Plumas County, California Bridges: Jamison Creek Bridge

November 2015 (40.7587, -120.6951) Jamison Creek Bridge

We'll finish our study of Plumas County bridges with a two span reinforced concrete box girder bridge that was built in 2003. The Jamison Creek Bridge (09C0045) crosses the creek on Johnsville Road in the town of Johnsville. The bridge is in Plumas Eureka State Park, which is a pretty environment, and was the incentive to make an ordinary bridge a little less ordinary with a stone facade. However, the rocky creek and the rocky bridge may be too much of a good thing.

Plumas County, California Bridges: Jamison Creek Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Los Angeles County, California Bridges: Ocean Blvd and Shoreline Drive Bridges across the Los Angeles River

August 1999 (33.7673 Degrees, -118.2051 Degrees) Los Angeles River Bridges

A few more miles and we've reached the City of Long Beach near the mouth of the Los Angeles River. Note the concrete lined channel is gone. At this location the river is more of a tidal estuary full of salt water creatures.

The Ocean Blvd. Bridge (53C0927) is a 15 span steel girder bridge that was built in 1959. Sharing the same substructure are the Shoreline Drive Bridges (53C0892L); a pair of 10 span concrete box girder bridges built in 1967. These bridges cross a bikeway, a railway, several highways and the river. This is a very popular area with tourist sites and industrial sites all competing for the same real estate.

Los Angeles County, California Bridges: Ocean Blvd and Shoreline Drive Bridges across the Los Angeles River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

San Mateo County, California Bridges: Sierra Point Overhead over Caltrain Tracks (3)

July 2014 (37.67422 Degrees, -122.38935 Degrees) Sierra Point OH

In Caltrans' nomenclature an overhead is a bridge that carries a highway over a railway. Overheads are required to have crashwalls which make perfect canvases for graffiti artists. The crashwalls on the Sierra Point Overhead show a variety of graffiti styles. It's nice how each artist made their contribution fit within the whole (and it's nice that Caltrans didn't paint over everything).

San Mateo County, California Bridges: Sierra Point Overhead over Caltrain Tracks (3) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

San Mateo County, California Bridges: Sierra Point Overhead over Caltrain Tracks (2)

July 2014 (37.67422 Degrees, -122.38935 Degrees) Sierra Point OH

This bridge, built in 1957, carries Highway 101 over railroad tracks (and Sierra Point Parkway) in South San Francisco. It's a 10-span steel girder bridge, with girders supported by steel floor beams. One end of each girder is bolted to a floor beam stiffener, and the other end was originally attached to a rocker bearing on top of a short seat on the floor beam. The floor beams are supported by 2–4 nonductile reinforced concrete columns. Originally, steel bearings sat atop the columns and were welded to the floor beams. The columns are supported by under-reinforced spread footings on stiff clay. The bridge abutments are on a 60° skew parallel to the railroad tracks, but the bents have no skew. This interesting configuration results in some floor beams being supported by the abutments. 

The bridge site has a 0.4g PGA and is about 16 km from the M_w=8.0 San Andreas Fault. The weak columns and poorly reinforced footings leave the bridge vulnerable to the earthquakes that frequently strike the San Francisco Bay Area. However, the proximity of the railroad limited the retrofit options. Therefore, this bridge was retrofitted with isolation bearings in 1985, making it the first isolated bridge in the United States. All the bearings at the columns and at the abutments were replaced by lead/rubber bearings, which were designed so that the seismic forces would be less than the capacity of the columns and footings. These lead/rubber bearings are rectangular, but round lead/rubber bearings are now used in other bridges because they provide much better performance, particularly for bridges that must move in all directions. To prevent the rocker-supported end of the steel girders from becoming unseated, 2.2-cm steel tie rods were used to connect them to the bolted girders on the other side of the floor beams.

After the retrofit, the bridge was instrumented with strong-motion accelerometers above and below the isolators. The epicenter of the 1989 Loma Prieta earthquake was about 100 km from the bridge site, and the measured acceleration at the bridge was 0.29g above the isolators and 0.31g below the isolators (parallel to the bridge). These two accelerations are about the same, which shows that the lead core did not yield during the earthquake and the bridge behaved elastically with no damage.

San Mateo County, California Bridges: Sierra Point Overhead over Caltrain Tracks (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

San Mateo County, California Bridges: Sierra Point Overhead over Caltrain Tracks (1)

August 1991 (37.674219 Degrees, -122.389354 Degrees) Sierra Point Overhead

The Sierra Point Overhead was the first bridge to be seismically isolated in the United States. It's a 10-span steel girder bridge built in 1957 and carrying State Route 101. The bridge is on such a high skew that the floor beams sit on pile extensions and the abutments. The columns (on spread footings) were not designed for strong earthquakes (it's 10 miles from the San Andreas Fault) and so it was retrofitted in 1985 with lead rubber bearings to reduce the inertia force to the substructure.

