Lintel beams are constructed to support the opening in walls when an infill wall is to be constructed between the wall opening and the ceiling beam. There are also other reasons for lintel beams, which are explained in detail in the last part of this article.
What is a drop?
Is it a structural element?
Answer: yes no
As structural elements we mainly consider pillars, beams, slabs, resistant walls, heads, piles, etc. These elements ensure the stability of the structure and transfer the load to the ground.
It is an independent element called
- Defenestration
- lintel
- Other openings
However, in some cases, a connection is made to concrete columns and beams when the openings are close to the column.
Let us briefly discuss the above types.
Defenestration
Normally the height of the window does not correspond to the height from one floor to another. If the facade has a brick wall, the structure must be supported above the window (between the window and the floor beam).
Bricks cannot be built directly into the window frame unless they are designed to do so. There usually needs to be something to support it.
So we built lintels.
It works like a beam and requires a structural connection with the support when the height of the wall to be fixed is significantly greater.
If the height of the support is smaller, it can rest on the same brick wall shown in Figure 2.
However, if there are problems with settlement, lateral loads on the building, etc., it is advisable to continue the falls to the support structure.
lintel
We do the same with the windows. However, most are built in-house. The number of external elements could be fewer, as there are few doors to the outside.
The same technical aspects discussed in window support can be followed in this case as well.
Types of falls
There are different categorizations depending on the type of materials to be used and their construction limitations.
Of all the following types of lintels, concrete is the most commonly used construction material.
- Concrete fall
- Falling wood
- Brick lintel
- Reinforced brick lintel
- steel
- Stone
Concrete lintel or reinforced concrete lintel
Although it is concrete, we always use reinforcement to absorb the tensile forces caused by the applied loads.
If adequate reinforcement is not provided, cracks may occur in the brick wall due to excessive deflections and uneven load distribution.
Using concrete as a building material can be easier compared to other materials. Furthermore, it is very difficult to continue the fall with other materials.
The sizing of the lintel beams is based on the existing loads and the span.
Based on the project details, typical details are drawn up so that the construction team can proceed with the construction without much difficulty. Once the span is known, lintel placement can be selected.
Depending on the project, there are basically two types of falls.
01. Built into all walls
In single storey buildings, lintels are provided on all walls and these are interconnected. Figure 01 shows the arrangement of continuous lintels.
Image 01: Continuous lintel beams
02. Built in certain areas
Other line types are more common in multi-story buildings. They are only provided in the respective opening and the beam does not continue through the wall. The beam rests on the wall. Figure 02 shows the single-span lintel beam.
Figure 02: Single span lintel beam
Lintel beams are not only used to support loads in wall openings. There are many other benefits listed below.
Advantages of lintel beams
- By placing and continuing lintels on all walls of small buildings, cracks in the wall due to thermal expansion, creep and shrinkage effects, differential settlement of structures, etc. are minimized.
- Particularly in single-story buildings, most of the time the weight of the structure is not evenly distributed over the area. The central part and the sanitary area are subject to a greater concentrated load than the peripheral area, the living area, etc.
- There is, therefore, the possibility of another settlement . If there is settlement and lintels are provided, cracks in the walls will be minimal.
- In most buildings without lintels, it is common for diagonal cracks to appear above windows/doors.
- The formation of new fissures beneath the winds can also be frequently observed. These cracks can only be avoided if the lintel beam continues along the walls.
- A lintel design as shown in Figure 2 will lead to long-term crack formation in small structures, especially in single-story buildings.
- The installation of lintels compromises the lateral stability of small buildings.
- In the event of an earthquake, most small buildings are severely damaged due to lack of moisture. It is very difficult to improve humidity in small buildings. However, the structure can be held together through the use of lintels.
- For structures near floodplains or where lateral loading from water pressure is expected, lateral stability is improved by lintels that connect all walls.
Typical lintel details
Figure 03 shows the type that can be used in civil construction to provide lintel beams. Dimensions and reinforcement details need to be checked for a specific project. In particular, the load on the lintel may vary from project to project. Therefore, the design must be adapted from project to project.
Figure 03: Typical detail of the lintel
In short, falls are very important in all types of structures. Especially in small buildings, such as single-story buildings, lintels must be placed along all walls to avoid possible cracks in the walls.
Falling wood
Although wood is a renewable resource, it is not commonly used to support openings unless there are architectural requirements for an incredible aesthetic appearance.
However, wood used to be the most commonly used building material. Therefore, it appears that most Kingdom period buildings used wood to support openings.
They used a much larger cross section to support the loads and the type of wood used appears to be more durable as some of it has not deteriorated to this day.
Regarding the use of wood as a construction material in such structures, the following key factors can be highlighted.
- If brick walls are built above wind, doors and openings, the wooden section must be designed to support this weight.
- Furthermore, thermal effects must also be taken into account in the design to minimize contractions and expansions of the brick wall in this area.
