Thursday, January 31, 2013

El Dorado County, California Bridges: Chili Bar (SR-193) Bridge across the South Fork of the American River

January 2013 (38.7658 Degrees, -120.8218 Degrees) Chili Bar Bridge
Similar to the South Fork of the American River Bridge carrying SR-49 west of Coloma, the South Fork of the American River Bridge carrying SR-193 is a little east of Coloma. However, this bridge was built in 1994 (instead of 1951), it's only two spans long, it has a fancy flared pier wall, barriers with recessed openings to simulate a balustrade railing, and it's a prestressed concrete cast-in-place box girder bridge.

Perhaps at this point we should look at a map to see where all the bridges we recently visited are located. At the left end of the Google topo map shown below is the SR-49 Bridge across the South Fork. After a big loop the South Fork travels between Marshall Gold Discovery State Park and Mount Murphy where the Coloma (Mount Murphy Road) Bridge is located. Then we travel upstream to the middle of the map to find the SR-193 (Chili Bar) Bridge across the South Fork (today's bridge).

In the next few days we'll visit the Rocky Creek Bridge (a little north of the South Fork) and then the beautiful Mosquito Road Bridge across the South Fork (on the right side of the map).
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El Dorado County, California Bridges: Chili Bar (SR-193) Bridge across the South Fork of the American River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Wednesday, January 30, 2013

El Dorado County, California Bridges: Mount Murphy Road Bridge across the South Fork of the American River (5)

January 2013 (38.8015 Degrees, -120.8906 Degrees) Mount Murphy Road Bridge
A couple of final photos showing the substructure of the Mount Murphy Road Bridge. The use of reinforced concrete was quite popular, even for the substructure of a steel truss bridge at the beginning of the 20th century. Note the nicely pointed edges of the hexagonal pier walls and the other architectural embellishments in the photo above. Also, we can see a pipe (probably to bring water to neighborhoods on the east side of the river) carried by the bridge.

In the photo below we can see the outline of the skinny formwork used to cast the approach spans, the abutment, and the retaining walls on the west end of the bridge. Note the depth of the deck increases at the support to handle the larger moment and shear.

Trees, rocks, slabs of concrete, etc. are scattered around the abutment in a jumble. Apparently, no one has attempted to landscape this bridge. Considering the history of the bridge and of Coloma I'm surprised that more of an effort hasn't been done to beautify the area around the bridge. Probably the frequent winter flooding has created such a mess around the piers and abutments that they finally gave up on beautifying the bridge site.
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El Dorado County, California Bridges: Mount Murphy Road Bridge across the South Fork of the American River (5) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Tuesday, January 29, 2013

El Dorado County, California Bridges: Mount Murphy Road Bridge across the South Fork of the American River (4)

January 2013 (38.8015 Degrees, -120.8906 Degrees) Mount Murphy Road Bridge
The Mount Murphy Road Bridge carries vehicles from State Route 49 through Coloma and across the South Fork of the American River. Note that Mount Murphy sits almost directly east of the bridge. A wooden guard rail does double duty protecting the steel truss and preventing pedestrians and vehicles from falling into the river (a concrete curb also helps). The 13.5 foot vertical clearance hopefully isn't too much of a hindrance to the local vehicles that use the bridge.

This bridge could easily be turned into a a protected historical structure and pedestrian bridge and a new road bridge could be built for vehicles. El Dorado County takes good care of it's bridges and so I'm sure that will probably happen in a few years (maybe for the bridge's 100th birthday).
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El Dorado County, California Bridges: Mount Murphy Road Bridge across the South Fork of the American River (4) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Monday, January 28, 2013

El Dorado County, California Bridges: Mount Murphy Road Bridge across the South Fork of the American River (3)

January 2013 (38.8015 Degrees, -120.8906 Degrees) Mount Murphy Road Bridge
The UglyBridges Website reports that the Mount Murphy Road Bridge carried 1,050 vehicles a day with 10% truck traffic during the 2000 inspection. I would say that was a fair assessment based on the number of vehicles I had to get out of the way for during my visit. Fortunately, the speed limit is only 5 miles an hour, perhaps because of the number of pedestrians that also use the bridge.

In the photo we see that two axle vehicles are limited to 14 tons, three axle vehicles are 21 tons, and four axles are limited to 27 tons. That seems pretty good for this little bridge. I wonder if the approach spans or the main truss span limits the vehicle weight?
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El Dorado County, California Bridges: Mount Murphy Road Bridge across the South Fork of the American River (3) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Sunday, January 27, 2013

El Dorado County, California Bridges: Mount Murphy Road Bridge across the South Fork of the American River (2)

January 2013 (38.8015 Degrees, -120.8906 Degrees) Mount Murphy Road Bridge
Another view of the Mount Murphy Road Bridge across the South Fork of the American River. According to the always reliable Bridgehunter, this bridge was built by D.M. Bassi and H. Williamson, and designed by Henry Lahiff.  It's a nine panel Pratt through truss with a width of 10.5 ft and a vertical clearance of 13.7 ft.   In 2011 the substructure was rated good, the superstructure was rated fair, and the deck was rated poor.

