Information for Strong-Motion Station
Leggett - Hwy 101/Confusion Hill Bridge
CGS - CSMIP Station 79421
Earthquakes recorded by this station
(Station Photograph - click to enlarge)(Sensor Layout - click to see PDF File)
Latitude 39.9213 N
Longitude 123.7634 W
Elevation (m) 245
Site Geology  
Vs30 (m/sec)  
Site Class  
No. of Spans3
Plan ShapeStraight
Total Length413 meters
Width of Deck13 m
Construction Date2009
Instrumentation2009. 21 accelerometers on the bridge. 3 accelerometers at a free-field site near North Abutment.
Superstructure TypeCast-in-place segmental concrete box girder (one-cell).
Substructure TypeHollow box concrete column; one column at each pier. The column height is 51.5 m and 51.25 m, at Piers 2 and 3, respecively.
Foundation TypePiers 2 and 3 are supported by pile caps on 11 1.5m-diameter CIDH concrete piles. Abutments are seat typed with PTFE bearings and supported on CIDH concrete piles.
RemarksThe bridge was instrumented during construction under the interagency agreement between Caltrans and DOC/CGS.