Friday, October 24, 2014

Shasta County, California Bridges: Sacramento River Trail Bridge (4)

October 2014 (40.6015 Degrees, -122.4443 Degrees) Sacramento River Trail Bridge
Dear readers. I am going to be cutting back on my bridge posts for awhile. However, my URL is www.bphod.com for Bridge PHoto Of the Day. If I'm going to provide bridge photos less frequently what can BPHOD stand for?
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Shasta County, California Bridges: Sacramento River Trail Bridge (4) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Thursday, October 23, 2014

British Columbia Province, Canadian Bridges: Capilano Bridge

June 2010 (49.3430 Degrees, -123.1150 Degrees) Capilano Bridge
Speaking of catenary bridges, a couple of years ago we visited the Capilano Bridge in a private park that cost $36 to enter. For some reason, they called the main attraction a suspension bridge and when I tried to explain to the park workers that it was a suspended bridge, they turned a deaf ear to my complaints.

It did cause my heart to beat a little faster as I walked across the bouncing deck high above Capilano Canyon. The bridge was originally built by George Grant MacKay (a Scottish engineer) in 1888 and the surrounding land was slowly developed as a tourist attraction over the next 126 years.
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British Columbia Province, Canadian Bridges: Capilano Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Based on a work at http://www.bphod.com.

Wednesday, October 22, 2014

Shasta County, California Bridges: Sacramento River Trail Bridge (3)

October 2014 (40.6015 Degrees, -122.4443 Degrees) Sacramento River Trail Bridge
Rather than the typical seat-type abutments found on most bridges, the Sacramento River Trail Bridge abutments helps carry the large tension force of the hanging bridge superstructure into the earth. The superstructure deepens as it approaches the abutments to separate the cables before they are anchored into the bedrock. The superstructure is composed of waffle slab segments with tapered edge elements carrying the barrier rail. I wonder if the cables are distributed across the deck or are concentrated along the sides?
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Shasta County, California Bridges: Sacramento River Trail Bridge (3) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Tuesday, October 21, 2014

Shasta County, California Bridges: Sacramento River Trail Bridge (2)

October 2014 (40.6015 Degrees, -122.4443 Degrees) Sacramento River Trail Bridge
Another view of the Sacramento River Trail (stressed-ribbon) Bridge. It was designed by Jiri Strasky, a Czech engineer who has built several of these bridges and has even written a book "Stress Ribbon and Cable-Supported Pedestrian Bridges" about them. However the concept of a catenary bridge is very old. Bridges made of ropes suspended over rivers were used by the Incas and Chinese for centuries. In the 1960s Leonel Viera designed the Maldonado Bridge in Uruguay by loading cables supporting precast segments with weights and then grouting the 'prestressed' structure together. 
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Shasta County, California Bridges: Sacramento River Trail Bridge (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Monday, October 20, 2014

Shasta County, California Bridges: Sacramento River Trail Bridge (1)

October 2014 (40.6015 Degrees, -122.4443 Degrees) Sacramento River Trail Bridge
We took a break from Tuolumne County bridges and rode our bikes along the Sacramento River in Redding on Sunday. The first bridge we visited is the longest stressed ribbon bridge in the U.S. The plaque on the railing is inscribed "This 13 foot wide 418 ft long concrete stressed ribbon bridge provides a clear span of the entire floodplain. The bridge is supported by 236 steel cables inside the bridge deck connected to rock anchors drilled deep into solid bedrock. This unique design was chosen to avoid damage to the natural rock outcropping along the river or encroachment into the floodplain with earth fill or bridge piers. The bridge was formally opened to the public on April 14, 1990."

We'll take a closer look at this interesting bridge tomorrow.
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Shasta County, California Bridges: Sacramento River Trail Bridge (1) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Sunday, October 19, 2014

Tuolumne County, California Bridges: Sourgrass Bridge across the North Branch of the Stanislaus River


June 2013 (38.32169 Degrees, -120.21739 Degrees) Sourgrass Bridge

The Sourgrass Bridge is a three span concrete box girder bridge on wide pier walls across the North Fork of the Stanislaus River. The previous bridge was destroyed by a mudslide in 1997. It looks like the original piers may have been used for the new bridge or maybe floods are a frequent occurrence at this location.

