Napa County, California Bridges: Larkmead Lane across the Napa River

December 2013 (38.56057 Degrees, -122.52206 Degrees) Larkmead Lane Bridge

Continuing up the Valley we came to the Larkmead Lane Bridge (21C0061) across the Napa River. This two span 'T' girder bridge has a decorative pier wall with a diaphragm that descends slightly below the girders. The bridge was built in 1926 and it's composed of two 42 ft long spans and a 20 ft wide deck. Perhaps the fad for stone masonry arch bridges had diminished by the 1920s or maybe they just wanted a bridge with more headroom.

An interesting suspension bridge sits next to the 'T' girder bridge complete with 'mini' towers. I'm surprised they just didn't put this pipe in the roadway bridge instead of building a separate bridge.

There's apparently a two span stone masonry arch bridge on Larkmead Lane over Dutch Henry Creek that I missed, but fortunately Craig Philpott took some photos of it for the Bridgehunter Website.

Napa County, California Bridges: Larkmead Lane across the Napa River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Napa County, California Bridges: Bale Lane Bridge across the Napa River

December 2013 (38.55641 Degrees, -122.50633 Degrees) Bale Lane Bridge

Continuing northwest we drove over the Bale Lane Bridge (21C0048) across the Napa River. This bridge is identical to yesterday's Lodi Lane Bridge. It's another 100 ft long single span pony truss with a 17 ft wide deck, but built in 1937. Napa County must have found it cheaper in the 1930s to place a steel truss span on a couple of concrete abutments rather that having to built a stone arch. Also a lot more water can go under these pony trusses without causing a flood.

Napa County, California Bridges: Bale Lane Bridge across the Napa River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Napa County, California Bridges: Lodi Lane Bridge across the Napa River

December 2013 (38.52727 Degrees, -122.49089 Degrees) Lodi Lane Bridge

The next bridge carries Lodi Lane across the Napa River. It's a single span pony truss bridge that was built in 1930. This Warren Truss is 100 ft long and it's only 17 ft wide. Craig Philpott has a couple of photos of the Napa River flowing over the bridge on the Bridgehunter Website.

Napa County, California Bridges: Lodi Lane Bridge across the Napa River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Napa County, California Bridges: Sanitarium Road Bridge across Canon Creek

December 2013 (38.53617 Degrees, -122.47426 Degrees) Sanitarium Road Bridge

The Seventh Day Adventists have a large community at the north end of Napa Valley. We passed a very nice Seventh Day Adventist Hospital on Sanitarium Road where we also found today's bridge.

The Sanitarium Road Bridge across Canon Creek is a small closed spandrel arch bridge, really more of a culvert by Caltrans' standards. Craig Philpott took a nice photo of Canon Creek at flood stage for the Bridgehunter Website. We can see the left over debris from the flood in today's photos. 

The problem with these little bridges and with closed spandrel arch bridges in general is that their shape restricts the amount of water and debris that can pass through, which often results in flooding. This is why Napa County eventually had to replace many of their historic arch bridges.

Napa County, California Bridges: Sanitarium Road Bridge across Canon Creek by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Napa County, California Bridges: Pratt Avenue Bridge across the Napa River

December 2013 (38.52074 Degrees, -122.47266 Degrees) Pratt Avenue Bridge

Continuing up the Napa Valley we arrived at the Pratt Avenue Bridge (21C0072) across the Napa River. The Napa River flows on the south side of the Silverado Trail and so bridges carrying traffic into the Napa Valley have their north abutment at the intersection with the Silverado Trail (see bottom photo).

The Pratt Avenue Bridge is a T girder bridge built in 1921. It is composed of two continuous 57 ft spans supported on a decorative pier wall and end diaphragm abutments. The exterior girders are big and the interior girders are small (see photo above). Perhaps the exterior girders are meant to support the intermediate diaphragms, which support the interior girders. The deck is only 19 ft wide, it carries about 1000 vehicles a day, and it's in satisfactory condition.

Napa County, California Bridges: Pratt Avenue Bridge across the Napa River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Napa County, California Bridges: Spring Mountain Road Bridges across York Creek

December 2013 (38.50707 Degrees, -122.49192 Degrees) Spring Mountain Road Bridges

Just northwest of St Helena, Spring Mountain Road and York Creek crisscross three times, resulting in three stone arches that were built in 1903. The first bridge was repaired with concrete on the east side and a waterline was placed next to it (see photo below).

