Sunday, May 2, 2010

Movable Bridges - Rio Vista Bridge

The Rio Vista Bridge is actually called the Sacramento River Bridge, but so is every other bridge over the Sacramento River (it's also called the Helene Madere Memorial Bridge). It's a vertical lift bridge built in 1960 that provides 270 ft of channel width and 146 ft of vertical clearance between the towers.

Vertical lift bridges have pulleys at the top of the towers. Cables are connected to the lift span and go up and over the pulleys where they are connected to counterweights hanging from the towers. The machinery  for lifting and lowering the span are mounted at the top of each tower. There is also equipment to keep the span level while it is lifted. The operator's house can be seen at the bottom of the far tower.

Although this bridge looks to be in a rural location, traffic can get backed up for miles on State Route 12 whenever the bridge is opened. We'll take a closer look at this bridge tomorrow.
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