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Tuolumne County, California Bridges: Sourgrass Bridge across the North Branch of the Stanislaus River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Saturday, October 18, 2014

Tuolumne County, California Bridges: New McKays Dam Bridge across the North Fork of the Stanislaus River

June 2013 (38.2320, -120.2958) New McKays Dam Bridge
New McKays Dam holds back the North Fork of the Stanislaus River. A single span steel highway bridge on seat-type abutments is just downstream of the dam. This area is very remote. The New McKays Dam Road is a series of switchbacks descending down to the river. We previously studied this bridge when we were in Calaveras County in June of 2013.
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Tuolumne County, California Bridges: New McKays Dam Bridge across the North Fork of the Stanislaus River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Friday, October 17, 2014

Tuolumne County, California Bridges; New Camp Nine Road Bridge across the Stanislaus River

June 2013 (38.12486 Degrees, -120.38432 Degrees) New Camp Nine Road Bridge
Continuing upstream along the Stanislaus River we arrived at the Camp Nine Pedestrian Bridge. This is another tall, modern-looking structure that provides a nice contrast to the rugged beauty of the Sierra Mountains. We previously visited this bridge in June of 2013 from the Calaveras County side of the river. It was built by the US Army Corp of Engineers to replace an old flood damaged bridge.  
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Tuolumne County, California Bridges; New Camp Nine Road Bridge across the Stanislaus River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Thursday, October 16, 2014

Tuolumne County, California Bridges: Parrots Ferry Bridge across the Stanislaus River

May 2013 (38.04583 Degrees, -120.44889 Degrees) Parrots Ferry Bridge
Another photo of the Parrots Ferry Bridge (32C0076) across the Stanislaus River. We last studied this bridge from the Calaveras County side of the river on June 7th, 2013. It's a 1293 ft long continuous prestressed concrete box girder bridge built in 1978. The center span is 640 ft long and I recall they did something to slow the sagging of the center span. All of these bridges over the Stanislaus River have haunched box girders and were built in the 1970s. It's another bridge named after a former ferry operator.
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Tuolumne County, California Bridges: Parrots Ferry Bridge across the Stanislaus River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Wednesday, October 15, 2014

Tuolumne County, California Bridges: State Route 49 Bridge across New Melones Lake

September 2005 (38.00667 Degrees, -120.49833 Degrees) New Melones Bridge
On the border between Calaveras and Tuolumne Counties is New Melones Lake formed by damming the Stanislaus River. Old State Route 49 crosses the lake carried by the New Melones Bridge (32 0040). Its a 2250 ft long, 6 span steel box girder bridge built in 1976. I discussed this bridge before on June 4, 2013 when we were studying Calaveras County Bridges. We are in the foothills of the Sierra Mountains and all of the rivers (except for the Smith River) are dammed.
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Tuolumne County, California Bridges: State Route 49 Bridge across New Melones Lake by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Tuesday, October 14, 2014

Tuolumne County, California Bridges: Jacksonville Road Bridge across the Tuolumne River

September 2014 (37.83694 Degrees-120.34500 Degrees) Jacksonville Road Bridge
As we drove into the Sierras on State Route 120 I kept catching glimpses of the Jacksonville Road Bridge (32C0057) across the Tuolumne River. This is a nine span 1441 ft long steel stringer bridge with 200 ft long river spans. The girders are made of Corten steel and the substructure is composed of eight-sided single column bents with odd tetrapod-shaped bent caps. Like the previous bridge, the deck is in 'Poor' condition despite carrying very little traffic. This bridge was built in 1970.
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Tuolumne County, California Bridges: Jacksonville Road Bridge across the Tuolumne River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Monday, October 13, 2014

Tuolumne County, California Bridges: James E. Roberts Bridge across the Tuolumne River

September 2014 (37.84167 Degrees-120.37667 Degrees) State Route 120 Bridge
We're traveling east from Stanislaus County into the foothills of Tuolumne County. Today's bridge was designed by Caltrans' former Chief Bridge Engineer Jim Roberts. He often talked about the problems of analyzing a highly curved continuous steel girder bridge in the 1960s. After he died they named the bridge he was proudest of after him. 

