The application of reinforced concrete structure is quite common, but not everyone knows its advantages and disadvantages to make the most suitable arrangement during construction. Besides, the designer of construction drawings also needs to know the structure to optimally arrange the components that make up the work to ensure quality products when put into use by the investor.
Reinforced concrete is a complex building material because concrete and reinforcement work together to bear the force.
Made from sand and gravel cement into an artificial stone with good compression resistance but very poor tensile strength. Reinforcing steel is a material that has both good tensile and compressive properties.
In order to increase the bearing capacity of the participating structures, reinforcement has been placed into the concrete, thereby giving birth to the concept of reinforced concrete.
The reason will be demonstrated through the following example:
Given a beam made of load-bearing concrete material as shown
When gradually increasing the load of the beam, we will see that the tensile stress of the beam section at the section 1-1 also increases.
When this tensile stress exceeds the tensile strength of the concrete, cracks will appear
The crack will gradually lengthen upwards and the beam will be broken, in the example above, the compressive stress of the concrete is still quite small (not yet fully utilized the compressive capacity of the concrete, but the beam has broken compared to the region). tensile strength of non-tensile concrete)
So such a conclusion is a waste of the compressive capacity of concrete. Therefore, the reinforcement will be added to the tensile area of the concrete, so that the tensile force will be carried by the reinforcement thereby increasing the bearing capacity.
And when there is reinforcement placed in the tensile zone of the concrete, when the compressive stress of the concrete reaches the compressive strength of the concrete, at the same time the tensile stress of the reinforcement also reaches the tensile strength of the reinforcement. steel.
Concrete and reinforcement can work together to help increase bearing capacity in structures because
Bonding force between concrete and reinforcement. Helping the structure in the process of bearing the load, the concrete can transfer the force to the reinforcement and the reinforcement can also transfer the force to the concrete.
There is no chemical reaction between them and the concrete also covers the reinforcement to help protect the reinforcement from corrosion of the surrounding environment. Cement needs at least 250-270kg/m3 of concrete for the concrete to keep the reinforcement from corroding
The same coefficient of thermal expansion concrete is 0.000010 to 0.000015 while the coefficient of thermal expansion is 0.000012. If the environment changes within <100 degrees Celsius, there will be no significant internal stress in the structure, no damage to the adhesive force between the concrete and the reinforcement.
All-block reinforced concrete
Is a type of reinforced concrete where structural members are constructed by the method of joining formwork, placing reinforcement and pouring concrete at the position of structural members.
Advantages of having great rigidity and good dynamic strength
The good disadvantage of the material for the formwork is that it is often affected by the weather due to outdoor construction.
Assembled reinforced concrete
The type of reinforced concrete whose structure is divided into individual structural members to be able to be manufactured in factories or yards. Then transport to the construction site, then use a crane to assemble and connect them together into a complete structure as design drawings.
Advantages of reinforced concrete that saves materials for formwork and is not affected by weather due to construction at the factory
The disadvantage is that the construction of connecting components is often difficult and quite expensive. This particular type of structure should only be used when the structural members under construction are repeated at different locations in different works.
More reinforced concrete assembled
Is a type of reinforced concrete whose structure is formed by a combination of the method of assembly and the method of whole concrete.
The advantage of having high rigidity is that the formwork can be removed and the poles can be removed
The disadvantage of the construction and joining of the components is somewhat complicated, especially the good handling of the joints between the pre-cast concrete and the post-cast concrete. Should only be used when the structural members under construction are repeated at different locations in different works.
