A lintel beam positioned over openings in structures, such as doors and windows, to support the weight of the structure above. The width of a typical lintel is equal to the width of the wall with its ends integrated into the wall. Based on the material used in their construction, lintels are categorised into RCC lintels, steel lintels, concrete lintels, etc. While wood is still used as a lintel in developing countries, stronger building materials like bricks, concrete, and stones can also be employed, especially for commercial buildings. Also, using steel lintels has become common in contemporary times. The choice of material to be used in lintel beams profoundly depends on the viability, cost and overlying load above the lintel.

In this article, we will discuss all the aspects of Lintel, including Lintel meaning, different types of Lintels, their functions, including their advantages and disadvantages. The information contained herein shall help students in the upcoming SSC JE CE and RRB JE Civil preparation.

What is a Lintel?

Lintel is a form of beam provided above the door and window openings to sustain the overlying load and transfer the same to the adjacent wall or column. They serve the purpose of offering the bearing for masonry above the openings of doors and windows. Different types of lintels are employed, depending on the cost and suitability. These include Timber Lintels, Stone lintels, Reinforced Brick lintels and Steel lintels.

"bearing of lintel" typically refers to the structural support provided for a lintel in a building or architectural structure. The bearing of a lintel can vary depending on the design and construction of the building. 

Function of Lintel Beam

The various functions of Lintel beam include:

• Lintels bear the weight from the masonry above the openings of doors and windows.
• A Lintel beam is a crucial structural element in building construction that should meet the requirements for withstanding tension, compressive stress, and shear stress applied to it.
• By choosing ornamental lintels, the architectural attractiveness of the structure can be enhanced and embellished. In this context, lintel architecture should be given due precedence in such cases.
• Lintels can also be used as a load-bearing member at the entranceway. It is called as a lintel bridge.

Properties of Lintel

The followings are the general properties of a building lintel:

• A typical lintel beam terminates in a masonry wall. At times, they get impregnated into the ends of columns.
• Lintels are supported at both ends and they must be extended far enough to nullify any chances of excedence of stresses in the supporting brickwork, thereby ensuring overall safety. Notably, the minimum bearing length should be 10 cm.
• The weight transmitted through the lintels is further carried to the masonry walls or columns, whichever are connected to the lintels.
• Lintel beam can also serve the purpose of a vibrant structural element.
• Notably, the width of the supporting wall and the lintel width should be the same.

Guidelines for Lintel Construction 

IS 456:2000 enumerates the Lintel design principles. When designing a lintel, the engineer must adhere to all the building codes pertaining to Lintels. The major guidelines related to Lintel Construction are listed below. ( Note: These principles may change over time due to any amendments being made to the corresponding code). 

Lintel Beam Size:

• There should be a minimum bearing length of 10 cm available.
• The minimum width of the lintel beam should be 15 cm.
• Above apertures, a lintel span cannot be longer than 3.5 m.
• All concrete lintels should have suitable reinforcement.
• The reinforcing bars in RCC lintels must extend beyond 60 cm over the edge of the opening into the lintel supports.

Types of Lintel Beam

Lintel beam design can be classified based on span and materials. 

Classification Of Lintels Based On Span

Lintels are classified based on span:

Lintel Beam Or Cut Lintel

Thee lintels are supported by bearings to ensure that the weight is effectively transferred to the door and window frames. These lintels are frequently used in load-bearing constructions. 

Following are the minimum dimensions of the bearing or minimum size of lintel beam should be:

• 10 cm
• Height of the lintel beam
• 1/10th to 1/12th of the span of the lintel

Lintel Band Or Continuous Lintel

This lintel functions as a second tie beam, joining the columns of the structure together. These are mostly composed of reinforced cement concrete and are appropriate for use in

1. Framed structures.
2. Buildings with expansive soils.
3. Areas prone to earthquakes.

Classification Of Lintels Based On Materials

1. Timber lintel
2. Stone lintel
3. Reinforced brick lintel
4. Steel lintel

Timber Lintel

• Timber Lintels have been used since earlier times and are still used across the globe.
• They are primarily used in hilly places where wood is easily available. 
• In the event that there are additional large dividers, the timber lintel beam is constructed from two wooden pieces aided by wooden separators. 
• Occasionally, mild steel plates are placed at the top and bottom of wood lintels to act as reinforcement. Such lintel beam is known as Flitched lintel.

Fig 1: Timber Lintel

Advantages of Timber Lintel

• Simple to construct.
• These can be employed in temporary structures.
• No requirement of Formwork.
• No curing time.

Disadvantages of Timber Lintel

• Compared to the materials used in lintels, timber is highly expensive.
• If not properly maintained, timber lintels may degrade over time.
• It is prone to damage caused by fires.
• Timber lintels cannot be used in permanent constructions.
• The forces exerted on the lintel beam by tension, compression, and shear cannot be resisted b by wood.

Stone Lintel

• Stone Lintels are extensively used due to the abundance of stone.
• The most crucial aspect of the design of the Stone Lintel is thickness. 
• One single stone lintel or lintels consisting of several pieces of stone can be used.
• The depth of a Stone Lintel is 10 cm per metre of span, with a minimum overall depth of 15 cm. 
• Stone Lintels are used up to a span of 2 m.
• The thickness of lintel in case of Stone Lintels should be 4 cm, with the minimum thickness being 8 cm per 30 cm of span.
• It is pertinent to note that the weak tensile strength of stone causes fractures in such lintels, especially when subjected to frequent vibrations or shock loadings. 

