Composite construction

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Composite construction is a generic term to describe any building construction involving multiple dissimilar materials. Composite construction is often used in building aircraft, watercraft, and building construction. There are several reasons to use composite materials including increased strength, aesthetics, and environmental sustainability.

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Structural engineering

In structural engineering, composite construction exists when two different materials are bound together so strongly that they act together as a single unit from a structural point of view. When this occurs, it is called composite action. One common example involves steel beams supporting concrete floor slabs. [1] If the beam is not connected firmly to the slab, then the slab transfers all of its weight to the beam and the slab contributes nothing to the load carrying capability of the beam. However, if the slab is connected positively to the beam with studs, then a portion of the slab can be assumed to act compositely with the beam. In effect, this composite creates a larger and stronger beam than would be provided by the steel beam alone. The structural engineer may calculate a transformed section as one step in analyzing the load carry capability of the composite beam.

House building

A flitch beam is a simple form of composite construction sometimes used in North American light frame construction. [2] This occurs when a steel plate is sandwiched between two wood joists and bolted together. A flitch beam can typically support heavier loads over a longer span than an all-wood beam of the same cross section.

Deck construction

Composite wood decking

The traditional decking material is pressure-treated wood. The current material many contractors choose to use is composite decking. This material is typically made from wood-plastic composite or Fiberglass Reinforced Plastic (FRP). Such materials do not warp, crack, or split and are as versatile as traditional pressure treated wood. Composite decking is made through several different processes, and there are a multitude of sizes, shapes, and strengths available. Depending on the type of composite selected the decking materials can be used for a number of other construction projects including fences and sheds. [3] [4]

Composite steel deck

In a composite steel deck, the dissimilar materials in question are steel and concrete. A composite steel deck combines the tensile strength of steel with the compressive strength of concrete to improve design efficiency and reduce the material necessary to cover a given area. Additionally, composite steel decks supported by composite steel joists can span greater distances between supporting elements and have reduced live load deflection in comparison to previous construction methods. [5] [6] [7]

Cement-polymer composites

Cement-polymer composites are being developed and tested as a replacement for traditional cement. The traditional cement used as stucco rapidly deteriorates. The deterioration causes the material to easily crack due to thermo-processes becoming permeable to water and no longer structurally sound. The United States Environmental Protection Agency in conjunction with Materials and Electrochemical Research Corporation tested a cement-polymer composite material consisting of crumb rubber made from recycled rubber tires and cement. It was found that 20% crumb rubber can be added to the cement mixture without affecting the appearance of the cement. This new material was tested for strength and durability using American Society for Testing and Materials (ASTM International) standards. [8]

High-performance composites

A newer but growing sector in the composite construction sector is the high-performance decking that comes from companies like Trex Decking and Fiberon. [9] [10] High performance composite decking has emerged in recent years to combat earlier generations of composite decking like wood plastic composite (WPCs) that were struggling to maintain credibility in the marketplace. [11]

Research is showing now, however, that consumers are choosing composite decking products over wood 11 times to 1. Initial concerns regarding moisture intrusion in composite decks has led to the rise of high performance decking products with protective shells, often referred to as “capped composite decking.” [12]

Capped composite decks have a high performance finish with the addition of the shell that is often called a “cap-stock.” This shell covers either all four sides of the composite board or just the top and sides, depending on the brand. Manufacturers apply the cap to the board using a process called co-extrusion. Most capped composite decking comes with some kind of warranty against stains and fading. [12]

See also

Related Research Articles

Concrete Composite construction material

Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most widely used building material. Its usage worldwide, ton for ton, is twice that of steel, wood, plastics, and aluminum combined. Globally, the ready-mix concrete industry, the largest segment of the concrete market, is projected to exceed $600 billion in revenue by 2025. This widespread use results in a number of environmental impacts. Most notably, the production process for cement produces large volumes of greenhouse gas emissions, leading to net 8% of global emissions. Other environmental concerns include widespread illegal sand mining, impacts on the surrounding environment such as increased surface runoff or urban heat island effect, and potential public health implications from toxic ingredients. Significant research and development is being done to try to reduce the emissions or make concrete a source of carbon sequestration, and increase recycled and secondary raw materials content into the mix to achieve a circular economy. Concrete is expected to be a key material for structures resilient to climate disasters, as well as a solution to mitigate the pollution of other industries, capturing wastes such as coal fly ash or bauxite tailings and residue.

