Castellated Beams: History, Properties, and Advantages

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A castellated beam is a type of beam in which an I-beam is sliced longitudinally along its web in a specified pattern. The objective is to use the cutting pattern to separate and reunite the beam with a deeper web.

These beams are classified based on the shape of the holes provided in the web section. Hexagonal, circular (also known as cellular opening), octagonal, diamond, etc., are the most common shapes of openings.

Castellated beams have 1.5 times more depth than the parent section, while their weight is almost the same. Welding square or rectangular plates between the cut halves creates an even deeper castellated beam with octagonal holes in its body.

History of Castellated Beams

The Castellated beam name is derived from the Latin word "castellatus" meaning "built like a castle having regular openings in walls like a castle." These beams were designed as structural channels to improve the depth and strength of the beam without adding more material or weight. 

Engineers faced steel shortages after WWII, and they discovered that castellated beams were cheap to build and had an excellent strength-to-weight ratio. 

As a result, castellated beams have been the preferred building solution since the 1950s and were commonly used in Europe to decrease the cost of steel structures due to the low ratio of labor cost to material cost.

Properties of Castellated Beams

The properties of castellated beams are:

1. Highly Efficient Steel

The principal property of a castellated beam is that we can increase the depth of the beam without increasing its weight. As a result, castellated beams are highly efficient when it comes to enhancing the load-bearing capacity. They have 40% more moment-carrying capacity with no added steel.

2. Beam Length

The length of the beam can be increased up to 28 m which makes the castellated beam optimal for wide-span and wide-open bay designs.

3. Asymmetric Design

Unique split fabrication of beam gives the ability to lower the weight of the top half of the beam, thus increasing the load-carrying capacity while minimizing the weight of the beam.

4. Other Properties

1. The design and erection of the castellated beam are elegantly simple. 
2. The physical characteristics of the castellated beam can be changed to achieve several goals. This beam can be customized from section to section; thus, the castellated beam is extremely versatile.
3. The weight of the beam can be lowered up to 40% when compared to the wide flange steel beam.

Advantages of Castellated Beams

 The advantages of castellated beams are:

1. The length of the castellated beam can be extended up to 90 ft.
2. A castellated beam enhances the aesthetic appearance of a structure.
3. It allows natural light into the structure.
4. Castellated beam lowers the floor-to-floor height as MEP lines are passed through the web openings.
5. Castellated beams have a higher moment carrying capacity with no added steel
6. The depth of the beam can be increased up to 66 inches.
7. Installation is fast and easy as the span of the beam is longer.
8. Handling of the beam is easy due to the lighter weight
9. The installation cost of castellated beam is 10% less compared to concrete beam
10. Castellated beam requires low maintenance
11. It has a high stiffness-to-weight ratio
12. It minimizes the floor vibration issues
13. The overall cost of the structure will be reduced as castellated beams are more economical.
14. The beam can be designed asymmetrically in case of increased loads
15. It can be used in the construction of precast and prestressed concrete slab floor construction.

Application of Castellated Beams

Castellated beams were most commonly used for parking garages because of their long-span capabilities. Nowadays, castellated beams are used in all types of floor and roof structures.

FAQs

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