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In architecture and structural engineering, a space frame or space structure is a truss-like, lightweight rigid structure constructed from interlocking struts in a geometric pattern. Space frames can be used to span large areas with few interior supports. Like the truss, a space frame is strong because of the inherent rigidity of the triangle; flexing loads (bending moments) are transmitted as tension andcompression loads along the length of each strut.

Space frames are typically designed using a rigidity matrix. The special characteristic of the stiffness matrix in an architectural space frame is the independence of the angular factors. If the joints are sufficiently rigid, the angular deflections can be neglected, simplifying the calculations. The simplest form of space frame is a horizontal slab of interlocking square pyramids and tetrahedra built from aluminium or tubularsteel struts. In many ways this looks like the horizontal jib of a tower crane repeated many times to make it wider. A stronger form is composed of interlocking tetrahedra in which all the struts have unit length. More technically this is referred to as an isotropic vector matrix or in a single unit width an octet truss. More complex variations change the lengths of the struts to curve the overall structure or may incorporate other geometrical shapes.

A space frame refers to a spatial structure whose members are connected rigidly to each other so that they transfer moment and shear in addition to axial forces. In comparison, space trusses are pin-jointed and as a result, their members are in tension or compression and do not transfer moment or shear. In most cases, the additional reduction in member forces and deflection of space frames is less than 10% as compared to space trusses. Therefore, the additional material required to provide rigid connections does not justify the saving in the size of structural members. As a result, the term “space frame” is also the term used for pin-jointed three-dimensional structures, such as space trusses. Space frames are also called ‘braced frameworks’, ‘latticed structures’ or ‘reticulated structures’. Space frames are either constructed from prefabricated modular units (modular system) or individual members assembled together using different types of connectors or nodes (nodular system). These systems are typically proprietary. It is also possible to construct space frames by field-welding members to each other; this is generally a more costly alternative. When field welding, the joints are considered to be rigidly connected, capable of transferring moment and shear in addition to axial forces.

A steel building is a metal structure fabricated with steel for the internal support and for exterior cladding, as opposed to steel framed buildings which generally use other materials for floors, walls, and external envelope. Steel buildings are used for a variety of purposes including storage, work spaces and living accommodation. They are classified into specific types depending on how they are used.Steel buildings first gained popularity in the early 20th century. Their use became more widespread during World War II and significantly expanded after the war when steel became more available. Steel buildings have been widely accepted, in part due to cost efficiency. The range of application has expanded with improved materials, products and design capabilities with the availability of computer aided design software.

Advantages:

Steel provides several advantages over other building materials, such as wood:

• Steel is a “green” product; it is structurally sound and manufactured to strict specifications and tolerances. It is also energy efficient. Any excess material is 100% recyclable.
• Steel does not easily warp, buckle, twist or bend, and is therefore easy to modify and offers design flexibility. Steel is also easy to install.
• Steel is cost effective and rarely fluctuates in price.
• Steel allows for improved quality of construction and less maintenance, while offering improved safety and resistance.
• With the propagation of mold and mildew in residential buildings, using steel minimizes these infestations. Mold needs moist, porous material to grow. Steel studs do not have those problems.

TYPES

Some common types of steel buildings are “straight-walled” and “arch,” or Nissen or Quonset hut. Further, the structural type may be classed as clear span or multiple span. A clear span building does not have structural supports (e.g. columns) in the interior occupied space.
Straight-walled and arch type refer to the outside shape of the building. More generally, these are both structural arch forms if they rely on a rigid frame structure. However, curved roof structures are typically associated with the arch term.
Steel arch buildings may be cost efficient for specific applications. They are commonly used in the agricultural industry. Straight-walled buildings provide more usable space when compared to arch buildings. They are also easier to blend into existing architecture. Straight-walled buildings are commonly used for commercial, industrial, and many other occupancy types.
Clear span refers to the internal construction. Clear span steel buildings utilize large overhead support beams, thus reducing the need for internal supporting columns. Clear span steel buildings tend to be less cost efficient than structures with interior columns. However, other practical considerations may influence the selection of framing style such as an occupancy where interior structural obstructions are undesirable (e.g. aircraft hangars or sport arenas).
Long Bay buildings are designed for use in bay spans of over 35′. They use prefabricated metal frames combined with conventional joists to provide larger openings and clearances in buildings.