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. A replacement for the SRSS method in seismic analysis [Edward L Wilson] on *FREE* shipping on qualifying offers. A Replacement for the SRSS Method in Seismic Analysis. Front Cover. Edward L. Wilson. Wiley, – Structural analysis (Engineering).
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Figure 2 shows the typical response spectrum weismic terms of acceleration as a function of frequency ref. As a result, all the optimization results for the 4 different initial designs showed good agreement with each other properly. There is no specific provisions regarding combination of spatial components, except that in letter f of Section 2. Sensitivity Analysis of the Replacement Problem. The directional effects of an earthquake are combined with the following rules: There is no specific requirement.
The combination of the effects of the seismic components is discussed in paragraph 4. sess
For what regard the mode combination, paragraph Then, the seismic analysis for each direction can be performed separately and then combined by the square root of the sum of the squares SRSS. The percentage rule was put forward by Newmark and Thw first. Thus the structural design optimization of a small vertical-axis wind turbine could be successfully accomplished. The EC definition is more conservative than R. This paper offers also page 49 a short discussion of the directional combination procedure: To overcome and prevent these undesirable problems, structural design optimization of methor small vertical axis wind turbine has performed, in this study, for seismic qualification and lightweight by using a Genetic Algorithm GA subject to some design constraints such as the maximum stress limit, maximum deformation seisnic, and seismic acceleration gain limit.
He provides the following recommendations page Scientific Research An Academic Publisher. This statement is supported referring to a detailed discussion on this issue developed by Menun and Der Kiureghian in and Equipment Inspection Method and Weibull Analysis.
Seismic effects combination
According to this book, this approach introduces a maximum error of 4. Regarding the number of modes, in para. The effects of each modes for a given direction of the seismic action shall be combined with the CQC rule see para.
No other rules are specified for non-building structures dealt with in Chapter The percentage rule is therefore adopted. The periodic modal responses of an earthquake are combined with the following rules: According to ECparagraph 4.
As mentioned by Gupta in ref. Periodic responses are dominant in the region of amplified spectral displacement, amplified spectral velocity and amplified spectral rsplacement. The reeplacement method is never explicitly cited, but the theoretical bases for it are provided in Chapter 4, where the superposition of the i-modes is provided as linear combination with coefficients C i that have different values for different modes but can be approximated by the value 0.
The percentage rule is also proposed in paragraph 4. In general, this alternative method is slightly conservative for most cases and is quite adequate since its degree of conservatism is relatively small. The rigid responses wnalysis rigid components of responses are combined algebraically.
This condition is equivalent to the one adopted by R.
Labor Omnia Vicit Improbus. Figure 1 shows the typical conceptual shape of a response spectrum in terms of velocity as a function of frequency ref.
A replacement for the srss method in seismic analysis. | Article Information | J-GLOBAL
Recently, there is a growing interest in seismic qualification of ridges, buildings and mechanical equipment worldwide due to increase of accidents caused seizmic earthquake. For response spectrum RS analysis, the R.
Severe earthquake can bring serious problems in the wind turbines and eventually lead to an interruption to their electric power supply. This subject is dealt with in several standards or regulatory guides among which the following are examined herein below: If uncoupled response replacenent the structure is expected, then only one time history is required.
As replacfment alternative the SRSS rule can be used. Subscribing you accept the TOC. The periodic response corresponds to the transient phase in theory of vibrations.
World Journal of Engineering and TechnologyVol. In general, if the frequencies of the modes are sufficiently separated, the SRSS method may be applied.
The effects due to the different directions of the seismic replaceemnt shall be combined with the percentage rule see para. Also, the structural design optimizations were conducted for the four different initial design variable sets to confirm robustness of the optimization algorithm used. The dotted lines refer to the case of multiple narrow-banded response spectrum with two or more peaks of acceleration. The maximum seismix is 1. When modes are to be considered closely spaced is matter of discussion and any standards provides a slightly different rule.
Sviluppato con Drupal da Gmg Net Srl. The equations are written as follows: The rigid response corresponds to the steady-state phase in theory of vibrations.