Marin County, California Bridges: Alexander Avenue Bridge across the Larkspur - Corte Madera Path

December 2015 (37.93001, -122.53203) Alexander Avenue Bridge

The Alexander Avenue Bridge (27C0150) has a short pony arch main span and long slab approach spans. It was designed and built in 1925 by Larkspur city engineer John Oglesby. It originally crossed over the Northwestern Pacific Railroad, which was eventually turned into a bicycle and foot path.

The bridge was listed as a historic place in 1984 but it was so deteriorated and seismically unsafe that the city considered replacing it. Eventually it was rehabilitated and retrofitted by the Hanna Group in 2012 at a cost of $1.4 million (paid for with state and federal funds). Work was completed in 2014 by the Ghilotti Construction Co.

The bridge looks a little odd with brand new columns supporting an aged superstructure and with the tall columns and tall arches supporting such a short span. Also the steep approaches look a little funny. I guess all of these peculiarities make it into a unique and interesting bridge.

Marin County, California Bridges: Alexander Avenue Bridge across the Larkspur - Corte Madera Path by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Sichuan, China's Bridges: An Zhou Bridge (3)

July 2008 (31.633 Degrees, 104.439 Degrees)

A view of the bridge members under the deck that had enough shear cracks that it was decided to reduce traffic onto the bridge. It's just south of the Beichuan, which was destroyed by landslides. The survivors had been evacuated and the area was closed to visitors (such as us).

Sichuan, China's Bridges: An Zhou Bridge (3) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License.

SIchuan, China's Bridges: An Zhou Bridge (2)

July 2008 (31.633 Degrees, 104.439 Degrees) An Zhou Bridge

A look from the deck of the An Zhou Bridge. This landscape is pretty dramatic, with the Tibetan Pleateau rising in the distance, which unfortunately is the cause of the many earthquakes in the area. The government was spending a lot of money on infrastructure at the time of the earthquake and much of it had to be rebuilt.

Sichuan, China's Bridges: An Zhou Bridge (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License.

Sichuan, China's Bridges: An Zhou Bridge (1)

July 2008 (31.632 Degrees, 104.439 Degrees) An Zhou Bridge

Traveling north from Chengdu, we looked at bridges damaged during the May 12, 2008 Wenchuan Earthquake. The An Zhou Bridge is about 100 miles north of Chengdu, in the foothills between the Sichuan Plain and the Tibetan Plateau. It's a pretty two span pony arch and the lack of cross-bracing on top may have allowed it to move enough to damage the stiffer elements under the deck. The bridge was partially closed, by putting railing partially across the deck, perhaps to limit the size of vehicles and their speed.

Sichuan, China's Bridges: An Zhou Bridge (1) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License.

Japan's Bridges: Nagamachi Railway Bridges in Miyagi Prefecture (2)

June 2011 (38.2336 Degrees, 140.8891 Degrees) Nagamachi Bridges

A closer look (from the other side) at the Nagamachi Railway Bridges. A reinforced concrete arch rib along each side supports hangers that go through the ties to carry the floor beams. The three bridges are about 44 meters long and have concrete shoes that rest on the abutment seats. The bridges have no cross-bracing, which makes them concrete pony arches.

Japan's Bridges: Nagamachi Railway Bridges in Miyagi Prefecture (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.