What are reinforced concrete beams?

Before understanding the concept of what a reinforced concrete beam is, you need to understand what a beam is. Because in addition to concrete beams, there will be other types of beams, so understanding what a beam is is very important.

What are beams?

Beams are basic structural members, acting as force-bearing bars (mainly bending). They can be horizontal or inclined to support the wall and roof beams above.

Beams are divided into many different types and materials. Of course, the size of the beam will depend on the area of ​​the house to decide.

Some of the most common types of beams are: floor beams, roof beams, crane beams... Within each type of beam, there will be main beams, secondary beams...

What is the concept of reinforced concrete beams?

Reinforced concrete beam is a type of structure consisting of concrete and steel reinforcement. From these two main materials, reinforced concrete beams will be created. They are usually rectangular or square in shape. The size of reinforced concrete beams depends on the area of ​​the construction project.

Concrete is a mixture of three main components: Cement, Sand, and Stone. So it can be said that beams Reinforced concrete beams are a mixture of Cement, Sand, Stone and Steel (Steel includes iron Fe and Carbon C and some other chemical elements)

Reinforced concrete beams are bending structures. In fact, besides bending, reinforced concrete beams can also withstand compression. However, the compression resistance is lower than the flexural resistance. That's why when it is said that beams are bending structures, people will understand that the ability to withstand bending is the main thing.

What materials are included in the structure of reinforced concrete beams? 

The structure of reinforced concrete beams will be classified according to the reinforced concrete part. In addition to the three materials that make up concrete mentioned above: cement, sand and stone. In the reinforcement section there are also:

• Load-bearing longitudinal reinforcement: With a diameter ranging from 12-40mm and usually made from steel groups AII, AIII, or CII, CIII. Has the function of bearing the stresses arising from the effect of load. 

• Structural longitudinal reinforcement: Depending on the type of project, the size when placed into the steel beam is different. But the main effect of the structural core will be the frames or mesh that reduce the shrinkage of concrete. From there, evenly distribute the loads when compressing the beam

• Reinforcement: Is one of the types used mainly to withstand horizontal forces. The diameter is not as large as other types of vertical reinforcement but will have a minimum diameter of 4mm

• Oblique reinforcement: Is one of the types of reinforcement used to enhance the shear capacity of beams. This oblique reinforcement is a section that may or may not be present in the beam. Depending on the type of construction project, it is necessary to use this type of diagonal reinforcement or not.  

• Reinforcement protection layer Ao: Is one of the parts in the structure of reinforced concrete bridges. 

This layer is one of the protective layers that prevents the steel in the beam from being affected by rust. This part is distinguished as the distance from the outside edge of the concrete to the reinforcement. 

The distance from one reinforcement to the edge of the other reinforcement is calculated by the clear distance (a conventional size that allows water to flow or light to pass through but nothing can obstruct it). as follows: 

+) Ao1 ≥ 1cm when h ≤ 25cm;

+) Ao1 ≥ 1.5cm when h > 25cm.

+) Ao2 ≥ 1.5cm when h ≤ 25cm;

+) Ao2 ≥ 2cm when h > 25cm.

The structure of reinforced concrete beams includes many different materials 

Working principle of reinforced concrete beams 

The main function of reinforced concrete beams is to withstand the load of forces. From there, keep the project from sinking or being destroyed. To know the working principle of reinforced concrete beams, we can rely on the following evolution:

• When the load is applied moderately, the beam remains fairly intact

• When the load increases above the normal level, straight cracks and inclined cracks appear at the angles with the beam axis.

• When the load reaches its limit, the beam will break or perpendicular cracks will appear at the interface.