The rehabilitation and seismic base isolation of Pasadena City Hall involves strengthening the existing building foundations and the creation of a "moat" around the entire perimeter of the building to allow for ground movement independent of the building. Base isolation will complete the rectangular plan with a new east basement structure that ties the building together as a unit, and cuts the building off from the existing foundations. New grade beams will tie the existing footings together, base isolators that act as shock absorbers between the original foundation and the building above will be inserted and a structural diaphragm installed, tying the basement columns and walls together. The isolators change earthquake forces from having a high frequency with sharp movements to having a low frequency with slower motion. Basement light wells exist at the exterior perimeter except at the corners. These wells are to be incorporated as part of the moat for the base isolation system and must be shored and the walls removed and replaced extending down approximately four feet below the existing light well floor.
Aesthetics, Air Quality, Cultural Resources, Cumulative Effects, Geology/Soils, Hazards & Hazardous Materials, Hydrology/Water Quality, Noise, Transportation, Vegetation
California Department of Conservation (DOC), California Department of Fish and Wildlife, South Coast Region 5 (CDFW), California Department of Parks and Recreation, California Department of Transportation, District 7 (DOT), California Regional Water Quality Control Board, Los Angeles Region 4 (RWQCB), California State Lands Commission (SLC), Caltrans, Division of Aeronautics, Department of Toxic Substances Control, Office of Historic Preservation, Resources Agency, State Water Resources Control Board, Division of Water Rights, California Native American Heritage Commission (NAHC)
Reviewing Agency Comments
California Native American Heritage Commission (NAHC)
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