The Size of Maya Vaults
The size of the Maya vault in structures varied with the function of the building. The sizes ranged from small spaces to 12 foot × 20 foot interior spaces. The construction of large interior spaces for assembly was not practical—not because of structural limitations, but for environmental reasons. The lack of dynamic ventilation combined with the tropical heat made large assembly spaces a liability.
The usual size of a vault in a royal residence was approximately the size of the traditional Maya house or ná. It is logical to consider this living space as the prototypical living space used during the Classic Period. In modern architecture, the 12 foot × 20 foot suite is a typical room size for hotels and dormitories.
The Maya Vault as a Finished Chamber
The Maya vault is a structural element that had multiple applications and was employed to develop long-span, single-story and multistory structures. The interior spaces of vaults in Maya buildings were finished with a surface coat of stucco plaster that provided a comfortable and attractive interior space; a cool, waterproof living facility; and a safe shelter from hurricanes and tropical storms.
The finished structural stonework of the walls would have presented a rough surface even when laid up in a workmanlike manner. The interior spaces of Maya vaults were finished with a smooth plaster coat of stucco. The plaster finish included the walls, floors, and ceiling areas. After the plaster coating, the walls were polished or painted with solid colors or murals, depending on the usage of the space. Figure C-5 indicates a plaster finish basically intact 1,400 years after application. Note that the vast majority of the ceiling structure of Maya vaults had a curved surface. This is not a circular curve. When analyzed, it appears that this curve has a convex shape similar to a parabola. This ceiling shape, when coated with smooth white stucco, would have the ability to magnify and reflect a light source in the vaulted room and greatly enhance illumination. Simple lamps with fuel and a cotton wick could provide a light source, with the light magnified multiple times from the white curved surface of the ceiling and the walls. Studies of Maya life in the Classic Period have indicated they cooked with cotton seed oil. This fuel was the popular lamp oil in mid-19th-century America until kerosene became available. Cotton was a major crop for the Maya; therefore, it is logical that cottonseed oil served as fuel for Maya lamps and that the white parabolic ceiling enhanced the light source in the room.
The floor surface was paved to complete the accommodations. The door opening featured a covering of cloth, woven mat, or animal hide that provided privacy and security, while permitting air flow into the interior spaces. The sides of the door openings featured an assembly for supporting a pole or cord for hanging the cloth. These devices are recessed cord connections to hold back the closure system at the top or at the bottom.
Timber Beam Structures, Stone Columns, and Composite Columns
High-strength tropical timber was used by Maya engineers for spanning bridges, roofs, and floors. Examples of these structures include the bridge at Pusilha, the palace tower at Palenque, and the sweat house at Piedras Negros. In several cases, the timber beams were used with a concrete topping. This system then became a composite structural material, and the total strength exceeded the sum of parts.
Stone columns were used to support large door openings and the attendant stone lintels and timber roof beams. The typical stone column was assembled from prefabricated “drums” of stone and assembled in situ with connectors between adjacent drums. These columns were used singularly or in rows to create a post-and-beam structural system.
Column support systems were used in several applications, such as the mid-span support of lintels for large door openings and the development of openings in wall of the exterior vaults. The columns were quite large with diameters of 0.96 meters. The columns elements were constructed off-site and sized to be transported to the site by a single bearer. The column shells were then assembled and filled with cast-in-place concrete. This methodology formed a large column using smaller fabricated segments. This type of column was used at the palace at Edzná.
Special Types of Maya Structures Using Technological Magic
Maya structural engineering met the challenge of functional requirements for special structures. These special structures were configured with a unique geometry that presented challenges for Maya technology. These structures used the basic components of the arch, vault, and construction materials described previously, but each type of structure used a creative twist that set it apart.
Multistory Structures
The design and construction of Maya high-rise structures produced buildings that surpassed the height of multistory structures throughout the world. Maya engineering of multistory building construction used a step-back structural system of trapezoidal arch and vault structures. This structural technique of stepping multistory structures has functional advantages that enhance light, ventilation, and vertical access, while increasing structural capabilities (Figure 7-7). Multistory buildings, though not widespread, were exquisite examples of Maya engineering. Notable examples were at the cities of Xtampak and Edzná (Figure C-13).
The palace at the ancient city of Xtampak is a graceful structure rising to three levels in height. This landmark building exhibits Maya structural engineering technology in a multistory configuration (Figure C-13). The long dimension of the vaults is parallel with the outer facade and features a series of colonnaded openings to enhance light and ventilation. The interior vaults have typical openings between units.
