Characteristics of reinforced concrete
It is a collection of steel reinforcement or that resist tensile concrete, and resistant to compressionIt is a mixture of aggregates, consisting of gravel, sand and crushed stone, cement and water. There are frames of longitudinal type that follows the longitudinal axis of a compartment and those type of cross that is placed along the axis perpendicular.
He manages to carry the compressive forces of 15 MPa and 60 MPa even, but less resistant to tractionIt is only 1/10th of its capacity that supports the compression. To compensate for this weakness, the parties subject to towing efforts are equipped with steel bars that support both the traction and pressure.
To do this, the steels are placed in key areas of this material consistent. For a reinforced concrete slab, they are set up at the media for the top and at the bays for those who are low.
It is necessary to make the right choice parts for reinforcements, their attachment and their arrangement in this material. This allows for a proper recovery is essential, because the fittings shall be protected against oxidation.
The beams used
The beams are protected by steel type main longitudinal. This is to recover the tensile decline following the. Add to this those type of transverse frames and brackets for the shearing forces.
The latter is a parameter that varies the space between the frames. For a high shear, they are compressed near the supports and when it is less, but rather in the middle of the rafters.
This equipment requires an investment and a commitment of adequate reinforcement reabsorbing the tensile. This prevents cracks and concrete failureIt is possible to notice cracks in 1/10mm, they are not harmful to the thickness.
The coating on the distance between the steel formwork and separations as well as that between the barsIt is 2.5 cm in safe locations exposed to storms and condensationIt is 3 cm in urban areas, 4-5 cm in areas near the sea. Thus, there must be a minimum dosage of 400 kg/m3.
There are frames for which the bottom fiber concrete has low tensile strength. When matched loads are increased, cracks appeared at 45 ° in the two areas of support. This proves the low resistance of the material in shear.
The appearance of the break will be delayed if transverse reinforcement is placed with the support. Like the longitudinal reinforcement, they preserve the crack opening. |
