engineering

Lally column

Lally column is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Lally column rather than just read about it. In short: A Lally column is a round or square thin-walled structural steel column filled with concrete, and oriented vertically to provide support to beams or timbers stretching over long spans. Historically, Lally columns were made of steel up to 6.4 millimeters (1⁄4 in) in thickness; today, that has been reduced in instances to 1.5 millimeters (0.06 in).

Key takeaways

Lally column belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Lally column to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Lally column from memory before moving on to harder problems.

Reference excerpt

A Lally column is a round or square thin-walled structural steel column filled with concrete, and oriented vertically to provide support to beams or timbers stretching over long spans. Historically, Lally columns were made of steel up to 6.4 millimeters (1⁄4 in) in thickness; today, that has been reduced in instances to 1.5 millimeters (0.06 in). As engineered structural load-bearing components, Lally columns must be installed to their specific design specs.

Fabrication

A Lally column is formed of tubular steel. It is then filled with concrete, which carries a share of the compression load, and helps prevent local buckling of the shell. In addition to its low cost, an advantage of a generic Lally column over a custom structural steel column (or conventional I-beam) is that it may be purchased in its tubular state and cut to length on a construction site with standard jobsite power tools such as an angle grinder or reciprocating saw fitted with appropriate metal cutting blades. Lally columns are generally not as strong or durable as conventional structural steel columns. The term "Lally column" is sometimes confused with a screw jack, a temporary rather than permanent steel support.

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, United States, and Boston during the period 1898–1907. He was issued four U.S. patents on composite columns: Nos. 614729, 869869, 901453, and 905888. Patent No. 869869 was assigned to the U.S. Column Company of Cambridge, Massachusetts.

Design development Early Lally columns were made with structural steel, "standard" pipes, with wall thicknesses slightly less than 6.4 millimeters (1⁄4 in). Modern Lally columns are typically made with 16-gauge (approximately 1.5 millimeters or 0.06 inches) 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

External links Examples of Uses History of inventor John Lally

Worked examples

Example 1 — a first encounter with Lally column

Start with the simplest possible case. Write down what Lally column claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Lally column before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Lally column ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Lally column

In research: Lally column appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Lally column in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Lally column is common in secondary-school and first-year university syllabi. It links to neighbouring topics Architecture stubs, Structural engineering, Structural steel, so understanding it makes those chapters shorter.
In everyday life: Look for Lally column outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Lally column in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Lally column means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Lally column out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Lally column in simple terms?

Why does Lally column matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Lally column?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Lally column.