One of the big efforts in the U.S. over the last 10 years has been providing local agencies with money to evaluate scour at bridge foundations. However, this bridge has not been evaluated for scour (as of 2011) and the foundation hasn't even been identified. The bridge has a sufficiency rating of 0 out of 100 (structurally deficient) because of substandard load carrying capacity and inadequate roadway geometry. The cost to replace the bridge has been estimated at about $2 million. Because the bridge is almost 100 years old, and eligible for the national Register of Historic Places, I don't think replacement is an option. More likely, it will become a pedestrian bridge and a roadway bridge will be built beside it.
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El Dorado County, California Bridges: Mount Murphy Road Bridge across 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.

Saturday, January 26, 2013

El Dorado County, California Bridges: Mount Murphy Road Bridge across the South Fork of the American River (1)

January 2013 (38.8015 Degrees, -120.8906 Degrees) Mount Murphy Road Bridge
Continuing upstream along the South Fork of the American River to the town of Coloma where the California Gold Rush began. My son and I arrived on a Saturday afternoon but the town was empty except for the many people dressed in 19th Century garb. I recalled 15 years ago when my son's class had traveled to Coloma to relive the history of the Gold Rush (they spent another day at Sutter's Fort in Sacramento).

Near the center of town is the Mount Murphy Road Bridge (just west of Mount Murphy as shown in the Google earth photo below). It is a 489 ft long bridge with a 162 ft long Pratt truss center span and with reinforced concrete through girder side spans. This bridge was built in 1915 and is just the latest of many bridges built near this site that were eventually swept away by winter floods.
In 1849, Jim Stephens built a footbridge with a 25 cent toll a little upstream of this site. In 1850 John Little and Edward Raun built a wagon toll bridge that earned $20,000 in just three months. California's first covered bridge was built at this site in 1852. A pedestrian suspension bridge was at this site from 1881 until it was replaced by the current bridge. I imagine each bridge was built a little higher above the river resulting in the current bridge surviving for almost 100 years.

We'll take a closer look at the bridge tomorrow.
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El Dorado County, California Bridges: Mount Murphy Road Bridge across 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.

Friday, January 25, 2013

El Dorado County, California Bridges: South Fork of the American River Bridge

January 2013 (38.8086 Degrees, -120.9015 Degrees) South Fork American River Bridge
About a dozen winding miles upstream from the Salmon Falls Bridge is the State Route 49 Bridge across the South Fork of the American River. It is a seven span, steel stringer bridge on pier walls that was built in 1951 by Caltrans. This bridge must be continuous for several spans because there are only a single pair of bearings at each pier. Probably there is a hanger system to allow for temperature movement. A nice concrete deck overhang supports a balustrade railing. Some graffiti on the east bank suggest this is a place where young people congregate. State Route 49 crosses many big rivers as it travels through 'gold' country.
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Thursday, January 24, 2013

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.
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Wednesday, January 23, 2013

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.
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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.

Tuesday, January 22, 2013

Palm Beach County, Florida Bridges: Florida Turnpike UC over Glades Road

December 2012 (26.368 Degrees, -80.171 Degrees) Florida Turnpike UC
I only had an afternoon to photograph a few bridges in Florida. Hopefully, I'll have future opportunities to photograph the many historic, modern, and interesting Florida bridges.

A useful resource for my visit was "Historic Highway Bridges of Florida,"published by the Florida Department of Transportation. I wonder if there was a request from the Federal Highway Administration for each state to make a public record of their historic bridges? Caltrans published "Historic Highway Bridges of California" in the 1990s.

While I was in Florida, I noticed that many of the highway bridges had Mechanically-Stabilized Earth (MSE) abutments. This has been an area of intense study at Caltrans since we rely on the soil around our abutments to reduce the displacements of shorter bridges during earthquakes. Currently, we are requiring that large diameter piles support the ends of our bridges when MSE Walls support the bridge approaches.

