Mendocino County, California Bridges: Highway 101 Bridge across the Russian River

August 2017 (38.95389, -123.10167) Russian River Bridge

We've gone back to Mendocino County to look at bridges we missed during our last trip in August. California built a realignment of Highway 101 in 1933 that included this bridge over the Russian River. We can see in the photo above that the bridge has long (steel girder) approaches on both ends. The main span is a steel through truss bridge but with such a high skew that the portal and sway braces are attached to the previous panels. In the plan view below we can see more clearly how the end panels are cut to accommodate the skewed bracing.

The main span is 245 ft long and the total bridge is 1125 ft long over the Russian River flood plain. The Russian River is the second longest waterway in California with a length of 110 miles. It was originally called the Ashokawna by the First Nation people and then Slavyanka by Russian fur traders in 1817. It's a surprisingly wild river, especially during the winter. Beavers were once hunted along the river and even today 8 ft long sturgeons have been caught in its deeper regions.

The river flows south nearly parallel to Highway 101 causing the bridge to have its high skew. Past our bridge it eventually turns west for about 40 miles before emptying into the Pacific near Jenner. Despite the river being somewhat isolated I counted about 20 major bridges crossing the river including it's forks (the East Russian River) and tributaries (Austin Creek). You can look at some of these interesting bridges on my website or on the Bridgehunter website.

The vertical clearance of the through truss is limited by the cross bracing at the top. The minimum vertical clearance = 15' - 4", which makes the bridge structurally deficient (see photo below). We can also see in the photo below that the road is climbing out of the Alexander Valley and over the Mayacamas Mountains to the north (shown in the background).

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Butte County, California Bridges: Enterprise Bridge Carrying Lumpkin Road across the South Fork of the Feather River

August 2015 (39.53636 degrees, -121.33944 degrees) Enterprise Bridge

Every river flowing out of the Sierras (except for the Smith River near California's northern border) is dammed at least once before it reaches the valley. The Oroville Dam was completed in 1968 and filled the branches of the Feather River with Lake Oroville. Long, tall bridges were needed to cross these swollen river branches.

Last week we looked at the West Branch of the Feather River Bridge. In today's blog we've moved to the southeast side of Lake Oroville to look at the Enterprise Bridge (carrying Lumpkin Road) across the South Fork of the Feather River. The Enterprise Bridge (12C0199) is a 1175 ft long continuous three span deck truss bridge that was built in 1967. As can be seen in the photos, California's drought has reduced the South Fork to a trickle.

These continuous truss bridges were popular for medium long spans in the 1960's. However, I doubt if they would be built today. All of the bridges with spans between 400 to 1000 ft in length that have been built recently in California have either been concrete arches (like at Devil's Slide) or segmentally constructed concrete box girder bridges (like the new Benicia Martinez Bridge). California hasn't even built a long span steel girder bridge let alone a steel truss in many years.

Butte County, California Bridges: Enterprise Bridge Carrying Lumpkin Road across the South Fork of the Feather River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Butte County, California Bridges: State Route 70 Bridge across the West Branch of the Feather River

The Sacramento is the largest river in California and the Feather River is its principal tributary. We previously visited bridges on the Feather River in Yuba County. However, the really big bridges are across the branches higher up in the Sierras.

The first bridge we visited is the State Route 70 Bridge across the West Branch of the Feather River (12 0134). It's a double deck truss bridge that carries the highway on the top deck and the Southern Pacific Railroad on the lower deck.

This bridge is composed on four, 576 ft long Warren truss spans for a 2730 ft total length (with the approach spans). The always reliable Eric Sakowski states, "The second highest double decker road and rail bridge in the world after the Pit River Bridge, the West Branch Feather River cantilever bridge is one of 4 high spans that cross Lake Oroville in Northern California. The creation of America’s deepest man-made lake started in the early 1960s when construction began on the Oroville Dam. Completed in 1968, the earth fill structure is the highest in the United States measuring 770 feet (235 meters) from base to crest."

I'll visit bridges across Lake Oroville and across the various branches of the Feather River over the next few weeks.

Butte County, California Bridges: State Route 70 Bridge across the West Branch of the Feather River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Napa County, California Bridges: Bale Lane Bridge across the Napa River

December 2013 (38.55641 Degrees, -122.50633 Degrees) Bale Lane Bridge

Continuing northwest we drove over the Bale Lane Bridge (21C0048) across the Napa River. This bridge is identical to yesterday's Lodi Lane Bridge. It's another 100 ft long single span pony truss with a 17 ft wide deck, but built in 1937. Napa County must have found it cheaper in the 1930s to place a steel truss span on a couple of concrete abutments rather that having to built a stone arch. Also a lot more water can go under these pony trusses without causing a flood.

