Information for Strong-Motion Station
Antioch - San Joaquin River Bridge
CGS - CSMIP Station 67771
Earthquakes recorded by this station
(Station Photograph - click to enlarge)(Sensor Layout - click to see PDF File)
Latitude 38.0278 N
Longitude 121.7514 W
Elevation (m) --
Site Geology  
Vs30 (m/sec)  
Site Class  
No. of Spans70
Plan ShapeStraight
Total Length9,432 feet (1.8 miles)
Width of Deck43.5 feet
Construction Date1978, 2012 (retrofit)
Instrumentation1998 - 18 sensors on the bridge and a free-field site; 2002 - 73 sensors on the bridge plus a 18-sensor geotechnical array.
Superstructure TypeOriginal: Lightweight RC deck on two steel girders for Spans 1-40. Spans 41-70 are RC slab spans on concrete columns. Abutment 1 is a seat type and Abutment 71 is a diaphragm type. Retrofit: (a) replace existing bearings with friction pendulum isolator bearsings at Abutment 1, Piers 2 through 41,
Substructure TypeOriginal: 2-column RC piers from Piers 2 to 41. 4-column RC piers at slab spans. Retrofit: (a) post-tension pier cap at P2 to P39, (b) install steel braces between columns at Piers 12 to 31, (c) install steel jackets on RC columns at slab spans, and (d) remove existing concrete curtain walls at sl
Foundation TypeConcrete piles; no retrofit on foundations.
RemarksThe bridge was instrumented under the interagency agreement between Caltrans and DOC/CGS in 1998 with 18 sensors. The bridge was re-instrumented with 73 sensors during retrofit. A geotechnical array with 6 depths between Piers 35 and 36 was also installed during retrofit.