The techniques utilized in the construction of the structure were applications of known Maya technology. The use of composite stone and cast-in-place concrete for tall structures was common in Maya engineering. The use of high-strength henequen rope by the Maya has been well documented by archaeologists, and the application of the Maya arch is found in the majority of Maya structures. This lone example of a long-span bridge in the Maya world can be explained by the lack of rivers and surface waters in the northern Yucatán. However, suspension bridges of shorter spans, as we have seen, have degraded and are gone forever. The concept of this landmark bridge structure provides a logical solution to the question of how this lively urban center could operate on a year-round basis.
Digital Tools and Proof of Reconstruction of Maya Technology
The initial computer applications for the reconstruction of the Maya suspension bridge were initiated in 1992. Advances in digital tools have increased exponentially since that time. The original analysis was reviewed using high-speed digital computers in 2006 by the international engineering firm of Ove Arup. The analysis was part of a television presentation for the History Channel. The structural design passed all the requisite tests of engineering stability. Furthermore, a rigorous computer analysis of the bridge structure was carried out by Dr. Horacio Ramirez de Alba from the University of Mexico and was published in the technical journal CIENCIA ergo sum.
Figure 10-11: Rendering of Maya bridge at Yaxchilan. Author’s image.
The discovery and reconstruction of the Maya Bridge was published in Civil Engineering Magazine in April. 1995 and National Geographic Magazine in October 1995. After the publishing of the discovery, interest increased in the scientific community. In 2006, the History Channel produced an episode relating to the Maya bridge. In preparation for this production, new computer-generated graphics were prepared. The original computer graphics of the structure had become outmoded, and new computer software technology was used to regenerate high-definition graphics for the reconstruction of the bridge and develop a three-dimensional computer fly-through of the city of Yaxchilan and its bridge.
This reconstruction of Maya innovation would not have been possible without the use of digital tools and computer simulation, and the modeling of engineering creativity. This expansion of the capabilities of digital tools has enabled practitioners to leap forward in the investigation and analysis of archaeo-engineering issues.
The Longest Bridge in the Ancient World
The first civil engineers in the Americas archived a historical technological feat by combining advanced materials of construction with proven structural design skills and creative construction techniques. The breathtaking structure spanning the Usumacinta River solved the critical need for a lifeline for the city of Yaxchilan. This engineering project may have been the most creative and dramatic project ever carried out by Maya technology. This bridge has been awarded its rightful place in world engineering history.
Engineering historian Dr. Neal FitzSimons researched and developed a chronological record reflecting the construction of bridges throughout history. Dr. FitzSimons developed a chart of the longest known bridges in the world, starting in 600 BC with a 69-foot-long bridge built by the Etruscans and extending to the completion of the Brooklyn Bridge in 1883. The list includes the Maya suspension bridge over the Usumacinta River. A review of Dr. FitzSimons’s records indicates that the Maya bridge at Yaxchilan, constructed in the seventh century, was the longest bridge in the world until 1377, when Italians built a fortified stone bridge with a span of 72 meters over the Adda River at Trezzo, Italy.
The Maya solved a critical transportation issue for a city and found a place in world engineering history. The bridge at Yaxchilan was the longest bridge in the world from AD 700 to 1377, a period of 677 years. Though the superstructure of the bridge at Yaxchilan has crumbled during the last millennium and the remaining piers are a ghost of their past, this bridge has secured its place in history.
11
Maya on the Move
Through the jungle and over the seas, Maya transportation technology systems enabled the movement of trade goods and materials over the roads of the Maya domain and to distant ports in the seas engulfing the Yucatán Peninsula. The transport systems of the Maya operated on raw manpower for transporting material between cities, building construction projects, and powering their seagoing cargo vessels. The lack of indigenous working animals in the Americas was overcome by Maya creativity. They innovatively applied manpower as an efficient substitute for animal power. Ingenious methods of manpowered transport systems on land and at sea enabled the Maya civilization to succeed and prosper during the Classic Period and beyond the conquest.
Death in the Pleistocene: Mother Nature’s Practical Joke
At the end of the Pleistocene Era (2,000,000 to 10,000 years ago), North and South America were populated with a wide variety of animals that have now gone extinct. The majority of the now-vanished species were large mammals, known as megafauna. The extinct animals were massive beasts, including the 20,000-pound mastodon, 6-foot-tall giant ground sloths, sabre-tooth tigers, 10-foot-tall short faced bear, and a range of other exotic animals. They included creatures that originally evolved in North America including equus, the modern horse, and camelops, the modern camel. The herds of these species had split into two groups. The Northern band migrated west across the Bering land bridge and the other traveled south into North America. The northern bands of horses and camels migrated to Siberia and then across Asia. These animals became domesticated and supplied the power and transportation for all the great civilizations of Asia, Africa, and Europe. The southern herds remained in North America and were victims of mass extinction at the end of the last Ice Age. Their demise deprived the Americas of beasts of burden. The majority of this extinction had occurred when man migrated to the continent. After the extinction, a great number of megafauna, defined as any animal more than 100 pounds in weight, survived to the 21st century. These include deer, bears, cougars, moose, alligators, and humans. The largest extant American land animal is the bison, which can weigh up to 2,200 pounds.
