What is a response spectrum used for?
Response spectra are very useful tools of earthquake engineering for analyzing the performance of structures and equipment in earthquakes, since many behave principally as simple oscillators (also known as single degree of freedom systems).
What is SRSS method?
SUMMARY. It is well-known that the application of the Square-Root-of-Sum-of-Squares (SRSS) method in seismic analysis for combining modal maxima can cause significant errors. Nevertheless, this method continues to be used by the profession for significant buildings.
What are the results of response spectrum analysis?
Response spectrum analysis is a method to estimate the structural response to short, nondeterministic, transient dynamic events. Examples of such events are earthquakes and shocks. Since the exact time history of the load is not known, it is difficult to perform a time-dependent analysis.
What is CQC method?
iA Complete Quadratic Combination (CQC) method is proposed which reduces errors in modal combination in all samples studied. The CQC method degenerates into the SRSS method for systems with well-spaced natural frequencies.
Is response spectrum analysis static or dynamic?
linear-dynamic
Response-spectrum analysis (RSA) is a linear-dynamic statistical analysis method which measures the contribution from each natural mode of vibration to indicate the likely maximum seismic response of an essentially elastic structure.
How do you create a response spectrum shock?
An SRS is generated from a shock waveform using the following process:
- Specify a damping ratio for the SRS (5% is most common)
- Use a digital filter to model an SDOF of frequency, fn and damping ΞΎ.
- Apply the transient as an input and calculate the response acceleration waveform.
What is the response spectra of the ground motion?
Ground motion response spectrum is defined as a graphical relationship of the peak response of a single-degree-of-freedom (SDOF) oscillator having certain damping to dynamic motion or forces.
What is CQC modal combination method?
Abstract. The CQC rule for modal combination is extended to include the quasi-static contribution of truncated modes and the effects of input narrow-bandedness and cut-off frequency. A simple measure of the error in approximating a high-frequency modal response by its quasi-static contribution is derived.
What are the parameters we considered in seismic analysis?
In general, the intensity parameters can be classified into peak, spectral, and energy parameters. Twenty parameters have been selected to represent the seismic excitation. They have been chosen from all three seismic parameter categories.
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.
Is response spectrum linear analysis?
Response-spectrum analysis (RSA) is a linear-dynamic statistical analysis method which measures the contribution from each natural mode of vibration to indicate the likely maximum seismic response of an essentially elastic structure.
What is the difference between equivalent static method and response spectrum method?
What is R factor? Equivalent Lateral Force (ELF) Analysis & Response Spectrum Analysis are types of linear elastic analysis but the difference is, one is static analysis while the other is dynamic analysis. ELF analysis is based on an assumption of static cantilever beam.
What is SRS shock testing?
SRS Pyroshock testing is commonly used to determine a test article’s ability to tolerate the mechanical stress waves produced by a high frequency, high-G shock event, such as rocket stage separations.
What is an SRS plot?
A Shock Response Spectrum (SRS) is a graphical presentation of a transient acceleration pulse’s potential to damage a structure. It plots the peak acceleration responses of a bank of single degree-of-freedom (SDOF) spring, mass damper systems all experiencing the same base-excitation as if on a rigid massless base.
What are the three elements of ground motion?
Selecting, scaling, and orienting three components of ground motions for intensity-based assessments at far-field sites – N.
What is acceleration response?
Acceleration response spectra giving the maximum acceleration of the mass of the structure can be used to calculate the maximum horizontal forces acting on the structure and to assess the resulting deformations of the structure. From: Comprehensive Structural Integrity, 2003.
What is difference between SRSS and CQC method?
The CQC method degenerates into the SRSS method for systems with well-spaced natural frequencies. ice the CQC method only involves a small increase in numerical effort, it is recommended that the new approach be used asa replacement for the SRSS method in all response spectrum calculations.