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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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.

Also, the structural design optimizations were conducted for the four different initial design variable sets to confirm robustness of the optimization algorithm used.

No other rules are specified for non-building structures dealt with in Chapter When modes are to be considered closely spaced is srds of discussion and any standards provides a slightly different rule.

According to this book, this approach introduces a maximum error of 4. Scientific Research An Academic Publisher. The effects of each modes for a given direction of the seismic action shall be combined with the CQC rule see para. The combination rule to be used for individual modal responses depends upon whether the responses are periodic, rigid or both see R. In seismic response analysis two types of combinations are to be considered: This condition tor equivalent to replaceent one adopted by R.

The combination of the effects of the seismic components is discussed in paragraph 4.

A replacement for the srss method in seismic analysis. | Article Information | J-GLOBAL

Subscribing you accept the TOC. According to ECparagraph 4. The percentage rule is also proposed in paragraph 4. The maximum value is 1.

Seismic effects combination

Simply shifting the starting time of a given accelerogram does replacemeht constitute the establishment of a different accelerogram. Sviluppato con Drupal da Gmg Net Srl. There is no specific requirement. This statement is supported referring to a detailed discussion on this issue developed by Menun and Der Kiureghian in and The dotted lines refer to the case of multiple narrow-banded response spectrum with two or more peaks of acceleration.


As an alternative the SRSS rule can be used. In general, this alternative method is slightly conservative for most cases and is quite adequate since its degree of conservatism is relatively small. Recently, there is a growing interest in seismic qualification of ridges, buildings and mechanical equipment worldwide due to increase of accidents caused by earthquake.

Severe earthquake can bring serious problems in the wind turbines and eventually lead to an interruption to their electric power supply.

Seismic effects combination | Studio Alicino

Periodic responses are dominant in the region of amplified spectral displacement, amplified spectral velocity and amplified spectral acceleration. He provides the following recommendations page This paper offers also page 49 a short discussion of the directional combination procedure: For response spectrum RS analysis, the R.

Thus the structural design optimization of a small vertical-axis wind turbine could be successfully accomplished. The percentage rule is therefore adopted. To overcome and prevent these undesirable problems, structural design optimization of a 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 limit, and seismic acceleration gain limit.

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 action shall be combined with the percentage rule see para.

As mentioned by Gupta in ref. The periodic modal responses of an earthquake are combined with the following rules: SRSS3 method would have a rather large error if the natural periods of the structure are close to each other, namely modal correlation coefficients of structure are large.


For what regard the mode combination, paragraph The equations are written as follows: The directional effects of an earthquake are combined with the following rules: World Journal of Engineering and TechnologyVol. Equipment Inspection Method and Weibull Analysis. The percentage 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 xnalysis coefficients C i that have different values for different modes but can be approximated by the value 0.

The rigid response corresponds to the steady-state phase in theory of vibrations. Regarding the number of modes, in para. This subject is dealt with in several standards or regulatory guides among which the following are examined herein below: The EC definition is more conservative than R.

The percentage rule was put forward by Newmark and Rosenblueth first. If uncoupled response of the mfthod is expected, then only one time history is required. Both periodic and rigid responses occur in the intermediate region between amplified spectral acceleration and high-frequency region DE in Figure 1 and Figure 2.

Sensitivity Analysis of the Replacement Problem.

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As a result, all the optimization results for the 4 different initial designs showed good agreement with each other properly. The rigid responses and rigid components of responses are combined algebraically. Figure 2 shows the typical response spectrum in terms of acceleration as a function of frequency ref.