Table of Contents
- 1 What does spectral response acceleration mean?
- 2 How do you find spectral acceleration?
- 3 What is the difference between spectral acceleration and pseudo spectral acceleration?
- 4 What is meant by spectral response?
- 5 What is spectral acceleration in earthquake?
- 6 Why is it called pseudo acceleration?
- 7 How is peak acceleration related to spectral acceleration?
- 8 What is Planck acceleration?
- 9 What is the cause of spectral lines?
What does spectral response acceleration mean?
Spectral acceleration is a measure of the maximum force experienced by a mass on top of a rod having a particular natural vibration period. Short buildings, say, less than 7 stories, have short natural periods, say, 0.2-0.6 sec. Tall buildings have long natural periods, say 0.7 sec or longer.
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.
What is the difference between spectral acceleration and pseudo spectral acceleration?
For zero damping, pseudo-spectral acceleration is identical to spectral acceleration Sa. However, for damping other than zero these two are slightly different. Nevertheless, for damping levels encountered in most engineering applications the two may be considered to be practically equal.
What is CQC and SRSS?
For the classically damped linear system in which all the modes are real, the square root of the. sum of squares (SRSS) method and complete quadratic combination (CQC) method of combining. maximum modal responses (Kiureghian[1]) are widely used to determine the maximum seismic responses. for structures.
What is difference between acceleration and spectral acceleration?
PGA (peak acceleration) is what is experienced by a particle on the ground. SA (spectral acceleration) is approximately what is experienced by a building, as modeled by a particle on a massless vertical rod having the same natural period of vibration as the building.
What is meant by spectral response?
The spectral response describes the sensitivity of the photosensor to optical radiation of different wavelengths. The photocells used in photosensors are sensitive to a wider range of wavelengths than what the human eye sees.
What is spectral acceleration 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.
Why is it called pseudo acceleration?
Then the approximate acceleration is re-written as proportionate to relative displacement u, that is the so called pseudo acceleration. As in most cases, we only care about the value not the sign, so the pseudo acceleration is written as: apsu=ω2nu.
What is modal combination?
A modal combination rule is formulated here to estimate peak floor accelerations in a multistoried building directly in terms of the dynamic properties of the building and pseudo spectral acceleration ordinates of the base excitation.
What is CQC combination?
A Complete Quadratic Combination (CQC) method is proposed which reduces errors in modal combination in all examples studied. The CQC method degenerates into the SRSS method for systems with well-spaced natural frequencies.
What is Planck acceleration?
The Planck acceleration is the acceleration from zero speed to the speed of light during one Planck time. It is a derived unit in the Planck system of natural units.
What is the cause of spectral lines?
Spectral Line. This causes an electron to be promoted into a higher energy level, and the atom, element or molecule is said to be in an excited state. Emission lines occur when the electrons of an excited atom, element or molecule move between energy levels, returning towards the ground state.
What are spectral lines used for?
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules.
What is particle acceleration used for?
A particle accelerator used for physics experiments usually accelerate streams of subatomic particles in opposite directions at velocities near the speed of light. They then manipulate and collide these beams; the particles that make up the beams smash against each other and break apart.