The next bridge has some of the stones from the top of the barrier missing. It looks like they built the arch, then the spandrel wall, then a stone bridge deck, and finally a stone barrier wall on top.

The last bridge uses red stones for the arch. Note that York Creek flows at a sharp angle to this bridge.

All three bridges have plaques with the completion date and the names of the county supervisors at the time the bridges were built. 

The Spring Mountain Road Bridges are similar to those on Stanley Lane that we studied on December 3rd. However, these bridges are still carrying trucks and cars. Spring Mountain Road carries 1500 vehicles a day and the bridges have sufficiency ratings of about 50. 

Napa County, California Bridges: Spring Mountain Road Bridges across York Creek by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Napa County, California Bridges: State Route 29 across Sulphur Creek

December 2013 (38.50285, -122.46615 Degrees) Main Street Bridge

Today's structure is another Sulphur Creek Bridge (21 0016) but on Main Street (SR 29) in the town of St Helena. It's very similar to the previous bridge: a 60 ft long stone arch span built at the beginning of the last century, but this bridge was widened on the west side with precast girders in 1975.

The original bridge was built by A. Martini, designed by G.H. Wallace, and it's owned by Caltrans. During the last inspection the bridge scored good for the deck, superstructure, and substructure, it had a sufficiency rating of 60, and it carried over 18,000 vehicles a day.

This bridge is on a 35 degree skew. I wonder if it's even possible to build a skewed arch? More likely they put the bridge deck on a skew. Also, I wonder if the quarry can cut stones so that they span the whole width of the arch? You just order the stones 30 ft long and place them on the wooden form? However, if you built a skewed arch every stone would have to be a different length.

Napa County, California Bridges: State Route 29 across Sulphur Creek by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Napa County, California Bridges: Pope Street Bridge across Sulphur Creek

December 2013 (38.5050 Degrees, -122.4638 Degrees) Pope Creek Bridge

Continuing west on Pope Street is a 60 ft long single span stone arch bridge over Sulphur Springs. The bridge was built in 1908 but widened to 24 ft with an exterior girder on stone abutments in 1950.

This bridge carries 3000 people a day but has a sufficiency rating of only 25. Unlike the Zinfandel Lane Bridge, this bridge has poor bank protection, which has been deteriorated from previous floods.

Napa County, California Bridges: Pope Street Bridge across Sulphur Creek by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Napa County, California Bridges: Pope Street Bridge across the Napa River

December 2013 (38.51117 Degrees, -122.45581 Degrees) Pope Street Bridge

Continuing up the Napa River we arrived at the Pope Street Bridge (21C0109), a three span stone arch bridge on pier walls. I would imagine the spans are nicely balanced to prevent the arching force from pushing over the piers. Not only is each span arched but the bridge is on a vertical curve that peaks in the middle of the bridge.

The Pope Street Bridge is 177 ft long but only 18 ft wide. It was built by R. H. Pithie in 1894 for horse-drawn carriages but it's strong enough to handle the 3000 trucks and cars that drive over it every day (with a sufficiency rating of 50). The bridge was put into the National Register in 1972. The stone came from the Wing Quarry which supplied many of the surviving stone structures in this part of Napa County.

The piers have sharp cutwaters on the upstream side to deflect the rocks and tress that come downstream during floods. The bridge is really in remarkable shape for a 120 year old structure built without any reinforcement. I imagine Napa County does an extra good job of maintaining it. The bridge sits next to Napa Valley College and Stonesbridge Park and so it must be a source of pride to the surrounding community.

Napa County, California Bridges: Pope Street Bridge across the Napa River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Napa County, California Bridges: Zinfandel Lane Bridge across the Napa River

December 2013 (38.49500 Degrees, -122.42583 Degrees) Zinfandel Lane Bridge

The next bridge across the Napa River is the Zinfandel Lane Bridge (21C0002), a two span closed spandrel masonry arch bridge built in 1913. The bridge is composed of two 43 ft long spans and like the other bridges we've recently studied over the Napa River it has only a 19 ft wide deck.

