2 votes

Hill Road Bridge


Hill Road Bridge

Photo taken by Craig Philpott in May 2010


BH Photo #164852


Street View 


Through truss bridge over Mill Creek on Hill Road
Mendocino County, California
Open to traffic
Built 1925
Eight panel pin connected Pennsylvania Through truss
Length of largest span: 120.1 ft.
Total length: 123.0 ft.
Deck width: 17.4 ft.
Vertical clearance above deck: 15.2 ft.
Approximate latitude, longitude
+39.74889, -123.18083   (decimal degrees)
39°44'56" N, 123°10'51" W   (degrees°minutes'seconds")
Approximate UTM coordinates
10/484507/4399902 (zone/easting/northing)
Quadrangle map:
Jamison Ridge
1300 ft. above sea level
Average daily traffic (as of 2014)
Inventory numbers
CA 10C-111 (California bridge number)
BH 11132 (Bridgehunter.com ID)
Inspection report (as of August 2018)
Overall condition: Poor
Superstructure condition rating: Fair (5 out of 9)
Substructure condition rating: Good (7 out of 9)
Deck condition rating: Poor (4 out of 9)
Sufficiency rating: 31.2 (out of 100)
View more at BridgeReports.com

Update Log 

  • May 11, 2010: Updated by Craig Philpott: refined truss design name
  • May 10, 2010: Updated by Craig Philpott: Added photos
  • March 9, 2010: Updated by Craig Philpott: Added street view updated design



Hill Road Bridge
Posted May 11, 2010, by James Baughn (webmaster [at] bridgehunter [dot] com)

This bridge may have been cobbled together from parts out of a different bridge. In the high-res version of the first photo, look at the second vertical from the left. There's a gusset plate (or something) about two-thirds of the way up. That suggests to me that something else was connected to that girder at one time.

Hill Road Bridge
Posted May 11, 2010, by Anthony Dillon (spansaver [at] hotmail [dot] com)

This may well be a very early example of a Pennsylvania through truss. First of all is the overall small size of it. More importantly is the lack of any portal or sway bracing, which is unheard of on a normal sized Pennsylvania truss.

This is a unique landmark that will hopefully be preserved.

Hill Road Bridge
Posted May 11, 2010, by Craig Philpott (cphilpott [at] puc [dot] edu)

Regarding the age. I agree with you that this bridge is probably older then the 1925 date. There is no data plate on the bridge that I could find and I suspect this is one of the common cases out here in the west where the bridge was installed "here" in 1925 after service in an earlier unknown location.

Hill Road Bridge
Posted May 11, 2010, by Robert Elder (robertelder1 [at] gmail [dot] com)

I would classify this bridge as a Pennsylvania truss. This design had several subtle variations. I would not be surprised if this bridge is older than the 1925 date. Pin-connections were almost completely phased out by about 1912-1915.

Hill Road Bridge
Posted May 10, 2010, by Craig Philpott (cphilpott [at] puc [dot] edu)

This bridge needs a more precise type description. I could use some help on this one. I am not familiar with this particular configuration of a Pratt type truss.