Napa County, California Bridges: Bale Lane Bridge across the Napa River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Napa County, California Bridges: Lodi Lane Bridge across the Napa River

December 2013 (38.52727 Degrees, -122.49089 Degrees) Lodi Lane Bridge

The next bridge carries Lodi Lane across the Napa River. It's a single span pony truss bridge that was built in 1930. This Warren Truss is 100 ft long and it's only 17 ft wide. Craig Philpott has a couple of photos of the Napa River flowing over the bridge on the Bridgehunter Website.

Napa County, California Bridges: Lodi Lane Bridge across the Napa River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Calaveras County, California Bridges: Ponderosa Way Bridge across the North Fork of the Calaveras River

April 2013 (38.31722 Degrees, -120.60194 Degrees) Ponderosa Way Bridge

Today's bridge is similar to the other Ponderosa Way Bridges that we've studied. They all carry US Forest Service roads and they all cross over North Forks (of the American River, the Mokelumne River, and the Calaveras River).

However, the previous two Ponderosa Way Bridges were pony trusses while today's bridge is a deck truss. For some reason, the usually reliable Bridgehunter calls it a pony truss and Uglybridges calls it a through truss! This is probably because no one has been willing to drive the severely rutted Ponderosa Way for two miles to see it. Once I got to the bridge site, I had to climb over lots of poison oak to get close enough to take a photo. The river is narrow and so heavily forested that I could only photograph the bridge through the brush.  I assume you could drive across the bridge but I didn't try. The bridge has an operating rating of 27 tons  and my Ford Pickup weighs 2.5 tons.

The Ponderosa Way Bridge (30F0002) is a two span Warren truss bridge that was built in 1935. The spans are 75 ft long and the bridge is 169 ft long so there are also short approaches (see photo below).

The 2010 inspection said the substructure is satisfactory, the superstructure is fair, and the deck is critical. Since the substructure is concrete pier walls and the superstructure is a 78 year old steel truss and the deck is made of crumbling timbers, I would agree (see photo below).

However, since the bridge is on an unmaintained road, it probably doesn't matter. It carried 100 vehicles a day in 1983, which was the last time someone put a counter on the bridge. It's only 13.5 ft wide and it has good wooden curbs and steel barrier rails. It had a sufficiency rating of 43.5 (from the 2010 inspection) and the engineer estimated it would cost $815,000 to improve the bridge from 'Structurally Deficient."

Calaveras County, California Bridges: Ponderosa Way Bridge across the North Fork of the Calaveras River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

El Dorado County, California Bridges: Salmon Falls Road Bridge over the South Fork of the American River (2)

August 2005 (38.773 Degrees, -121.036 Degrees) Salmon Falls Road Bridge

A closer look at the Salmon Falls Road Bridge. I took this photo with a Nikon SLR on a tripod instead of my usual point and shoot camera. I don't know if that is the reason but the colors seem richer in this photo.

The long shadows at the fasteners suggest that bolts were used instead of rivets, which makes sense for a bridge built in 1953. For such an old bridge, it still looks brand new. El Dorado County must do a good job of maintaining its bridges.

El Dorado County, California Bridges: Salmon Falls Road Bridge over the South Fork of the American River (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

El Dorado County, California Bridges: Salmon Falls Road Bridge over the South Fork of the American River (1)

August 2005 (38.773 Degrees, -121.036 Degrees) Salmon Falls Road Bridge

Back to California and to the bridges in the Sierra Nevada foothills and mountains. We previously explored Placer County and Nevada County to the north. Now we'll look at bridges in El Dorado County to the south.

El Dorado County is south of the Middle Fork of the American River, north of the Kit Carson Trail, and between Lake Tahoe and Folsom Lake (map courtesy of Wikipedia). It's where James W. Marshall found gold at Sutter's Mill in Coloma.

Today's bridge carries Salmon Falls Road over the South Fork of the American River just east of Folsom Lake. It's a 509.9 ft long steel girder bridge with a 228 ft long Warren truss center span. The bridge was built in 1953, probably as part of the rerouting of Salmon Falls Road with the construction of Folsom Dam. The old road was to the west and became innundated when Folsom Lake formed behind the dam.

I went to the end of Old Salmon Falls Road today to see if I could see the old bridge, but the water level was still too high. Luckily, other people have posted photos of the old bridge when the lake was lower such as some nice photos by Smugmug.

