Friday, August 31, 2012

Niigata, Japan's Bridges: Heisei O'Hashi across the Sabaishi River (2)


August 2007 (N37.3888° E138.5767°) Heisei O'Hashi

Another photo of the Heisei OHashi, a continuous two span prestressed concrete box girder bridge over the Sabaishi River.
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Niigata, Japan's Bridges: Heisei O'Hashi across the Sabaishi River (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Thursday, August 30, 2012

Niigata, Japan's Bridges: Kaiun Bridge across the Sabaishi River (8)

August 2007 (37.3918° 138.5806°) Kaiun Bridge
As the abutment on the Kaiun Bridge was pushed forward due to lateral spreading during the Kashiwazaki Earthquake, the elastomeric bearings became severely distorted. It looks like the entire backwall was sheared off, perhaps by lateral spreading or by the girders striking the backwall.

A transverse shear key sits undamaged beside the bearing. The steel keys either did a good job of preventing transverse motion or the earthquake shook the bridge mainly in a longitudinal direction.

In the photo below, we can see one of the brackets for a cable restrainer attached to the girder web. The restrainer has a spring at the end, perhaps to handle temperature movement or to prevent a hard impact during shaking.

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Niigata, Japan's Bridges: Kaiun Bridge across the Sabaishi River (8) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Wednesday, August 29, 2012

Niigata, Japan's Bridges: Kaiun Bridge across the Sabaishi River (7)

August 2007 (37.3918° 138.5806°) Kaiun Bridge
The expansion joints on the Kaiun Bridge were tightly closed after the Kashiwazaki Earthquake because the abutments had been pushed forward due to lateral spreading. I've noticed Japan's bridges usually have steel finger joints while California's bridges tend to have elastomeric joint seals.
At the ends of the expansion joints are black plastic diaphragms, maybe to prevent banging of the deck against the backwall. If that was the intention however, it didn't prevent shear cracking at the bottom of the backwall. The red steel barrier rail has a telescoping connection to handle the movement of the joint.
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Niigata, Japan's Bridges: Kaiun Bridge across the Sabaishi River (7) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Tuesday, August 28, 2012

Niigata, Japan's Bridges: Kaiun Bridge across the Sabaishi River (6)

August 2007 (37.3918° 138.5806°) Kaiun Bridge
I can't remember what the broken blue cylinder's original purpose was on the abutment seat. Perhaps it has something to do with the watery stain on the slope paving?
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Niigata, Japan's Bridges: Kaiun Bridge across the Sabaishi River (6) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Monday, August 27, 2012

Niigata, Japan's Bridges: Kaiun Bridge across the Sabaishi River (5)

August 2007 (37.3918° 138.5806°) Kaiun Bridge
Another view of the Kaiun Bridge. It looks like the bridge may have been instrumented (see metal boxes at closest abutment). Instrumentation allows engineers to compare recorded accelerations with the results of FEM analysis to improve bridge modeling techniques. In the photo below we can see they connected the two boxes with a suspended cable so it wouldn't break during strong shaking.
We can also see the water main that was brought over to the Kaiun Bridge after the nearby utility bridge was damaged by the Kashiwazaki Earthquake. Also note the stain on the short wingwall showing how much the embankment has settled.
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Niigata, Japan's Bridges: Kaiun Bridge across the Sabaishi River (5) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Sunday, August 26, 2012

Niigata, Japan's Bridges: Kaiun Bridge across the Sabaishi River (4)

August 2007 (37.3918° 138.5806°) Kaiun Bridge
A view of the south abutment on the Kaiun Bridge. The ends of bridges are often decorated in Japan, in this case with plinths supporting panels showing peach orchards and wheat fields.

Note how much the ground has settled around this bridge. In the photo below, we can see that the abutment did not completely escape some damage. The big elastomeric bearings are distorted due to the abutment being pushed forward by lateral spreading of the surrounding soil.
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Niigata, Japan's Bridges: Kaiun Bridge across the Sabaishi River (4) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Saturday, August 25, 2012

Niigata, Japan's Bridges: Kaiun Bridge across the Sabaishi River (3)

August 2007 (37.3918° 138.5806°) Kaiun Bridge
The area around the Kaiun Bridge suffered a lot of soil-related damage during the Kashiwazaki Earthquake. The embankments supporting a nearby utility bridge settled, breaking the waterline (see photo below), and a new line was put on the sidewalk of the Kaiun Bridge (see above).
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Niigata, Japan's Bridges: Kaiun Bridge across the Sabaishi River (3) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Friday, August 24, 2012

Niigata, Japan's Bridges: Kaiun Bridge across the Sabaishi River (2)

August 2007 (N37.3918° E138.5806°) Kaiun Bridge

Another photo of the Kaiun Bridge across the Sabaishi River. Note the incinerator plant behind the bridge with a broken smokestack and the areas of landslides and liquefaction.
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Niigata, Japan's Bridges: Kaiun Bridge across the Sabaishi River (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Thursday, August 23, 2012

Niigata, Japan's Bridges: Bridges over the Omigawa (6)


August 2007 (37.343 Degrees, 138.482 Degrees) Omigawa Bridges
A last few photos of the Yoneyama Bridge. This bridge is supported on two tall four-legged towers, two shorter two-legged piers, and seat type abutments. Note in the photo above, the rain from the bridge deck is allowed to pour onto the concrete foundation. The bridge went through an elaborate retrofit after the Kobe Earthquake that is credited with protecting it from serious damage during the 2007 Kashiwazaki Earthquake.
The retrofit included the vertical restrainers (above) that kept the superstructure supported on its steel roller bearings (below).

