What Is Lally Column? What Are The Strengths Of The Lally Column?
What Is Lally Column?
A Lally column is a steel column for structural purposes with a thin shell, less than ¼ inch thick, leaving most of the interior as open space. To enhance its stability, the column is typically filled with concrete, which provides compressive resistance and prevents local buckling.
The concrete-filled Lally column is widely used vertically, especially in basement construction, providing support for the first floor’s wood beams. John Lally invented and patented the design, and utilized it in his construction business, which led to the column’s name.
A Lally column differs from conventional structural steel in that it can be cut to length on-site with basic tools like a plumber’s pipe cutter or reciprocating saw. However, it is not as strong or durable as conventional steel columns. The term “Lally column” is sometimes mistakenly applied to other prefabricated steel columns.
What Are The Strengths Of The Lally Column?
The Lally column is known for its structural stability. Made of cost-effective materials like steel and concrete, it also has versatility as it is mostly hollow and can be easily cut with smaller tools. These advantages make it a popular choice among construction workers.
Weaknesses Of The Lally Column
A lally column’s strength depends on the quality of materials used. Poor concrete and steel result in rapid wear and tear. Also, moisture can cause corrosion in lally columns. However, they are still popular for supporting various structures and whether it’s suitable for you depends on your specific needs.
Installing A Lally Column
The following instructions are for the installation of an adjustable steel lally column on a solid concrete floor footing and beneath a solid load-bearing beam such as a laminated veneer lumber (LVL) beam. To begin, measure the vertical distance that the column will span.
Each class of lally column has an adjustable range, typically four inches. When choosing a column, ensure that it is slightly shorter than the distance to be spanned. For instance, if the height to be supported is eight feet, select a column that ranges from 7′ 9″ to 8′ 1″. Minimizing the elevation of the screw portion of the column helps to increase its strength.
Next, attach the metal plate to the bottom of the LVL beam, pre-drilling holes to prevent cracking. Remove the plate once it is in place. Then, attach the plate to the top of the lally column.
Turn the machine screw on the column so that it is about 1/2-inch short of the floor to the bottom of the beam. Slide the column into place, following the manufacturer’s instructions for placement direction.
Some columns are placed with the machine screw on the top, while others are placed at the bottom. Turn the screw until the column is snug against the beam, without jacking it up.
Finally, if the adjustment mechanism’s lever is removable, remove it and keep it in a safe location. It may be necessary to make adjustments in the future, so keep the lever nearby.