The cross section of the palace clearly displays the load paths for gravity loads and their structural members (Figure 7-7). It is noted that the second and third structures are set back in order for the outer wall on the second level to bear co-linear with the inner walls of the first level. This geometry directs the forces from the upper stories to traverse axially downward through a load path down into the composite concrete walls. The upper walls do not transmit their gravity loading directly through the trapezoidal arch structure, but align with vertical walls. The core or interior of the multistory structure lies beneath the grand staircase in the palace. An interior, winding stairway traverses upward to access all levels. The five-story palace at the city of Edzná is a graceful example of Maya art, architecture, and structural engineering. The configuration of the building uses the step back structural system that aligned the walls of the vaults as the building stepped upward. This geometry developed a sound structure and delivered a dramatic architectural form. The exterior stair system is unique; the Maya trapezoidal arch and concrete slabs were used to span stairs at the floor levels producing a continuous stair system (Figure C-9 and Figure C-10).
Circular Maya Structures
A number of Maya cities boasted circular structures that are considered to be astronomical observatories. The Maya were unparalleled as astronomers, and it is logical that these scientific people would construct a structure dedicated to celestial observation and designed to functionally optimize astronomical studies. A circular structure with an unobstructed view of the horizon would be an excellent place for star-gazing.
Figure 7-7: Structural diagram of high-rise Maya building showing clear load paths to foundations. Author’s image.
Some cities designed their observatories as circular structures with functional interior space and exterior walkways and roof platforms; others erected, tall circular structures that were constructed of solid materials, including concrete and stone, without functional interior spaces. Instead, these structures used exterior stairs and observation platforms on the top. Examples of this solid structure include the tall circular tower at the city of Cobá in the Yucatán (Figure C-14). The structure features exterior steps on the facade to the top of the tall tower. This tall structure would be a logical design to observe the cosmos over the tall rainforest trees. The basic design criteria for 360-degree fields of clear vision would require a tall structure; the cone-shaped tall structure would resolve this iss
ue. The structure consists of exterior stonework with a mass concrete infill. This structure was first called the “sorbet” by French archaeologists due to the cone shape of the ruined structure.
The most noted Maya observatory is the circular structure termed the “caracol” at the city of Chichen Itza. The observatory at Chichen Itza applies the Classic trapezoidal arch structural system in a circular plan configuration and is a fine example of Maya engineering. The interior of this cylinder-shaped structure is formed by tall Maya vault construction in a closed circular plan with a stairway at the center column. Figure 7-8 indicates the cross section of the “caracol” structure.
The circular vault uses the Maya arch as its basic building block. However, the arch forms a circular shape rather than the linear shape used in building vaults. Observatories did not have the advantage of optical equipment for observing the stars, but the circular-shaped structure became the astronomical observation instrument. Wall openings and markers were used as fixed points for indicating certain astronomical events, calendric dates or the changing of seasons.
The city of Mayapán in the Northern Yucatán has a circular observatory with functional interior space (Figure C-12). This observatory is not a towering structure, but is sited in the middle of the city with clear views of the heavens. The terrain is flat in this area of the Yucatán, and the sight lines to the horizon are not obstructed.
Figure 7-8: Circular structure configured by generating the Maya arch into circular vault. Author’s image.
Temple Structures and Roof Combs
Temples were located on the summit of tall pyramids or solid platforms rising above the plaza level (Figure C-16). Temples were relatively small structures with one or two interior vaults creating a sanctuary within the building. The exterior of the temple was adorned with multi-colored sculptural art and murals that presented a dramatic scene. The roof of the temple supported a tall superstructure or framework known as a roof comb. The roof comb was adorned with decorative sculptural elements that enhanced the heaven-reaching goals of the rulers. It has been postulated by archaeologists that certain roof combs featured special sound and light effects created to enhanced the wonderment of the temple structure. Special effects were produced through environmentally driven devices such as wind chimes and mirrors.
The roof comb atop the elevated temple was analogous to a modern billboard. Intended to promote propaganda and incite awe in the populace, it was also an excellent example of creative Maya engineering. The Maya engineers designed the structure of the roof comb as a three-dimensional space frame with an open matrix of vertical and horizontal concrete members. The vertical plane of the roof comb had a surface that has more open space than solid structure. Maya technology understood the advantage of open, lightweight roof comb structures to minimize lateral and vertical loadings. This geometry was intended to reduce wind forces, to lower the weight of gravity loading, and to minimize seismic forces on the temple structure.
The temple and roof comb were constructed of structural members with high-strength materials that were designed to resist extreme environmental forces in the Maya regions. Many temples and roof combs are intact after 1,500 years of resisting numerous earthquakes and thousands of hurricanes. The location of the temples at the top of the tallest structures in the Maya world resisted the magnified forces from seismic event acceleration, and they were required to resist the highest loads from hurricanes forces due to their unsheltered height above the ground surface.
