A cable-stayed bridge has one or more towers, from which cables support the bridge deck. A distinctive feature are the cables or stays, which run directly from the tower to the deck, normally forming a fan-like pattern or a series of parallel lines. This is in contrast to the modern suspension bridge, where the cables supporting the deck are suspended vertically from the main cable, anchored at both ends of the bridge and running between the towers. The cable-stayed bridge is optimal for spans longer than cantilever bridges and shorter than suspension bridges. This is the range within which cantilever bridges would rapidly grow heavier, and suspension bridge cabling would be more costly.
Piedras Negras is the modern name for a ruined city of the pre-Columbian Maya civilization located on the north bank of the Usumacinta River in the Petén department of northwestern Guatemala. Piedras Negras is one of the most powerful of the Usumacinta ancient Maya urban centers. Occupation at Piedras Negras is known from the Late Preclassic period onward, based on dates retrieved from epigraphic information found on multiple stelae and altars at the site. Piedras Negras is an archaeological site known for its large sculptural output when compared to other ancient Maya sites. The wealth of sculpture, in conjunction with the precise chronological information associated with the lives of elites of Piedras Negras, has allowed archaeologists to reconstruct the political history of the Piedras Negras polity and its geopolitical footprint.
Yaxchilan is an ancient Maya city located on the bank of the Usumacinta River in the state of Chiapas, Mexico. In the Late Classic Period Yaxchilan was one of the most powerful Maya states along the course of the Usumacinta River, with Piedras Negras as its major rival. Architectural styles in subordinate sites in the Usumacinta region demonstrate clear differences that mark a clear boundary between the two kingdoms.
The ancient Romans were the first civilization to build large, permanent bridges. Early Roman bridges used techniques introduced by Etruscan immigrants, but the Romans improved those skills, developing and enhancing methods such as arches and keystones. There were three major types of Roman bridge: wooden, pontoon, and stone. Early Roman bridges were wooden, but by the 2nd century stone was being used. Stone bridges used the arch as their basic structure, and most used concrete, the first use of this material in bridge-building.
Tonina is a pre-Columbian archaeological site and ruined city of the Maya civilization located in what is now the Mexican state of Chiapas, some 13 km (8.1 mi) east of the town of Ocosingo.
The Usumacinta River is a river in southeastern Mexico and northwestern Guatemala. It is formed by the junction of the Pasión River, which arises in the Sierra de Santa Cruz and the Salinas River, also known as the Rio Chixoy, or the Rio Negro, which descends from the Sierra Madre de Guatemala. It defines part of the border between Guatemala and the Mexican state of Chiapas, then continues its northwesterly course, meandering through the Mexican state of Tabasco to the Gulf of Mexico.
A simple suspension bridge is a primitive type of bridge in which the deck of the bridge lies on two parallel load-bearing cables that are anchored at either end. They have no towers or piers. The cables follow a shallow downward catenary arc which moves in response to dynamic loads on the bridge deck.
The Niagara Cantilever Bridge or Michigan Central Railway Cantilever Bridge was a cantilever bridge across the Niagara Gorge. An international railway-only bridge between Canada and the United States, it connected Niagara Falls, New York, and Niagara Falls, Ontario, located just south of the Whirlpool Bridge, and opened to traffic in 1883, it was replaced by the Michigan Central Railway Steel Arch Bridge in 1925.
The Lacandon Jungle is an area of rainforest which stretches from Chiapas, Mexico, into Guatemala. The heart of this rainforest is located in the Montes Azules Biosphere Reserve in Chiapas near the border with Guatemala in the Montañas del Oriente region of the state. Although much of the jungle outside the reserve has been cleared, the Lacandon is still one of the largest montane rainforests in Mexico. It contains 1,500 tree species, 33% of all Mexican bird species, 25% of all Mexican animal species, 56% of all Mexican diurnal butterflies and 16% of all Mexico's fish species.
Tatiana Proskouriakoff was a Russian-American Mayanist scholar and archaeologist who contributed significantly to the deciphering of Maya hieroglyphs, the writing system of the pre-Columbian Maya civilization of Mesoamerica.
A tied-arch bridge is an arch bridge in which the outward-directed horizontal forces of the arch(es) are borne as tension by a chord tying the arch ends rather than by the ground or the bridge foundations. This strengthened chord may be the deck structure itself or consist of separate, independent tie-rods.
Motul de San José is an ancient Maya site located just north of Lake Petén Itzá in the Petén Basin region of the southern Maya lowlands. It is a few kilometres from the modern village of San José, in Guatemala's northern department of Petén. A medium-sized civic-ceremonial centre, it was an important political and economic centre during the Late Classic period (AD 650–950).
Pajaral, otherwise known as El Pajaral, is the modern name for a mid-sized ruined city of the pre-Columbian Maya archaeological site located to the south of the San Pedro Martir river in the Petén department of Guatemala. The name El Pajaral was coined by archaeologist Ian Graham, who discovered the site in the 1970s, and refers to the numerous birds he encountered there during his survey.
Zapote Bobal is the modern name for a pre-Columbian Maya archaeological site located south of the San Pedro Martir river in the Petén department of Guatemala. The name Zapote Bobal was coined by archaeologist Ian Graham, who discovered the site in the 1970s. It refers to the large number of Zapote Bobo trees, which grow near abundant sources of water in the Petén Basin. The site languished in archaeological obscurity until 2003, when epigrapher David Stuart connected the archaeological site of Zapote Bobal with a name repeatedly mentioned in the inscriptions of sites like Piedras Negras and Yaxchilan. That name was the toponym Hix Witz, or "Jaguar Hill" Scholars had recognized this name for over 20 years, and its connection to a real place prompted the creation of an archaeological project at Zapote Bobal in 2003, the Proyecto Peten Noroccidente (PNO). It is currently directed by James Fitzsimmons and Laura Gamez.
Altar de Sacrificios is a ceremonial center and archaeological site of the pre-Columbian Maya civilization, situated near the confluence of the Pasión and Salinas Rivers, in the present-day department of Petén, Guatemala. Along with Seibal and Dos Pilas, Altar de Sacrificios is one of the better-known and most intensively-excavated sites in the region, although the site itself does not seem to have been a major political force in the Late Classic period.
A lintel or lintol is a type of beam that spans openings such as portals, doors, windows and fireplaces. It can be a decorative architectural element, or a combined ornamented/structural item. In the case of windows, the bottom span is referred to as a sill, but, unlike a lintel, does not serve to bear a load to ensure the integrity of the wall. Modern-day lintels may be made using prestressed concrete and are also referred to as beams in beam-and-block slabs or as ribs in rib-and-block slabs. These prestressed concrete lintels and blocks can serve as components that are packed together and propped to form a suspended-floor concrete slab.
Sak tzʼi is an archaeological site of the pre-Columbian Maya civilization. It is located in the municipality of Ocosingo of the Mexican state of Chiapas. The ruins are notable for having the earliest urban remains in the Upper Usumacinta region, as well as a unique ancient theater for elite use. The ancient identity of the site is subject to debate.
The history of Maya civilization is divided into three principal periods: the Preclassic, Classic and Postclassic periods; these were preceded by the Archaic Period, which saw the first settled villages and early developments in agriculture. Modern scholars regard these periods as arbitrary divisions of chronology of the Maya civilization, rather than indicative of cultural evolution or decadence. Definitions of the start and end dates of period spans can vary by as much as a century, depending on the author. The Preclassic lasted from approximately 3000 BC to approximately 250 AD; this was followed by the Classic, from 250 AD to roughly 950 AD, then by the Postclassic, from 950 AD to the middle of the 16th century. Each period is further subdivided:
