Cornerstone was retained by Gelfand Partners Architects through the Mayor’s Office of Housing to provide structural engineering services in support of a major modernization and seismic retrofit of the 1969 seven-story concrete building.  Cornerstone was asked to review the previous seismic assessment and address the seismic deficiencies in the building.  After confirming that the existing lateral system was seismically deficient, Cornerstone consulted with the design team and determined that ductile shear walls needed to be added to the building to withstand lateral forces and balance the torsional irregularity.  Cornerstone consulted with the contractor to develop the construction access schemes for new micro-pile foundations and pile caps necessary to anchor the shear walls.  In order to maximize programming efficiency for the users and work within property line constraints, a combination of both internal and external shear walls elements was developed to balance the needs of the users, seismic safety, architectural programming, and contractor access.