Bridges of Mexico: Xonacatepec OC across 150D in the State of Puebla

September 2017 (19.0674, -98.1181) Xonacatepec Road OC

Driving west on 150D we approached a very strange looking overcrossing carrying Xonacatepec Road across the expressway. Note the diagonal tower with cables on the east side of the bridge supporting the two northern spans. You can't see from the photo (shot while hanging out of the passenger window) but there is an identical tower on the west side supporting the two southern spans. The diagonal towers positioned asymmetrically from each other must provide torsional and bending moments. Perhaps the asymmetrically positioned cable towers are to compensate for the torsion due to the highly skewed bridge?

A year ago there were no service roads and the overcrossing had fewer spans (see above). Looking at a later photo shows the new overcrossing being built (shown below). Note the tower that will support the cables sitting on the north shoulder (in the photo below). There's another tower sitting on the south shoulder on the west side of the bridge.

Looking at a photo of the bridge deck (below), we can see that this wide bridge was able to handle traffic during construction by working on half the bridge while allowing traffic to ride on the other half. Once that half was rebuilt, traffic was moved onto it while the other half was rebuilt.

One last photo (below) of the overcrossing through the (dirty) rear window. You can clearly see the diagonal towers on opposite ends and opposite sides of the bridge. What I find particularly interesting is that the engineer was allowed to design such an unusual structure on an interstate highway. I think California's bridge engineers may be too cautious and conservative to design something so unusual.

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Willamette River Crossings: Marion Street Bridge in Salem, Oregon

July 2017 (44.94556, -123.04250) Marion Street Bridge

A hundred yards south of last week's Union Street Railway Bridge is the westbound Marion Street (I-22) Highway Bridge. This bridge is 2400 ft long and 56 ft wide with a steel plate girder superstructure. It was the longest plate girder bridge west of the Mississippi when it was built (in 1952).

The bridge's most unusual feature is that it's supported on pier walls having gothic arch openings. Gothic arch shapes were also used on the nearby Independence Bridge and in some of the arch bridges by Conde McCullough along the Oregon coast. The designer of the Marion Street Bridge, Glenn S. Paxson succeeded McCullough as Oregon's Chief Bridge Engineer and may have used the arches as a tribute to his old boss.

Before this bridge was built, all the traffic across the Willamette was carried on the adjacent Center Street Bridge. In fact, looking at the construction photo below (courtesy of the City of Salem), it appears that this bridge originally had only a single pier at each support (it was widened in the 1980s). That explains why the steel plate girders continue along the approaches on the original bridge but have been switched to concrete for the approaches of the widening (see photo above).

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Monterey County, California Bridges: Parkfield-Coalinga Road Bridge across Little Cholame Creek (and the San Andreas Fault)

We've traveled to the east side of Monterey County after spending two months along the coast. This week's bridge is in the town of Parkfield, which is famous for experiencing a moderate earthquake on the average of every 21 years (1857, 1881, 1901, 1922, 1934, 1966, 2004).

 The Parkfield-Coalinga Road Bridge (44C0141) crosses over Little Cholame Creek, which is also the surface trace of the San Andreas Fault (the source of these recurring earthquakes).  The fault is right lateral, which means when you face it, the plate across from you is moving to the right (see figure below). Therefore, a bridge crossing a right lateral fault would eventually have a flattened 'S' shape.

The photo below was taken by the US Geological Survey on September 29, 2004, one day after the 2004 earthquake. They reported that the bridge has about 5 ft of offset (due to the 2004 earthquake, the 1966 earthquake, and due to aseismic creep).  However, the photo shows the bridge rail with a reverse 'S' shape. However, the abutments may have allowed the ends of the bridge to slide instead of restraining them.

In the photo below, we can see the girders are sitting on a seat-type abutment with shear keys a few feet to each side. Professor Goel reported that after the 2004 earthquake, "Angle iron apparently installed in an effort to restrain transverse motion of the superstructure at the bearings was knocked free."

I took photos of the abutments and piers to try to understand what happens to a bridge over a fault. 

