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.

Contents

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.

Ships

Contemporary drawings of composite construction The Composite Construction - 322.jpg
Contemporary drawings of composite construction
Internal view of HMS Gannet, with the iron frames and timber planking visible Rifled muzzle loader HMS Gannet.JPG
Internal view of HMS Gannet, with the iron frames and timber planking visible

In 19th-century shipbuilding, composite construction was the use of an iron hull framework which was covered in timber planking to provide the water-tight skin of the hull. If properly insulated fastenings were used on the timber, the underwater hull could be covered with copper sheathing without the problem of galvanic corrosion. Copper sheathing prevented fouling and teredo worm, but could not be used on iron hulls. The iron framework of composite ships was less bulky and lighter than timber, so allowing more cargo in a hull of the same external shape. The weight saving was particularly significant. The strength and stiffness allowed sailing vessels to be driven hard as the accumulated straining of the hull did not produce the leaks that would develop in the older wooden built ships. [2] :84–88

Composite hulls were used for the majority of the clippers built from the mid-1860s. Early experiments with the system started with a patent issued in 1839, under which the steamer Assam was built. Other patents followed, with differing methods of electrically insulating the iron frames and fastenings from the copper sheathing. [2] :84–88

Surviving examples are HMS Gannet (1878), a steam and sail-powered warship, and the clipper Cutty Sark.

House building

A flitch beam is a simple form of composite construction sometimes used in North American light frame construction. [3] 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. [4] [5]

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. [6] [7] [8]

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. [9]

See also

Related Research Articles

<span class="mw-page-title-main">Reinforced concrete</span> Concrete with rebar

Reinforced concrete, also called 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.

<span class="mw-page-title-main">Lumber</span> Wood that has been processed into beams and planks

Lumber is wood that has been processed into uniform and useful sizes, including beams and planks or boards. Lumber is mainly used for construction framing, as well as finishing. Lumber has many uses beyond home building. Lumber is referred to as timber in the United Kingdom, Europe, Australia, and New Zealand, while in other parts of the world the term timber refers specifically to unprocessed wood fiber, such as cut logs or standing trees that have yet to be cut.

<span class="mw-page-title-main">Engineered wood</span> Range of derivative wood products engineered for uniform and predictable structural performance

Engineered wood, also called mass timber, composite wood, human-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.

<span class="mw-page-title-main">Boat building</span> Design and construction of floating vessels

Boat building is the design and construction of boats and their systems. This includes at a minimum a hull, with propulsion, mechanical, navigation, safety and other systems as a craft requires.

<span class="mw-page-title-main">Railroad tie</span> Support for the rails in railroad tracks

A railroad tie, crosstie, railway tie or railway sleeper is a rectangular support for the rails in railroad tracks. Usually laid perpendicular to the rails, ties transfer loads to the track ballast and subgrade, hold the rails upright and keep them spaced to the correct gauge.

<span class="mw-page-title-main">Beam (structure)</span> Structural element capable of withstanding loads by resisting bending

A beam is a structural element that primarily resists loads applied laterally across the beam's axis. Its mode of deflection is primarily by bending, as loads produce reaction forces at the beam's support points and internal bending moments, shear, stresses, strains, and deflections. Beams are characterized by their manner of support, profile, equilibrium conditions, length, and material.

<span class="mw-page-title-main">Deck (building)</span> 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.

<span class="mw-page-title-main">Joist</span> Horizontal framing structure

A joist is a horizontal structural member used in framing to span an open space, often between beams that subsequently transfer loads to vertical members. When incorporated into a floor framing system, joists serve to provide stiffness to the subfloor sheathing, allowing it to function as a horizontal diaphragm. Joists are often doubled or tripled, placed side by side, where conditions warrant, such as where wall partitions require support.

This page is a list of construction topics.

<span class="mw-page-title-main">Laminated veneer lumber</span> Engineered Wood Product used in wood frame construction

Laminated veneer lumber (LVL) is an engineered wood product that uses multiple layers of thin wood assembled with adhesives. It is typically used for headers, beams, rimboard, and edge-forming material. LVL offers several advantages over typical milled lumber: Made in a factory under controlled specifications, it is stronger, straighter, and more uniform. Due to its composite nature, it is much less likely than conventional lumber to warp, twist, bow, or shrink. LVL is a type of structural composite lumber, comparable to glued laminated timber (glulam) but with a higher allowable stress. A high performance more sustainable alternative to lumber, Laminated Veneer Lumber (LVL) beams, headers and columns are used in structural applications to carry heavy loads with minimum weight.

<span class="mw-page-title-main">Framing (construction)</span> Construction technique

Framing, in construction, is the fitting together of pieces to give a structure support and shape. Framing materials are usually wood, engineered wood, or structural steel. The alternative to framed construction is generally called mass wall construction, where horizontal layers of stacked materials such as log building, masonry, rammed earth, adobe, etc. are used without framing.

<span class="mw-page-title-main">Formwork</span> Molds for cast

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.

<span class="mw-page-title-main">Structural steel</span> 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.

<span class="mw-page-title-main">Domestic roof construction</span> The supporting structure of a roof

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.

<span class="mw-page-title-main">Sandwich-structured composite</span> Material composed of two thin, stiff skins around a lightweight core

In materials science, 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 of low strength, but its greater 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.

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.

<span class="mw-page-title-main">Structural material</span>

Structural engineering depends on the knowledge of materials and their properties, in order to understand how different materials resist and support loads.

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, Nabil A.; Booth, Michael (August 2006). "Innovative Mid Rise Construction" (PDF). Structure Magazine. Archived (PDF) from the original on September 30, 2006. Retrieved 2024-05-09.
  2. 1 2 MacGregor, David R. (1983). The Tea Clippers, Their History and Development 1833-1875. Conway Maritime Press Limited. ISBN   0-85177-256-0.
  3. DeStefano, P.E., Jim. "Flitch Plate Beams: Design Guide" (PDF). Structure Magazine. Archived (PDF) from the original on September 27, 2007. Retrieved 2024-05-09.
  4. 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.
  5. "Recycling Facts". Trex Company, Inc.
  6. "Composite Construction". steelconstruction.info. Retrieved 2014-11-09.
  7. "Composite Steel Joist - Steel Joist Institute (SJI)". Archived from the original on 2014-10-06. Retrieved 2014-11-09.
  8. "Structural Steel in Construction". ConstructionKnowledge.net. Retrieved 2014-11-09.
  9. 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