Friday, January 31, 2014

El Dorado County, California Bridges: Old Salmon Falls Road Bridge across the South Fork of the American River

January 2014 (38.76056 Degrees, -121.06064 Degrees) Old Salmon Falls Road Bridge
We came back from Florida to find California in the middle of a drought. The normally wide Folsom Lake had diminished to the rivers that existed before Folsom Dam was completed in 1955.
I thought it would be interesting to see the old Salmon Falls Road Bridge, which had been submerged below the lake when the dam was completed. We have previously studied the new Salmon Falls Road Bridge that was built in 1953 to carry traffic on the diverted roadway once the old bridge was submerged.
The old Salmon Falls Road Bridge was built in 1883.  It's about three miles upstream on the southern arm of Folsom Lake (which used to be the South Fork of the American River). The bridge had been built to connect the village of Salmon Falls with Mormon Island.
You can see the lake's normal boundary because that was where the brown grass ends. I was surprised at the hundreds of people that were examining the bridge when we arrived. Apparently, many people were curious about how the bridge would look after being submerged under water for most of the last 68 eight years. However, the bridge was in remarkably good condition.
The old Salmon Falls Road Bridge is composed of six simple reinforced concrete spans resting on pier walls. Each span is a slab with concrete barrier walls that act like exterior girders and with a slight haunch to these girders under the soffit at the piers. The bridge surface is exposed aggregate, which may be just on the surface or perhaps the structural members are filled with these round pebbles.
The only damage I could see to the bridge was that the spans were not perfectly centered on the pier walls and the approaches had washed away, causing the approach barriers to collapse. If the drought continues, the bridge could continue to function as a pedestrian bridge.
Sitting a little to the east of the Salmon Falls Bridge are the remains of another bridge that had once been used by pedestrians and equestrians to cross the South Fork of the American River.
The abutments of the South Fork of the American River Pedestrian Bridge are all that remain of what was a long but narrow structure. The backwall is embossed with 'V. Watkins, December 1918' which must have been the builders name and the year the bridge was built.
A variety of reinforcement is still protruding out of the wingwalls and backwall that may have supported a timber deck and rails. A little to the south of the pedestrian bridge is what looks like a single span bridge, which (like the pedestrian bridge) is gone except for the abutments (and maybe part of a concrete slab between them). The bridge looks like it crossed Sweetwater Creek, which drained into the South Fork, but I don't know the name of the bridge.
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El Dorado County, California Bridges: Old Salmon Falls Road Bridge across the South Fork of the American River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Thursday, January 30, 2014

Broward County, Florida Bridges: I-75/I-95/I-595 Interchange

January 2014 (26.08234, -80.1687 Degrees) I-95/I-75/I-595 Interchange
The cities in south Florida cling to the east coast to avoid the enormous wet grasslands (see Google earth photo below). The main east-west highway through this densely populated sliver of land is I-95. Driving back and forth along I-95, the bridges I observed were mostly connectors and overcrossings (see photo above).
These bridges are composed of steel or precast concrete girder simple spans tied together with a concrete deck and sitting on single or multi-column bents. Again, not particularly attractive but they get the job done.
However, while driving by the Fort Lauderdale airport I saw the big I-95/I-595/I-75 interchange with each connector painted a different color. I couldn't get much of a photo in the gathering darkness, but looking at Google earth in 'Street View' I was able to find a nice picture of this structurally uninspiring but delightfully colored interchange.
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Broward County, Florida Bridges: I-75/I-95/I-595 Interchange by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Wednesday, January 29, 2014

Miami-Dade County, Florida Bridges: Metromover Monorail Line in Downtown Miami

January 2014 (25.7896 Degrees, -80.1902 Degrees) Miami Metromover
A few last photos before leaving Florida. The Miami Metromover is a free, automated public transportation system. It carries millions of passengers a day and has been a catalyst for the development of the downtown area (see map below). The photos are at the north end of the line by the Adrienne Arsht Center Station (above the elevated tracks). More information about the Metromover can be found at Wikepedia as well as several other websites.
At the north end the Metromover is composed of four continuous steel plate girders supported on 'C' bents. Each pair of girders supports a single rail which carries an electric single or two car train in each direction. The Metromover is a strictly utilitarian system that may not be attractive but provides an essential service to the downtown Miami region.
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Miami-Dade County, Florida Bridges: Metromover Monorail Line in Downtown Miami by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Tuesday, January 28, 2014

