What Are Beams and Columns in Structural Engineering?

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Beams and columns are two types of structural elements that play a vital part in transferring the weight and pressures on a structure to the foundations and into the earth in a safe manner. Although beams and columns are made of the same shapes and materials, they serve different purposes and are constructed differently.

Beams are horizontal structural elements that carry loads parallel to their longitudinal axis. Consider a gymnastics balance beam. It's a 15-foot-long rectangular object that's supported on both ends. When a person walks on the beam towards the middle, their weight acts as a vertical downward force acting perpendicular to the beam's longitudinal direction.

Beams are utilised to sustain the weight of a building's floors, ceilings, and roofs while also transferring the load to a vertical load bearing element. To support the cumulative weight of stacked walls or other beams and transfer the load to the supports, larger and heavier beams known as transfer beams are sometimes employed.

Beam design or sizing necessitates an understanding of fundamental physics principles as well as engineering statics. A structural engineer is qualified and equipped to examine the loads operating on a beam, calculate the forces and stresses acting on it, and select the appropriate material, size, and shape. Structural design of beams in new buildings, as well as restoration or strengthening of existing beams in a structure, are part of the engineering consulting services I deliver to my clients.

In the case of a new building, the size and type of materials for beams that work best for the structure are more flexible. Steel section beams, reinforced concrete, grouted masonry, and wood beams are the most typical types of materials I offer to my clients. All materials have advantages and disadvantages, although they are often chosen based on their cost, size, and fire rating.

There are a few elements I consider when working on the structural design of a new beam or the restoration of an existing one. The amount of weight acting on the beam, the length or span of the beam, the clear height available below the beam or any geometry limitations, the beam's deflection limits, the material's strength, and the fire rating and resistance are all aspects to consider. When designing columns, similar considerations are made.

Columns are vertical structural elements where the load is transferred parallel to the longitudinal axis as compression, and sometimes as tension . For example, think of a rectangular table with four legs at the corners. The weight of the table and all the objects on the table is transferred to the floor through the legs acting in compression. In this case the legs can be considered as columns.

Columns are used to support floor/roof beams and the columns of the floor above. The columns at the bottom floor of a tall building must carry the accumulative weight of all the floors above. This is why the location of columns ideally should be consistent throughout all floors. This is not always possible especially with a challenging architectural design where each floor has a different layout. In such cases I often encourage clients to engage the structural design team early in the project to collaborate with the architects to brainstorm the most ideal column layout.

When designing a column in a new building I take a few factors into consideration. I start with calculating the weight of floors/roof supported by the column then choose the material and size as required. The height of the column plays a major part in the overall size of the column. A column that supports 1000 pounds and is 10 feet tall may need to be twice as large as a column supporting 1000 pounds and is 20 feet tall. It all depends on the columns geometry and material properties.

Hopefully this gives you a good idea as to what beams and columns are in a structure and building, and why they are very important structural elements that cannot be overlooked. Next time you walk into a building or drive over a bridge, try taking a look around and figure out which elements you see are used as beams and which are columns. If you are stuck or have any questions with regards to the structure you are looking at, feel free to leave a comment below and we would be happy to help you out!