San Mateo County, California Bridges: Sierra Point Overhead over Caltrain Tracks (1) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

San Mateo County, California Bridges: State Route 280 Bridge across San Mateo Creek

September 2009 (37.53000, -122.36000) San Mateo Creek Bridge

We last studied the San Mateo Creek Bridge (35 0199) in 2010. It is a continuous five span steel I girder bridge that was built in 1967. There was considerable attention paid to the aesthetics of this bridge. The Happy Pontist wrote in 2010 that the Italian structural engineer Pier Nervi came to California in the 1960s and worked on several bridge designs including the San Mateo Creek Bridge. Note in the figure below how Nervi designed the columns to twist 90 degrees so they are stiffer transversely at the top and stiffer longitudinally at the bottom. The bottom includes a one-way pin that allows the columns to rotate transversely while remaining fixed for longitudinal motion. Thus the columns are made stronger for the large transverse moments at the top and for the large longitudinal moments at the bottom. 

Arthur Elliott in his book 'Bridge Aesthetics around the World' showed many sketches for the design of the piers on the San Mateo Creek Bridge. However, in most of these drawings and in the completed bridge the piers don't look sufficiently integrated to the superstructure. 

San Mateo County, California Bridges: State Route 280 Bridge across San Mateo Creek by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Contra Costa County, California Bridges: Scofield Avenue UC in Richmond

December 2008 (37.93263 Degrees, -122.39709 Degrees) Scofield Avenue UC

The Scofield Avenue Undercrossing (28 0140L) carries State Route 580 from the east end of the Richmond-San Rafael Bridge over a Chevron refinery. It's an eleven span steel girder bridge supported on skewed steel outrigger bents. The bridge was built in 1956 and retrofitted with restrainers on the steel girder in-span hinge seats in 1988 (see photo below). 

Even with the restrainers the seat widths look uncomfortably short. This bridge could use another retrofit (or a replacement) but sitting over an refinery makes the whole project a lot more complicated.

Contra Costa County, California Bridges: Scofield Avenue UC in Richmond by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Yuba County, California Bridges: Colusa Highway (Route 20) Bridge across the Feather River

October 2013 (39.14333 Degrees, -121.60667 Degrees) Colusa Highway Bridge

Continuing northward we arrived at the  24-span Feather River Bridge and Overhead (18 0009) a continuous steel girder bridge that carries the Colusa Highway (Route 20) over the river. It was built in 1947 and widened in 1994. 

The Feather River BOH has a length of 2674 ft including two 160 ft long haunched girder spans across the river. It's 68 ft wide and carries four traffic lanes and sidewalks. 

The long approach structure is supported on oval columns projecting up from pierwalls. My favorite feature is the delicate pale green railings with twisted vertical elements and wave-like horizontal elements.

Yuba County, California Bridges: Colusa Highway (Route 20) Bridge across the Feather River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

Kagoshima Prefecture, Japan Bridges: Nagayoshi Bridge across the Kotsuki River

September 2013 (31.6003 Degrees, 130.5381 Degrees) Nagayoshi Bridge

As we continue upstream the bridges across the Kotsuki River get fancier (or at least their barrier rail and lampposts get fancier). The Nagayoshi Bridge is a two span steel girder bridge on a very wide pier wall.

The Nagayoshi Bridge has decorative wooden timbers stuck to the vertical rails, tall thickened lampposts attached to protrusions on the exterior girders, widened bridge ends, and signposts at the beginning and end of the bridge (see below).

Kagoshima Prefecture, Japan Bridges: Nagayoshi Bridge across the Kotsuki River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.
Based on a work at http://www.bphod.com.

Kagoshima Prefecture, Japan's Bridges: Josei Footbridge across the Kotsuki River

September 2013 (31.5980 Degrees, 130.5402 Degrees) Josei Footbridge

The Josei Footbridge is almost identical to the Shinshoincho Footbridge except the girder, railing, and overhang were painted aquamarine (and the bridge deck doesn't widen at the ends). The footbridges are at the south and north ends of Josei Junior High School on the west side of the river and were probably built to carry the school children. On the east side of the river is a large grassy hill with many places to observe the Sakurajima Volcano across the bay.

Kagoshima Prefecture, Japan's Bridges: Josei Footbridge across the Kotsuki River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

Kagoshima Prefecture, Japan's Bridges: Shinshoincho Footbridge across the Kotsuki River

September 2013 (31.5947 Degrees, 130.5422 Degrees) Shinshoincho Footbridge

The next bridge across the Kotsuki River is a footbridge with grey girders, a white overhang, and aquamarine barrier rails (I use the colors to help identify the bridges). The Shinshoincho Footbridge is a continuous two span steel girder bridge. The girders are shallow at the abutments and deepen to a maximum depth over the rectangular pier. The barrier rail is bowed upward between the posts, perhaps to resemble gates.