The most interesting thing about this bridge is the elaborate scour protection on the banks, which give this old stone bridge an odd appearance. However, Craig Philpott has some photos of the river flowing at flood stage on the Bridgehunter Website and the concrete revetment is doing a good job of protecting the bridge.

Napa County, California Bridges: Zinfandel Lane Bridge across the Napa River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Napa County, California Bridges: Oakville Cross Road over the Napa River

December 2013 (38.44083 Degrees, -122.39500 Degrees) Oakville Cross Road

The next bridge across the Napa River is the Oakville Cross Road Bridge (21C0069), a two span 'T' girder bridge built in 1922. The bridge is composed of two 45 ft long spans and like yesterday's Oak Knoll Avenue Bridge it has only a 19 ft wide deck. Note that this reinforced concrete bridge is supported by a stone masonry pier. Perhaps the pier was from a previous bridge that was built at this site?

Perhaps because of the narrow width, the unreinforced masonry wall, or the under-reinforced T girders, this bridge has a sufficiency rating of only 7.0. Oakville Cross Road, Oak Knoll Avenue, Trancas Street, etc. are the main east-west corridors across Napa Valley and so they carry quite a bit of traffic.

Napa County, California Bridges: Oakville Cross Road over the Napa River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Napa County, California Bridges: Oak Knoll Avenue Bridge across the Napa River

December 2013 (38.36778 Degrees, -122.30278 Degrees) Oak Knoll Bridge

Immediately west of the Silverado Trail, Oak Knoll Avenue crosses over the Napa River Overflow and the Napa River. I photographed the Napa River Bridge  but I somehow missed the arch and T beam bridges across the Overflow. However, Craig Philpott took a nice photo of the 1910 Stone Arch Bridge (21C0104) for the Bridgehunter Website.

The Oak Knoll Avenue Bridge (21C0067) was built in 1930 over the Napa River. It's a 130 ft long three span T girder bridge with a 61 ft long center span. It's only 19.4 ft wide between the barriers and supported by decorative pier walls and end diaphragm abutments.

Next to the T girder bridge is a little suspension bridge. I assume a farmer owns the land on both sides of the river and finds it convenient to haul goods using a wheel that rides on the cable. Or it could be used for some much different purpose.

Napa County, California Bridges: Oak Knoll Avenue Bridge across the Napa River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Napa County, California Bridges: Soda Creek Pedestrian Bridge

November 2013 (38.50114 Degrees, -122.25770 Degrees) Soda Creek Pedestrian Bridge

North of Trancas Street, the Silverado Trail (State Route 128) is the main route along the east side of Napa Valley. Following it out of town we arrived at a sandwich shop with an old bridge in the picnic area.

The Soda Creek Pedestrian Bridge is a two span stone arch built 100 years ago. It had grass and trees growing from its deck when we visited in November and the creek was dry, but Craig Philpott has a nice photo with the creek overflowing.

Napa County, California Bridges: Trancas Street Bridge across the Napa River

December 2013 (38.32491 Degrees, -122.28426 Degrees)

Traveling west from the Trancas Street Bridge (across Milliken Creek) is a huge vineyard. On the other side is the rather plain-looking Trancas Street Bridge (21C0003) across the Napa River.  It's a three span 'T' girder bridge that was built in 1960.

Today, Napa County is very committed to the production of wine. However, 100 years ago it was more involved in mining. An interesting book, "Mines and Mineral Resources of the Counties of Colusa, Glenn, Lake, Marin, Napa, Solano, Sonoma, and Yolo" was written by Walter Bradley of the California State Mining Bureau and published in 1915. It describes mining operations including the mining of stone from the Wing Quarry, which was used for the construction of the Trancas Street Bridge across Milliken Creek and the old Trancas Street Bridges across the Napa River.

Bradley writes, "The Big Trancas” and “Little Trancas” bridges near Napa, Napa County, were constructed from the light, yellowish to gray, trachytic tuff quarried from the Wing Quarry (Newman) located on the Berryessa road about 6 miles northeast of Napa." 

The Big Trancas Bridge was a three span closed spandrel arch bridge but there's no mention of the single span through truss sitting beside it. The arch bridge was built in 1913 and both bridges were replaced in 1960 by the current 342 ft long by 64 ft wide 'T' girder bridge.

Napa County, California Bridges: Trancas Street Bridge across the Napa River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.