Humans migrating to the American continent found poor candidates for beasts of burden. It is interesting to point out the irony in the humor of Mother Nature. She sent herds of indigenous horses and camels from the Americans into Asia, where they served as the power source for the great conquering empires, and then, in the Americas, she extinguished the life of these same animals. When next seen in the Americas, the horse had a Spanish conquistador on its back.
The Classic Maya never became aware of Mother Nature’s practical joke played on the Americas. The Holocene extinction had erased all of the animals that could potentially be domesticated and used as beasts of burden. The Maya were not aware of the very existence of such an animal. Wild animals lack the traits of trustworthiness and mild temper that characterize the true domesticated working animal, and they cannot be tamed. However, the Maya were successful in the domestication of certain animals, including the dog, and animals with agriculture applications such as turkeys, ducks, and stingless bee.
In South America, llamas and alpacas were domesticated, in addition to guinea pigs. The llama used as a pack animal can carry up to 65 pounds. A Maya porter could transport more than 120 pounds. Feeding the llama requires a total of 8.8 pounds of corn a day whereas a Maya porter only requires 2 pounds per day of corn. The Maya used their creativity too find a feasible substitute for animal power. The alternate solution was a plentiful and economical source of kinetic energy: Maya manpower.
Development of Maya Transport Technology: Why Not Use the Wheel?
Along with being referred to as a Stone Age culture, archaeologists cast Maya technology in a negative light when they state that the civilization did not understand the concept of the wheel for transport. As the Maya culture progressed, hunter, and gatherers turned into farmers, and the need for powered transport increased. The need for power supply then ramped up with
the rise of villages, towns, and cities. Maya farmers and technicians developed methods of using manpower to supply the kinetic energy to lift, transport, and mobilize loads required for the implementation of agriculture, construction, and transportation.
So if the Maya technicians were so intelligent, say doubters, why did they not use a wheeled vehicle for transport? Examples of small toys with wheels with axels crafted by Maya are exhibited in museums. Then why was this important invention not used in the fabrication and use of wheeled vehicles for transport? First consider that, because of the lack of dray animals, the only source of kinetic energy available for the Maya was manpower supplied by their own workforce. To take advantage of the properties of the wheel, the construction of a wheeled wagon or cart would be required. The wagon would be constructed with a trace connected to the front of the vehicle to accommodate men rigged in harnesses. Applying the same energy to weight formula that was used on the large freight wagons pulled by horses or mules in the 19th century to calculate the number of animals required to pull a heavily loaded freight wagon, the number of animals was calculated using the loaded weight of the wagon and the weight of the animals. Each dray animal was considered capable of pulling a load equal to its own weight. The loaded wagon weight divided by the animal’s weight calculated the number of animals needed to pull the wagon. This equation initiated the old expression “pulling their weight.”
The Maya wagon would be fabricated of timber just as the European wagon. Assume, for this example, that the wagon weighted 1,000 pounds and could transport a payload equal to 1,000 pounds. The sum of the load and wagon would be equal to a total of weight 2,000 pounds. Using the standard “pulling their weight” criteria for calculating the number of pulling beasts for a wagon load. The weight of the wagon and load equaled 2,000 pounds and the weight of Maya workforce required were 20 men weighing in at 100 pounds each. Then a total of 20 haulers/pullers weighing a total weight of 2,000 pounds would be required. To equal the weight of the wagon and its load, simplistically it would require 10 men to pull the weight of the cart and 10 men to haul the load. That would be an average of 50 pounds of net payload carried by each 20-man team. Not a very good efficiency rating when Maya technology had developed manpowered transport devices that enabled a porter to transport a load of 125 pounds each. That is a 250-percent advantage over the use of a wheeled transport. It is easy to see the advantage of transport by porter over pulling a manpowered wheeled vehicle. For the Maya, the lack of work animals was the difference between the use of the wheel and the necessity to use manpower for transport.
The Maya developed a man-powered transport device known as the tumpline. This device enabled a single man to carry more than 125 pounds with relative ease. Using the heavy wagon, 20 men could only transport 50 pounds each, or a total of 1,000 pounds, of useful load. On the other hand, 20 porters could transport 2,500 pounds of useful load using a tumpline. In addition to the poor load-carrying capacity of wheeled transport, travel over the rough terrain and muddy jungle tracks made the wagon an overall poor alternate. The tumpline-equipped team could easily negotiate the rough terrain while transporting more than twice the load as a wheeled vehicle. It is apparent that the Maya logically recognized the disadvantage of a wheeled vehicle. The wheel without the use of a heavy, hoofed beast of burden was a negative factor in the economic game plan of the Maya civilization. Pulling the wagon loads required more than twice the kinetic energy per pound compared with a man with a tumpline load. Thus, Maya technology was built around manpower, and utilized its capabilities and advantages in a wide variety of applications. The wheel was not unknown in the Maya world. The circular motif of the wheel was depicted in art and architecture and used on toys, but in the evolution of Maya transportation technology it was a dead-end branch.