The bridge widens at the ends to allow walkers and bicyclists to veer onto the bridge. Masonry endposts have plaques that identify the bridge. Stairs on the west levee have railings at the top to help people onto the bridge.

A great blue heron stood next to the bridge hunting for a meal. As I continued walking upstream the bird would fly ahead to keep a comfortable distance between us. Eventually, it must have gotten tired of being interrupted and flew across the river.

Kagoshima Prefecture, Japan's Bridges: Shinshoincho Footbridge across the Kotsuki River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

Kagoshima Prefecture, Japan's Bridges: Takashi Bridge across the Kotsuki River

September 2013 (31.5925 Degrees, 130.5433 Degrees) Takashi Bridge

Adjacent to yesterday's railway bridge is a continuous two span steel girder roadway bridge. The Takashi Bridge is similar to other bridges across the Kotsuki River with a custom-designed barrier rail, sculpted end posts giving the bridge name, a hammerhead bent cap with simulated stone surface, and a pastel-colored exterior girder on the overhang.

Kagoshima Prefecture, Japan's Bridges: Takashi Bridge across the Kotsuki River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

Calaveras County, California Bridge; Dogtown Road Bridge across San Domingo Creek

June 2013 (38.13278 Degrees, -120.56583 Degrees) Dogtown Road Bridge

The next Dogtown Road Bridge (30C0049) is a two span steel girder bridge with a timber deck that crosses over San Domingo Creek.

The Dogtown Road Bridge is 43 ft long with a 25 ft span and an 18 ft long span. The bridge is 17.4 ft wide with a 14 degree skew and it was built in 1940.  The picture below is actually a collage made from two photos.

Calaveras County, California Bridge; Dogtown Road Bridge across San Domingo Creek by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Calaveras County, California Bridges; Sheep Ranch Road Bridge across O'Neil Creek

May 2013 (38.22083 Degrees, -120.47000 Degrees) Sheep Ranch Road Bridge

Continuing north on Sheep Ranch Road just past the town of Sheep Ranch is another single span steel girder bridge that was built in 1930 and rehabilitated in 1955. The Sheep Ranch Bridge (30C0040) across O'Neil Creek is 41 ft long, 26 ft wide, and carries about 300 vehicles a day.

Calaveras County, California Bridges; Sheep Ranch Road Bridge across O'Neil Creek by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Calaveras County, California Bridges; New Camp Nine Road Bridge across the Stanislaus River (2)

June 2013 (38.12486 Degrees, -120.38432 Degrees) New Camp Nine Road Bridge

A few last photos of the Camp 9 Road Bridge.  A long paper was written by the US Bureau of Reclamation (USBR) about the the Old Camp Nine Bridge, which was a little upstream of the new bridge (see map below).
According to the USBR report, "The original Old Camp Nine Bridge was constructed around 1907. It is speculated that the bridge was originally built to service the town of Camp Nine, which once stood where the Stanislaus Powerhouse is now located. The bridge was constructed of steel with wooden trusses. The bridge was substantially modified for use during construction of the new Stanislaus Powerhouse in 1961. Engineering drawings indicate that the bridge was updated with a new deck, approaches, and braces; and the main span was reinforced. Hand-laid rock walls, which have been determined to be eligible for listing under the National Register of Historic Places (NRHP) are present on both sides of the bridge. The New Melones Dam was built in the early 1980s. Initial filling of the reservoir began in 1983. A new bridge was constructed by the U.S. Army Corps of Engineers (USACE) approximately 1 mile downstream from the old bridge and turned over to PG&E as a replacement for the Old Camp Nine Bridge. The Old Camp Nine Bridge was abandoned with the construction of the New Melones Reservoir, and the new bridge is the current access over the Stanislaus River to Former Forest Route (FR) 3N03. From the new bridge, Camp Nine Road was realigned on the west side of the river to access the Collierville Powerhouse at Clarks Flat as part of the North Fork Stanislaus River Project that was constructed between 1985 and 1990."

I took the photo below of the approaches to the Old Camp Nine Bridge. The old bridge was removed in the 1970s after the construction of the new bridge and before construction of the new dam.

The New Camp Nine Road Bridge is a continuous three span steel girder bridge on tall reinforced concrete piers built across the Stanislaus River by the USACE in 1973. We have entered the Sierra Nevada Mountains and the river has become a rapids about seven miles upstream of the Parrot Ferry Road Bridge and the New Melones Reservoir.

Calaveras County, California Bridges; New Camp Nine Road Bridge across the Stanislaus River (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.