How Are Seismic Coefficients Calculated?

What is R factor in seismic design?

Response modification factor (R) has a main function in the seismic design of new construction materials and is a seismic design parameter in equivalent static analysis.

It determines the nonlinear performance of building structures during strong earthquakes..

What is the difference between peak ground acceleration and spectral acceleration?

Peak acceleration is a measure of the maximum force experienced by a small mass located at the surface of the ground during an earthquake. … Spectral acceleration is a measure of the maximum force experienced by a mass on top of a rod having a particular natural vibration period.

What is SA G in earthquake?

Spectral acceleration (SA) is a unit measured in g (the acceleration due to Earth’s gravity, equivalent to g-force) that describes the maximum acceleration in an earthquake on an object – specifically a damped, harmonic oscillator moving in one physical dimension.

What is Overstrength factor?

The overstrength, which is specified as member or structural capacity, is usually defined using overstrength factor, which may be defined as the ratio of maximum base shear in actuel behavior to first significant yield strength in structure. … Definition of non-linear parameters.

How do you find spectral acceleration?

The spectral response acceleration, Sa, is calculated as follows: 1. For the interval 0 ≤ T < T0 (0 ≤ T < 0.12 s), Sa = SDS(0.4 + 0.6T/T0) Eq 11.4-5 Sa = 0.55g(0.4+0.6T/0.12) = (0.22 + 2.75T)g.

Why Delhi is having so many earthquakes?

According to experts, Delhi’s geographical location makes it prone to frequent earthquakes, as it lies in the Himalayan foothills. Scientific studies have highlighted that the Indian plates are continuously driving towards the Eurasian plates at a rate of 5-6 cm per year.

What are the four types of seismic zones?

Based on the past seismic history, Bureau of Indian Standards grouped the country into four seismic zones namely Zone-II, Zone-III, Zone-IV and Zone-V. Of all these four zones, Zone-V is the most seismic active region whereas Zone-II is the least.

Is Delhi safe from earthquake?

Delhi falls under the fourth-highest seismic zone, which makes it vulnerable to earthquakes. Zone V is seismically the most active region and Zone II the least. Parts of the Himalayan boundary in North and Northeast India, Rann of Kutch and Andaman and Nicobar islands are categorised under Zone V.

What is seismic coefficient?

The Seismic Coefficients are dimensionless coefficients which represent the (maximum) earthquake acceleration as a fraction of the acceleration due to gravity. Typical values are in the range of 0.1 to 0.3. … A POSITIVE vertical seismic coefficient represents a vertical seismic force directed DOWNWARDS.

What is Zone factor in earthquake?

Zone factors are given on the basis of expected intensity of the earthquake in different zones. In IS Code, it is given based on the Maximum Considered Earthquake (MCE) and service life of the structure in a zone.

What is pseudo static?

Pseudostatic analysis is one of the simplest approaches used in earthquake engineering to analyze the seismic response of soil embankments and slopes. … The soil behavior was modeled by the Mohr-Coulomb constitutive relationship.

How is accelerator coefficient calculated?

Accelerator Coefficient. This is the level of induced investment as a proportion of a rise in National income accelerator coefficient = Investment/change in income.

What is pseudo dynamic analysis?

Pseudo-dynamic method of analysis, considering the effect of earthquake loading, shear and primary waves, results in more realistic values of earth pressures than the commonly used pseudo-static method.

Is code 1893 for earthquake PDF?

It is to serve this purpose that IS 1893 : 1962 ‘Recommendations for earthquake resistant design of structures’ was published and revised first time in 1966. … Clauses on concrete and masonry dams were modified, taking into account their dynamic behavionr during earthquakes.

What is the response coefficient r )?

In the International Building Code 2000 (IBC 2000 [1]), the response modification coefficient (R) is used to calculate the reduced design seismic forces of a structural system, and the deflection amplification factor (Cd) to convert elastic lateral displacements to total lateral displacements, including the effects of …

How is SS and s1 calculated?

INTRODUCTION The tool clearly notes the values quoted from GSHAP are rough approximations based on the probabilistic 10%-in-50-year peak ground accelerations (PGA’s). The GSHAP values are multiplied by 2 to approximate 2%-in-50-year PGA values, and then multiplied by 2.5 and 1.0, respectively, to estimate SS and S1.

What is acceleration coefficient?

The principle of acceleration coefficient shows the relationship between the demand for consumer goods and the demand for capital goods i.e. capital investment. … According to Kurilara, “The accelerator coefficient is the ratio between induced investment and an initial change in consumption expenditure.”

How is earthquake acceleration measured?

During an earthquake, ground acceleration is measured in three directions: vertically (V or UD, for up-down) and two perpendicular horizontal directions (H1 and H2), often north-south (NS) and east-west (EW).

How do you find acceleration from coefficient of friction?

The friction force depends on the mass of an object plus the coefficient of sliding friction between the object and the surface on which it slides. Subtract this force from the applied force to find the acceleration of the object.

What is seismic design category B?

Elements of structures in Seismic Design Category B must be. designed for both lateral earthquake forces and vertical earthquake forces.