A Lally column is a round or square thin-walled
structural steel
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, ...
column
A column or pillar in architecture and structural engineering is a structural element that transmits, through compression, the weight of the structure above to other structural elements below. In other words, a column is a compression member. ...
filled with concrete and oriented vertically to provide support to
beams or timbers stretching over long
spans.Lally columns are an engineered Component and as such must be installed exactly as the design engineer specified.
Fabrication
The steel shell of a Lally column is filled with
concrete
Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wi ...
, which carries a share of the compression load, and helps prevent local buckling of the shell.
The advantage of a Lally column over conventional structural steel is the ability to cut it to length on a construction site with simple
hand tool
A hand tool is any tool that is powered by hand rather than a motor. Categories of hand tools include wrenches, pliers, cutters, files, striking tools, struck or hammered tools, screwdrivers, vises, clamps, snips, hacksaws, drills, and kni ...
s such as a plumber's
pipe cutter or a
reciprocating saw
A reciprocating saw is a type of machine-powered saw in which the cutting action is achieved through a push-and-pull ("reciprocating") motion of the blade. The original trade name Sawzall is often used in the United States, where Milwaukee Electr ...
. Lally columns are generally not as strong or durable as conventional structural steel columns. The term "lally column" is sometimes incorrectly used in reference to other types of
prefabricated
Prefabrication is the practice of assembling components of a structure in a factory or other manufacturing site, and transporting complete assemblies or sub-assemblies to the construction site where the structure is to be located. The term is u ...
steel columns.
Invention
The Lally column is named after a U.S. inventor, John Lally, who owned a construction company that started production of these columns in the late 19th century. He resided in
Waltham, Massachusetts
Waltham ( ) is a city in Middlesex County, Massachusetts, United States, and was an early center for the labor movement as well as a major contributor to the American Industrial Revolution. The original home of the Boston Manufacturing Company, th ...
and
Boston
Boston (), officially the City of Boston, is the state capital and most populous city of the Commonwealth of Massachusetts, as well as the cultural and financial center of the New England region of the United States. It is the 24th- mo ...
during the period 1898–1907. He was issued four U.S.
Patent
A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an enabling disclosure of the invention."A p ...
s on composite columns: #614729, #869869, #901453, and #905888. Pat. #869869 was assigned to the U.S. Column Company of
Cambridge, Massachusetts
Cambridge ( ) is a city in Middlesex County, Massachusetts, United States. As part of the Boston metropolitan area, the cities population of the 2020 U.S. census was 118,403, making it the fourth most populous city in the state, behind Boston, ...
.
Design development
Early Lally columns were made with structural steel, "standard" pipes, with wall thicknesses slightly less than 1/4". Modern Lally columns are typically made with 16
ga. (approx. 0.06") shells. Modern Lallies are therefore much lower in strength than the older ones (typically less than half the strength), and are also much more subject to damage by corrosion in moist environments.
Modern Lally columns are primarily intended as somewhat stronger and more durable substitutes for wood posts in light-frame wood construction, although they are sometimes also used with steel beams.
References
1 Adjustable Steel Columns, October home inspections
External links
Examples of Uses History of inventor John LallyHome Inspection maintenance
Structural engineering
Structural steel
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