Fig 2: Stone Lintel

Advantages of Stone Lintels

• Stone Lintels offer an attractive look and give a nice appearance.
• Due to the easy availability of stones, these lintels are extensively used.
• They can be used in both temporary and permanent structures.
• No requirement of curing.
• No formwork is needed in such lintels.

Disadvantages of Stone Lintels

• The tensile strength of Stone lintel is low.
• Timber lintels are prone to failure and cracks when subjected to shock waves or vibrations caused by earthquakes.
• Lower workability of stones due to their heavy weight makes their handling and transportation difficult. 
• Stone Lintels cannot be used for long spans.

Reinforced Brick Lintel

• Reinforced Brick lintel beam is employed when the span is greater than 1 m and the overlying load is heavy.
• The depth of the reinforced brick lintel should be a multiple of 10 cm.
• The bricks are placed so that there is a lengthwise gap of 2 to 3 cm between them. This allows for the insertion of mild steel reinforcing bars. 
• To close the gaps, a cement mortar (1:3) ratio is employed.
• Every third vertical joint of the Reinforced Brick lintel beam has a 6 mm-diameter vertical stirrup.
• Bars of 8 to 10 mm diameter with crank-up ends serve as the main reinforcement.

Fig 3: Reinforced Brick lintel

Advantages of Brick Lintel

• Brick Lintels are widely used due to the affordability of bricks.
• These lintel beams can be used for short periods.
• The thermal coefficient of the lintel beam and the masonry is the same since they are both constructed of the same material. As a result, thermal stress-related fractures can be prevented.

Disadvantages of Brick Lintel

• Bricks are weak in tension and are thus prone to tension cracks.
• Brick lintels are only capable of supporting light weights.
• Brick Lintels cannot be used for long spans.
• Formworks are required during construction as support.
• The minimum curing period is about 14 to 21 days.

Steel Lintels

• When there are large opening gaps and substantial superimposed loads, a steel lintel beam may be appropriate.
• These lintel beams are made of rolled steel joists, or individual channel sections that can be used in groups of two or three, or in combination. 

Fig 4: Steel Lintel 

Advantages Of Steel Lintel

• These lintels can be used for long spans.
• Steel is lightweight, making it easy to handle.
• Steel is a strong and durable building material that can be formed into any shape.
• No formwork or curing is required.

Disadvantages Of Steel Lintel

• It is prone to catching fire.
• It is expensive.

Reinforced concrete lintel

Reinforced concrete lintel: A lintel made of reinforced concrete that provides structural support across an opening in a building or structure.

Brick lintel

Brick lintel: A lintel made of bricks that is used to support the load above an opening, typically in masonry construction.

Uses of Lintel Beam

• Lintels are used for structural support across openings in buildings.
• They bear the load above openings, preventing sagging or collapsing.
• Lintels can contribute to architectural design and aesthetic appeal.
• They span openings, allowing for the installation of doors, windows, etc.
• Lintels reinforce masonry and help distribute loads, preventing damage.

Construction Material of Lintel Beam

• Concrete lintels: Lintels made of concrete, which are commonly used for their strength and durability.
• Steel lintels: Lintels made of steel, known for their high strength and load-bearing capacity.
• Brick lintels: Lintels constructed using bricks, often used in masonry construction for their compatibility with surrounding brickwork.
• Stone lintels: Lintels made of stone, which can provide a visually appealing and natural aesthetic to the structure.
• Composite lintels: Lintels constructed using a combination of different materials, such as concrete and steel, to leverage their respective advantages.

Lintel Beam Design

The design of a lintel beam involves structural analysis to ensure it safely carries the loads acting over an opening (like a window or door) and transfers them to the surrounding masonry. RCC (Reinforced Cement Concrete) lintels are most commonly used in modern buildings due to their strength and versatility.

Key Design Parameters

• Span (L): Width of the opening the lintel covers.
• Bearing: Minimum 150 mm bearing on each side over the support wall.
• Depth (D): Commonly taken as 1/10 to 1/12 of the span, with a minimum of 100 mm.
• Width (b): Generally equal to the wall thickness (e.g., 230 mm).
  Load Considerations:
  • Dead Load: Self-weight of wall and lintel.
  • Live Load: Floor/roof loads transferred through the wall.
  • Superimposed Load: Load above the lintel from the structure.

Types of Lintel Beams

Here are the major types of lintel beams used in construction, along with concise explanations:

Calculations of Loads Acting on Lintels

Calculating loads acting on lintels involves considering the weight of the structure above the lintel and any additional loads applied to it. The specific calculations depend on factors such as the type of lintel, the span of the opening, the materials used, and the applicable building codes.

Conclusion

That brings us to the end of this blog. This blog subsumed all the relevant details for Lintels, their functions and their types. The information should provide a fillip to your exam preparation. To leave no stone unturned in ensuring your selection, we recommend you to get enrolled in the AE/JE Civil Coaching. To propel your preparation, you should visit the Testbook App.

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