Frequency determines the number of complete displacements of a body from the initial point of rest within the unit of time 1 sec The amplitude of oscillation is the metric magnitude of a periodic motion of a body that oscillates around its initial equilibrium position. The amplitude of the oscillation and the frequency determine the magnitude of the acceleration. The acceleration of a body falling to the ground is 9.81m / sec = 1g To measure the acceleration of the ground reaching below the base of the structure we use (g) eg constructions can withstand 0.50 g for a short time The magnitude of the earthquake is measured by the acceleration that will eventually reach below the base and not by the magnitude of the Richter scale itself. The acceleration that reaches below the base depends on the magnitude of the earthquake, the focal depth, the distance of the structure from the center of the earthquake and the soil conditions between the earthquake and the structure. Duration is called the event time of the earthquake. Acceleration and duration determine the disaster rate. A structure can withstand high acceleration (1/2 g) for a short time or vice versa low acceleration for a long time. The strength of the construction depends on the magnitude of the acceleration, the duration of the earthquake as well as the seismic damping mechanisms available. Each body has a specific frequency that oscillates and it depends on its height. When the ground frequency coincides to be the same as the construction frequency we have the tuning. During the tuning all the energy of the earthquake is transferred on the construction and if the construction does not have seismic damping mechanisms then the oscillation amplitude gradually increases over time, so the construction receives increasing seismic loads until it is destroyed. In today's seismic design, the inelastic displacement of the structures is considered inevitable and they try to mitigate the damage by using various seismic damping mechanisms. In addition to the above, there are too many unbalanced factors that can cause disaster and in most modern seismic structures. The factors that determine the seismic behavior of structures are numerous, and in part probable. 1) The direction of the earthquake is unknown. 2) the exact content of the seismic excitation frequencies is unknown. 3) duration unknown 4) acceleration unknown Even the maximum possible accelerations given by seismologists, and determine the coefficient of seismic design have a probability of exceeding, greater than 10%. The correlation of quantities such as "inertial stresses - damping forces - elastic forces - dynamic construction characteristics - construction ground interaction - forced ground motion" is non-linear and determines the response of structures to the earthquake. According to modern regulations, the seismic design of buildings is based on the requirements of competent cross-sectional design and plasticity. The inevitable inelastic behavior under strong seismic excitation is directed at selected elements and failure mechanisms. Poor design of the sections around the nodes and the limited plasticity of the elements lead to major failures I mentioned all of the above to understand that when a static study is signed the earthquake can destroy you along with the building its people and its contents. Nothing is certain with an earthquake, and this is because when some of the above factors, such as resonance, long duration and high acceleration, coincide, then the inelastic displacement will not be difficult to pass at a breaking point. Conclusion. Today's seismic design is uninterrupted because it can not control deformation. Seismic damping by different mechanisms may help in the smooth absorption of seismic energy, but there is no guarantee that the structure will stand upright. 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. Here we see that there is a great need to change the seismic design. We need an anti-seismic design that controls deformations regardless of whether we have coordination, long seismic duration and high acceleration, as well as being accessible in poor countries. I believe that the method I propose (pre-tensioning + anchoring to the ground of all sides of the walls with diaphragm function) will increase the response of the structures and reduce the construction costs, because if the construction is stronger than we need then we remove reinforcing steel and bases and drop the cost.
Dear Aparma.
I'm talking about the Mercalli scale. The Mercalli scale does not measure the energy released by an earthquake, like the Richter scale. Instead, it deals with the effects of an earthquake in a given area, and is an ideal measurement for use in densely populated cities. The scale ranges from 1 to 12, where 1 scores the seismic vibration recorded only by seismographs and 12 scores the vibration with the most catastrophic consequences, ie an earthquake that would cause total destruction to any human structure and change the geographical relief of the area.
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Dear Ammar Abdul Aziz Alibeg
I mention the coordination of construction-ground frequencies (same period)
Dear Faraed Salman
The Richter scale measures the specific energy secreted by an earthquake.
It does not measure the acceleration that reaches below the base of the construction and determines the intensity of the earthquake on the construction.
Civil engineers design based on the acceleration that reaches the area and not on the energy of the earthquake that is released in the epicenter.
The Mercalli scale measures the acceleration ( g ) and duration that reaches a specific area and determines the disaster index table
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