Bridges of Mexico: The Hermanos Serdán Blvd. Bicycle Viaduct in Puebla City

September 2017 (19.09170, -98.2296) Viaducto de Bicicleta de Puebla Ciudad

On September 24th I went with the Geotechnical Extreme Events Reconnaissance (GEER) Team to investigate the September 19th Mexico Earthquake. The group was mostly interested in looking at landslides and soil settlement but I did manage to photograph a few bridges.

Puebla is a modern city and a showcase for Mexican culture. Among its many attractions is an elevated viaduct for bicyclists (and pedestrians) in the median of Hermanos Serdan Blvd. This structure is 7.6 km long and just one of several bike paths in the city. The photos above show the elevated bicycle roundabout at Hermanos Serdan Blvd and Avenue Francisco Villa in Sanctorum.

What's particularly nice about the viaduct is the diversity of structures. The roundabout is a steel truss on steel truss piers but there are also cable-stayed structures (shown above), long stretches of steel stringers on oddly crossed steel piers (shown below), as well as arches (see bottom photo). The one unifying feature is that all the structures are steel and they're all painted white. 

In the next couple of months we'll look at new and old bridge structures in Puebla, Morales, and Mexico City that I photographed between stops to study earthquake damage. Interested readers can also see a similar set of photos that I took following the 2003 Colima, Mexico Earthquake.

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Bridges of Lyon, France: Passerelle de la Paix across the Rhone River

September 2016 (45.7868 degrees, 4.8545 degrees) Passerelle de la Paix

A few hundred yards downstream from the Viaduc SNCF is the Passerelle de la Paix (Footbridge of Peace). The bridge connects Cite Internationale (east of the Rhone) to Saint-Clair (west of the Rhone). The idea of a peace bridge was to bring intercultural harmony between the two communities since Cite Internationale is French and Saint Clair has a large immigrant population.

The bridge project was first proposed by the Metropolis of Lyon (Grand Lyon) in 1994. A design competition was held and eventually won in 2009 by Dietmar Feichtinger (Architects) and Schlaich, Bergermann, and Partner (Engineers). Construction began in 2012 and the bridge opened in 2014.

The 220 m (710 ft) long bridge is composed of two cantilever space truss sections. The bridge supports a timber deck on the top and another timber deck to the side with an asymmetric tubular steel structure. The two decks meet in the middle to form an 8 meter (26 ft) wide public space.

The foundations were constructed at each riverbank while the bridge was being assembled offsite. Then it was brought onsite by two barges and set in place (see photo below). Note the suspension structure that was used to support the bridge before it was placed on the foundations (photo below by Michael Zimmerman).

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Mexico's Bridges: Puente El Tapon

Continuing north from Viaduct Beltran on Route 54D across a narrow ravine on the one span El Tapon Bridge. This is another of those reinforced concrete slabs supported on a metal understructure like we saw on my blog of November 16th. That blog received an interesting comment from Norrin, who said that these truss-like structures haven't performed too well and have even failed.

This bridge reminds me of a prefabricated bridge system like the old Bailey Bridges that could be easily transported and set up in the field. At Caltrans we often use the undercarriages of old railroad cars as temporary bridges. Maybe this system is similar. It looks like it could be used as falsework to support bridge forms when pouring concrete superstructures.

Note the PVC pipe sticking out of the concrete barrier rail. This must be the deck drainage system to prevent the bridge from carrying too much water and possibly hydroplaning vehicles. Usually, we drain the deck with ducts that carry the water through the columns, which is a pain since the columns are already stuffed with reinforcement. Also, the ducts are always getting filled with debris and are hard to clean.

The truck that we see crossing the bridge has a tandem trailer (illegal in California) and it's carrying what looks like an heavy load of bags of cement and rebar cages. This suggests that at least this single-span bridge with its odd understructure was well-designed.

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

Mexico's Bridges: Overcrossing near Tonila

Continuing north on Route 54D toward Guadalajara, the road goes through a series of cuts in the mountains. Driving through one of these cuts, I got my first glimpse of a kind of bridge I've never seen before.

Under the deck of a reinforced concrete single span overcrossing (a bridge over the highway) is what I would call a structural steel space truss. It's made up of eight-legged elements connecting the concrete slab to longitudinal and transverse steel elements. Apparently, these thin elements are strong enough to increase the bending resistance of this structure.

This type of structure is apparently very popular in Colima. There is a water main supported by a similar structure 140 ft away, and single span and two span bridge undercrossings (a bridge carrying the highway) a few miles to the north.

Mexico's Bridges: Overcrossing near Tonila by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.