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.
 
Shasta County, California Bridges: Antlers Bridges (4) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

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.
 
Shasta County, California Bridges: Antlers Bridges (3) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

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.
 
Shasta County, California Bridges: Antlers Bridges (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

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.


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