A practical mathematical way to find the cubic meters of reinforced concrete in small structures is to multiply the number 0.245 by the floor area and the result shows the cubic meters of the structures (without the bases) Floor 100 sq.m. X 0.245 = 24.5 cubic meters. The specific weight of reinforced concrete is 2450 kg / m3 The 24.5 cubic meters X the 2450 kg = 6025 kg or close to 60 tons. A floor of 100 sq.m. only its concrete 24.5 m3 weighs 60 tons. Each cubic meter of reinforced concrete has a steel reinforcement of approximately 140 kg / m3 The 24.5 cubic meters of the floor of 100 sq.m. X 140 kg / m3 = 3430 kg of steel the floor of 100 sq.m. One of the thousands of prestressing steel available on the floor, with a cross section of 20 mm, has a lifting capacity of 63 tons. That is, a single steel raises the floor in the air, while in an earthquake the construction presents problems. Why so much waste on steel, and why do earthquakes fail?

Answer. Seismic loads triple the intensities But this steel reinforcement is excessive even for a large earthquake. And yet, construction fails easily in a major earthquake. What's wrong? I will give answers to this big question below. Above I mentioned the tensile strength of steel. However, a reinforced concrete structure is also made of concrete. The compression concrete specifications are very good. It does not have good standards for all other forces such as shear, tensile strength. For example, the specifications of concrete in compression are 12 times stronger than in tensile strength. In reinforced concrete, steel and concrete work together with the mechanism of affinity. The cooperation between concrete and steel is achieved through the mechanism of relevance. When we say the mechanism of relevance we mean the combined action of the mechanisms which prevent the relative sliding between the bars of the steel reinforcement and the concrete that surrounds them. The mechanism of the connection consists of the adhesion, the friction and in the case of steel bars with embossed shape, the resistance of the concrete which is trapped between the ribs. The combined action of these mechanisms creates a radial development of shear stresses applied to the concrete and steel interface. When these stresses reach their limit value, the relevance is destroyed, by breaking the overlay concrete along the steel bars, and detaching the steel from the concrete. .

Shear stresses are created on the interface of the two materials. . The question is whether the concrete withstands the strong shear stresses imposed by the tensile strength of the steel; No it can not withstand and for this reason we have the pulling or otherwise slipping of steel through the concrete, and the destruction of the coating concrete around the steel. Conclusion 1) The premature shear failure of the coating concrete cancels the ability of the steel to tensile, because it does not manage to take on the tensile loads it can, because the cooperation wants two. Conclusion. The coherence mechanism is at least insufficient for these two materials. That is, if you put steel in butter, there will never be cooperation because butter does not withstand the pull of steel. If you put more pieces of steel in the butter or concrete you will have greater strength; Is it a Question? Solution There is also the concrete-steel co-operation mechanism of the prestressing which imposes compression on the concrete cross-section to equalize the tensile stresses that the affinity mechanism would receive. There is no steel-concrete connection in the prestressing mechanism, so the shear failure is non-existent. The prestressing mechanism strains the concrete only with compression which it can withstand because it can withstand 12 times more compression than it can withstand tensile stress, and it strains the steel only with tensile strength in which it is awesome. Even the protruding walls have a high rigidity, ie a small deformation, so they do not transfer deformation to the trunk of the beam with which it is connected to it at the node. Other causes of the relevance mechanism that pre-tensioning solves are as follows. A reinforced concrete wall, when its trunk is bent, one side is compressed and the other is stretched. That is, one side shrinks and the other grows. There is a point in its cross section where compression and tension have the maximum force. This point is the critical failure area. This point is responsible for the brittle failures of the structures in the earthquake. If we stop the bending of the wall we will eliminate the critical failure area. Is there a design method to stop the bending and the critical failure area? Yes there is. As we said the stretching side grows. If, with an unrelated tendon, we apply transverse compressive forces to the highest level of the cross-section of the wall side, greater than the tensile forces, then we have stopped the bending and the critical failure area. One problem was solved. Well now we have a rigid wall in terms of lateral earthquake strength without critical failure area. Like a rigid wall that is, its overturning moment will be transmitted through the nodes where it is connected to the beams, on their logs and after bending them easily as rigid as it is, it will break them. Another problem? There is a solution? Yes there is. If the protruding unrelated tendon that stops bending does not stop at the base foot of the wall, but extends and anchors into the ground, then the forces of the earthquake are deflected into the ground. The knots will not present great torques, capable of breaking the beams. For this reason I do not join the base of the sole with the ground but I join the upper ends of the sides of the walls with the ground with tense tendons without relevance. The reason is that with this method I stop both the torque of the nodes coming from the bend, and the critical failure area of ​​the wall. The critical failure area of ​​the walls is created in the cross section of the wall which is close to the base. This creates a potential difference in the adhesion of the reinforcement and the concrete. With the method of the invention, the tense unrelated tendon which is both embedded in the ground and the upper end of the wall, there is no potential difference or critical failure area. The problem of deformation with fringe failures is solved! In addition, the application of compressive stresses to the wall cross-section succeeds in increasing the cross-sectional strength of the developing floor and base intersections, increases the active cross-section, improves the sloping trajectories, and reduces cracks. The ground anchor mechanism increases the strength of the ground so that it can accept higher compressive loads. .

Why do we install steel reinforcement joining the construction of the beam and the slab with the balconies? Answer In order not to overturn. I do the same. I join the upper part of the wall with the ground so that it does not overturn in the earthquake ................................. ..............

. 2. Why do we apply prestressing to very large openings instead of simple steel reinforcement? Answer Because prestressing reduces flexion, and increases active cross-section. This is what I do to reduce the bending of the walls ...........

Why do I want to reduce the bending and torque of the walls? Answer Because the walls are connected to the beams and any change in the vertical position of the wall deforms the beams as well. The bending of the trunk of the wall and their overturning moment are the factors that break the beams and fall If we stop the overturning moment and the bending of the wall, how will the beam be deformed? .