Seismic retrofit to a 10 level, 195,630 SF cast-in-place structure originally built in 1963. The retrofit required strengthening of exterior footings and walls from both the interior and exterior of the building. This involved massive excavations to 34′ below ground level and interior footing tie-downs to minus 45′ from the lowest point in the building. Overaa installed 1’7″ concrete column cladding to 103′ above the Plaza level and 1’7″ x 5’6″ high spandrel beams the entire length of the building. We used 6′ wide x 50′ long mast climbers, drill rigs that can fit through 3’x7′ openings, and environmentally friendly equipment such as vacuum attached drills and water blasting versus sand blasting. The building remained occupied during construction.