El Dorado County, California Bridges: Salmon Falls Road Bridge over the South Fork of the American River (1) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Japan's Bridges: Sendai Airport Railway Viaduct in Miyagi Prefecture

June 2011 (38.155 Degrees, 140.927 Degrees) Sendai Airport Railway Viaduct

A long viaduct, completed in 2007, carries trains between Sendai Station and Sendai Airport.  The airport, which is along the coast, was hit by the March 2011 tsunami. The resulting waves washed away cars and a few airplanes without producing much structural damage to the airport. The viaduct was more seriously damaged and wasn't brought back into service until October.

This photo shows the 150 m long two span steel truss that carries the viaduct over a small river about a mile north of the airport. The many equilateral triangles identify it as a Warren Truss, which was invented in 1848 by James Warren.

We can still see the impact of the tsunami such as the knocked over fence, standing water, and dead plants three months after the tsunami.

Japan's Bridges: Sendai Airport Railway Viaduct in Miyagi Prefecture by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

Utah's Bridges: Elgin Bridge over the Green River

May 2006 (38.985 Degrees, -110.150 Degrees) Green River Bridge

In May, 2006 I drove to Green River State Park for a five day (400 mile) bike ride around southeastern Utah. The Green River is an oasis in the middle of a vast desert. On the west side of the river is the town of Green River and on the east side is the town of Elgin. Both towns prospered with the coming of the railroad in the 1880s. The grade at Green River is the lowest point on the rails, but it's still almost a mile above sea level. Lying in my sleeping bag at night I could hear the trains crossing the bridge at the southern edge of the campground.

I'm not sure what the first railroad bridge across the Green River was like. However, there are a dozen photos taken by George Edward Anderson of a four span through truss bridge being built around 1900 on the Brigham Young University Library Website. The current Elgin Bridge is a three span Warren truss bridge with the truss panels subdivided with vertical members in order to carry bigger loads. According to The Bridge Hunter, this bridge is composed of three 170 ft spans for a total length of 510 ft. It's only 18 ft wide and sits on masonry piers and seat-type abutments. I couldn't find when the current bridge was built or if they ever moved the tracks. I have a vague memory of the tracks being moved at some point, but maybe I'm confused.

The tracks are owned by the Union Pacific and used by Amtrak's California Zephyr, which takes three days to go from Emeryville, California to Chicago, Illinois. I've taken this trip in a sleeper car and it's a very nice experience.

Utah's Bridges: Elgin Bridge over the Green River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

Australia's Bridges: Camellia Bridges across the Parramatta River in NSW

March 2011 (-33.815 deg., 151.026 deg.) Camellia Bridges

Alan commented in yesterday's blog that the superstructure of the Camellia Utility Bridge may originally have been on the Camellia Railway Bridge. The evidence suggests that he's right. We can see in the photo above that the piers of the two bridges are equally spaced, making the placement of the three spans onto the steel column caps of the utility bridge fairly straightforward.

I mentioned in a previous blog several reasons why we often see new and old bridges side by side. Alan brought up the additional point that a parallel bridge can be used as a detour during construction and that moving the superstructure onto an adjacent structure allows trains to cross the river while the new bridge is being built. 

It is likely that the three trusses on the utility bridge were originally on the railway bridge. We can see how the railway bridge is narrow at the two ends. This matches the width of the trusses. The Heritage Council article mentioned that the original railway bridge had a wrought iron latticed truss. However, I think that may have been from an even earlier era (when the masonry abutments were first built). The laced and riveted Warren trusses must have replaced the wrought iron trusses when a stronger bridge was required. It's a little odd that there is no deck on the utility bridge, but perhaps it was removed as needless weight when they moved the trusses to their new location.


The new railway bridge is also an interesting structure. For one thing it is very wide for a single set of tracks. Perhaps they planned to widen the ends and add another track in the future? More likely the old abutments are considered of historic value and so they may not be allowed to widen the ends of the bridge. Also, it is a little unusual to build a truss bridge when box girders can provide longer spans at less cost. It's even more unusual to build a pony truss without any lateral support from cross-braces. It's also unusual to build a continuous three span truss that is over three hundred feet long. Was it shipped on a barge or somehow fabricated on the site? The steel pier legs that descend from the truss make it a much stiffer, almost rigid structure. Also, it looks like a very lightweight walkway is attached to the west side of the railway bridge.

Australia's Bridges: Camellia Bridges across the Parramatta River in NSW by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

Peru's Bridges: Puente Pampa Blanca over the Tambo River

Puente Pampa Blanca (White Prairie Bridge) is a two span though truss on two column bents and seat-type abutments. Each span is 150 ft long and 30 ft wide. The bridge crosses the Rio Tambo about five miles north of Puente Freyne. It carries Route 18, which goes north, crosses the river, and then turns northeast along the east side of this fertile valley (see Google Map).

