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A monolithic dome (from Greek mono- and -lithic, meaning "one stone") is a thin-shell structure cast in a one-piece form. The form may be permanent or temporary and may or may not remain part of the finished structure. Monolithic domes are a form of monolithic architecture.
The igloo may be the earliest form of monolithic dome. While it is constructed of blocks of compressed snow, these blocks melt and re-freeze to form a strong, homogeneous structure. The dome-like shape of the igloo exhibits the two major advantages of a dome-shaped structure: great strength, and good insulation. The strength is due to the natural strength of the arch, and the insulation is due to the minimal surface area of a spherical section.
The first modern monolithic dome structure was built in Provo, Utah, by architect Lee C. Knell, and opened in 1963 as an ice skating rink. Called Turtle Reams after its 1967 conversion into a general store by new owner Paul Ream, the building stood until it was demolished in 2006 for new construction.
Turtle Reams was built by first creating a mound of dirt in the desired shape of the shell, an ellipsoidal section 240 feet (73 m) long, 160 feet (49 m) wide and 40 feet (12 m) high. The mound was then covered in a grid of rebar, to provide strength, and a layer of concrete approximately 4 inches (100 mm) thick. After the concrete was cured, the dirt was excavated through the doorways, leaving the roof standing in its place. The floor was then poured to finish the structure.
Today, monolithic domes are used in a variety of residential, commercial and industrial projects. Because of the strength, durability and economics, they are used to store large amounts of various commodities in the cement, fertilizer, agricultural, power and mining industries. Due to their structural integrity, they are used as the containment buildings at some nuclear power plants. Forms have been made using nearly every common structural material, including air-pressure-supported fabric.
Modern construction differs significantly from the original concrete-over-dirt method. The current methods were developed by three brothers from Idaho: David, Barry, and Randy South. The first dome built using these method was constructed in April 1976 in Shelley, Idaho:
In instances where necessity requires economical construction for multiple small and basic dwellings, the dome can be built without insulation and the air form can be removed after completion and re-used to build additional domes.
The dome, when finished, is earthquake, tornado and hurricane resistant (the US Federal Emergency Management Agency rates them as "near-absolute protection" from F5 tornadoes and Category 5 Hurricanes). Recently, a number of monolithic domes constructed using MDI techniques have survived major disasters:
The demolition of Reams’ Turtle also demonstrated the durability of the monolithic dome structure. A wrecking ball demolished a strip several feet wide around the perimeter of the structure, without a collapse. When a doorway on one side was pulled down, the dome finally tipped over, and collapsed.
The monolithic dome, for a number of reasons, is very energy efficient. The spherical sections of the dome offer minimal surface area for the volume they contain, so there is less surface for heat transfer with the outside air. The one piece construction of the monolithic dome also eliminates many of the seams through which air can leak, though this is mitigated to some degree in residential domes by the addition of multiple doors and windows. By placing the insulating foam on the outside of the concrete shell, the concrete acts as a thermal mass inside the building, reducing interior temperature fluctuations far more than the traditional home's insulation inside of a brick or stone veneer.
While the monolithic dome has numerous demonstrated engineering advantages, there are also some disadvantages, both engineering and social.
Social disadvantages of monolithic domes are to a large degree shared by geodesic domes, due to the similar shape and unorthodox construction. These disadvantages are:
The largest monolithic dome in the world is the home of Faith Chapel Christian Center in Birmingham, Alabama, which is 72 feet (22 m) tall, and 280 feet (85 m) in diameter. [2] Inside is a floor area of 74,500 square feet (6,920 m2) in two levels. [3]
Some communities in the United States have chosen to use monolithic dome technology in the construction of new schools. [4] A map [5] of recently built monolithic dome schools can be found here:
A residential house, the monolithic "Dome of a Home" in Pensacola Beach, Florida, has experienced several hurricanes since it was built. [6]
Masonry is the craft of building a structure with brick, stone, or similar material, including mortar plastering which are often laid in, bound and pasted together by mortar; the term masonry can also refer to the building units themselves. The common materials of masonry construction are bricks and building stone such as marble, granite, and limestone, cast stone, concrete blocks, glass blocks, and adobe. Masonry is generally a highly durable form of construction. However, the materials used, the quality of the mortar and workmanship, and the pattern in which the units are assembled can substantially affect the durability of the overall masonry construction. A person who constructs masonry is called a mason or bricklayer. These are both classified as construction trades.