The first bridge at this site was built in 1936 (according to the University's Space Research Association) but it was replaced in 1960 with the current steel stringer bridge. However the 1960 bridge was recently retrofit with new concrete bent caps cast under the existing superstructure and with new CIDH piles cast on each side of the 'H' pile supports. The retrofitted structure obviously hadn't been around for the 1964 temblor, but the bridge may still have the displaced shape from the earlier earthquake.

During an earthquake, the bents on each side of the fault move in parallel but opposite directions. The superstructure is restrained to follow this offset by the bearings, the angle irons, and eventually by the concrete shear keys and to take on the noticeable 'S' or 'Z' shaped configuration.

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Los Angeles County, California Bridges: Balboa Boulevard Bridges across the Los Angeles River

August 2009 (34.1796 Degrees, -118.5011 Degrees) Los Angles River Bridges

After traveling about five miles down a concrete-lined channel, the Los Angeles River turns back into a normal river for two miles through Woodley and Balboa Parks. The Balboa Blvd Bridges (53C1095 and 53C1096) are two parallel seven span structures; one with steel girders built in 1941 and one with concrete girders built in 1964. Both bridges were widened in 1996 with sidewalks on both sides. The bridges have pretty columns and barrier rails.

Los Angeles County, California Bridges: Balboa Boulevard Bridges across the Los Angeles River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Los Angeles County, California Bridges: Mason Avenue and Vanowen Street Bridges across the Los Angeles River

August 2009 (34.1937 Degrees, -118.5784 Degrees) Los Angeles River Bridges

We're continuing downstream and are now where Mason Avenue and Vanowen Street cross over the Los Angeles River (at right angles to each other). Each of these bridges is an example of how an attractive barrier rail can turn a boring bridge into something exciting! The more distant Mason Avenue Bridge (53C1244) has a muscular railing that's integral with the bridge and gives it a powerful appearance. The Vanowen Street Bridge (53C1362) has a whimsical recurrent theme (of wheels? of traveling?) cast into the barrier and a pretty metal rail on top that makes you feel like your traveling somewhere nice.

Los Angeles County, California Bridges: Mason Avenue and Vanowen Street Bridges across the Los Angeles River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

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.

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.

San Francisco County, California Bridges: Central Freeway Viaduct

July 2014 (37.76924 Degrees, -122.40890 Degrees) Central Freeway Viaduct

South of yesterday's West Approach to the Bay Bridge is the mile long Central Freeway Viaduct. At one time it was planned to make the viaduct part of an elevated loop around the city, but after it was damaged during the Loma Prieta earthquake it was torn down except for the portion that connects Mission Street to the 101/I-80. The Central Viaduct is made of steel columns and steel girders and so it was difficult to increase its seismic resistance. Doubler plates and restrainers were added to improve it's displacement capacity.

San Francisco County, California Bridges: Central Freeway Viaduct by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

San Joaquin County, California Bridges: Forest Lake Underpass across Lower Sacramento Road

April 2014 (38.21389 Degrees, -121.29194 Degrees) Forest Lake Underpass

Today we are leaving Santa Cruz for San Joaquin County. Instead of concrete arch and haunched girder bridges there are a lot of movable bridges and railroad bridges. San Joaquin County is between the Bay Area and the Mountains and has many rivers, expressways, and railways crossing its borders.

I couldn't find much written about today's bridge. The Forest Lake UP (29C0132) was likely built at the beginning of the 20th century. Although it has a concrete facade, it is actually a two span steel girder bridge. When it was built, there must have been pedestrians who found it convenient to walk under the 14 ft long western span while horse drawn vehicles used the 23 ft long main span. The surrounding area has changed but the bridge remains the same. While I was photographing it several freight trains crossed over the spans.

San Joaquin County, California Bridges: Forest Lake Underpass across Lower Sacramento Road by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

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. 

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.

Tokushima Prefecture, Japan Bridges; Bridges across Konaruto Channel (1)

November 2013 (34.1892 Degrees, 134.6125 Degrees) Konaruto Channel Bridges

Shikoku Island is separated from Honshu Island by the Seto Inland Sea. The three routes of the Honshu-Shikoku Bridge Project were built to connect Shikoku Island to the more developed Honshu Island and allow Shikoku to better participate in the social and economic life of the country. 