Reinforced concrete Concrete with rebar

Reinforced concrete (RC), also called reinforced cement concrete (RCC) and ferroconcrete, is a composite material in which concrete's relatively low tensile strength and ductility are compensated for by the inclusion of reinforcement having higher tensile strength or ductility. The reinforcement is usually, though not necessarily, steel bars (rebar) and is usually embedded passively in the concrete before the concrete sets. However, post-tensioning is also employed as a technique to reinforce the concrete. In terms of volume used annually, it is one of the most common engineering materials. In corrosion engineering terms, when designed correctly, the alkalinity of the concrete protects the steel rebar from corrosion.

Lumber Wood that has been processed into beams and planks

Lumber, also known as timber, is wood that has been processed into beams and planks, a stage in the process of wood production. Lumber is mainly used for construction framing, as well as finishing. Lumber has many uses beyond home building.

Floor Walking surface of a room

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.

Engineered wood Range of derivative wood products engineered for uniform and predictable structural performance

Engineered wood, also called mass timber, composite wood, man-made wood, or manufactured board, includes a range of derivative wood products which are manufactured by binding or fixing the strands, particles, fibres, or veneers or boards of wood, together with adhesives, or other methods of fixation to form composite material. The panels vary in size but can range upwards of 64 by 8 feet and in the case of cross-laminated timber (CLT) can be of any thickness from a few inches to 16 inches (410 mm) or more. These products are engineered to precise design specifications, which are tested to meet national or international standards and provide uniformity and predictability in their structural performance. Engineered wood products are used in a variety of applications, from home construction to commercial buildings to industrial products. The products can be used for joists and beams that replace steel in many building projects. The term mass timber describes a group of building materials that can replace concrete assemblies. Broad-base adoption of mass timber and their substitution for steel and concrete in new mid-rise construction projects over the next couple decades could help mitigate climate change.

Beam (structure) Structural element capable of withstanding loads by resisting bending

A beam is a structural element that primarily resists loads applied laterally to the beam's axis. Its mode of deflection is primarily by bending. The loads applied to the beam result in reaction forces at the beam's support points. The total effect of all the forces acting on the beam is to produce shear forces and bending moments within the beams, that in turn induce internal stresses, strains and deflections of the beam. Beams are characterized by their manner of support, profile, equilibrium conditions, length, and their material.

Deck (building) Surface similar to a floor, but typically constructed outdoors and connected to a building

In architecture, a deck is a flat surface capable of supporting weight, similar to a floor, but typically constructed outdoors, often elevated from the ground, and usually connected to a building. The term is a generalization from the deck of a ship. A level architectural deck may be intended for use by people, e.g., what in the UK is usually called a decked patio. "Roof deck" refers to the flat layer of construction materials to which the weather impervious layers are attached to a form a roof. It is known as the "roof deck", and they may be either level or sloped.

Fibre-reinforced plastic is a composite material made of a polymer matrix reinforced with fibres. The fibres are usually glass, carbon, aramid, or basalt. Rarely, other fibres such as paper, wood, or asbestos have been used. The polymer is usually an epoxy, vinyl ester, or polyester thermosetting plastic, though phenol formaldehyde resins are still in use.

This page is a list of construction topics.

Formwork

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.

Structural steel Type of steel used in construction

Structural steel is a category of steel used for making construction materials in a variety of shapes. Many structural steel shapes take the form of an elongated beam having a profile of a specific cross section. Structural steel shapes, sizes, chemical composition, mechanical properties such as strengths, storage practices, etc., are regulated by standards in most industrialized countries.

Flitch beam

A flitch beam is a compound beam used in the construction of houses, decks, and other primarily wood-frame structures. Typically, the flitch beam is made up of a vertical steel plate sandwiched between two wood beams, the three layers being held together with bolts. In that common form it is sometimes referenced as a steel flitch beam. Further alternating layers of wood and steel can be used to produce an even stronger beam. The metal plates within the beam are known as flitch plates.[1] Flitch beams were used as a cost-effective way to strengthen long-span wooden beams, and have been largely supplanted by more recent technology.

