What Is an I Beam and Why Is It Used?

I beam is a shape of structural steel used in buildings and it is also known as H, W, wide, universal beam or rolled joist. They are designed to play a key role as a support member in structures. These beams have the capacity to withstand various types of loads.

Its name was given so because of the resemblance of its cross section to the letter I. These beams are frequently utilized to form beams and columns in a variety of dimensions and specs. It is crucial for civil engineers and foremen to understand the importance of I beams in steel structures.

Design of an I Beam

An I beam is designed by using two long-drawn out planes called flange, connected by a perpendicular component called web. The whole body of this structural member has an I or H shaped cross section. Alongside with the steel, beams made out of aluminum alloys and low alloy steels also exist to be used in different purposes such as bridges, building frames etc.

I beams are produced in various dimensions, thicknesses, widths and other specs for various applications. Customers classify I beams according to their material type and sizes. For instance, a 12-inch in depth and 20 pounds/foot in weight beam is specified as 12×20. Contractors select appropriate dimensions of beams for their project’s needs. When decisions are being made, following factors should be considered:

  1. Deflection. Thickness of I beam should be adequate enough for minimizing the deflection.
  2. Vibration.  As little vibration as possible should be aimed when choosing the I beam. Stiffness and mass of the beam is important in this regard.
  3. Bending. Bulk body of the I beam should be strong enough to withstand yield stresses. Otherwise bending occurs.
  4. Buckling. Torsional stresses cause I beam to buckle which can lead to undesired consequences. Flanges should be selected accordingly.
  5. Tension. Selecting an I beam with right web thickness is vital to prevent rippling or buckling under tension.

I beams are designed to bend rather than buckle when under high load. Density of the beam is non-uniform. Regions where the axial fibers are located have higher density to counterbalance the highest stress point. Beams having small cross section area are more ideal since less material is needed without compromising from the desired shape.

Where I Beams Are Used?

I beams are intensively used in different applications of steel construction area. Frames and vital support elements are where generally I beams are used. Strong and supportive structure is ensured with the usage of steel I beams. Usage of I beams can be economically beneficial since they reduce the necessity to use too many support components. Versatile and dependable nature makes them indispensable for every contractor and engineer.

I I beams are frequently used in constructions because they are simply functional. Unidirectional bending behavior of I beams are one of their best unique properties. Web component is responsible from withstanding against shear stresses while flanges put resistance against bending. They are capable of meeting a variety of loads with no buckling. Since the I shape does not require usage of excessive steel, they can be considered cost effective. There always exists a suitable type of I beam for every construction purpose. Applicability of these beams for all construction scenarios gives its famous name “universal beam” for a good reason.


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