Digital Synthesis of Response-Design Spectrum Compatible Earthquake Records for Dynamic Analyses

Introduced in this paper are several alternative ground-motion intensity measures ( IMs) that are intended for use in assessing the seismic performance of a structure at a site susceptible to near-source and/or ordinary ground motions. A comparison of such IMs is facilitated by defining the “efficiency” and “sufficiency” of an IM, both of which are criteria necessary for ensuring the accuracy of the structural performance assessment. The efficiency and sufficiency of each alternative IM, which are quantified via (i) nonlinear dynamic analyses of the structure under a suite of earthquake records and (ii) linear regression analysis, are demonstrated for the drift response of three different moderate- to long-period buildings subjected to suites of ordinary and of near-source earthquake records. One of the alternative IMs in particular is found to be relatively efficient and sufficient for the range of buildings considered and for both the near-source and ordinary ground motions.

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An economic solution for stabilising a slender arch roof

Bulletin of the New Zealand Society for Earthquake Engineering ◽

10.5459/bnzsee.19.2.93-103 ◽

1986 ◽

Vol 19 (2) ◽

pp. 93-103

Author(s):

D. D. Spurr

Keyword(s):

Reinforced Concrete ◽

Computer Program ◽

Seismic Response ◽

Special Study ◽

Concrete Cracking ◽

Linear Dynamic ◽

Earthquake Records ◽

Dynamic Analyses ◽

Non Linear ◽

Prestressing Strand

A special study was made to evaluate the seismic response of the ribs of four reinforced concrete arch aircraft hangars and to assess methods of strengthening the ribs. The study was based on a series of non linear dynamic analyses of the arch ribs, with particular consideration being given to the choice of earthquake records, to the effect of P-delta actions on the arch responses and to the validity of the behaviour predicted by the computer program. The analyses indicated that the arch ribs could become unstable as a result of the P-delta effect acting in combination with reduction in the rib stiffness due to concrete cracking. However, the study also shows that the arches can be stablised very economically by using prestressing strand to provide cross bracing.

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Selection and Scaling of Ground Motion Time Histories for Structural Design Using Genetic Algorithms

Earthquake Spectra ◽

10.1193/1.1719028 ◽

2004 ◽

Vol 20 (2) ◽

pp. 413-426 ◽

Cited By ~ 113

Author(s):

Farzad Naeim ◽

Arzhang Alimoradi ◽

Shahram Pezeshk

Keyword(s):

Ground Motions ◽

Response Spectra ◽

Single Individual ◽

Least Mean Square ◽

Scaling Factors ◽

Design Spectrum ◽

Earthquake Ground Motions ◽

Earthquake Records ◽

Target Spectrum ◽

Scaling Methods

This paper presents a new approach to selection of a set of recorded earthquake ground motions that in combination match a given site-specific design spectrum with minimum alteration. The scaling factors applied to selected ground motions are scalar values within the range specified by the user. As a result, the phase and shape of the response spectra of earthquake ground motions are not tampered with. Contrary to the prevailing scaling methods where a preset number of earthquake records (usually between a single component to seven pairs) are selected first and scaled to match the design spectrum next, the proposed method is capable of searching a set consisting of thousands of earthquake records and recommending a desired subset of records that match the target design spectrum. This task is achieved by using a genetic algorithm (GA), which treats the union of 7 records and corresponding scaling factors as a single “individual.” The first generation of individuals may include a population of, for example, 200 records. Then, through processes that mimic mating, natural selection, and mutation, new generations of individuals are produced and the process continues until an optimum individual (seven pairs and scaling factors) is obtained. The procedure is fast and reliable and results in records that match the target spectrum with minimal tampering and the least mean square of deviation from the target spectrum.

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Confounding contaminants in mass spectrometric reaction monitoring

10.26434/chemrxiv.7488737.v1 ◽

2018 ◽

Author(s):

Gilian T. Thomas ◽

Landon MacGillivray ◽

Natalie L. Dean ◽

Rhonda L. Stoddard ◽

Lars Yunker ◽

...

Keyword(s):

Mass Spectrometry ◽

Mass Spectrometric ◽

Negative Ion ◽

Reaction Monitoring ◽

Schlenk Flask ◽

Dynamic Analyses ◽

Rubber Septa ◽

Negative Ion Mode ◽

Mode A

<p>Reactions carried out in the presence of rubber septa run the risk of additives being leached out by the solvent. Normally, such species are present at low enough levels that they do not interfere with the reaction significantly. However, when studying reactions using sensitive methods such as mass spectrometry, the appearance of even trace amounts of material can confuse dynamic analyses of reactions. A wide variety of additives are present in rubber along with the polymer: antioxidants, dyes, detergent, and vulcanization agents, and these are all especially problematic in negative ion mode. A redesigned Schlenk flask for pressurized sample infusion (PSI) is presented as a means of practically eliminating the presence of contaminants during reaction analyses.</p>

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