Girder bridge

A girder bridge is a bridge that uses girders as the means of supporting its deck. The two most common types of modern steel girder bridges are plate and box.

Sandwich-structured composite

A sandwich-structured composite is a special class of composite materials that is fabricated by attaching two thin but stiff skins to a lightweight but thick core. The core material is normally low strength material, but its higher thickness provides the sandwich composite with high bending stiffness with overall low density.

This is an alphabetical list of articles pertaining specifically to structural engineering. For a broad overview of engineering, please see List of engineering topics. For biographies please see List of engineers.

Glass fiber reinforced concrete (GFRC) is a type of fiber-reinforced concrete. The product is also known as glassfibre reinforced concrete or GRC in British English. Glass fiber concretes are mainly used in exterior building façade panels and as architectural precast concrete. Somewhat similar materials are fiber cement siding and cement boards.

Fiber-reinforced concrete or fibre-reinforced concrete (FRC) is concrete containing fibrous material which increases its structural integrity. It contains short discrete fibers that are uniformly distributed and randomly oriented. Fibers include steel fibers, glass fibers, synthetic fibers and natural fibers – each of which lend varying properties to the concrete. In addition, the character of fiber-reinforced concrete changes with varying concretes, fiber materials, geometries, distribution, orientation, and densities.

Open web steel joist

In structural engineering, the open web steel joist (OWSJ) is a lightweight steel truss consisting, in the standard form, of parallel chords and a triangulated web system, proportioned to span between bearing points.

T-beam

A T-beam, used in construction, is a load-bearing structure of reinforced concrete, wood or metal, with a T-shaped cross section. The top of the T-shaped cross section serves as a flange or compression member in resisting compressive stresses. The web of the beam below the compression flange serves to resist shear stress and to provide greater separation for the coupled forces of bending.

This glossary of structural engineering terms pertains specifically to structural engineering and its sub-disciplines. Please see glossary of engineering for a broad overview of the major concepts of engineering.

References

  1. Rahman, N. A., & Booth, M. (2006, August). Innovative Mid Rise Construction. Retrieved from Structure Magazine: http://www.structuremag.org/archives/2006/August-2006/C-CI-Innovative-Mid-Rise-Aug-06.pdf Archived September 30, 2006, at the Wayback Machine
  2. http://www.structuremag.org/archives/2007/June%202007/D-From%20Exp%20Flitch%20Plates%20DeStefano-pac-5-10-07.pdf Structure Magazine Archived September 27, 2007, at the Wayback Machine
  3. Composite Decking. (n.d.). Retrieved June 22, 2010, from ToolBase Services: "Composite Decking". Archived from the original on 2013-04-16. Retrieved 2010-06-26.
  4. "Recycling Facts". Trex Company, Inc.
  5. "Composite Construction - Steelconstruction.info" . Retrieved 2014-11-09.
  6. "Composite Steel Joist - Steel Joist Institute (SJI)". Archived from the original on 2014-10-06. Retrieved 2014-11-09.
  7. "Structural Steel in Construction from Construction Knowledge.net" . Retrieved 2014-11-09.
  8. Loutfy, R. O. (2005, April 25). National Center For Environmental Research, US EPA. Retrieved June 14, 2010, from Final Report: Cement-Polymer Composites From Recycled Polymers for Construction: http://cfpub.epa.gov/ncer_abstracts/index.cfm/fuseaction/display.abstractDetail/abstract/6970/report/F
  9. "Trex". Trex Company, Inc. Retrieved 3 September 2013.
  10. Presley, Aaron (May 22, 2014). "Fiberon decking (several styles of composite lumber for decks)" . Retrieved 2019-07-12.
  11. Gwatney, Brent (2013). "Two Decades of Composite Decking: Where the Industry Has Been and What's Next". GreenExpo365.com. Archived from the original on 2013-09-21. Retrieved 2013-09-09.
  12. 1 2 Booker, Tom (2013). "10 Things You Should Know About Composite Decking". Decks of Distinction.[ permanent dead link ]