Inca rope bridge

BridgeTypePix
type_name = Inca rope bridge


image_title = Newly reconstructed, the last of its kind
sibling_names = None
descendent_names = Simple suspension bridge
ancestor_names = Rope bridge
carries = Pedestrians, livestock
span_range = Short
material = Grass or other fiber rope, appropriate decking material
movable = No
design = Low
falsework = No

Inca rope bridges were simple suspension bridges over canyons and gorges ("pongos") to provide access for the Inca Empire. Bridges of this type were suitable for use since the Inca people did not use wheeled transport - traffic was limited to pedestrians and livestock. These bridges were an intrinsic part on the Inca road system and are an excellent example of Inca innovationFact|date=February 2008 in engineering. They were frequently used by Chasqui runners delivering messages throughout the Inca EmpireFact|date=March 2007.

The construction of these bridges amounted to a pair of stone anchors on each side of the canyon with massive cables of woven ichu grass linking these two pylons together. Adding to this construction, two additional cables acted as guardrails. The cables which supported the foot-path were reinforced with plaited branches. This multi-structure system made these bridges strong enough to even carry the Spaniards while riding horses after they arrived. However, these massive bridges were so heavy that they tended to sag in the middle, and this caused them to sway in high winds.

Part of the bridge's strength and reliability came from the fact that each cable was replaced every year by local villagers as part of their mita public service or obligation. In some instances, these local peasants had the sole task of maintaining and repairing these bridges so that the Inca highways or road systems could continue to function.

The greatest bridges of this kind resided in the Apurimac Canyon along the main road north from Cuzco. These bridges spread in length across the 220 feet (67 m) canyon and are 118 feet (36 m) above the river.

Renewing the last bridge

After a full year of use the last Inca grass-rope bridge sags and must be replaced for safety. Even though there is a modern bridge nearby, the folk in the region keep the ancient tradition and skills alive by renewing the bridge. Several family groups have each prepared a number of grass-ropes to be formed into cables at the site, others have prepared mats for decking, and the reconstruction is a communal effort. In ancient times the effort would have been a form of tax, with participants coerced to perform the rebuilding; nowadays the builders have indicated that effort is performed to honor their ancestors and the Pachamama (Earth Mother). The event has also been supported by video productions for Nova and the BBC and is becoming a minor tourist attraction, with some small tolls charged for tourists to use the road during the festival to walk the newly completed bridge. There is, however, no consistent or guaranteed support for these efforts and tourism remains a relatively minor motivation for the bridge rebuildingFact|date=March 2007.

The old bridge sags
()


Notice how much less the new bridge sags


Builders gather during the renewal


Preparing side lashings


Main cable and hand-ropes are in place


Lashing the hand-ropes to the main side cables.


Trimmed mat rolls form the bridge deck.


The new bridge is now complete and in use.


Bridge in use during the rainy season.

ee also

* Simple suspension bridge - the Inca rope bridge built with modern materials and structural refinements
* Suspension bridge - modern suspended-deck type
* The Inca Bridge - rope bridge, secret entrance to Machu Picchu
* The Carrick-a-Rede Rope Bridge - a rope suspension bridge in Northern Ireland

References

; Sources consulted

* Chmielinski, Piotr (1987). "Kayaking the Amazon". National Geographic Magazine, v. 171, n. 4, p. 460-473.
* Finch, Ric (2002). "Keshwa Chaca: Straw Bridge of the Incas". Ithaca, N.Y.: South American Explorer, n. 69, fall/winter 2002, p. 6-13. – Copies of this issue may still be available for purchase from the South American Explorer.
* Gade, D. W. (1972). "Bridge types in the central Andes". Annals of the Association of American Geographers, v. 62 (1), p. 94-109. – Showed the bridge at Huinchiri and predicted the art of building it would be lost within another generation, which proved untrue.
* Hurtado, Ursula (pub. date unknown). "Q'eshwachaka: El Puente Dorado". Credibank (magazine published by Credibank in Peru), p. 22-23. – Describes the documentary film directed by Jorge Carmona.
* Malaga Miglio, Patricia, and Gutierrez, Alberto (pub. date unknown). "Qishwachaca". Rumbos (magazine published in Peru), p. 30-34.
* McIntyre, Loren (1973). "The Lost Empire of the Incas". National Geographic Magazine, v. 144, n. 6, p. 729-787.
* McIntyre, Loren (1975). "The Incredible Incas and Their Timeless Land". Washington D.C.: National Geographic Society, 199 p.
* Nova (1995). "Secrets of Lost Empires: Inca" (1995). PBS TV program, available on video.
* Roca Basadre, David, and Coaguila, Jorge, eds. (2001). "Cañon delApurimac, La Ruta Sagrada del Dios Hablador". Lima: Empresa Editora ElComercio, 78 p.
* Squier, Ephraim George (1877). "Peru: Incidents of Travel and Exploration in the Land of the Incas". New York: Harper Bros., 577 p.
* Time-Life Books (1992). "Incas: Lords of Gold and Glory". Lost civilizations. Alexandria, Va: Time-Life Books.
* Von Hagen, Victor (1955). "Highway of the Sun". New York: Duell, Sloan and Pearce, 120 p.
* Wilder, Thornton (1927). "The Bridge of San Luis Rey". Grosset & Dunlap, Pubs., 235 p. – Fictional account of the fall of a rope bridge with loss of life.

; Endnotes

External links

* [http://www.rutahsa.com/k-chaca.html The Last Inca Suspension Bridge: A Photo Album] (various images of Inca Bridges and pathways, old and new.)
* [http://www.bu.edu/bridge/archive/2003/03-21/bridge.html Boston University, Inca Bridge to the past]
* [http://www.loc.gov/today/cyberlc/feature_wdesc.php?rec=3839 Library of Congress lecture on Inca bridges]