As a result of California State Law enacted in 1994, Sharp Memorial Hospital in San
Diego, CA required an extensive seismic retrofit in order to remain in service past January
1, 2015. When built in 1972, the structure was founded on spread footings below the
core columns. While these footings remain in service to support static dead loads and
live loads, high capacity micropiles were needed to resist overturning moments that would
occur at the base of the columns in a seismic event. Rather than tying the micropiles into
the existing footings, the micropiles were anchored directly to the retrofitted column base
plates. Complicating the installation was the fact that the hospital needed to remain fully
operational throughout the entire construction. Not only were the micropiles to be
installed in severely limited access conditions, complex management of phase
construction, dust control, and spoils management were required to comply with the
hospital’s infection control policy.
This paper will discuss the complex nature of this project in further detail. Additionally, it
will highlight the benefits of how partnering between Contractor, Owner, Engineers, and
manufacturers resulted in an efficient, safe, and cost effective solution to an extremely
difficult foundation problem.
Subjects: high capacity micropiles, seismic retrofit, communication, limited access
Author: Peter Speier, P.E.
Publisher: ISM, DFI, ADSC