Peru's Bridges: Puente Bolivar (4)

One last photo of Puente Bolivar. There's something strange about such a long viaduct that carries only a single lane of traffic. It's as if each car was a tiny train on its long trip above the valley floor.

Perhaps the City of Arequipa just needed an excuse to keep the bridge in service. There are alternative routes half a mile to the north and south. Also, there are wide sidewalks on both sides of the deck, so the bridge's main purpose may be as a pedestrian overcrossing.

I was looking through the blogs and websites for information about Puente Bolivar and I found a comment from a Peruvian that Gustave Eiffel hadn't really designed this bridge. According to the writer, an architect had done some research and it was just a myth!

Based on its appearance, I find it hard to say whether Puente Bolivar is the work of Gustave Eiffel. Ponte Maria Pia and the Garabit Viaduct are magnificent structures that look like the Eiffel Tower turned into bridges (see David Billington's The Tower and The Bridge). They don't seem to have anything in common with this rather plain structure. Ponte Internationale and the Rouzat Viaduct have interesting superstructures rather than the rather plain triangular truss elements on Puente Bolivar. Still, there is something evocative of Eiffel in this structure. I just don't think it's one of his major works.

Peru's Bridges: Puente Bolivar (4) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Peru's Bridges: Puente Bolivar (3)

Another view of Gustave Eiffel's Puente Bolivar (Puente de Fierro). This bridge was built out of little more than small angles, rods, and plates. It was designed by Eiffel and the plans and parts were sent from Europe to be assembled at the site. It's hard to imagine that this delicate structure ever supported a steam locomotive.

The towers are bolted to stone masonry piers. Diagonal elements provide lateral stability to the four tower legs. Floor beams are at each vertical member and support a concrete deck. I like the lace-like railing on the deck. I wonder if it was part of the original structure or if it was added later?

It seems strange to have such a long viaduct just to cross the Rio Chili. Perhaps it was economical to build a 500 meter long viaduct so that the track could maintain it's grade across the valley. In the map below, we can see to the east of the bridge an railroad yard and train station whose tracks used to go onto the bridge.

Peru's Bridges: Puente Bolivar (3) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Peru's Bridges: Puente Bolivar (2)

Another view of Gustave Eiffel's Bolivar Bridge, popularly known as Puente de Fierro (the Iron Bridge).

I like the pretty neighborhoods that the viaduct goes through with their mix of  Spanish colonial and flat-roof modern homes. The modernist (mid 20th century) style must have made quite an impression on Peruvians.

I wonder though what it's like to have a viaduct in front of your house?

I noticed that some of the squares under the towers have been turned into flower gardens. That they maintain and continue to use this 120 year old structure suggests that the people in Arequipa are proud to have a bridge designed by Eiffel in their city.

Peru's Bridges: Puente Bolivar by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Peru's Bridges: Puente Bolivar (1)

Another old bridge in Arequipa, which was designed by Gustave Eiffel in 1882. Although it's nice, it is not one of his more beautiful structures.

Puente Bolivar is a 488 meter long iron viaduct. Most of the viaduct is composed of four legged towers with little deck truss spans between the towers. A long span over the Rio Chili looks very much like a Fink truss, which was designed by Albert Fink of Germany in the 1860's according to the excellent Wikipedia entry on truss bridges.

In this type of truss, we can see diagonal tension members being used to support vertical elements at the eighth points of the span. I like how we can clearly see the forces being carried on this type of truss.

At the time it was built, I believe this bridge was used to carry a  railroad on it's way to Cuzco. Now its used to carry a single lane of vehicles west into the city. We'll take another look at this interesting structure tomorrow.

Peru's Bridges: Puente Bolivar (1) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Arch Bridges: Alsea Bay Bridge

Oregon is fortunate to have many lovely bays along its coast. It is also fortunate to have had Conde B McCullough as the chief bridge engineer when US101 was being constructed during the Great Depression. As a result, there are a dozen beautiful bridges crossing the rivers and bays along Oregon's coast.

However, when the existing Alsea Bay Bridge began to deteriorate due to the saltwater environment, an equally handsome and innovative bridge, designed by Semyon Treygor at HNTB was built in 1991. The main span is a 450 foot long reinforced concrete through-arch with long approaches supported on 'Y' shaped piers. The replacement bridge was built with a thicker concrete cover to resist the salt-water spray. All that is left of Conde McCullough's original bridge are the concrete viewing platforms at each end of the new bridge.

Arch Bridges: Alsea Bay Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution 3.0 United States License.