The Technology of the Tumpline: The Optimization of Manpower
The manpowered tumpline was the load-carrying mechanism that moved the Maya economy. The tumpline-equipped bearer transported trade goods, merchandise, and agriculture products, and carried construction material up and into the construction of the superstructure of monumental buildings without beasts of burden.
The tumpline consisted of a leather head strap that was positioned on the top of the head to direct loads from the skull and directly into the spinal column. The ends of the head strap were attached to a 3-foot-long tail or tension strap. The strap was connected to the frame or load container supporting the load. The tails were aligned with the center of the mass of the load to be transported. The head strap then carried the tension loads transmitted from the load to the top of the head.
The tumpline was a simplistic tension-based mechanism that distributed loading from the mass of the burden directly onto the load paths that frame the human body (Figure 11-1). The loads were vectored into the human skeletal structure from the skull, which supported the load, down the spinal column and directly into the pelvic arch, then into the bone systems of the legs and the support system of the feet. This interaction between loads and the human frame optimizes the natural resistance of the structural skeleton and reduces fatigue while minimizing the strain on muscles.
The advantage of the tumpline made the task of transporting material more efficient with the load aligned with the spine rather than being supported by muscles in the shoulders and back. Figure 11-1 details the pattern of load-bearing vectors of the tumpline and the load paths being transferred down through the skeletal system into the roadway surface. To position the tumpline, after placing the tumpline on top of the head, the bearer then leaned forward to balance and align the load, and started his march. The tumpline enabled the bearer with a heavy load to travel along level roadways at a pace of that could cover 15.5 miles (25 kilometers) per day. The pace in rough, rugged terrain would be slower, but a sure-footed porter would travel faster than a beast of burden.
The tumpline was used as a vertical lifter in construction operations, not unlike a modern material elevator. The bearer would place construction material such as stones, concrete, sascab, or soil in a container on his tumpline. The bearer would climb up ladders or scaffolding with the weight of construction material and his tumpline attached to his head, rendering his hands free to safely climb. These cargadores were the teamsters of the Maya culture.
The efficiency of the tumpline aided in moving large quantities of merchandise and materials at a low cost. Using a tumpline, the bearer could carry a load approximately equal to his weight. The ability to carry large loads relative to this small body size and the ability to pace himself was dependent on taking rest stops to regulate his heart rate and energy expenditure. He would rest by sitting his tumpline loads on load-resting platforms called lab. The bearers were multi-disciplined; in addition to being cargo carriers, the tumpline was a transportation device for passengers. A chair was attached to the tumpline of a single bearer. The occupant would sit in the chair facing backward. This type of manpowered transport continued to be used by the elite into the 18th and 19th centuries in Mexico and Central America.
Figure 11-1: Drawing of tumpline indicating distribution of forces from the weight of the load. Author’s image.
Figure 11-2 illustrates a mural at Calakmul that shows a rare view of everyday activities in Maya life. The painting depicts a Maya bearer supporting a large pot filled with goods supported by a tumpline. Note the intricate web of rope placement securing the pot to the tumpline. It is a brilliant study in vectors.
Teams of bearers carried large loads over great distances. They were easier to maintain than beasts of burden. Working animals would require feeding, water, and currying. However, the self-sufficient bearer raised his own food, fed, watered, and curried himself. He was the horse, cart, and stable hand all combined into a single, dynamic package. The tumpline is still employed as a cargo carrier in contemporary Latin America. It is a common sight to observe men, women, and even children carrying loads with tumplines as they travel along rural roads and in markets. Their payloads range from fi
re wood to packs of merchandise and agriculture products.
The tumpline was an important symbol of load-carrying in Maya culture. It is part of an ancient hieroglyphic symbol representing the burden of each solar year or 365-day Haab year transported by the ancient Maya time lords. The burden of each year is carried on the back by one of the four bearers of time. The burden and responsibility of that year is carried on the back of a time lord and supported by a tumpline stretched across the forehead. The time lord gives that year its quality, or personality. The tumpline is a prime example of comparative analysis; it was developed by other cultures throughout the planet and can be found in Nepal, India, and Africa. The other cultures also had beasts of burden for transport, but the tumpline was superior to work animals in the economics of transport and on mountainous terrain. The word tumpline is another outlandish name given to a native device by archaeologists. The Maya word for the device is mecapal. Tumpline is the word for the same device used by the native Mohegans of Connecticut.
Figure 11-2: Ancient tumpline bearer from mural at Calakmul. Author’s image.
An overview of the variety of cargo transported by the tumpline will show the integral part that the tumpline played in agriculture, trade, construction, and other cargo transport. A review of the wide range of material indicates the influence that the foot freighters of the Maya had on the construction and wealth of the city-states. The following wide range of goods, materials, and agriculture products were transported by tumpline:
The Lost Secrets of Maya Technology Page 27