I had mentioned earlier that the Intracoastal Waterway bridges were regularly repainted. Unfortunately, the same can't be said of highway bridges. I would recommend that concrete bridges shouldn't be painted, since it's an unnecessary expense, and they look bad when the paint starts to peel.
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Monday, January 21, 2013

Palm Beach County, Florida Bridges: George Bush Blvd. Bridge across the Intracoastal Waterway

December 2012 (26.474 Degrees, -80.062 Degrees) George Bush Blvd. Bridge
Continuing north we arrived at the George Bush Boulevard Bridge across the Intracoastal Waterway. We walked along residential streets trying to reach the bridge without success. I couldn't find any public access to the bridge. I wonder how maintenance crews get to it? Perhaps the lack of access is appropriate for a bridge named after a U.S. president (George Herbert Walker Bush). The former president vacationed in Delray Beach in the 1980s and 1990s.

Since I couldn't take a photo of the substructure, I came back onto the deck and was rewarded with a bridge opening. I was fortunate to see it since it only opens on demand. You can see that the sidewalks overhang steel girders, which are attached to counterweights that lift up each leaf like a teeter-totter.

The George Bush Blvd. Bridge was built in 1949, it's 270 ft long, in satisfactory condition, and carries about 8,000 vehicles a day. It's 35.1 ft wide but only provides 5.9 ft of vertical clearance above the channel. It was closed for five months in 2010 for a rehabilitation and it was closed again in July of 2012 for emergency repairs. They must leave the bascule spans open when the bridge is closed down for repairs because otherwise no one could use the Intracoastal Waterway.
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Palm Beach County, Florida Bridges: George Bush Blvd. Bridge across the Intracoastal Waterway by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Sunday, January 20, 2013

Palm Beach County, Florida Bridges: Atlantic Avenue Bridge across the Intracoastal Waterway (3)

December 2012 (26.46139-80.06417) Atlantic Avenue Bridge
The view from the deck of the Atlantic Avenue Bridge. They do a nice job of keeping fresh paint on the bridges along Florida's coast. This is the most populated area of southern Florida. A mile to the west is a vast grassland covered in a inch of water, the widest river in the world.

In this photo we see the bridge operator standing at his doorway talking to a visitor. It seems like there aren't too many ships traveling through this part of the waterway. There may be more activity when storms travel up the coast. Further south the waterway carries more vessels, especially near the Port of Miami.
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Saturday, January 19, 2013

Palm Beach County, Florida Bridges: Atlantic Avenue Bridge across the Intracoastal Waterway (2)

December 2012 (26.46139-80.06417) Atlantic Avenue Bridge
Another view of the Atlantic Avenue Bridge. Well-designed fenders braced with battered piles protect the bascule piers from errant vessels. A sign on the far fender gives the name of the bridge. A second sign on the railing gives the VHS Channel (9) to notify the operator that a vessel is approaching. A third sign notifies sailors that the bridge will open on the 1st and 3rd quarter of each hour. Stop lights (and hanging lamps) alert boaters that the bridge is closed. Signs on each pier inform approaching ships that they are in the City of Delray Beach.

The bridge is surrounded by palms, sea grapes, and other tropical vegetation.
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Friday, January 18, 2013

Palm Beach County, Florida Bridges: Atlantic Avenue Bridge across the Intracoastal Waterway (1)

December 2012 (26.46139, -80.06417) Atlantic Avenue Bridge
Continuing north we arrived at the Atlantic Avenue Bridge, which carries State Route 806 over the Intracoastal Waterway in Delray Beach. We can see it has a two leaf bascule span over the channel. The bridge is 235.2 feet long, it provides 80 feet of channel width and only 9 feet of vertical clearance. It was built in 1952, carries 11,600 vehicles a day, has a sufficiency rating of 63 out of 100, and is in 'Good' structural condition.
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Thursday, January 17, 2013

Palm Beach County, Florida Bridges: Linton Blvd. Bridge across the Intracoastal Waterway (2)

December 2012 (26.4397 Degrees-80.0650 Degrees) Linton Blvd. Bridge
Another photo of the Linton Blvd. Bridge. I wonder why the approach spans are precast girders while the end spans are steel girders? It must somehow be more convenient for the bascule span to lock-up against steel girders. Note how the end spans are made up of many girders while each bascule leaf is made up of two very deep girders and a lot of cross-bracing.
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Wednesday, January 16, 2013

Palm Beach County, Florida Bridges: Linton Blvd. Bridge across the Intracoastal Waterway (1)

December 2012 (26.4397 Degrees, -80.0650 Degrees) Linton Blvd. Bridge
It's about four miles north from the Spanish River Bridges to the Linton Boulevard Bridge in Delray Beach. Maybe that's why the bridge carries over 20,000 vehicles a day. Still, that's a lot of traffic for a seven mile long road that's blocked by the Loxahatchee Swamp to the west and by the Atlantic Ocean to the east.

The Linton Blvd. Bridge is a 1,388 ft long structure that was built in 1981. They call it a single bridge but it's 102 ft wide with two parallel leafs that open independently. According to the Uglybridges Website, the bridge provides about 26 ft of vertical clearance over the channel in the closed position and a lot more clearance near the east side of the channel at low tide (the bascule pier is on the west side of the channel).

