An existing low-rise office building at Westfield Century City already had a four-level basement, creating an opportunity to reuse portions of the existing basement walls during redevelopment.
The construction plan retained the existing basement walls instead of removing them and installing a conventional soldier-pile-and-lagging perimeter at those locations.
A bracing scheme held back the walls with a tieback on a strongback supporting the wall at existing decks while staying out of the way of proposed decks.
The strength of the existing wall was key to the brace layout. Deep utilities and a bridge pier affected tieback coordination, while cantilever piles were used where adjacent structures already existed at matching depths.
