Saturday, August 29, 2015

Butte County, California Bridges: Old Bidwell Bar Bridge

August 2015 (39.53747 Degrees-121.45417 Degrees) Old Bidwell Bar Bridge
The first suspension bridge (ropes hung above an obstacle) predates recorded history. The first iron suspension bridge was built (appropriately) by the Tibetan bridge engineer Thangtong Gyalpo in the 15th century. The first US suspension bridge was the Jacob's Creek Bridge in Pennsylvania built in 1801. The first California suspension bridge was the Bidwell Bar Bridge built across the Middle Fork of the Feather River in 1855 (see photo below).
Bidwell Bar was a gold rush town that was founded after John Bidwell discovered gold there in 1848. The town experienced a rapid boom and an equally rapid bust until the bridge was just about all that remained. When the Oroville Dam was built in 1965, the town was submerged and the bridge (along with a historic orange tree and toll building) was moved to its present location (Kelly Ridge Park) in a state boat launch facility about a mile west of its original location.
When I drove to the park entrance in August, the ranger told me the bridge was inaccessible because the road had been blocked by fencing surrounding houseboats in dry dock. I was irritated that after all of the trouble to move the bridge the park had closed it to the public. However, the bridge turned out to be readily accessible to anyone willing to hike up a hill (although photos suggest the bridge was less accessible before the drought). Another thing that bothered me is that timber piles now supported the bridge rather than having the suspension cables carry the 240 ft long span.
The Bidwell Bar Bridge was fabricated in Troy, New York and shipped around the southern tip of Chile to California. The towers are atop stone abutments and composed of four iron pipes stamped with 'Starbuck's Metal Works of Troy, NY. The pipes at each tower form a pyramid with saddles on the top that support two suspension cables. Regularly spaced hangers support timber floor beams that carry the deck. The bridge is a California Historical Landmark and a Historical Civil Engineering Landmark.
Creative Commons License
Butte County, California Bridges: Old Bidwell Bar Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Saturday, August 22, 2015

Butte County, California Bridges: Route 162 Bridge across the Middle Fork of the Feather River

August 2015 (39.54987 Degrees-121.42988 Degrees) Lake Oroville Bridge
This week's bridge crosses over the Middle Fork of the Feather River. The water level is so low now that the bridge looks like it did when it was first built. It's a suspension bridge, which is one of the easier long span bridges to build. Once you drape the cables over the towers (and anchor them) you can just work from each end hanging the superstructure until they meet in the middle.
Chico State University has archived many photos that were taken during construction of the bridge and the dam. It's surprising how many long span bridges were designed and built during the period when the dams were being constructed. Sepulveda Dam was completed by the USACE in 1941, Shasta Dam was built by the USBR in 1945, Oroville Dam was built by the CDWR in 1965, etc. Who were all these bridge engineers?  There seems to be a boom period for different places when money is available and amazing infrastructure is created.
This week's bridge has several names. It's called the Bidwell Bar Bridge because it replaced an old bridge by that name (that we'll look at next week). It's called the Lake Oroville Bridge because its the most impressive of the bridges over Lake Oroville. Caltrans calls it the Middle Fork of the Feather River Bridge (12 0188) after the obstacle that it crosses. It carries the Olive Highway, which is also called the Oroville-Quincy Highway and it's officially called California Route 162.
The main span is 1108 ft long and the entire bridge is 1793 ft long. The roadway is 28 ft wide with sidewalks on both sides of the roadway. It's an interesting bridge because it is on a horizontal curve with the suspension cables anchored to the side of the deck. Note how there are no back stays on the bridge. Instead, there are concrete piers to support the back spans on both ends of the bridge. Eric Sakowski writes that it's the highest reservoir bridge in the US. The towers are 350 ft tall and were built about 300 ft above the bottom of the river.
Creative Commons License
Butte County, California Bridges: Route 162 Bridge across the Middle Fork of the Feather River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Sunday, August 16, 2015

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.
Creative Commons License
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.

