Inca rope bridge

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Rope bridge
Newly reconstructed, the last of its kind
Ancestor	None - this is a foundational type
Related	None
Descendant	Simple suspension bridge
Carries	Pedestrians, livestock
Span range	short
Material	Grass or other fiber rope, appropriate decking material
Movable	No
Design effort	low
Falsework required	No

Inca Rope bridges were simple suspension bridges over canyons and gorges 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 innovation in engineering. They were frequently used by Chasqui runners delivering messages throughout the Inca Empire.

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.

Contents 1 Renewing the last bridge 2 External links 3 See also 4 References

[edit] 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 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 rebuilding.

The old bridge sags (Slide show)	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.

[edit] External links

• The Last Inca Suspension Bridge: A Photo Album (various images of amazing Inca Bridges and pathways, old and new.)
• Boston University, Inca Bridge to the past

[edit] See also

• Simple suspension bridge - the inca rope bridge built with modern materials and structural refinements.
• Suspension bridge - modern suspended-deck type
• Carrick-a-Rede Rope Bridge

[edit] References

• Incas: Lords of Gold and Glory, 1992, Virginia: Time-Life Books.

• 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. [Shows the bridge at Huinchiri and predicts the art of building it will be lost within another generation; fortunately, this prediction has proven untrue, and ethnic/adventure tourism may help save this bridge for posterity.]

• 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. For more information on the documentary film, contact llactaNØ•SPAMmanta@hotmail.com (remove NØ•SPAM to decode address)

• 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.

• Roca Basadre, David and Coaguila, Jorge, eds., 2001, Cañon delApurimac, La Ruta Sagrada del Dios Hablador: Lima, Empresa Editora ElComercio, S.A., 78 p.

• Secrets of Lost Empires: Inca, 1995, NOVA program, available on video.

• Squier, Ephraim George, 1877, Peru: Incidents of Travel and Exploration in the Land of the Incas: New York, Harper Bros., 577 p.

• Von Hagen, Victor, 1955, Highway of the Sun: New York, Duell, Sloan and Pearce, 120 p.

• Chmielinski, Piotr, 1987, Kayaking the Amazon: National Geographic Magazine, v. 171, n. 4, p. 460 - 473.

• 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)