Why Are Steel Columns Encased In Concrete?
Why Are Steel Columns Encased In Concrete?
Steel columns are typically encased in concrete to increase their structural strength and protect them from corrosion. The concrete also acts as a fireproofing material, reducing the risk of fire damage to the columns. Additionally, the concrete helps to dampen vibrations and prevent structural damage caused by movement or seismic activity. Encasing steel columns in concrete also helps to create a uniform and aesthetically pleasing look for the structure.
Concrete encased steel (CES) composite columns are those columns in which structural steel is encased inside reinforced concrete. By combining both materials, columns can handle a large load with a lesser cross-sectional area.
The reinforced concrete protects the steel from corrosion and weathering, while the steel provides strength and stiffness to the column.
CES composite columns are often used in buildings that are exposed to severe weather conditions, as the reinforced concrete can help protect the steel from corrosion. Additionally, CES composite columns are often used in buildings that are subjected to large lateral loads, as the steel can help resist buckling and shear failure.
While CES composite columns have many advantages, they can also be more expensive than traditional steel or concrete columns. Additionally, installing CES composite columns can be more difficult and time-consuming than traditional columns.
How Big Should Concrete Columns Be?
A reinforced concrete column (RCC) is a structural element that is used to support the weight of a building or bridge. The column should be designed to resist the bending and shear forces that are applied to it.
The size and shape of the column will be determined by the amount of load that it will have to carry. The standard size of an RCC column should not be less than 9”x 9” (225mm x 225mm) with 4 bars of 12mm Fe500 Steel with m20 grade of concrete.
It is recommended 9″ × 12″ (230mm × 300mm) standard size of RCC column for ground floor residential buildings. However, the size of the column may vary depending on the load that it has to carry. Columns should be designed to carry the loads they are expected to support. The size of the column should be based on the most significant expected load.
Do Concrete Columns Need Rebar?
Concrete resists compressive pressures, but it requires a steel reinforcing bar, also known as rebar, to deal with tensile stresses, which tend to rip it apart.
The primary function of columns as support structures is to withstand compressive forces, however, this is not always the case. Other forces are also at work, and downward forces can be converted from a vertical to a horizontal direction. Concrete columns can bend or rupture outward if not properly reinforced.
Here’s how to rebar columns:
Using a rebar cutter, cut the vertical parts of the column from the No. 4 rebar. Depending on the size of the column, a typical column contains four vertical parts.
Make the length the same as the distance between the top of the column and the bottom of the footing. Bend the last six inches of each vertical bar 90 degrees with a rebar cutter’s bending tool. The vertical bars should now be in the shape of an L.
The bottom of the L will aid in the integration of the column and the footing. The vertical parts’ height should now allow for three inches of space above and below the rebar.
Make rectangular stirrups out of the No. 3 rebar to encircle the vertical bars. Cut enough pieces to fit them vertically in the column at one foot in the center. Make each section four inches shorter than the column’s circumference.
Using the bending tool, bend the rectangular stirrups. Make each stirrup four inches shorter and four inches wider than the column’s length and breadth. This leaves 12 inches for overlapping. Tie each end of the overlap with pliers and tie wire.
Insert all of the upright pieces into the stirrups first, and then knot the top and bottom stirrups to form the shape of the rebar “cage.” Tie each of the four upright parts onto one of the rectangular stirrups’ four corners.
Tie them together securely using a tie wire. Make sure the bottom section of each L shape points away from the column’s center.
Slide the stirrups between the top and bottom stirrups into place with one foot in the center. Connect each corner to one of the upright bars.
Use dobies, which are tiny concrete blocks used for spacing and inserting rebar, to raise the final cage over the bottom of the foundation.
The dobies should keep the cage three inches above the ground, and the top of the cage three inches below the top of the column. Pour the footing while the rebar cage is still in place. After the footing has dried, construct the column forms around the rebar.
