Information for Strong-Motion Station
San Francisco; Transamerica Tower
NSMP Station 1239
Earthquakes recorded by this station
Ambient Records for NP1239
(Station Photograph - click to enlarge)(Sensor Layout - click to see PDF File)
Latitude 37.7952 N
Longitude 122.4028 W
Elevation (m) 5
Site Geology  
Vs30 (m/sec)  
Site Class  
No. of Stories above/below ground60/4 (the 48th story is the highest occupied floor
Plan Shaperegular
Base Dimensions174 x 174 ft
Typical Floor DimensionsThe floor dimensions reduce linearly with a slope of 10% from ground level to the roof
Design Date1972
Instrumentation1985, 24 accelerometers on 8 levels in the building.
Vertical Load Carrying System2.5" of concrete cover over 3" concrete filled corrugated steel decking spot welded to the floor beams supported by steel columns.
Lateral Force Resisting SystemTubular space-truss systsm around the perimeter between the second and fifth floors and steel moment-resisting frame above the fifth floor. The below ground levels consist of rigid shear-wall box.
Foundation Type9-ft-thick mat foundation