Composite construction

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. It is not to be confused with the Composite order which is a specific order of classical architecture that combines elements of the Ionic and Corinthian orders.

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

The traditional decking material is pressure treated wood. The current material many contractors choose to use is composite decking. This material is made from plastic reinforced with plastic to give it strength and longevity. 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]

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 effecting the appearance of the cement. This new material was tested for strength and durability using American Society for Testing and Materials (ASTM International) standards. ^[4]

See also

• Structural analysis
• Composite material
• Reinforced concrete
• Framing (construction)
• Construction

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
2. ^ http://www.structuremag.org/archives/2007/June%202007/D-From%20Exp%20Flitch%20Plates%20DeStefano-pac-5-10-07.pdf Structure Magazine
3. ^ Composite Decking. (n.d.). Retrieved June 22, 2010, from ToolBase Services: http://www.toolbase.org/Technology-Inventory/Decks-Patios-Fences/composite-decking
4. ^ 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