The James E. Roberts Bridge (32 0018) carries State Route 120 across the Tuolumne River. It is a 1394 ft long six span steel girder bridge with 350 ft long spans over the river. The substructure is composed of single column bents with upside down triangular bent caps. At one time they were planning to build right and left superstructures but lack of funding or perhaps the Sierra Club prevented Caltrans from increasing the capacity of SR 120. All of these two lane roads carrying travelers in and out of Yosemite Park can try the patience of drivers.

Like many of the bridges in the Sierras the deck of the Jim Roberts Bridge is in bad shape. Deicing salts may have been used and chains and heavy trucks have exacerbated the deterioration of the deck. Caltrans is fortunate to have enough room to put another superstructure on the existing substructure while they repair or replace the old deck.
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Tuolumne County, California Bridges: James E. Roberts Bridge across the Tuolumne River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Sunday, October 12, 2014

Stanislaus County, California Bridges: Old La Grange Bridge across the Tuolumne River

September 2014 (37.66584 Degrees-120.46175 Degrees) Old La Grange Bridge
In the 1850s the town of La Grange was a trading center for the many gold prospectors in the area. At the peak of the Gold Rush, the town had a population of about 5000 residents. A ferry was located in La Grange across the Tuolumne River, which was operated by Nathan McFarland and later by Anthony McMillan. In the 1880s a bridge was built at the site. The current bridge was built in 1914, but instead of being named the McMillan Ferry Bridge it was simply called the La Grange Bridge. Similar to the Old Basso Bridge, the Old La Grange Bridge was retired from service when the new State Route 132 Bridge was built to the north across the Tuolumne River in 1987.
Instead of a long Pennsylvania truss span like the Old Basso Bridge, the Old La Grange Bridge has two Pratt truss spans over the Tuolumne River and trestle spans for the approaches. The bridge is 552 ft long (making it much longer than the Old Basso Bridge) with two 162 ft long truss spans (similar to the generic drawing above).
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Stanislaus County, California Bridges: Old La Grange Bridge across the Tuolumne River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Saturday, October 11, 2014

Stanislaus County, California Bridges: State Route 132 Bridge across the Tuolumne River

September 2014 (37.64722 Degrees-120.49500 Degrees) State Route 132 Bridge
Just north of yesterday's Old Basso Bridge is the bridge that replaced it. The State Route 132 Bridge (38 0154) across the Tuolumne River is a three span continuous prestressed concrete box girder structure that was built in 1987. It's 494 ft long with a 180 ft long main span and supported by single column bents and end diaphragm abutments. It carries about 1500 vehicles a day and is in 'Good' condition.
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State Route 132 Bridge across the Tuolumne River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Friday, October 10, 2014

Stanislaus County, California Bridges: Old Basso Bridge across the Tuolumne River

September 2014 (37.64553, -120.49589 Degrees) Old Basso Bridge
There are many older bridges across the Tuolumne River in Stanislaus County but most of them are now closed to traffic. The Old Basso Bridge is a 373 ft bridge with a 286 ft long Pennsylvania through truss main span. These are a type of Pratt truss that includes a polygonal top chord, pins and cross-braces at different heights, and diagonal members that continue across several panels (see generic example below).
This type of design allowed lightweight structures and very long spans. It was named after the Pennsylvania Railroad that favored this design. We previously encountered this truss at the Healdsburg Bridge in Sonoma County.
E. H. Annear was the county engineer and Pacific Construction was the builder for this bridge in 1911. The bridge was retired from service when the new State Route 132 was built a little to the north in 1987. The Bridge was named after Angelo Basso (1846 to 1933) who operated a ferry across the Tuolumne River until the bridge was built at this site. Many bridges in the area were named after the previous ferry operator.
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Stanislaus County, California Bridges: Old Basso Bridge across the Tuolumne River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Thursday, October 9, 2014

Stanislaus County, California Bridges: Knight's Ferry Bridge across the Stanislaus River (2)

September 2014 (37.81876 Degrees, -120.66442 Degrees) Knight's Ferry Bridge
There's a well-written summary of the Knight's Ferry Bridge in the Historic American Engineering Record (HAER) Website. Interested readers can learn about the history of bridge building in California and about the design of this bridge.