The structural stability and strength of the roof comb and the temple were dependent on the inherent stability of the roof comb structure. Roof combs were constructed with different architectural configurations based on the style of the region. The similarity of the roof combs in different sites lay in the open framework of the structure and its integration with the strength of the cast-in-place concrete materials of the temple construction. The geometry varied with the regional style of the art and architecture of the edifice.
The roof combs at Palenque are constructed of cast-in-place concrete in a vertical configuration space frame. The majority of the Palenque roof combs are open to reduce lateral loads and gravity loads. The front and rear facade of roof comb members align with vertical members in the temple structures. The lateral and vertical loads from the roof comb are resisted by the temple structure.
The roof comb at Temple 33 at Yaxchilan features a structural system construction of a cast-in-place concrete A-frame configuration. The roof comb has openings in the north and south facades. However, the object of reducing weight and surface area was for reducing seismic and lateral forces. The structural resistance of the roof comb is achieved by a combination of the action of the angular A-frame and bending about the horizontal axis of the large vertical members. The front and rear facades align with the interior vertical walls of the temple.
The architectural and structural configurations of roof combs at the city of Tikal are of a different architectural and structural design than other Maya sites. These roof combs are high vertical structures that do not have openings in the facades. Rather than utilize the facades as armatures for sculpture placement, the facades themselves appear to have been carved with monumental sculptures. The roof combs have a larger base then other examples of Maya roof combs. The interiors of the Tikal roof combs seem to be open volumes. The front and rear walls of the structure vary from approximately 4 meters thickness at the base to thinner wall thickness at the top. The interior spaces between the roof comb walls are transected at intervals with horizontal diaphragms, which are connected to the outer walls.
The Tikal engineers took a different approach to resisting lateral and vertical forces generated by the large roof comb. The completely enclosed roof comb offered a strong structural system. The thick walls at the front, rear, and sides developed a tube-like structure for resisting lateral loadings. The interior diaphragms proportioned lateral loads between the walls that, in turn, transferred the roof comb loads down to the temple structure, and then into the pyramid structure.
Pyramid Structures
As travelers stood at the entrance of a great Maya city, they would be awed by the beauty and towering heights of its monumental structures. The single Maya structure that caused shock and awe to the observers was the grandiose soaring pyramid topped with a gorgeous temple and a towering art-festooned roof. This trio of structural elements was elevated high above the rainforest canopy and proclaimed the power of the city and the wealth of the ruler.
Maya pyramid structures rose to heights of more than 230 feet, a height that was not exceeded for a millennium. They were taller than the Leaning Tower of Pisa, which topped out in 1319 at 183.27 feet, and the world’s first sky scraper, constructed in Chicago in 1885 with a height of 185 feet. Maya pyramid builders were ahead of their time in the construction of tall structures.
The structure of the basic construction of a pyramid did not apply innovative structural mechanisms devised by Maya engineers, but was a mass structure that applied the sum of Maya technology, including cast-in-place concrete, cut stone, carved art, the tools of surveying, and accurate measurements in the construction. The exterior skin or facade was constructed of composite stone and concrete that encapsulated the structural mass comprising the interior core of the pyramid. The interior of the pyramids, with few exceptions, did not contain functional spaces such as vaulted chambers or passageways. One exception would be the Temple of the Inscriptions pyramid at Palenque, which held the tomb of Pakal.
In many cities, pyramids were constructed in stages and grew in size as the city expanded. Buried beneath the tall pyramids were the remains of earlier pyramids (Figure 7-9). The encapsulation of one or more earlier pyramids was driven by the desire for display of power by the rulers, who wanted to outdo their predecessors with a grander show of the art, architecture, and soaring height of the temple. Examples of multiple phases of pyramid construction include the Pyramid of the Magician at Uxmal and El Castillo at Chichen Itza (Figure
C-16).
Whether the pyramid was a stand-alone project or staged efforts over several centuries, the implementation of the core was constructed by a series of compartmentalized retaining structures. The core of the pyramid was contained by retaining structures built just inside the perimeter of the new exterior (Figure 7-9).
The exterior of the four-sided triangular was often stepped upward in a ziggurat of nine levels, terminating at a temple platform. Many pyramids have steep, smooth, curved corners with up to four grand staircases on the various faces of the pyramid leading from the ground to the temple atop the looming structure. The designers of the pyramids often used structural geometry and the movement of the sun to create illusions of shadows and light during festival days. Many pyramids have the tendency to reflect sound that appears to be falling rain or bird calls.
Figure 7-9: Pyramid construction indicating staged structures with mass infill confined by retaining walls. Author’s image.
Tower Structures
Maya towers rose above the central plaza of many city centers. It is possible that some towers had astronomical functions with markers for changes in the seasons. The structure could have been used as watch towers for earthly matters or erected to elevate the status of a ruler. Towers were sometimes stand alone structures or were part of a larger building.
The Lost Secrets of Maya Technology Page 17