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Niigata, Japan's Bridges: Bridges over the Omigawa (6) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Wednesday, August 22, 2012

Niigata, Japan's Bridges: Bridges over the Omigawa (5)

August 2007 (37.343 Degrees, 138.482 Degrees) Omigawa Bridges
Another photo of the Yoneyama Bridge.  I wonder if the bridge would look nicer if it were another color? Its strange how it was just plopped down in this residential neighborhood.

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Niigata, Japan's Bridges: Bridges over the Omigawa (5) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Tuesday, August 21, 2012

Niigata, Japan's Bridges: Bridges over the Omigawa (4)

August 2007 (37.343 Degrees, 138.482 Degrees) Omigawa Bridges
Another view of the Yoneyama Bridge with the Aumegawa Bridge behind it. The steep valley created by the Omigawa River has created a barrier that the Horukiru Expressway and Highway 8 (and Japan Rail) all cross with bridges.
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Niigata, Japan's Bridges: Bridges over the Omigawa (4) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Monday, August 20, 2012

Niigata, Japan's Bridges: Bridges over the Omigawa (3)

August 2007 (37.346° 138.488°Yoneyama Bridge

Another view of the Yoneyama Bridge carrying Highway 8 over the canyon formed by the Omigawa. The JR Jinetsu Bridge is emerging from a tunnel on the left.
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Niigata, Japan's Bridges: Bridges over the Omigawa (3) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Sunday, August 19, 2012

Niigata, Japan's Bridges: Bridges over the Omigawa (2)

August 2012 (37.3469 Degrees, 138.4875 Degrees) Omigawa Bridges
 Another view of Omigawa Beach looking down from the headlands. You may have to click on the photo to see the one span pedestrian bridge across the river's mouth. A little further inland is the JR Shinetsu bridge across the Omigawa. We can see a blue tarp covering a damaged building roof due to the Kashiwazaki Earthquake. Many of these small villages were isolated by landslides that occurred during the earthquake. The entire view is from between the legs of the Yoneyama Bridge.
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Niigata, Japan's Bridges: Bridges over the Omigawa (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Saturday, August 18, 2012

Niigata, Japan's Bridges: Bridges over the Omigawa (1)

August 2012 (37.3469 Degrees, 138.4875 Degrees) Omigawa Bridges
I'm returning to the beginning of our trip through Kashiwazaki with some additional photos.

This is a beach south of Kashiwazaki where the Omigawa flows into the Sea of Japan. A one span pedestrian bridge crosses at the river's mouth below headlands, retaining walls, and the Yoneyama Bridge. Tomorrow we'll view the beach from atop the Yoneyama Bridge.
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Niigata, Japan's Bridges: Bridges over the Omigawa (1) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Friday, August 17, 2012

Thursday, August 16, 2012

Niigata, Japan's Bridges: Nagomi Bridge across the Sabaishi River

August 2007 (N37.3904° E138.5908°) Nagomi Bridge
This is a three span steel girder bridge on pier walls and seat-type abutments.  There was evidence of fine grain soil being ejected at depth to the ground surface along with settlement of the saturated riverbanks.
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Niigata, Japan's Bridges: Nagomi Bridge across the Sabaishi River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Wednesday, August 15, 2012

Niigata, Japan's Bridges: Kaiun Bridge across the Sabaishi River

August 2007 (N37.3918° E138.5806°) Kaiun Bridge

About 1/2 km upstream from the Heisei Bridges (across the Sabaishi River) sits the four span continuous steel girder Kaiun Bridge, which had a one meter settlement of the south approach during the 2007 Kashiwazaki Earthquake.
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Niigata, Japan's Bridges: Kaiun Bridge across the Sabaishi River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Tuesday, August 14, 2012

Niigata, Japan's Bridges: Heisei O'Hashi across the Sabaishi River

August 2007 (N37.3888° E138.5767°) Heisei O'Hashi

On the other side of the island formed by the meandering Sabaishi River is the Heisei O'Hashi, which means the 'big' Heisei Bridge. It is bigger than the Heisei Bridge on the other side of the island. 

This is a continuous, two-span, haunched concrete box girder bridge supported on seat-type abutments and a big caisson.  During the earthquake, the north bridge embankment settled about 400 cm.  There were also signs that the bridge underwent shaking and pounding. 
Although the abutments were on piles, the bearings were distorted, indicating that the abutments had been pushed toward the river.
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Niigata, Japan's Bridges: Heisei O'Hashi across the Sabaishi River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Monday, August 13, 2012

Niigata, Japan's Bridges: Heisei Bridge across the Sabaishi River

August 2007 (37.3894° 138.5742°) Heisei Hashi
After looking at the toll road (the Horukiru Expressway) and the major expressway (Highway 8) going through town, we walked along the Sabaishi River that flows through Kashiwazaki. This river frequently floods its banks, leaving a deep layer of uncompacted sediment that liquefies after every earthquake. However bridge engineers were aware of this weak soil and supported their bridges on deep strong piles. The resulting liquefaction and lateral spreading during earthquakes slides around the piles (founded on firmer material) without causing bridge damage.

In the map below we can see that the Heisei Hashi crosses at a meander that created a large island in the river. In the photo above I am standing on the island photographing the east side of Heisei Hashi. The island had settled and spread due to ground shaking during the Kashiwazaki Earthquake.
In the photo below, I am standing on the other side of the bridge photographing the approach on the west side which has also settled several feet. However, this single span box girder bridge had abutments supported on piles that were undamaged by the earthquake and were able to carry traffic once new approaches were constructed. Compare this with several bridges across the Avon River in Christchurch where the abutments were damaged due to lateral spreading during last year's earthquake.
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Niigata, Japan's Bridges: Heisei Bridge across the Sabaishi River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.