When the City of Los Angeles decided to renovate and expand the famous landmark, it was determined early on that the added structure should be done below the existing structure so as to not take away from its signature appearance. Cefali & Associates was contracted to engineer an underpinning and shoring system to protect the 75 year old structure.
A combination of cantilever and tied back soldier piles were used to retain the earth below the small portion of the site not requiring underpinning. The balance of the site required a new visitor center to be constructed beneath the existing concrete building. Underpinning consisting of post and beam steel pipes and wide flange shapes were used to jack-up and support the heavy structure.