Information for Strong-Motion Station
Oakland - 18-story City Hall
CGS - CSMIP Station 58675
Earthquakes recorded by this station
(Station Photograph - click to enlarge)(Sensor Layout - click to see PDF File)
Latitude 37.8054 N
Longitude 122.2725 W
Elevation (m) 12
Site Geology Shallow alluvium over rock (sandstone)
Vs30 (m/sec) 295 (inferred)
Site Class D
Remarks/Notes Site information sources
No. of Stories above/below ground18/1
Plan ShapeRectangular
Base Dimensions124' x 179'
Typical Floor Dimensions66' x 102'
Design Date1911 & 1992 (Retrofit)
Instrumentation1995. 21 accelerometers, on 6 levels in the building.
Vertical Load Carrying System5 inch thick concrete slabs supported on load bearing structural steel framework.
Lateral Force Resisting SystemRiveted steel frames infilled with either brick masonry, unreinforced concrete masonry, or hollow clay tiles. Retrofitted with high damping rubber base isolators below the 1st floor, concrete shear walls (floors 1 through 6), and concentric steel braces (floors 7-13). Steel braces were also added to the clock tower.
Foundation Type2'-4" deep concrete mat. Columns are supported on steel beams embedded in the concrete mat.
RemarksBuilding suffered extensive damage during the 1989 Loma Prieta Earthquake. Strong-motion records were obtained at the basement and 16th floor of the building during the 1957 San Francisco earthquake.