- The deflection of the wooden board should be limited as much as possible. A deflection lower than specified in the standards can provide an additional advantage in the long term.
- As the durability of wood is one of the main concerns, appropriately treated wood that meets durability requirements can be used.
- Wood is more susceptible to fire than our materials like concrete and brick. If exposed to fire, it may cause all or part of the building to collapse.
- The choice of wood should be based on the fire resistance considered for construction. For example, if the building is designed for one-hour fire protection, the wood used in construction must be able to withstand the loads for at least one hour.
- Additionally, improper construction, such as selecting incorrect sizes to accommodate loads, can cause serious problems upon completion.
Brick lintels
- Bricks are one of the most used construction materials today. This has also been the case throughout history.
- Furthermore, there are/were buildings that have not just one floor, but multiple floors.
- So why don't we use bricks to support the openings?
- If the opening sizes are not larger or about 1 m or less, bricks can be used to support the loads.
- Additionally, flat or curved brick supports can be seen in modern buildings. They are usually designed to provide an attractive view.
- The most important load transfer mechanism in this type of structure is pain.
- To smoothly transfer loads to other areas, there must be brick walls on both sides of the opening.
Reinforced brick lintel
As the brick cannot absorb the tensile stresses that arise in the middle of the opening, it collapses or serious cracks occur.
The bond between the cement-sand mortar and the brick also deteriorates over time. This also affects the system's load capacity.
To increase the tensile strength of the bricks, reinforcement is placed inside the wall to absorb tensile stresses.
As shown in the figure above, reinforcement can be inserted into the wall to act as a tension element.
In addition, the combination of brick and concrete beam can also be called reinforced brick lintel.
Furthermore, the reinforcement used in this nature work will be smaller, around 6 to 10 mm thick bars.
steel lintel
Structural members are used in construction to support openings in walls. As mentioned previously, there must be a structural or non-structural element that supports the loads directly above the opening.
Wide steel lintels can be seen in steel buildings. However, they can also be observed in other buildings.
If the architect needs to make changes to the building, he or she can generally use steel as a substitute for the other materials discussed above to support the loads.
In modern construction, there are methods to hide steel profiles in the brick wall. Even if we use a universal beam as a lintel beam, it can be hidden by concreting.
When the same surface is required, especially when using wire-cut bricks, it is difficult to use steel. However, as shown in the image above, this can be done quite easily.
The appearance is good, with no structural problems or cracks.
Since steel is not a particularly resistant material to environmental influences, it must be adequately covered or protected against corrosion.
Steel corrosion can be prevented by applying anti-corrosion paints or using galvanized steel.
Rockfall
It is not common to use stone as a strong building material. In particular, tensile stresses do not cause any defects in this material, although it reacts very well to compressive loads.
However, in ancient buildings, stone beams were used as support beams. The sizes of the cross sections are quite large compared to other elements used for this purpose.
If we use stone in construction, the following can also be taken into consideration.
- Since stones are relatively heavier compared to bricks, when using brick walls to support stones, special attention should be paid to the load-bearing capacity of brick walls.
- Brick walls must be constructed in such a way as to withstand the loads. If the brick wall is not strong enough, it may crack over time.
- The stone thickness could be maintained 100mm per 1000mm period. However, these values largely depend on the load on the stone beam.
- Construction costs would be significantly higher than with other types of construction.
- Due to its heavy weight, care must be taken to place the stone beam in the correct location.
Fall repair
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Brick lintels : Tend to tear not only due to applied stresses, but also due to thermal effects. Therefore, there is always a risk of cracks in brick walls. Furthermore, it is very difficult to replace bricks with cracks, other than strengthening them through modifications. There are different methods to treat fissures.
- Construction mortar injection . The traditional method of injecting soil into concrete cracks can be used. Additionally, some pressure can be applied to ensure the floor moves everywhere. It is recommended to inject from one point and allow the material to penetrate the wall. Small tubes can be inserted along the crack to observe penetration and fill it appropriately. The article was published in Permagard provides information on drop repairs.
- Laying tension wires . Wires or rods inserted into the wall can be used to evenly transfer or distribute the tensile load to the other area. The following figure shows one such arrangement that can be used.
- Wood : If there is excessive damage or deformation, it is advisable to replace the wood rather than repair it. Additionally, when replacing the wood supporting the wall, support for the brick wall must be provided. It is also important to ensure that the wood exerts the same pressure on the brick wall. Otherwise, downward movement of the wall will occur, which may cause cracks in the wall.
- Steel: The durability of steel is a controversial issue. When using steel, care should always be taken and regular maintenance carried out as a method of repair. Furthermore, if it is badly damaged, it can be replaced like wood.
- Stone: This is not a ductile material. Its fault may be a brittle fracture. Therefore, sufficient sections must be provided that can bear the load during construction. However, brick walls can crack due to the high concentrated loads placed on them. Furthermore, the rigidity of the stone is affected by cracks. The repair method described above, which may be applicable to brick walls, is applicable.