Miami-Dade County, Florida Bridges: Port Causeway Bridges

January 2014 (25.78000, -80.18333) Port Causeway Bridges
Just south of MacArthur Causeway is the curvaceous Port Causeway and its neighboring railway and highway bridges connecting Miami to the Port of Miami.
The Port Blvd Bridges (FDOT #875000 and 875001) are parallel cast-in-place prestressed concrete box girder bridges that were built in 1991. The superstructures are supported on flared single column bents with bearings. A longitudinal joint is between the two bridges. The bridges are 16 span 2521 ft long bridges that slowly rise and fall to provide a shipping channel next to the movable spans on the adjacent bridges.
The Rickenbacker Causeway is about a mile to the south but I didn't get a chance to photograph it. That bridge, the bridges across south Biscayne Bay, and all the bridges connecting the Florida Keys will have to wait for another trip to Florida.
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Miami-Dade County, Florida Bridges: Port Causeway Bridges by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Monday, January 27, 2014

Miami-Dade County, Florida Bridges: The MacArthur Causeway across Biscayne Bay

January 2014 (25.78694 Degrees, -80.18111 Degrees) MacArthur Causeway
Just south of the Venetian Causeway is the MacArthur Causeway. Shown in the Google earth photo below, the MacArthur Causeway goes between Miami and the southern tip of Miami Beach.
On the western end of the causeway are two parallel 'T' girder bridges that are currently being connected with a center widening. The SR 41 A1A (I-395) Bridge ( FDOT #870771 and #870772) is an 18 span, 2454 ft long bridge that slowly climbs over the western portion of the Intracoastal Waterway and Biscayne Bay. It was built in 1995 and is currently being widened.
The MacArthur Causeway was begun in 1917 and has been continuously worked on ever since. In 1942 it was named after General Douglas MacArthur. It was a six lane highway and so I imagine that it will soon become an 8 lane highway. In the photo below we are looking at the Causeway from the Miami shoreline next to the Port of Miami.
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Miami-Dade County, Florida Bridges: The MacArthur Causeway across Biscayne Bay by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Sunday, January 26, 2014

Miami-Dade County, Florida Bridges: Venetian Causeway across Biscayne Bay

January 2014 (25.7898 Degrees, -80.1832 Degrees) Venetian Causeway
Continuing south, we arrived at the Venetian Causeway, a series of roads and bridges built in 1926 between islands in Biscayne Bay. According to 'Historic Highway Bridges of Florida,' it is the oldest causeway in Miami-Dade County and consists of 12 bridges across one natural and five human-made islands.
The causeway is about 2.5 miles long between Miami and Miami Beach. In 1913 a long timber trestle bridge was built from the mainland to what was to become Miami Beach. In 1925-26 the Bay Biscayne Improvement Company and the Raymond Concrete Pile Company replaced the trestle structure with the current bridges. Whenever an engineer finds out that an old bridge is supported on Raymond piles, he or she knows that an expensive repair job will be required, because these piles have almost no reinforcement. Many of these bridges underwent repairs from 1996 to 1997 but somehow they managed to retain their historic status. Much more information on this causeway is available in the above referenced book.
Most of the bridges were built very low to the water and so the bascule spans are constantly opening and closing to allow passage of boats  through the bay. All the bridges are very similar with crisscrossed concrete barriers and haunched concrete 'T' girder spans on pile extensions.
The westernmost bridge is the long, tall Venetian Causeway Bridge between Miami and Biscayne Island (shown above). It's a 2000 ft long bridge with a double bascule span and a grand entrance on the west side with obelisks marked 'Venetian Way' and 'Short Way.'
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Miami-Dade County, Florida Bridges: Venetian Causeway across Biscayne Bay by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Saturday, January 25, 2014

