk, high cost and significant time to construct. Also, the process associated with obtaining the property owners’ permission to perform the work is a major factor that must be considered. Situations where the approval of work related to protection of adjacent buildings involves political or non-technical issues must be avoided. In light of these concerns, it is our goal to minimize the extent of underpinning by implementing measures to avoid the need for underpinning such as: increasing the stiffness of the earth support system (i.e. reduced strut spacing, adopt thicker walls); improving the ground (i.e. jet grouting); specifying the excavation sequence; and using underpinning as the last resort.   

GZA has extensive experience with various underpinning techniques including: concrete pit; jacked piles; bracket piles; and drilled piles.