Viaduct Beltran is an odd four-span bridge. The first pier is supported at the bottom of a ravine, making it many times taller than if it had been moved farther or closer to the first abutment. The second pier is actually two bents placed twenty feet apart. My feeling is that the superstructure is balanced on the two bents, but the first abutment was too far away so they had to support it on the long first pier.
I imagine the superstructure was segmentally constructed. It's a haunched, prestressed concrete, box girder bridge. The superstructure is continuous, but it just sits on the piers (with a downward projecting element between transverse shear keys).
We'll take another look at this interesting bridge tomorrow and I welcome your thoughts or any information you may have on it. I wonder how long the spans are and how tall the first pier is?
Mexico's Bridges: Viaduct Beltran (1) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.