U.S. Nuclear Regulatory Commission

Six years after completion, this 18-story federal office building was exhibiting cracking and loosening of the marble and granite facing on the precast concrete cladding system.  Experts working on behalf of the GSA had recommended a $13.7 million replacement program for the stone.  RRJ was retained in 1994 on behalf of the building developer to investigate the cladding system and make repair recommendations.

RRJ’s investigation involved field and laboratory stone testing and finite element analysis modeling to define stone panel performance criteria necessary to identify stones requiring supplementary anchorages.  Once developed, all of the cladding stones on the building were tested using the criteria.  Of the approximately 14,000 stones on the building, 890 required repair.

RRJ prepared design and contract documents for all required repairs, including auxiliary anchorage installation, crack repair, and replacement of stones with excessive damage.  RRJ developed quality assurance measures for the construction, inspected the repairs, and performed construction administration.  Final repair construction costs totaled less than $1 million.

In 2007, RRJ consulted with McMullan & Associates to direct a limited stone investigation of 440 stones previously identified by another engineering firm as being displaced.  Reanchoring repairs were recommended for four of the stones.