Monday, September 29, 2014

Stanislaus County, California Bridges: Seventh Street Bridge across the Tuolumne River (2)

September 2014 (37.62694 Degrees, -120.99389 Degrees) Seventh Street Bridge
The Seventh Street Bridge (38C0023) is a 14 span, 1170 ft long closed spandrel arch that was built in 1916. It's the design of John B. Leonard who specialized in innovative concrete bridges. This structure is composed of steel truss elements encased in wet concrete. Leonard built several of them in California but this was the most impressive. The steel truss was supposed to take the place of reinforcement, but it's missing the perimeter shear and confinement steel. Anyway, the bridge appears to be having some structural problems where the truss elements meet at midspan. 
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Stanislaus County, California Bridges: Seventh Street Bridge across the Tuolumne River (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Sunday, September 28, 2014

Stanislaus County, California Bridges: Seventh Street Bridge across the Tuolumne River (1)

September 2014 (37.62609, -120.99367) Seventh Street Bridge
We're going to spend the next few weeks following the Tuolumne River into the Sierra Mountains. We start our journey in the City of Modesto, which  appeared surprisingly depressed as I began photographing the bridges that crossed the Tuolumne in Modesto. I had parked my big Ford pickup on the shoulder of 7th Street, but so many homeless people were walking along the shoulder that I felt bad that my parked truck was pushing them into the road.

The 'Lion Bridge' is a long arch bridge that carries Seventh Street across the Tuolumne River in downtown Modesto. It is another of the odd, original bridges that were designed by John B. Leonard at the beginning of the 20th century. This is one of four 'canticrete' bridges he designed that are steel trusses encased in concrete.

We are currently screening bridges for a new retrofit program in California. One of the screeners said that concrete encased in steel performs well while steel encased in concrete performs poorly. We'll take a closer look at this bridge as we ponder his words tomorrow.
Creative Commons License
Stanislaus County, California Bridges: Seventh Street Bridge across the Tuolumne River (1) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.