Information for Strong-Motion Station
San Francisco Bay - Dumbarton Bridge
CGS - CSMIP Station 58596
Earthquakes recorded by this station
(Station Photograph - click to enlarge)(Sensor Layout - click to see PDF File)
Latitude 37.5050 N
Longitude 122.1200 W
Elevation (m) --
Site Geology  
Vs30 (m/sec)  
Site Class  
No. of Spans43
Plan ShapeStraight
Total Length8,600 feet (1.6 miles)
Width of Deck85 feet
Construction Date1982, 2013 (retrofit)
Instrumentation1987 - 26 sensors on the bridge and 2 free-field sites; 2013 - 109 sensors on the bridge and 2 geotechnical arrays.
Superstructure TypeMain span: Steel box girders with lightweight concrete deck. Approach spans: concrete box girders. Retrofit on main span: (a) Replacement of existing bearings with friction pendulum system bearings at pier cap, (b) installation of new steel cross frames in steel box girders at Piers 16 and 31, (c) strengthening of existing steel cross frames in steel box girder at each pier, (d) hinge retrofit, and (e) replacement of deck joints at Piers 16 and 31 with new seismic joint assembly to accomodate increased joint movements.
Substructure TypeInclined hollow reinforced concrete columns. 2 columns per bent. Retrofit: (a) expansion and strengthening of pier caps in order to accommodate new isolator bearings at Piers 16 to 31, and (b) addition of concrete frames as backwall seat at Piers 1 and 44.
Foundation TypePrestressed concrete and steel piles. Retrofit: (a) expansion and strengthening of pile caps with reinforced concrete overlay at Piers 17 through 30, and (b) strengthening of existing slabs of east and west trestle structures with 4 ft diameter CIDH piles on both sides of selected bents.
RemarksThis toll bridge was originally instrumented by Caltrans in 1985 with 26 sensors on the bridge plus 2 free-fields. The bridge was re-instrumented with 109 sensors on the bridge plus 2 geotechnical arrays during retrofit.