A roof is the top covering of a building, including all materials and constructions necessary to support it on the walls of the building or on uprights, providing protection against rain, snow, sunlight, extremes of temperature, and wind. A roof is part of the building envelope.
An earth shelter, also called an earth house, earth bermed house, or underground house, is a structure with earth (soil) against the walls, on the roof, or that is entirely buried underground.
A floor is the bottom surface of a room or vehicle. Floors vary from simple dirt in a cave to many layered surfaces made with modern technology. Floors may be stone, wood, bamboo, metal or any other material that can support the expected load.
A geodesic dome is a hemispherical thin-shell structure (lattice-shell) based on a geodesic polyhedron. The triangular elements of the dome are structurally rigid and distribute the structural stress throughout the structure, making geodesic domes able to withstand very heavy loads for their size.
A structural insulated panel, or structural insulating panel, (SIP), is a form of sandwich panel used in the construction industry.
A concrete block, also known as a cinder block in North American English, breeze block in British English, concrete masonry unit (CMU), or by various other terms, is a standard-size rectangular block used in building construction. The use of blockwork allows structures to be built in the traditional masonry style with layers of staggered blocks.
A concrete shell, also commonly called thin shell concrete structure, is a structure composed of a relatively thin shell of concrete, usually with no interior columns or exterior buttresses. The shells are most commonly monolithic domes, but may also take the form of hyperbolic paraboloids, ellipsoids, cylindrical sections, or some combination thereof. The first concrete shell dates back to the 2nd century.
Ferrocement or ferro-cement is a system of construction using reinforced mortar or plaster applied over an "armature" of metal mesh, woven, expanded metal, or metal-fibers, and closely spaced thin steel rods such as rebar. The metal commonly used is iron or some type of steel, and the mesh is made with wire with a diameter between 0.5 mm and 1 mm. The cement is typically a very rich mix of sand and cement in a 3:1 ratio; when used for making boards, no gravel is used, so that the material is not concrete.
Insulating concrete form or insulated concrete form (ICF) is a system of formwork for reinforced concrete usually made with a rigid thermal insulation that stays in place as a permanent interior and exterior substrate for walls, floors, and roofs. The forms are interlocking modular units that are dry-stacked and filled with concrete. The units lock together somewhat like Lego bricks and create a form for the structural walls or floors of a building. ICF construction has become commonplace for both low rise commercial and high performance residential construction as more stringent energy efficiency and natural disaster resistant building codes are adopted.
The Xanadu Houses were a series of experimental homes built to showcase examples of computers and automation in the home in the United States. The architectural project began in 1979, and during the early 1980s three houses were built in different parts of the US: one each in Kissimmee, Florida; Wisconsin Dells, Wisconsin; and Gatlinburg, Tennessee. The houses included novel construction and design techniques, and became popular tourist attractions during the 1980s.
Formwork is molds into which concrete or similar materials are either precast or cast-in-place. In the context of concrete construction, the falsework supports the shuttering molds. In specialty applications formwork may be permanently incorporated into the final structure, adding insulation or helping reinforce the finished structure.
Precast concrete is a construction product produced by casting concrete in a reusable mold or "form" which is then cured in a controlled environment, transported to the construction site and maneuvered into place; examples include precast beams, and wall panels for tilt up construction. In contrast, cast-in-place concrete is poured into site-specific forms and cured on site.
Domestic roof construction is the framing and roof covering which is found on most detached houses in cold and temperate climates. Such roofs are built with mostly timber, take a number of different shapes, and are covered with a variety of materials.
Concrete cover, in reinforced concrete, is the least distance between the surface of embedded reinforcement and the outer surface of the concrete. The concrete cover depth can be measured with a cover meter. The purpose of concrete cover is to protect the reinforcement from corrosion, fire, and other potential damage.
Building insulation materials are the building materials that form the thermal envelope of a building or otherwise reduce heat transfer.
Spray foam is a chemical product created by two materials, isocyanate and polyol resin, which react when mixed with each other and expand up to 30-60 times its liquid volume after it is sprayed in place. This expansion makes it useful as a specialty packing material which forms to the shape of the product being packaged and produces a high thermal insulating value with virtually no air infiltration.
Concrete is produced in a variety of compositions, finishes and performance characteristics to meet a wide range of needs.
Tornadoes, cyclones, and other storms with strong winds damage or destroy many buildings. However, with proper design and construction, the damage to buildings by these forces can be greatly reduced. A variety of methods can help a building survive strong winds and storm surge.
