Monterey County, California Bridges: San Lucas Road Bridge across the Salinas River

July 2016 (36.11697, -121.02749) San Lucas Road Bridge

We pick up the Salinas River again in the town of San Lucas about 40 miles south of Chualar. The (Lockwood) San Lucas Road Bridge (44C0007) is a six span, 870 ft long truss bridge that was built in 1915. The west end of the bridge is composed of two pin connected Pratt truss spans (see photo below) and the east end is composed of four Warren truss spans (see photo above). Perhaps the older looking Pratt trusses were the original design from 1915 and the newer looking Warren trusses were added as part of the rehabilitation in 1960? Actually, that makes little sense since the bridge has to be at least four spans long to cross the river. Note that the bridge is a single lane, which means you need to be sure a driver on the other side of the bridge is going to wait before you set off across this long structure.

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Miyagi, Japan's Bridges: Kitakami River Bridge (9)

March 2012 (38.547 Degrees, 141.423 Degrees) Kitakami Bridge

A last few photos of the Kitakami Bridge. The truss spans that remained were still attached to HDPE-wrapped cable restrainers between the floor beams and the piers.

The photo below shows a plaque giving the dates for design and construction of this bridge. I wonder if the Ministry is planning on replacing it?  In the previous photos we saw construction equipment and activity just upstream.

Starting tomorrow, we'll head north on Route 45 to look at some more tsunami-damaged and repaired bridges.

Miyagi, Japan's Bridges: Kitakami River Bridge (9) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License.

Miyagi, Japan's Bridges: Kitakami River Bridge (8)

March 2012 (38.547 Degrees, 141.423 Degrees) Kitakami Bridge

A few more photos of the damaged abutment on the Kitakami Bridge. Bridge owners are now wondering if it's possible to design seat-type abutments that can securely anchor the superstructure during tsunami.

Miyagi, Japan's Bridges: Kitakami River Bridge (8) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License.

Miyagi, Japan's Bridges: Kitakami River Bridge (7)

March 2012 (38.547 Degrees, 141.423 Degrees) Kitakami Bridge

We saw in a previous blog how the truss spans had been scarred by debris carried by the tsunami. However as seen in the photo above the five southeastern spans remained on their piers and were still functional. The waves must have been higher and faster along the northwest shore where the spans were carried upstream. Note the damaged concrete shear keys, cable restrainers, and broken bearings on the abutment and pier.

The missing spans were originally supported on the bank that is  dry during low tide (see photo below).

Miyagi, Japan's Bridges: Kitakami River Bridge (7) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License.

Miyagi, Japan's Bridges: Kitakami River Bridge (6)

March 2012 (38.547 Degrees, 141.423 Degrees) Kitakami Bridge

To avoid the damaged substructure elements on the Kitakami Bridge, the new spans step around them. The barrier rail snakes over these steps to form a two-lane bridge deck. I guess that's how you make a curved alignment out of straight superstructure segments.  That explains the odd placement of the new spans.  However, I'm still unsure why plastic pipes are sticking out of the ground in the photo below.

Miyagi, Japan's Bridges: Kitakami River Bridge (6) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License.

Miyagi, Japan's Bridges: Kitakami River Bridge (5)

March 2012 (38.547 Degrees, 141.423 Degrees) Kitakami Bridge

Looking up (into the sun) at the broken members that once connected two trusses of the Kitakami Bridge.  The purpose of these elements was carefully explained to me, but now I've forgotten the explanation. The next truss span was dragged from its piers and so these top members were broken.

A photo of the damaged abutment, which was subsequently abandoned. Note the various devices that were meant to keep the truss seated that were broken as it was carried away. Also note the replacement bridge spans (with blue girders) behind the abutment. The Ministry was able to quickly drive piles and set these replacement spans onto Route 45 while they pondered the future for this region.

Miyagi, Japan's Bridges: Kitakami River Bridge (5) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License.

Miyagi, Japan's Bridges: Kitakami River Bridge (4)

March 2012 (38.547 Degrees, 141.423 Degrees) Kitakami Bridge

Three views of damage to the truss members of the Kitakami Bridge, most likely from wave-borne debris during last year's tsunami.

Miyagi, Japan's Bridges: Kitakami River Bridge (4) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License.

Miyagi, Japan's Bridges: Kitakami River Bridge (3)

March 2012 (38.547 Degrees, 141.423 Degrees) Kitakana Bridge

Some more photos of the Kitakana Bridge, which lost several spans during the Tohoku earthquake. New steel girder spans have replaced the lost truss spans at the north end of the bridge. They built the new spans next to the old substructure and so the deck veers to the east to avoid them (as seen on the bus driving up to the site).

A year later you can still see the old truss spans in the river a few hundred feet upstream. Perhaps in Japan they leave the remnants of past disasters as reminders to the public.

Miyagi, Japan's Bridges: Kitakami River Bridge (3) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License.