There are three long routes on the Honshu-Shikoku Bridge Project. The westernmost route is the Nishi-Seto Expressway, which includes nine long span bridges and connects Imabari to Onomichi. We studied the construction of several of these bridges in my blog in July of 2009. The middle route is the Seto-Chuo Expressway which carries both highways and railways and includes six long span bridges. The eastern route is the Kobe-Awaji-Naruto Expressway, which is 89 km long and includes some of the longest and most difficult bridges to construct.

Today's bridges are at the southern end of the Kobe-Awaji-Naruto Expressway on Shikoku Island. We'll take a closer look at these bridges tomorrow.

Tokushima Prefecture, Japan Bridge; Bridges across Konaruto Channel (1) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

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

September 2013 (31.5922 Degrees, 130.5437 Degrees) Railroad Bridge

The next bridge carries railroad tracks across the Kotsuki River. The bridge has two deep steel girder spans across the river as well as through girder approach spans. The piers along the levees have backwalls to handle the transition from through girder to deck girder spans. The river pier is supported on a very large caisson projecting ten feet above the river bottom. The bridge carries electric lines to power the trains.

This bridge doesn't look like it was built to carry high speed trains (even though bullet trains would be traveling slowly close to the station). It's just north of Kagoshimachuo Station but I noticed on the map that there is another set of tracks perpendicular to these tracks going into the station. Since Kagoshimachuo Station is the final stop for the Shinkansen it makes sense that the tracks would end at the station (see map below).

Note that both railroad lines go into tunnels (red dots) soon after leaving the station. On our trip from Tokyo to Kagoshima we spend a lot of time underground after leaving Honshu for Kyushu.

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

Yolo County, California Bridges: Pioneer Memorial Bridge across the Sacramento River

July 2013 (38.57111 Degrees, -121.51611 Degrees) Pioneer Memorial Bridge

We've been working our way downstream along the Sacramento River, which is the eastern border of Yolo County. About 1/2 a mile south of yesterday's 'I' Street Bridge is the big (39 span) Sacramento River Viaduct (24 0004L/R), which is the principal interstate arterial (6346 ft long) over streets, highways, railroad tracks, and the Sacramento River. It includes connector ramps on both sides of the river (see figure below). We used to practice rope climbing on the part of the bridge over the Caltrans' maintenance yard on the east side of the river.

Most of the Sacramento River Bridges have an official and popular name and the Sacramento River Viaduct is commonly referred to as the Pioneer (or Pioneer Memorial) Bridge. It's a haunched (for the long spans over the river) steel girder bridge. Steel must have been a popular material for Sacramento River crossings in the 1960s. The bridge carries over 100,000 vehicles a day which has worn down the concrete deck (the current deck condition is rated poor (3 out of 9)). 
The part of the bridge across the river in Yolo County crosses an empty yard while the city of West Sacramento attempts to develop this area. The city of Sacramento on the east side of the river has similar hopes and aspirations for their riverfront.

Yolo County, California Bridges: Pioneer Memorial Bridge across the Sacramento River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

El Dorado County, California Bridges: Sciaroni Road Bridge across the North Fork of the Cosumnes River

March 2013 (38.6689 Degrees, -120.5332 Degrees) Sciaroni Road Bridge

The first bridge across the North Fork of the Cosumnes River is an single span steel girder structure with a timber deck. The girders are supported on end bents in front of metal retaining structures. The girders have rivets supporting a diaphragm near the support. The bridge was built in 1965.

The river is very shallow and clear at this location. The Sciaroni Bridge is 79 ft long, about 10 ft longer than the Sweeney Road Bridge and about 40 ft longer than the Happy Valley Road Bridge downstream. The river starts off flat and wide before cutting through a stone canyon as it travels west through El Dorado County.

El Dorado County, California Bridges: Sciaroni Road Bridge across the North Fork of the Cosumnes River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.