Using the language we've adopted from The Happy Pontist, this truss only has posts in the 'upward-pointing' triangles. In this photo you can see the floor beams supporting the deck at the bottom of each post and at the point of every 'downward-pointing' triangle. I believe the Happy Pontist explained that the additional posts we often see are there to provide lateral stability to the frame and are not needed when ample cross-bracing is provided to support the compression chord.

We've just looked at three Warren truss bridges. Puente Montalvo is a through truss with posts only in the 'upward-pointing' triangles. Puente Freyne is a deck truss with posts only in the 'downward-pointing' triangles. Puente Pampa Blanca is a through truss with posts only in the 'upward-pointing' triangles. This suggests that when the deck is at the bottom of the truss the vertical tension members are supported by 'upward-pointing' triangles. When the deck is at the top of the truss the vertical compression members are supported by 'downward-pointing' triangles.

In the photo above, we can see that Puente Pampa Blanca was being completed when we visited the site in 2001. If I recall correctly, the only damage from the earthquake was to some steel bearings. I'm not sure why, but I don't find this bridge to be as elegant as Puente Freyne or Puente Rio Sihuas. Perhaps it's just the red paint.

Among the many excellent tools provided by Google (besides this easy-to-use blogging program) is an automatic Spanish to English translator that I've used for the many articles I've read on the bridges of Peru. Of course it's not perfect. Anyway, here is what an article said about the opening of the bridge after Google translated it.

Pampa Blanca Bridge integrated into development. In an emotional popular act was attended by the Minister of Transport and Communications Engineer Luis Chang Reyes, l 29, was inaugurated last September Pampa White Bridge in distritro Cocachacra, an old dream coming true of the whole Province.

Bridge construction Pampa Blanca, whose cost exceeds five million suns, has been executed pursuant to an agreement signed between the private sector represented by the companies Terminal Internacional del Sur Tisure S. A. Central and S. Sugar Chucarapi A. whose combined economic contribution to the contributions of the Provincial Municipality of Islay Municpalidad Deistrital of Cochchacra and Ministry of Transport and Communications have made this work possible, as a clear indication that by entering into with private companies can accelerate the pace of our development.

Hopefully, some slight meaning has been retained. The bridge was made possible by funds provided by local governments and agricultural industries in the area. This ensured that their products could be quickly shipped to world markets. Note the green fertile valley that surround the river and the dry white cliffs on the edges of the satellite photo below.

Peru's Bridges: Puente Pampa Blanca by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Mexico's Bridges: Puente Rojo del Ferrocarril (2)

Another view of the railroad bridge near Coquimatlan. This through steel truss is carried by big rocker bearings. Note the man under the bridge throwing a fishing net into the river.

Today I watched the film In the Pit by Juan Carlos Rulfo, which was recommended by Norrin in a comment to this blog. The film follows laborers and ironworkers building the elevated portion (the Second Deck) of Mexico City's Periferico Freeway.

The film referred to a Mexican legend that the devil requires a human life during the construction of every bridge to keep it standing.  Rulfo had a nice shot at the end of the film from a helicopter of mile after mile of freeway. It really gave a sense of how much work was required to build about 20 km of elevated expressway. The movie had lots of moments of humor, sweetness, frustration, and anger expressed by the construction workers that made the film engrossing. I think we're fortunate that the owners gave Rulfo access to the construction site.

You can rent the movie (it's available on Netflix) or you can look at photos of the freeway at skyscrapercity on the Internet.

Mexico's Bridges: Puente Rojo del Ferrocarril (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Mexico's Bridges: Puente Rojo del Ferrocarril (1)

This is a classic single-span Warren truss bridge on stone masonry abutments. All the main truss members are wide flange girders. It's a couple miles south of Puente Juarez and west of Coquimatlan.

This bridge supports railroad tracks without ballast. The wooden ties rest on steel channels supported on the floor beams, which in turn are supported by the vertical hangers.

The abutments were cleanly mortared with extruded joints and built with three steps. The lowest step is under the bottom chord and may be used for jacking up the truss. The second step supports the truss and the tracks run across the top.

The bridge appears to be in good condition. It crosses over a little stream that may be a branch of Rio Armeria. It seems like a rather light structure to carry heavy trains, but that's what makes truss bridges so effective.

Mexico's Bridges: Puente Rojo del Ferrocarril (1) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.