The columns are elastic with low dynamics. The walls, the wells, are rigid with great dynamics. The columns when rocking in the elastic displacement area consume seismic energy because through friction they convert the seismic kinetic energy into thermal energy. When the earthquake is large and they undergo inelastic displacement, they create cracks in the beams, releasing the seismic energy (plasticity) But the truth is that they offer almost no dynamic reaction because they recede due to elasticity and allow the rigid walls to absorb all the force of the earthquake. For this reason the columns in static calculations are used to receive only static loads while the walls to receive both static and dynamic seismic loads. For this reason the walls fail first in the earthquake. That which is elastic bends (columns) and that which is rigid (walls) is overturned. If we create anchoring of the wall with the foundation ground + apply compressive forces to its cross section then neither it will bend nor it will be overturned. The shear force of base will pick up the wall without any problem. This was shown by the simulation and the experiments I did .. The shear failure as well as the critical failure area will disappear along with the bend. Deformation along with failures will be eliminated. Why do we need plasticity if we can control deformation? Pre-tension walls are considered elastic in high-rise structures. The walls simply show smaller cracks due to prestressing.
Experiment Findings Simulation and numerical investigation of seismic system behavior
Check https://www.sciencedirect.com/topics/materials-science/plastic-deformation
Also check https://www.sciencedirect.com/topics/engineering/deformation-plasticity
Kindly follow
https://www.researchgate.net/deref/https%3A%2F%2Fwww.sciencedirect.com%2Ftopics%2Fmaterials-science%2Fplastic-deformation
As shown in the simulation diagrams of the shear force of the base and displacement of building, when the bearing capacity of the construction is increased, a simultaneous similarity of the available plasticity was observed.
Experiment Findings Simulation and numerical investigation of seismic system behavior
The plasticity of structural elements and structures made of reinforced concrete is characterized by their ability to deform beyond the leakage limit, without significantly reducing their strength.
According to § 5.2.1 of EC8 there is a design option of the available plasticity of the building. Reinforced concrete buildings can be studied with two different design methods. a) To be designed having the necessary ductility which means to have the required - necessary ability to consume seismic energy, but without losing their resistance to all loads during the rocking of the earthquake. b) To be designed with low ductility, ie low energy consumption, but with very high dynamics. The behavior of the structure during an earthquake is basically a horizontal displacement (let's forget for a moment any vertical component) that is repeated a few times. If the displacement is small enough to hold all the members of the structure within the elastic region, the energy generated is energy stored in the structure (in the body of the elements) and then released to restore the structure to its original shape. Like the spring. This energy storage and then its performance in the opposite direction applied by the spring, in the construction is stored and released by the pillar and the beam. In short, all the acceleration of the earthquake is converted into stored energy in the structure. As long as the displacement holds each part of any member within an elastic region, all the energy stored in the structure will circulate at the end of the cycle, in the opposite direction. This displacement region is called the elastic region, in which no failures are observed. If the seismic energy (measured by ground acceleration) is too large, it will produce excessively large displacements that will cause a very high curvature in the vertical and horizontal elements. If the curvature is too high, this means that the rotation of the sections of columns and beams will be well above the elastic area (Compressive deformation of concrete over 0.35% and reinforcement fiber tendencies above 0.2 %) beyond the leakage limit. When the rotation exceeds this limit of elasticity, the structure begins to "dissolve the energy storage" through plastic displacement, which means that the parts will have a residual displacement that will not be able to be recovered (while in the elastic region all displacements are recovered). Basically the design of the strength of a current building is limited to the limits of the elastic design range, and then goes to the default plastic leak areas, which are default areas of small and many leak failures, (usually designed to occur at the ends of the beams) so that it does not collapse the structure. This is the mechanism of plasticity that consumes seismic energy. (Structure collapses when oblique / failed columns fail) If the parts that experience the plastic deformations exceed the breaking point limit, and there are too many on the structure, the structure will collapse. These are the strength limits of today's seismic construction technology. The purpose of modern seismic regulation is to build structures that: a) In frequent earthquakes with a high probability of occurrence will not suffer anything, b) In medium probability earthquakes will suffer small, repairable damage and c) In very strong earthquakes of low probability to happen we will not have human lives lost. So we should not use the term "absolutely" in seismic constructions. We should use the term "quality" constructions which means application of at least the requirements of all modern regulations. The quality of constructions and their safety is also a function of the economic situation of the countries, among other factors. Understandably, poor countries cannot be compared to countries with strict modern anti-seismic regulations. Conclusion… there is no absolute seismic design today, and we should not refer to absolute seismic design, but to quality design. So there is a great need today to invent a more modern anti-seismic design that corresponds to the ultimate anti-seismic design, with lower construction costs.
Interesting question but it is away from my field. Following to see comments from experts.
Plasticity is the tool of the science of seismic structures made of reinforced concrete, with which manages better the inability to dynamically control the inelastic deformations and failures of structures under strong seismic excitation.
Three factors cause structural failure.
The bending, the overturning moment of the walls, and the problematic mechanism of concrete and steel cooperation, that of relevance.
We stop the bending of the vertical elements by applying compressive force to their cross section.
By the same method, we increase the response to the base shear.
The overturning moment of the wall is prevented when we join all its ends with the foundation ground.
And in the link what we need to do, to eliminate the problems of the relevance mechanism
https://www.researchgate.net/post/The_cancellation_of_the_strength_of_steel_specifications_in_concrete
Plasticity enables a solid under the action of external forces to undergo permanent deformation without rupture. Elasticity, in comparison, enables a solid to return to its original shape after the load is removed.
Dear Faraed Salman
Strongly Agree! But the elasticity is good because it returns without damage. Why do we want plasticity when we can control the displacement and have only elastic displacement?
You control the displacement only when the earthquake is small, or in large earthquakes, only if you add an external force coming from the ground to help the construction response.
Plasticity enables a solid under the action of external forces to undergo permanent deformation without rupture. Elasticity, in comparison, enables a solid to return to its original shape after the load is removed. Plasticity is important for development because it facilitates evolutionary change and speciation. Phenotypic plasticity can increase fitness, generate novelty, and facilitate evolution. Developmental plasticity is the environmentally sensitive production of alternative phenotypes during development, and it is a major contributor to biological diversity. Because plasticity appears to be regulated by heritable variation and thus subject to natural selection, it can play a prominent role in adaptation
A material has plasticity if it can receive large deformations when loaded (eg rubber). For reinforced concrete members and structures, plasticity is their ability to deform beyond the yield strength, that is, relatively large deformations, without a significant reduction in their strength.
Plasticity enables a solid under the action of external forces to undergo permanent deformation without rupture. Elasticity, in comparison, enables a solid to return to its original shape after the load is removed. Plasticity is the tool of the science of seismic structures made of reinforced concrete, with which manages better the inability to dynamically control the inelastic deformations and failures of structures under strong seismic excitation1.
Dear Chuck A Arize
Inelastic behavior of structures is inevitable in large earthquakes, and ductility with efficient joint design helps. But when we have the ability to design structures that do not deform inelastically and do not tip over, then why do we need plasticity?
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