Tuesday, August 11, 2015

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.
Creative Commons License
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.

Sunday, August 9, 2015

Phoenix Bridge Company

After posting thousands of pictures of bridges it's not surprising that I occasionally receive emails with corrections to my blog. In 2010 I showed a bridge in Arequipa, Peru which I incorrectly identified as by Gustav Eiffel. However, if I had studied the bridge more carefully, I would have realized it was supported by columns manufactured by the Phoenix Bridge Company. It wasn't until I received an email from Jeff Amerine with the Schuylkill River Heritage Center in Phoenixville, PA that I realized my error. Apparently the Phoenix Bridge Company had been very active in providing bridges to South America.
The Phoenix Bridge Company built over 500 bridges with their patented hollow column design. Just like Sears Roebucks, they published a catalog where buyers could chose one of their standard bridge designs (although some additional engineering was usually required). The columns were lightweight but strong and were an improvement over the cast iron columns that had previously been used for truss bridges. However, as the American Bridge Company (and reinforced concrete bridges) became more successful the Phoenix Bridge Company became less able compete and they eventually went out of business.

Friday, August 7, 2015

Unbuilt Bridges (5)

It's often beneficial to connect islands, countries, or even continents together. We've previously studied how Japan connected its four main islands together at the end of the twentieth century. Similarly, Italy would like to connect their mainland across the 3.1 km wide Strait of Messina to the island of Sicily. Projects to bridge the Strait have been proposed throughout history, but the canyon-like bathymetry of Messina would require a main span of 3 km, which is one and a half times greater than the main span of the world's longest bridge (the Akashi-Kaikyo Bridge in Japan). The latest project to bridge the Strait was proposed by Silvio Berlusconi in 2009 before it was abandoned again in 2013.
A more ambitious project would be to cross the 80 km wide Bering Strait between Alaska and Russia. Such a project would present a variety of challenges due to the weather, the politics, the expense, etc. However, the Strait is only about 55 meters deep and has the Diomede Islands to provide a respite between two really long bridges. Currently Russian is proposing to built a $65 billion rail tunnel across the Strait. Such a connection might help warm relations between the US and Russia.
An even more ambitious project is a space bridge from the earth's equator to a synchronously orbiting satellite 36,000 km above the earth. The bridge would be built of lightweight carbon filaments under tension. The lower end would be pulled downward by gravity and the upper end would be pulled upward by centrifugal force. Vehicles could travel up and down the bridge carrying cargo and passengers to and from ships traveling through space.

Thursday, August 6, 2015

Unbuilt Bridges (4)

The most popular fantasy after 'bridges with buildings' in 'Unbuilt America,' (by Sly and Stone) are 'bridges with pipes.' If a building bridge represents the fantasy of watching travellers from the comfort of home than a pipe bridge represents the fantasy of travel through the birth canal. In the drawing above (from 'Design and the Environment' by Phyllis Kirby) a 'Pipeline for Autos,' from 1963 shows how vehicular protection can be provided in a cold and windy environment. It's an above ground tunnel composed of a cylindrical superstructure with piers and occasional towers for the substructure.
A variation on this theme is the 'Future Cities' by James Rossant (1973). In the above drawing his city resembles an organism with it's epidermis removed and it's circulatory system exposed. Bridges are just one of various pipelines carrying its circulatory systems through a city like an exposed anthill. The idea of communal living with minimal environmental degradation was a popular idea in Paolo Soleri's Arcosanti or in a megapolis like New York or Tokyo. The idea seems comforting, at least from this view high above the people's struggles.
Speaking of Soleri, almost all of his bridges are either tubular like the drawing above or partially exposed tubes like the Beast bridge we recently studied.  I wonder if in the future we will be protected from the sun, the air, and the weather in a completely sealed environment, riding along moving sidewalks and observing the outside through glass.