The Knight's Ferry Bridge is a four-span wooden Howe truss covered bridge. The Howe truss includes vertical members (the steel rods) in tension. The legs of the 'Xs' are trying to close (like pairs of scissors) and the rods are keeping them in place. Slat windows at the top chord and clear story windows between the panels bring light into the bridge. At the abutments the lower chords rest on large bedding timbers on top of mortared rubble stone. Timber posts provide additional support in front of the abutments.
There were only two bridges (other than logs and stepping stones) in California before 1850. With the Gold Rush the construction of toll roads and bridges flourished. California has gone full circle. Now roads and bridges are being built by private companies rather than being owned by the public.
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Stanislaus County, California Bridges: Knight's Ferry Bridge across the Stanislaus River (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Wednesday, October 8, 2014

Stanislaus County, California Bridges: Knight's Ferry Bridge across the Stanislaus River (1)

September 2014 (37.81876 Degrees, -120.66442 Degrees) Knight's Ferry Bridge
Twenty miles north of the Robert's Ferry Road Bridge is the Knight's Ferry Bridge across the Stanislaus River. The US Library of Congress wrote: 

The Knight's Ferry Bridge was built in 1863-64 to replace an 1857 uncovered wooden truss that was destroyed in a flood. This was an important crossing on the heavily traveled Stockton-Sonora Road during the California Gold Rush. The Knight's Ferry Bridge is the longest covered bridge west of the Mississippi River. 

This bridge is a 330 ft long Howe truss. It was posted to the National Register of Historic Places in 2012. There is a museum and many of the original buildings are still standing around this bridge. Unfortunately the bridge is a little worn out and signs prohibit the gathering of crowds onto the bridge. It was closed in 1981 and rehabilitated in 1989.
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Stanislaus County, California Bridges: Knight's Ferry Bridge across the Stanislaus River (1) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Tuesday, October 7, 2014

Stanislaus County, California Bridges: Roberts Ferry Road Bridge across the Tuolumne River (2)

September 2014 (37.63585 Degrees-120.61822 Degrees) Roberts Ferry Road Bridge
Basically, the Robert's Ferry Bridge is a cast in place box girder bridge supporting a timber structure. Probably not too many bridge enthusiasts would be happy with its form or its function. Not only does the bridge have to support the dead and live load, but it has to support the additional dead load of the roof on its main span. As can be seen below, the wooden structure is being supported by the concrete barrier.
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Stanislaus County, California Bridges: Roberts Ferry Road Bridge across the Tuolumne River (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Monday, October 6, 2014

Stanislaus County, California Bridges: Roberts Ferry Road Bridge across the Tuolumne River (1)

September 2014 (37.63585 Degrees-120.61822 Degrees) Roberts Ferry Road Bridge
A covered bridge is usually built to prevent a timber deck from deteriorating. Today's covered bridge was built to pay homage to an historic crossing on the Tuolumne River. A plaque beside the bridge states: 

"One of the most important stopping places on the Stockton-Mariposa Road, the first Tuolumne River Ferry was established 3/8 mile downstream from here by Alden Jackson and Dr. Benjamin Horr in 1850. Dr. Horr, who came to California in 1849 for the Gold Rush, was a State Assemblyman who in 1854 introduced the bill creating Stanislaus County. In 1851 Dr. Horr sold the ferry to Gallant Dickinson who again sold it, now including an adjacent hotel to Cornelius Osborn in 1857. The ferry and hotel were controlled by Osborn until 1862 when they were sold to John Roberts. In 1864 the ferry was either leased or sold to John Morley, moved upstream 3/8 of a mile to this location in 1865 and was again operated by John Roberts in 1872. It remained in Roberts' name until 1887 when he replaced it with a wooden truss bridge. In 1916 Stanislaus County constructed a new, toll-free steel truss bridge, which was used until destroyed by floods in January 1997. The present bridge, concrete with a wooden cover to blend in with the historic nature of this area, was completed in the same location in 1999."

That history must have been very important for the county to have built a covered concrete bridge at this site. But is that the best way to commemorate the past? The previous bridges were truss bridges.
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Stanislaus County, California Bridges: Roberts Ferry Road Bridge across the Tuolumne River (1) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.