Tuesday, March 31, 2015

Shasta County, California Bridges: Pit River Bridge (1)

May 2014 (40.7601 Degrees, -122.3182 Degrees) Pit River Bridge
The Pit River Bridge is a 1094 ft long double deck truss with a highway (I-5) on top and a railway (Southern Pacific) on the bottom. It was built in 1941 as part of the Shasta Dam Project. There's an excellent article on this impressive bridge on Eric Sakowski's Highest Bridges website. The only additional information that I have is that Caltrans was approached by California's Department of Water Resources (DWR) a few years ago to take ownership of this bridge. However, the bridge has never had a seismic retrofit and so Caltrans insisted that the bridge had to be safe for earthquakes before they could take it. Moreover, Caltrans told DWR that they would design the retrofit at what seemed a very high cost, and this was met with some consternation by DWR. However, they are both state agencies and so there is no actual cost to the state.
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Shasta County, California Bridges: Pit River Bridge (1) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Monday, March 30, 2015

Shasta County, California Bridges: Doney Creek Bridges (1)

March 2015 (40.88233 Degrees-122.38797 Degrees) Doney Creek Bridges
Just west of the old Antlers Bridge are two bridges at the mouth of Doney Creek. The bridge in the foreground is a Southern Pacific Railroad (deck truss) Bridge. Just behind it is a pretty arch bridge (6C0052) carrying Lakeshore Drive over Doney Creek. The highway bridge was built in 1927 by Harlan D. Miller. It includes a 182 ft long spandrel arch main span. Both bridges had to be raised when Shasta Dam was built across the Sacramento River in 1940. Of course, after several years of drought, the creek is close to its original elevation.
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Shasta County, California Bridges: Doney Creek Bridges (1) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Sunday, March 29, 2015

Shasta County, California Bridges: Antlers Bridges (4)

March 2015 (40.8808 Degrees, -122.3811 Degrees) Antlers Bridges
A view of the four segments of the new Antlers Bridge. Hopefully one day they will be joined together to create a single bridge. However, this project started back in 2008 and it probably won't be completed until sometime in 2016.

There are some projects that are a joy to work on, where the contractor has no other objective than to build the best bridge they can. Then there are projects where the contractor severely underbids their competitors in the hope they can make their money back by finding issues they can exploit with change orders.

I started work in bridge construction over 30 years ago in Riverside County. The best, most reasonable contractor in the 1980s was Kaiser Construction. They were such a pleasure to work for that every year the structure reps, resident engineers, and bridge inspectors in District 8 would give a dinner for them as a token of our appreciation.
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Shasta County, California Bridges: Antlers Bridges (4) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Saturday, March 28, 2015

Shasta County, California Bridges: Antlers Bridges (3)

March 2015 (40.8808 Degrees, -122.3811 Degrees) Antlers Bridges
When I read about bridges lasting centuries or even millennia it makes me wonder if they are still usable and at what cost? Caltrans bridges need constant attention to keep them in service and after about 75 years they usually need to be replaced. People praise the longevity of the Roman bridges, but the ones I've seen could never carry modern highway traffic.

The existing Antlers Bridge is a five span deck truss on pier walls that was built in 1941. After 75 years the bridge can't carry all the traffic on I-5 and the floor beams and deck stringers suffer from fatigue cracks. Interestingly, the trusses haven't had a recent inspection because the deck is on a 8% superelevation, which prevents the snooper (UBIT) truck from extending its arm under the bridge. Because the existing bridge will be torn down in 2016, another inspection of the truss won't be needed.

Caltrans typically has meetings with the community to reach consensus on bridge replacement projects. This can be a long process. An old timber bridge in Albion, California needed to be replaced but the community was quite attached to it. The New York Times wrote an article recently about the politics of replacing that bridge. When the talk was on replacing the Antlers Bridge, the community was hoping that new jobs and new residents would help revitalize the community, but that never took place.

We'll continue our discussion of the Antlers Bridges tomorrow.
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Shasta County, California Bridges: Antlers Bridges (3) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Friday, March 27, 2015

Shasta County, California Bridges: Antlers Bridges (2)

March 2015 (40.8808 Degrees, -122.3811 Degrees) Antlers Bridges
Currently, the new Antlers Bridge is composed of four segments; an abutment and bent at each end and two pier tables in the river. In the photo above we are looking at the most developed four column pier with a long cantilever and a traveler at one end. Note how the exterior forms on the traveler hang below the soffit due to the haunched girders. This bridge was one of the last projects by Caltrans chief of aesthetics, Javier Chavez who created two enormous large mouth bass above the columns. Also, the columns have the typical isolation above the flares to prevent the columns from acting like short, shear-critical members during an earthquake.
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Shasta County, California Bridges: Antlers Bridges (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Thursday, March 26, 2015

Shasta County, California Bridges: Antlers Bridges (1)

March 2015 (40.8808 Degrees, -122.3811 Degrees) Antlers Bridges
Jason Lynch invited me to the construction site of a segmentally-constructed, cast-in-place bridge that he designed across the Sacramento River. In the above photo, Jason is standing on the right and Ray Zelinski who built the first segmental bridge in California (the Pine Valley Bridge) is standing next to him. Jim Nicholls who is Caltrans Structures Rep. for the new Antlers bridge is standing next to Ray. Behind them is the existing Antlers Bridge, a 5-span continuous deck-truss bridge built in 1941 and the partially constructed new Antlers Bridge. They're standing on a trestle bridge that is being used to construct the new bridge. We'll take a closer look at the new Antlers Bridge in my next blog.

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Shasta County, California Bridges: Antlers Bridges (1) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.