Miami-Dade County, Florida Bridges: Julia Tuttle Causeway across Biscayne Bay

January 2014 (25.81028 Degrees, -80.15028 Degrees) Julia Tuttle Causeway
The Julia Tuttle Causeway carries State Route 195 across Biscayne Bay. It includes a highway on a human-made island in the middle of the bay and bridges at the two ends. The western bridge (FDOT #870301) is 2120 ft long with steel girder spans. The eastern bridge (FDOT #870302) is 1138 ft long with precast girders on parallel two column bents (shown below). Both bridges were built in 1959 and widened in 1990/1991.
Julia Tuttle is considered to be the founder of Miami. At the end of the 19th century she owned a large portion of the land in the area and successfully promoted it for development. The Julia Tuttle Causeway became famous because for several years the island was the only place that sexual offenders released from prison in Miami-Dade County were allowed to live. 
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Miami-Dade County, Florida Bridges: Julia Tuttle Causeway across Biscayne Bay by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Friday, January 24, 2014

Miami-Dade County, Florida Bridges: North Bay Causeway across Biscayne Bay

January 2014 (25.84500 Degrees, -80.14333 Degrees) North Bay Causeway
The Intracoastal Waterway widens to become Biscayne Bay between Miami and Miami Beach. Its a couple of miles wide and crossed by six causeways that we will look at over the next few days. I somehow missed the Broad Causeway to the north, but it can be studied on other websites. The North Bay Causeway is next (to the south) and includes long bridges between Miami, Pelican Island, North Bay Island, Treasure Island, and Miami Beach. The bridges at Miami and Miami Beach have bascule spans to allow boat travel through the Bay. The East Biscayne Bay Bridges (FDOT #870551 and 870085) are 17 span, 1030 ft long precast I girder bridges with a 90 ft bascule span in the center (see photo above).
The West Biscayne Bay Bridges (FDOT #870551 and 870083) are 17 span, 510 ft long concrete slab bridges with two bascule leafs in the center (see photo above).  Both the East and West Biscayne Bay Bridges sit on driven precast piles supporting bent caps. The bridges were built in 1971 with two way traffic but in 1973 parallel bridges were built (to carry eastbound traffic) and the original bridges were modified to carry just westbound traffic.
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Miami-Dade County, Florida Bridges: North Bay Causeway across Biscayne Bay by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Thursday, January 23, 2014

Miami-Dade County, Florida Bridges: Surfside Blvd Bridge across Indian Creek

January 2014 (25.87778 Degrees, -80.13028 Degrees) Surfside Blvd Bridge
Another aspect of life in Florida are the many gated communities on islands inside Biscayne Bay. The Surfside Blvd Bridge (FDOT #876100) across Indian Creek has a police station at one end to prevent uninvited guests (like me) from entering. A positive aspect of these semi-private bridges is that they appear to be well maintained (or at least frequently painted).
The Surfside Blvd Bridge is a 13 span reinforced concrete 'T' girder bridge that was built in 1930. The bridge is highly ornamented with columnated barriers supporting obelisks over the piers and with arch-shaped exterior girders. The bridge is eligible for registry as a historic place.
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Miami-Dade County, Florida Bridges: Surfside Blvd Bridge across Indian Creek by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Wednesday, January 22, 2014

Miami-Dade County, Florida Bridges: State Route A1A Bridge across Baker's Haulover Inlet

January 2014 (25.9000 Degrees, -80.12444 Degrees) SR-A1A Bridge
State Route A1A runs along Florida's Coastal Barrier Islands just east of the Intracoastal Waterway. These islands provide protection for shipping in the waterway from high waves and ocean storms. Breaks between the islands allow ships to travel in and out of the ocean and require bridges to carry traffic on SR A1A. 

The Intracoastal Waterway (to the north) merges with Biscayne Bay (to the south) at North Miami Beach. This is where the Baker's Haulover Inlet between Haulover Beach and Bal Habour is crossed by the State Route A1A Baker's Haulover Bridge (FDOT #870071).

Also named the Herman B. Fultz Bridge, it is a nine span (1257 ft long) continuous steel girder bridge that was built in 1950. The superstructure is composed of shallow stringers connected to deep floor beams supported by large girders on two column bents with very deep bent caps/diaphragms. Perhaps this interesting design is meant to help resist ocean storms?
Across the inlet the girders are smaller, without haunches, and the bent caps/diaphragms are also smaller. I guess the two ends of the bridge were made beefier while the middle of the bridge was made more compact. This design must be pretty successful since the bridge has stood for over 60 years and resisted many storms.
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Miami-Dade County, Florida Bridges: State Route A1A Bridge across Baker's Haulover Inlet by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.