In this article, we’re going to discuss about the various types of beams that are employed in construction. Beams are like the unsung heroes of the structural game, taking on the heavy lifting when it comes to carrying all those loads. So, if beams are missing from the equation, you can bet your bottom dollar that there won’t be any structure left standing.
Beam Definition in Strength of Materials (SOM)
A beam is a structural element that supports various loads and withstands vertical forces, shear, and bending. We can also define beam as a structural element which is designed to bear diverse loads, including the challenge of uniformly distributed loads, while effectively withstanding vertical forces, shear, and bending.
Types of Beams
Have you thought about what are the 6 main types of support conditions in beams? Following is the classification of a beam:
- According to Support at the End
- Simply Supported Beam
- Continuous Beams
- Overhanging Beams
- Cantilever Beams
- Fixed beams
- According to equilibrium condition
- Statically determinate beam
- Statically indeterminate beam
- Based on Construction Materials
- Reinforced Concrete Beams
- Steel Beams
- Timber beams
- Composite Beams
- Based on Cross-Section Shapes
- Rectangular beam
- T-section beam
- L-section beam
- Based on Geometry
- Straight beam
- Curved beam
- Tapered beam
- Based on Method of Construction
- Cast In-situ Concrete Beam
- Precast Concrete Beam
- Prestressed Concrete Beam
Let’s discuss about each type in detail.
According to Support at the End
Simply Supported Beam
A simply supported beam is named for its support at both ends. One end rests on a hinge support, and the other on a roller support, enabling horizontal movement. This type of beam experiences both shear stress and bending moment.
When discussing beam types, the continuous beam is essential to mention. Similar to a simply supported beam, it incorporates more than two supports. It has a hinged support at one end and a roller support at the other, with additional supports between them. Continuous beams find application in lengthy concrete bridges.
An overhanging beam combines features of a simply supported beam and a cantilever beam. It has one or both ends extending beyond the supports. Roller support is employed between the ends. This beam type inherits characteristics from both cantilever and simply supported beams.
Cantilever beams are structural elements with one end fixed and the other end free. This widely used beam type features in trusses, bridges, and various other structures. It bears loads across its span, experiencing both shear stress and bending moment.
This beam is fully fixed at both ends. It prevents vertical movement and rotation. It only experiences shear stress and lacks any bending moment. It has application in trusses and other structures.
According to equilibrium condition
Statically determinate beam
A beam is termed determinate if its analysis can be performed using basic equilibrium conditions. Support reactions are determined through these conditions: the summation of horizontal forces is zero, the summation of vertical forces is zero, and the summation of moments is zero. Examples include simply supported beams and cantilever beams.
Statically indeterminate beam
Equilibrium conditions alone are insufficient to determine reactions for a statically indeterminate beam. Therefore, analyzing such beams is more intricate compared to statically determinate ones.
Based on Construction Materials
Reinforced Concrete Beams
Fabricated using concrete and reinforcement, as depicted in Figure 5, a reinforced concrete beam is at times enveloped within reinforced concrete slabs, earning it the designation of a hidden beam or concealed beam.
Forged from steel, this type of beam finds utility across a multitude of applications. It has a similar application like Girder which is also used for heavy applications.
Crafted out of timber, the timber beam saw prevalent usage in the past. Nonetheless, its utilization within the construction sector has markedly diminished over time.
Composite beams are fashioned by integrating two or more distinct materials, such as steel and concrete.
Based on Cross-Section Shapes
A multitude of cross-sectional profiles for beams are accessible and employed in various sections of structures. These beams can be manufactured using materials like reinforced concrete, steel, or composites:
This beam finds extensive application in erecting reinforced concrete buildings. It has a diverse structural constructions.
Commonly, this beam type is integrated seamlessly with a reinforced concrete slab, forming a monolithic structure. On occasion, an Isolated T-beam is erected to enhance the compressive strength of the concrete. Furthermore, an inverted T-beam can be fashioned in alignment with the specific loading demands.
This variety of beam is fabricated as an integral part of the structure’s perimeter, unified with a reinforced concrete slab.
Steel cross sectional shapes include:
A multitude of cross-sectional shapes for steel beams exist. Each presents distinct advantages in specific conditions compared to other shapes.
Examples of these steel beam cross-sectional shapes include square, rectangular, circular, I-shaped, T-shaped, H-shaped, C-shaped, and tubular configurations.
Based on Geometry
A beam characterized by a linear profile is commonly referred to as a straight beam, and the majority of beams utilized in structures exhibit this straight configuration.
A beam featuring a curved profile is often encountered in scenarios such as circular buildings.
A beam possessing a tapered cross-sectional configuration is known as a tapered beam.
Based on Method of Construction
Cast In-situ Concrete Beam
This variety of beam is erected directly at the project site. Initially, formwork is established, after which fresh concrete is poured into the mold and left to solidify. Subsequently, the beam is subjected to imposed loads.
Precast Concrete Beam
This kind of beam is made within factory settings. It grants greater control over construction conditions as compared to on-site assembly. As a result, the concrete quality of the beam tends to be of higher caliber. Diverse cross-sectional shapes can be produced, including T-beams, Double T-beams, Inverted T-beams, and numerous others.
Prestressed Concrete Beam
The pre-stressed concrete beam is created by subjecting strands to tension before external loads are introduced onto the beam. Pre-tensioned concrete beams and post-tensioned concrete beams are both forms of pre-stressed concrete beams. They have their own distinct characteristics.
A deep beam exhibits a significant depth, as illustrated in Figure 21, and adheres to the ACI Code’s stipulation of having a clear span to depth ratio of less than four. Such beams support substantial loads by means of a compression force that combines both the load and the reaction. As a result, the strain distribution deviates from the linear pattern seen in conventional beams.
When dealing with heavy loads, it’s common to employ steel sections for the construction of beams.
What are Beam End Conditions?
Beam end conditions refer to how a beam is supported or restrained at its extremities. These conditions significantly influence the beam’s behavior under loads. Common types include simply supported (supported at both ends), cantilever (one end fixed, one end free), and fixed (both ends fully restrained). The choice of end conditions plays a crucial role in determining a beam’s structural response and overall stability in a given construction scenario.
Shear Force and Bending Moment in Beams
In the world of beams, shear force is like a sideways push, while bending moment is more about the twisting and turning. Shear force acts perpendicular to the length of the beam, trying to slice it, while bending moment makes the beam want to rotate. Understanding these forces is key to designing beams that can handle both the straight-up and twisting challenges they face.
What are the factors influencing beam selection?
Picking the right beam boils down to factors like how much weight it can handle, the span it needs to cover, the support it gets, material strength, cost, and the overall design of the structure. It’s like finding the perfect fit for the job at hand.
What are beams in construction?
Beams serve as horizontal structural component. They are capable of resisting vertical loads, shear forces, and bending moments. Their role involves transferring the loads applied along their length to endpoints such as walls, columns and foundations.
What do “cast in-situ” or “RCC” beams refer to?
RCC beams are fabricated using a combination of concrete and reinforcement bars, enabling them to withstand vertical loads, shear forces, and bending moments.
What is a continuous beam?
A continuous beam is characterized by having multiple supports distributed along its entire length, exceeding the standard two-point support configuration.
What are the types of support conditions in beams?
What are the types of beams based on support conditions?
1. Simply supported beam
2. Fixed beam
3. Cantilever beam
4. Continuous beam
What is a beam?
A beam is a structural component designed to bear a variety of loads.