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Wednesday, May 13, 2015

Inca walkway .... 90ft long Keshwa Chaca made with 'ichu' grass

Civilisations developed around water – near the vicinity of rivers, lakes and other water bodies which provided mankind ample of edible things and assisted cultivation.  But presence of water presented a problem as well – men had to move from one place to another and the waterbody will have to be crossed – only then mankind could communicate to the outside World – trade their merchandise, get the necessities from outside World.    The last remaining Inca rope bridge -  the Q'eswachaka, (also spelled Keshwa Chaca) spans the Apurimac River near Huinchiri, Peru, in the Province of Canas ~and this post is about this bridge.

The Inca Empire  was the largest empire in pre-Columbian America. The administrative, political, and military centre of the empire was located in Cusco in modern-day Peru. The Inca civilization arose from the highlands of Peru sometime in the early 13th century.   The official language of the empire was Quechua, although hundreds of local languages and dialects of Quechua were spoken.   The Incas never invented the wheel, never figured out the arch, and never discovered iron. But they were masters of fibre. They built ships out of fibre; made armour out of fibre.  Their greatest weapon, the sling, was woven from fibre  and was powerful enough to split a steel sword.  So when it came to solving a problem like how to get people and goods across the steep gorges of the Andes, it was only natural that they would think about the problem in terms of fibre. 

Five centuries ago, the Andes were strung with suspension bridges. By some estimates there were as many as 200 of them, braided from nothing more than twisted mountain grass and other vegetation, with cables sometimes as thick as a human torso. Three hundred years before Europe saw its first suspension bridge, the Incas were spanning longer distances and deeper gorges than anything that the best European engineers, working with stone, were capable of.   Over the centuries, the empire’s grass bridges gradually gave way, and were replaced with more conventional works of modern engineering. The most famous Incan bridge—the 148-footer immortalized by Thornton Wilder in The Bridge of San Luis Rey—lasted until the 19th century, but it too eventually collapsed. Today, there is just one Incan grass bridge left, the keshwa chaca, a sagging 90-foot span that stretches between two sides of a steep gorge, near Huinchiri, Peru. According to locals, it has been there for at least 500 years.

In  the desolate, 2-mile-high Andean altiplano, little else grows besides ichu, a tall needly grass that covers the mountainsides, feeds the llamas, and is the raw material from which the keshwa chaca is constructed. The walkway of the keshwa chaca consists of four parallel ropes with a mat of small twigs laid across, anchored at both ends by a platform of larger rocks. Two other thick ropes acts as arm-rails, and are connected to the walkway with a cobweb of smaller cord. Despite its seemingly fragile materials, modern load testing has found that in peak condition, the keshwa chaca can support the weight of 56 people spread our evenly across its length. 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 public service or obligation.

Local villagers risk their lives to rebuild ancient Inca walkway 100ft above a ravine using handmade grass ropes ~and thus, incredibly, the 90ft long Keshwa Chaca remains thanks to local villagers who rebuild the bridge each year using the same techniques as their Inca ancestors.  According to Daily Mail, it  takes three days to rebuild the Keshwa Chaca, which is done in June every year.  The raw material is 'ichu', a type of grass common on the sparse mountainsides of the Andes, which is braided into rope for the bridge. Each household in the four nearby villages is responsible for bringing 90 feet of braided grass rope. 

The bridge consists of five parallel 'ichu' ropes, which are braided to be about four inches thick, fastened at stone platforms on each side of the gorge. The floor or walkway is of small sticks and canes, fastened transversely with raw-hide strings, and two thick ropes are tied between the platforms as armrails. After the bridge has been built, it is left to disintegrate before being constructed again the next year.  Although it may look brittle, it has been proven to support the weight of 56 people standing across the walkway.

A real engineering marvel !!

With regards – S. Sampathkumar
28th Apr 2015.

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