Wednesday, August 5, 2015

Unbuilt Bridges (3)

The book 'Unbuilt America' by Allison Sky and Melissa Stone illustrates a variety of futuristic fantasies for the United States. A recurring image is a building combined with a bridge. In the past, the wealthiest merchants build their businesses on bridges. However, I don't know if the same strategy would work today. When Louis Mullgardt visited San Francisco in the 1920s everyone was debating whether to build a bridge across the Bay. Mullgardt's unsolicited proposal (shown above) included giant buildings for the piers and a 24 lane bridge deck across the Bay. His expert use of charcoal made this futuristic study look more like a renaissance drawing.
In Hugh Ferriss' drawing above (from 1929) apartment buildings were combined with a suspension bridge. Maybe it's the juxtaposition of a building facade on a bridge that causes a slight frisson of confusion and recognition.
If a suspension bridge can support buildings so can a truss bridge. The Big Four Bridge was a railroad bridge that was built in 1893 across the Ohio River between Louisville, Kentucky and Jeffersonville, Indiana. When the railroads abandoned the bridge several entrepreneurs suggested converting it into a mini-city with apartment buildings, restaurants, etc.. The composite photo/drawing by Arthur Foran in 1968 shows how he imagined it might look. However, the director of housing and building inspections eventually had the approaches removed as an eyesore. The idea of living on an old bridge reminds me of the William Gibson 'Sprawl Trilogy' that takes place on the Bay Bridge after it was damaged during the Loma Prieta earthquake and became home (he imagines) to thousands of squatters.

Monday, August 3, 2015

Strange Uses for Bridges (2)

Rendering of Juncal Viaduct with Turbines (Oscar Soto, ZECSA)
My sister sent me an article from Smithsonian Magazine about installing wind turbines on bridges to create electricity. In the drawing above, mechanical engineer Oscar Soto imagines how turbines could be installed on the Juncal Viaduct in the Canary Islands. He said that any place with wind speeds between 6 and 25 meters per second would work.

I imagine that bridges spanning mountain canyons like we saw in Mexico would have sufficient clearance for a wind turbine. However, tall bridges have enough trouble resisting high winds without having to resist the additional drag forces from having deep longitudinal diaphragms installed between their piers.

Sunday, August 2, 2015

Unbuilt Bridges (2)

Visionary artists often come up with bridge designs to illustrate their ideas and/or philosophies. Sometimes their bridges are built during their lifetimes, or after they're gone, but usually they remain tantalizing ideas that only exist in books. The architect Paolo Soleri believed that humans were migratory creatures and wanted to design high density cities (to minimize their impact on the environment) where they could stop between their travels. He built Arcosanti in the Sonoran Desert to test his ideas. His 'Beast' bridge (shown above) was designed to help carry his imagined tribal societies on their journey. It's a continuous concrete structure with the superstructure folded upward at midspan and folded downward at the supports. It actually looks a lot like Frank Lloyd Wright's 'Butterfly' bridge, which isn't surprising since they worked together at Taliesen in the 1940s. Most likely, they influenced each others designs. This bridge was in 'The Architecture of Bridges," a book that The Happy Pontist rated highly in a blog last week.
Buckminster Fuller developed a philosophy of tensegrity with structures composed of prestressed tension cables (on the outside) and isolated compression struts (in the middle). These truss-like structures are composed of elements loaded axially without any bending, shear, or torsion. Although a tensegrity bridge was never built in Buckminster Fuller's lifetime, the Kurilpa Bridge in Brisbane, Australia is said to have been designed (by Cox Rayner Architects and Ove Arup Engineers) using tensegrity principles.
Frank Gehry's structures are easily identifiable because of their undulating stainless steel surfaces. The BP (Millennium Park) Pedestrian Bridge in Chicago is a long steel box girder bridge (designed by SOM) that supports Frank Gehry's design. To help in the design and construction of his structures, Gehry's uses Grasshopper programming software, which is good at creating intricately folded surfaces. If you are a famous architect, most cities are happy to own your bridge (although even Gehry had to go through many iterations before his design was finally accepted).