Peru's Bridges: Culvert, Tunnel, or Bridge?

A low-resolution photo taken while leaving Arequipa. But what are we looking at?

We've often discussed whether it's cheaper to build a long trestle structure or a long embankment. Its amazing that an embankment with such steep sides (as shown in the photo) can support a roadway.

I was looking at the book Bridges, Canals, & Tunnels. They showed a 450 ft long timber trestle railroad bridge near Promontory Point, Utah.  It was so flimsy that they covered it with earth after it was built. However, I don't think this embankment has a timber structure underneath.

So is this structure a culvert, a tunnel, or a bridge? I would argue that it is a single span, filled spandrel arch bridge built to allow a grade separation between two highways.

Peru's Bridges: Culvert, Tunnel, or Bridge? by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Peru's Bridges: La Marina Blvd POC

A pretty pedestrian overcrossing (POC) across La Marina Blvd in Arequipa, Peru.

Three reinforced concrete hammerhead bents support two simple-span through-girder superstructures. Small shear keys keep the superstructure from moving transversely. There's a steel stairway at each end to get people on and off the structure.

I like the use of yellow and green paint to give the structure an Art Deco appearance. In the U.S. we seldom paint a concrete structure because of the increased maintenance costs. Maybe the cost of labor is smaller in Peru.

This POC takes pedestrians across a busy street to the east bank of the Rio Chili, which seems like an odd destination (see Google Earth Map). Perhaps its to take kayakers and fishermen safely to the river?

Peru's Bridges: La Marina Blvd POC by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Peru's Bridges: Puente Rio Chili

Its always interesting to study a new bridge. The Puente Rio Chili in Arequipa is a single span reinforced concrete box girder bridge with end-diaphragm abutments; basically a rigid frame. Note how the far abutment is only half covered in cobbles and has no wingwalls (it looks like they are about to be built) while the closer abutment is covered in sand and gravel with wingwalls extending along it's sides. Probably they were just completing the far abutment. There's a notch in the deck/backwall of the near abutment for an approach slab or roadway.

The bridge is about 200 ft long and 60 ft wide; a four lane bridge with a short median barrier cast in the middle and steel guardrails along the deck overhangs. Even at $50 per square foot, this bridge would have cost over half a million U. S. dollars. It looks like a modern highway bridge, but it doesn't connect to a major road or highway. There are just some farms and what looks like storage facilities on the other side of the river. It seems like a very expensive bridge just to be used by a farmer to bring his crops to market.

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

Peru's Bridges: Puente Bajo Grau (2)

Here is another view (looking to the south) of Puente Bajo Grau. The haunch looks much bigger on the right side of the bridge. I wonder if there's a moment connection on the west side and its free to move on the east side?

I guess I didn't take this photo since I'm standing with my earthquake buddy Bill Byers in the picture. Bill was the chief bridge engineer of the Burlington Northern Railroad for many years, he was quite active, and helped develop the seismic criteria for AREMA, the railway engineering manual.

Puente Bajo Grau crosses the Rio Chili at a large skew as the road goes to the northwest and forms a triangle with La Marina Blvd and Ejercito Avenue (see Google Earth Map below).

Peru's Bridges: Puente Bajo Grau (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Peru's Bridges: Puente Bajo Grau (1)

I'm standing on La Marina Blvd. looking north at Puente Bajo Grau, Puente Miguel Grau, and the Nevado Chachani Volcano. The statue of Miguel Grau can be seen just above Puente Bajo Grau's west abutment.

Puente Bajo Grau is another single span, reinforced concrete, haunched girder bridge. It's also another bridge with a water main along the exterior girder. The bridge has end diaphragm abutments, short wingwalls, and steel rails.

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

Peru's Bridges: Puente San Martin

Between Puente Bolivar and Puente Quinones is Puente San Martin. I decided to show this bridge, not because it is particularly interesting, but because two of the volcanoes that surround Arequipa are in the photo.

On the right is Volcan Misti with a conical shape as fine as Mt. Fuji. On the left is the Nevado Chachani Volcano with a complicated structure that includes several domes. Both volcanoes are about 6000 meters tall. Neither have erupted in a long time, but both are considered active.

San Martin is a single span, reinforced concrete, haunched girder bridge carrying two lanes of traffic. If you look closely, you can see a water main being carried along the exterior girder, which ruins the appearance of the haunched girder.

Jose de San Martin was an Argentine general who helped liberate (along with Simon Bolivar) South America from Spain. San Martin Road goes east from Freedom of Expression Park (Parque Libertad de Expresion) across the Rio Chili, across La Marina Blvd, around Martinez Circle (Ovalo Martinez), to the Southern Institute (Instituto del Sur). Arequipa is called the 'White City' because of all the white rock that has been quarried from the surrounding mountains for churches and government buildings.

The Rio Chili is crossed by a variety of interesting bridges from it's source in the Cordillera Occidental Mountain Range until it empties into the Pacific at the Valle de Quilca. Unfortunately, I've only photographed a few bridges in the city. Perhaps one day, I can make a survey of all the interesting bridges in Peru or at least, all the bridges that cross the Rio Chili.

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

Peru's Bridges: Puente Quinones and Puente Consuelo (2)

A look at the west abutment and west retaining walls for Puente Quinones and Puente Consuelo (along the Rio Chili). Note how this structure is much more detailed than most bridges or even buildings. The retaining wall is locked into the rock like a dam and has folds and ridges that must have taken a lot of work to form.

A pedestrian overcrossing (POC) was built over Abelardo Quinones Street. The retaining walls reach up to support the blue, open, four sided structure.

I guess I find this bridge to be overly elaborate. I prefer the structural simplicity of Puente Bolivar. Still, it's an interesting experiment, and better than a lot of unimaginatively-designed bridges.

Peru's Bridges: Puente Quinones and Puentes Consuelo (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Peru's Bridges: Puente Quinones and Puente Consuelo (1)

After spending a week looking at older bridges, we'll look at a few newer bridges before leaving Arequipa.

Puente Quinones and Puente Consuelo are a  pair of bridges that connect Abelardo Quinones to Consuelo Streets across the Rio Chili with ramps on and off La Marina Blvd.

The bridges were being completed when I took this photo. It's interesting how highly contoured the soffit is on these bridges. In this photo (looking south at La Marina Blvd) instead of a typical column flare, the soffit dips to take the shape of the column. The bridges remind me of sculptures by Naum Gabo. Just another sign of Arequipa's affinity for all things modern.

I'm surprised by the low vertical clearance of these bridges. I would imagine they would be hit by trucks carrying equipment, unless the city has an effective way of screening traffic onto La Marina Blvd.

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

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.