Yolo County, California Bridges: UC Davis Pedestrian Bridges across Putah Creek (1)

July 2013 (38.53280 Degrees, -121.75553 Degrees) Putah Creek Pedestrian Bridges

Where Putah Creek runs through the University of California at Davis, they have created an arboretum with a variety of vegetation (and bridges) along the Creek. One of their favorite types of pedestrian bridge is an arch made of big Glulam beams supported on abutments that are too close together so they force the beams to bow upward. They have built two of these bridges across Putah Creek on the west side of the arboretum.

In the top photo the deck is built directly on top of the Glulam beams and so the pedestrian has to climb up and down the arch. On the bridge shown below they have built a separate horizontal deck supported by spandrel columns above the arch. This is a nicer but more expensive option since it is really two bridges; the bridge in the top photo supporting a timber girder bridge on columns.

Yolo County, California Bridges: UC Davis Pedestrian Bridges across Putah Creek (1) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Yolo County, California Bridges: I-80 Bridges over Yolo Bypass

July 2013 (38.57056 Degrees, -121.59722 Degrees) I-80 Yolo Causeway

Continuing west on what  is now Interstate 80 we enter the Yolo Bypass (that was previously discussed when we visited the I-5 Bypass Bridge). This large basin fills with water during the winter and prevents flooding of East and West Sacramento. We can see where I-5 and I-80 cross the Bypass in the figure below.

The Yolo Causeway is actually two long viaducts (Yolo Causeway East (22 0045) and Yolo Causeway West (22 0044)) with a short embankment between them. The East Causeway is a 220 span prestressed concrete T girder bridge and the West Causeway is a 72 span prestressed concrete T girder bridge. These bridges were built in 1962.

The Causeway was retrofitted in 1997 with fiber reinforced polymer collars at the connection between the shafts and the shaft extensions. This should allow them to form strong pins during an earthquake that will prevent the connections from breaking. Also, every fifth bent cap had an extension built on the end to connect it to a large diameter shaft. During an earthquake these shafts will prevent the causeway from undergoing large displacements.

Similar to I-5 Bypass Bridge to the north, the I-80 Causeway also has a parallel railroad viaduct. However, these tracks carry Amtrak and Union Pacific freight trains and are in constant use.

Yolo County, California Bridges: I-80 Bridges over Yolo Bypass by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Yolo County, California Bridges: W80-E50 Connector Overcrossing

July 2013 (38.57583 Degrees, -121.56278 Degrees) W80-E50 Connector

Continuing west on US-50 we came to a cast-in-place concrete connector where US-50 connects to I-80. The W80-E50 Connector (22 0141F) is a 14 span (1576 ft long), continuous concrete box girder bridge that was built in 1969. It seems like all the expressways in Northern California were built in the 1960s.

A concrete superstructure provides a more satisfactory way to connect a concrete column since the connection can be made wider and taller, the main reinforcement can be well developed, and joint shear reinforcement can be provided. However, the one-way column flare is less than ideal since it reduces the effective length of the column and can turn it into a shear critical member. This is particularly true for the short columns at the ends of a connector ramp.

Yolo County, California Bridges: W80-E50 Connector Overcrossing by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.