Like the previous bridges, the Linton Blvd. Bridge has long approaches that gradually raise the bridge over the channel. However, this bridge is supported on pile caps and it has just single bascule leafs that provide 90 ft of lateral clearance.
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Tuesday, January 15, 2013

Palm Beach County, Florida Bridges: Spanish River Blvd. Bridges across the Intracoastal Waterway (3)

December 2012 (26.38634 Degrees, -80.07104 Degrees) Spanish River Blvd. Bridges
A view from behind a trestle pier at the bascule pier, operators house, and timber fenders of the Spanish River Boulevard Bridges. Four pile extensions were cased in concrete on the left pier while only three were cased on the right pier, suggesting this was a later repair. Note the trestle spans are precast concrete girders while the end spans are steel girders. In this photo we can clearly see the counterweights that rotate downward to lift up the bascule spans.
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Palm Beach County, Florida Bridges: Spanish River Blvd. Bridges across the Intracoastal Waterway (3) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Monday, January 14, 2013

Palm Beach County, Florida Bridges: Spanish River Blvd. Bridges across the Intracoastal Waterway (2)

December 2012 (26.38634 Degrees, -80.07104 Degrees) Spanish River Blvd. Bridges
A closer look at the bascule spans on the Spanish River Boulevard Bridges. I spent some time trying to understand the purpose of the blue box on the right side of the photo. I finally decided it must be a counterweight for the right bascule leaf. As the counterweights rotate downward between the white concrete sides of the piers the bascule leafs are raised into the air.
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Sunday, January 13, 2013

Palm Beach County, Florida Bridges: Spanish River Blvd. Bridges across the Intracoastal Waterway (1)

December 2012 (26.38634 Degrees, -80.07104 Degrees) Spanish River Blvd. Bridges
Continuing north are the two Spanish River Boulevard Bridges, which carry eastbound and westbound State Route 800 over the Intracoastal Waterway. The bridges are 486.9 ft long precast concrete trestles with movable steel bascule spans over the channel. They were built in 1971, carry 8,000 vehicles a day, and are in satisfactory condition. Today's photo shows the trestle approaches, the operator's house cantilevered from the bascule pier, and the fenders on the west side of the channel. We'll take a closer look at the bridges tomorrow.
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Palm Beach County, Florida Bridges: Spanish River Blvd. Bridges across the Intracoastal Waterway (1) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Saturday, January 12, 2013

Palm Beach County, Florida Bridges: Palmetto Park Road Bridge across the Intracoastal Waterway (3)

December 2012 (26.3506 Degrees, -80.0756 Degrees) Palmetto Park Road Bridge
A look at the deck (and steel sidewalk) on the Palmetto Park Road Bridge. The steel grating has bands of concrete, perhaps to provide a less slippery riding surface. Since the bridge was constructed in stages, I wonder if there are separate motors to raise the left and right sides of the bridge?

There are cables suspended from the barrier rails that are wrapped in a material to discourage birds from roosting. Perhaps the cables were added after the bridge was built to release shims or other locking devices that were deemed necessary after the bridge was put into service?
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Friday, January 11, 2013

Palm Beach County, Florida Bridges: Palmetto Park Road Bridge across the Intracoastal Waterway (2)

December 2012 (26.3506 Degrees, -80.0756 Degrees) Palmetto Park Road Bridge
A view from the sidewalk of the Palmetto Park Road Bridge. The county built the north side of the bridge, then they tore down the existing bridge, and then they built the south side of the bridge. The $5.4 million project allows taller boats under the bridge, which means less backed-up traffic, and the four lanes means twice as many vehicles traveling to and from Boca Raton's beaches (see Google earth photo below).
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Thursday, January 10, 2013

Palm Beach County, Florida Bridges: Palmetto Park Road Bridge across the Intracoastal Waterway (1)

December 2012 (26.3506 Degrees, -80.0756 Degrees) Palmetto Park Road Bridge
The Palmetto Park Road Bridge replaced a smaller movable bridge that was always being opened and closed until it wore out. The Coast Guard wanted it replaced with a movable bridge with at least 20 ft of vertical clearance but the County didn't want to build such a long, tall structure. The current bridge (completed in 1987) is 516 ft long with 13.8 ft of vertical clearance. It carries four traffic lanes with sidewalks and is 72.5 ft wide. Average daily traffic is over 15,000 vehicles, the bridge was designed for HS20 trucks, and it's in good shape. The operator's house has a airport control tower-like appearance, which is a good idea. The movable spans are twin leaf bascule members supporting an open grating deck.
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