Plumas County, California Bridges: Tobin Bridges across the North Fork of the Feather River

September 20015 (39.93592, -121.31588) Tobin Bridges

The North Fork of the Feather River Canyon is so narrow that there is barely enough room for a railway and a highway along its banks. Near Tobin, State Route 70 crosses under the Union Pacific Railway just as both routes cross over the river. Perhaps the river bend was too tight for the railroad, which had to cross the river to make a longer radius curve. This may have blocked the highway, which was forced to cross to the other bank. This dance between transportation routes continues (with an occasional dam or tunnel pushing them together or further apart) until the highway, the railway, and the river go in different directions near Keddie.

The Tobin Underpass (09 0005) is a 234 ft long, single span camelback Pratt truss (with the diagonal truss members oriented towards the center of the bridge) that was built in 1910. The North Fork Feather River Bridge (09 0004) is a 290 ft long, single span 'K' truss bridge (so named because of the configuration of the vertical and diagonal members) that was built in 1936 (see photo above). The dates of the bridges correspond to the dates when the railway and highway were built.

The highway bridge is rated as deficient (despite having been recently rehabilitated) mainly because there is no room in the narrow canyon to provide shoulders or other safety features to the bridge. It carries about 1000 vehicles a day. The railroad bridge is likely to also need some maintenance but continues to carry several freight trains a day.

Plumas County, California Bridges: Tobin Bridges across the North Fork of the Feather River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Plumas County, California Bridges: Storrie Bridge across the North Fork of the Feather River

September 2015 (39.91802 Degrees, -121.32107 Degrees) Storrie Bridge

After several miles along the north bank of the North Fork, State Route 70 returns to the south bank on a highly skewed bridge with two camelback pony truss spans over the river.

The Storrie Bridge (named after a nearby town) is a 360 ft long bridge that was built in 1936 by the Judson Pacific Company. It appears to be in good condition and it's eligible for the National Register of Historic Places. The original substructure was pier walls but it looks like a super-bent was built around at least one of the piers to improve its lateral capacity for earthquakes.

Pony truss bridges are nice because they don't have the vertical clearance problems of through truss bridges. However, the high skew must put some weird stresses on the girders whenever a big truck drives by.

Plumas County, California Bridges: Storrie Bridge across the North Fork of the Feather River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Plumas County, California Bridges: Rock Creek Bridges

September 2015 (39.8988 Degrees, -121.3589 Degrees) Rock Creek Bridges

The Union Pacific Railroad and California Route 70 run parallel to each other for about 50 miles along the North Fork of the Feather River. A few miles past the Pulga Bridges (where Rock Creek flows into the North Fork) is another juxtaposition of highway and railway bridges.

The highway bridge (09 0002) is a 330 ft long, three span river crossing with a 180 ft long Parker through truss center span across the North Fork. It was built in 1936 but the substructure was rebuilt on 2000. Those extra long bent caps look like they were built to carry a future widening (see photo below).

The railroad crosses Rock Creek with a steel trestle bridge that includes a Warren truss main span. We are going to see a similar style of adjacent railway and highway bridges as we continue to travel upstream along the Feather River through Plumas County.

Plumas County, California Bridges: Rock Creek Bridges by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Butte County, California Bridges: Poe Powerhouse Bridge across the North Fork of the Feather River

September 2015 (39.7278 Degrees, -121.4684 Degrees) Poe Powerhouse Bridge

Just north of Lake Oroville is the 'Big Bend' and several interesting bridges. Last week we looked at the beautiful Union Pacific North Fork Bridge. Today we're studying the nearby Poe Powerhouse Bridge. I previously mentioned all the dams (and powerhouses) along the North Fork of the Feather River. The only access to some of them are on dilapidated roads and bridges. The Poe Powerhouse is typical. You drive down a gravel road (Bardees Bar Road) full of switchbacks to the river and across an old truss bridge with weight restrictions that takes you to the powerhouse. The Poe Powerhouse consists of transformers and a 890 ft long penstock with a drop of 477 ft that produces 120 megawatts of electricity. The bridge and the powerhouse are owned by Pacific Gas and Power.

The Poe Powerhouse Bridge is 335 ft long with a single, 178 ft long deck truss span across the North Fork of the Feather River. The substructure consists of tapered concrete pier walls. The superstructure supports an 18 ft wide reinforced concrete deck that carries an unnamed road. The road is used by the powerhouse employees and by the occasional kayaker, although the many dams across the river must make kayaking a hassle.

Butte County, California Bridges: Poe Powerhouse Bridge across the North Fork of the Feather River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.