San Marcos Bridge
San Marcos Bridge
Puente San Marcos
Xicotepec de Juárez, Puebla, Mexico
722 feet high / 220 meters high
591 foot span / 180 meter span
Due for completion in 2012, the soaring San Marcos bridge will be the largest and tallest bridge on the final Nuevo Necaxa-Tihuatlán section of the México-Tuxpan highway now under construction. Extending from Mexico City to the Gulf of Mexico, the first and last thirds of the 182 mile (293 km) highway were finished in 2005. The difficulty in completing the highway lies in the central Nuevo Necaxa–Ávila Camacho section that runs for 23 miles (37 kms) along the mountainous San Marcos River gorge. To push the modern carretera through the steep terrain, the engineers will be constructing 9 tunnels and several high bridges. Three will exceed 100 meters including El Zoquita, Sin Nombre I and San Marcos. That total reaches 4 if you include the Texcapa Bridge near Huachinango which is 150 meters high and was completed during the first phase of the highway's construction in 2005.
Curving 722 feet (220 meters) above the San Marcos River, the prestressed concrete beam bridge will have the second highest bridge pier in the world after the Millau Viaduct in France. Rising 732 feet (223 meters) from the top of the foundation to the underside of the beam, pier number 4 will be 148 feet (45 meters) higher than those on either the Longtanhe or Kochertal viaducts in China and Germany. The San Marcos bridge pier is even taller than the road deck height of the bridge due to the top of the foundation being 46 feet (14 meters) below the water level of the San Marcos River.
You can see a construction site video from early 2010 that was taken from pier 2 high up on the south side of the San Marcos River canyon. A crane can be seen down at the river where the record breaking pier 4 will be rising throughout 2010. http://www.youtube.com/watch?v=-UyXbwwasCM&feature=youtube_gdata
Interestingly, the original design for the San Marcos River crossing was for a fin back bridge. A prestressed beam bridge with a highly variable depth of prestressing, the fin back is unique for having the internal cables at their highest as they pass over the piers, enclosed in a wall or “fin” of concrete. The hump-like profile may look similar to a cable stayed or extradosed bridge but the engineering has more in common with a beam bridge. Many consider the lower profile to be more attractive than a conventional prestressed beam bridge. Mexico has two other large fin back bridges including the Texcapa bridge which is also located on the México-Tuxpan highway and the Papagayo bridge located on the México City-Acapulco highway.
The first fin back bridge was built in Nuremberg, Germany for a commuter railway in 1969. In the U.S., the only one is the 1987-built Barton Creek bridge near Austin, Texas with a main span of 340 feet (103.5 mtrs).
Image by SCT.
Image by SCT.
Image by Vicente Gayosso.
Computer drawing by Proin 3D.
For those who might be interested, the list below shows the World's 10 Tallest Bridges as measured from the top of the foundation to the top of the tower. All are suspension or cable stayed bridges.
1. Millau Viaduct, France 336 meters
2. Russky Island Bridge, Russia 320 meters
3. Akashi-Kaikyo Bridge, Japan 300 meters
4. Sutong Bridge, China 300 meters
5. Stonecutters Bridge, China 290 meters
6. Gwangyang Bridge, South Korea 270 meters
7. Jingsha Bridge, China 267 meters
8. Great Belt East Bridge, Denmark 254 meters
9. Edong Yangtze Bridge, China 242.5 meters
10. Mezcala Bridge, Mexico 242 meters
A map of the most difficult stretch of highway between Nuevo Necaxa and Ávila Camacho.
When completed, the México-Tuxpan highway will connect Mexico City with the Gulf of Mexico 182 miles (293 kms) away.
The new carretera will open up new trade routes to the interior of the country as well as Mexico City.
San Marcos Bridge satellite image showing the long and deep gorge of the San Marcos River. The bridge will cross the river about a third of the way down from the top of image.