The Century Plaza Hotel in Century City is currently undergoing a $2.5 billion renovation.  The existing super structure of the 1964 historical hotel will remain.  However the four subterranean levels are currently being demolished to make room for two identical 46 story towers.  The Next Century Partners developer has stacked a top-notch team consisting of Gensler, Pei Cobb Freed, Rios Clementi Hale, Englekirk, Amec Foster Wheeler and Cefali, to name a few.  The excavation is designed to accommodate four subterranean parking levels and tower mat foundations extending down 70 feet at the deepest location.  Critical components of the shoring system occur along existing structures.  Cefali supports one of the adjoining lots with 35 foot temporary cantilever piles that allow for demolition of the existing structure which later get braced by tiebacks and preloaded 48 inch diameter rakers supported by a tieback restrained and reinforced concrete pad.  The tiebacks, rakers, soldier piles, and existing structures are outfitted with real-time instrumentation for monitoring shoring performance.  Coordination with existing buildings, deep utilities in the street and the future Metro Purple Line was a process comprised of reviews by Bureau of Engineering’s Excavation, Structural and Geotechnical groups, Building and Safety, MTA and multiple peer reviewers.