Designed in 1925 by architects John Austin, Albert C. Martin, and John Parkinson, the 27-story City Hall was the only building allowed to break the 13-story height limit maintained by the city until 1957. Thus, it became the city`s tallest building from its completion in 1928 until the late 1960s. Presenting an image befitting a major metropolitan center, its granite Beaux-Arts base supports a monumental, pyramid-capped tower. Although it incorporates Greek, Roman and Renaissance design elements, its spirit is purely American, symbolic of the optimism of the 1920s California. The interiors are Byzantine in style, in particular the central rotunda and public spaces, which are clad with marble and inlaid tile. The ceilings are decoratively painted. During the past 72 years, the tower has been damaged by earthquakes. Exterior terra cotta cladding, and interior unanchored masonry walls have cracked. As historic preservation architect for the seismic rehabilitation, which was initiated in 1993, Levin & Associates, in collaboration with Albert C. Martin Partners, Architects and Engineers, has developed the approach, standards, and alternatives which guide the seismic and code-upgrade methodology for the building`s historic areas. The hierarchy of historic significance for each area established by Levin enabled the engineers to propose solutions which preserve the most historically significant areas. Base isolation and conventional shear-wall are being implemented. The firm developed and negotiated alternative code compliance strategies, in consultation with the State Office of Historic Preservation, and created architectural plans for the areas of impact. Restoration guidelines for historic materials, decorative painting, historic light fixtures, and exterior terra cotta replacement, cleaning and repainting were developed in collaboration with conservators.