Ratio between peak inelastic and elastic responses with uncertain structural properties

2004 ◽  
Vol 31 (4) ◽  
pp. 703-711 ◽  
Author(s):  
H P Hong ◽  
J Jiang
Keyword(s):  
Structural Properties ◽  
Natural Vibration ◽  
Damping Ratio ◽  
Elastic Displacement ◽  
Vibration Period ◽  
Peak Displacement ◽  
Linear Elastic ◽  
Inelastic Displacement ◽  
The Mean ◽  
The Impact

A systematical assessment of the impact of the uncertainty in the natural vibration period and damping ratio on the peak displacement of linear elastic and elastoplastic single-degree-of-freedom systems is carried out using more than 200 strong ground-motion records. The assessment is based on the ratio of the peak inelastic displacement with uncertain structural properties to the peak linear elastic displacement and, the ratio of the peak linear elastic displacement to the yield displacement. Statistical analysis for the ratios obtained is presented. The analysis results indicate that the impact of the uncertainty in the damping ratio on these ratios is less significant than that of the uncertainty in the natural vibration period. The results also show that the consideration of uncertainty in the natural vibration period slightly alters the average peak displacement of the linear or elastoplastic systems. However, the coefficients of variation of these ratios change significantly, especially, if the mean of the natural vibration period is less than about 0.1 s. Simple to use empirical equations, based on the results obtained, are suggested in evaluating the mean and the coefficient of variation of the ratios considering the uncertainty in structural properties. Key words: seismic excitation, uncertainty, peak elastic displacement, peak inelastic displacement.

scholarly journals Inelastic Displacement Ratios for Evaluation of Degrading Peak – Oriented SDOF Systems

2017 ◽  
Vol 62 (1) ◽  
pp. 33-47 ◽  
Author(s):  
Muzaffer Borekci ◽  
Murat S. Kirçil ◽  
Ibrahim Ekiz
Keyword(s):  
Dynamic Instability ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Elastic Displacement ◽  
Hysteretic Model ◽  
Collapse Potential ◽  
Inelastic Displacement ◽  
The Mean ◽  
Displacement Demand ◽  
Inelastic Displacement Ratio

Estimation of the inelastic displacement demand (IDD) is an important part of the performance-based design. Coefficient method is one of the methods for the estimation of IDD and in this method, IDD is determined by multiplying elastic displacement demand with inelastic displacement ratio (CR ). Previous researches showed that structures deteriorate and also exhibit dynamic instability under severe earthquakes and these behaviors should be considered in the estimation of CR to estimate a reliable IDD. In this study, CR of the non-degrading bilinear hysteretic model and the degrading peak-oriented hysteretic model with collapse potential were determined and effects of degradation on IDD were investigated. Nonlinear time history analysis of SDOF systems were performed using considered hysteretic models. Furthermore a new equation is proposed for the mean CR of degrading SDOF systems. Also, effect of local site conditions and post-yield stiffness on the mean CR of degrading SDOF systems were investigated.

The Dynamic Characteristics Analysis of Liaocheng Guangyue Tower

2015 ◽  
Vol 744-746 ◽  
pp. 920-923
Author(s):  
Zhao Bo Meng ◽  
Yu Cao ◽  
Jie Jin
Keyword(s):  
Numerical Analysis ◽  
Dynamic Characteristics ◽  
Natural Vibration ◽  
Damping Ratio ◽  
Analysis Method ◽  
Vibration Period ◽  
Incentive Effect ◽  
First Order ◽  
Characteristics Analysis ◽  
Dynamic Characteristics Analysis

Taking Liaocheng Guangyue tower as an example, based on the on-site measurements, to determine its dynamic characteristics and provide a basis by numerical analysis method for determining traffic incentive effect on the ancient timber buildings. From the research, we can conclude that the first-order self-vibration frequency of Guangyue tower can be taken as 1.638Hz, the corresponding natural vibration period is 0.61s,the damping ratio is 1.098.

scholarly journals Reviewing Arch-Dams’ Building Risk Reduction Through a Sustainability–Safety Management Approach

2020 ◽  
Vol 12 (1) ◽  
pp. 392 ◽  
Author(s):  
Enrico Zacchei ◽  
José Luis Molina
Keyword(s):  
Safety Management ◽  
Damping Ratio ◽  
Calculated Data ◽  
Deformation Analysis ◽  
Management Approach ◽  
Hydrological Process ◽  
Dam Foundation ◽  
Vibration Period ◽  
Arch Dams ◽  
The Impact

The importance of dams is rapidly increasing due to the impact of climate change on increasing hydrological process variability and on water planning and management need. This study tackles a review for the concrete arch-dams’ design process, from a dual sustainability/safety management approach. Sustainability is evaluated through a design optimization for dams´ stability and deformation analysis; safety is directly related to the reduction and consequences of failure risk. For that, several scenarios about stability and deformation, identifying desirable and undesirable actions, were estimated. More than 100 specific parameters regarding dam-reservoir-foundation-sediments system and their interactions have been collected. Also, a summary of mathematical modelling was made, and more than 100 references were summarized. The following consecutive steps, required to design engineering (why act?), maintenance (when to act) and operations activities (how to act), were evaluated: individuation of hazards, definition of failure potential and estimation of consequences (harm to people, assets and environment). Results are shown in terms of calculated data and relations: the area to model the dam–foundation interaction is around 3.0 Hd2, the system-damping ratio and vibration period is 8.5% and 0.39 s. Also, maximum elastic and elasto-plastic displacements are ~0.10–0.20 m. The failure probability for stability is 34%, whereas for deformation it is 29%.

scholarly journals Reviewing Arch-Dams’ Building Risk Reduction

2020 ◽  
Author(s):  
Jose-Luis Molina ◽  
Enrico Zacchei
Keyword(s):  
Safety Management ◽  
Damping Ratio ◽  
Deformation Analysis ◽  
Management Approach ◽  
Hydrological Process ◽  
Process Variability ◽  
Vibration Period ◽  
Arch Dams ◽  
Definition Of ◽  
The Impact

The are thousands of large dams over the globe. The importance of dams is rapidly increasing due to the impact of climate change on increasing hydrological process variability and on water planning and management need. This study tackles a review for the concrete arch-dams’ design process, from a dual sustainability/safety management approach. On one hand, Sustainability is evaluated through a design optimization for dams´ stability and deformation analysis. On the other hand, safety is directly related to the reduction and consequences of failure risk. For that, several scenarios about stability and deformation, identifying desirable and undesirable actions, were estimated. More than 100 specific parameters regarding dam-reservoir-foundation-sediments system and their interactions have been collected. Also, a summary of mathematical modelling was made, and more than 100 references were summarized. The following consecutive steps, required to design engineering (why act?), maintenance (when to act) and operations activities (how to act), were evaluated: individuation of hazards, definition of failure potential and estimation of consequences (harm to people, assets and environment). Results show that the area to model the dam–foundation interaction is around 3.0 Hd2, the system-damping ratio and vibration period is 8.5% and 0.39 s. Also, maximum elastic and elasto-plastic displacements are ~0.10–0.20 m. The failure probability for stability is 34%, whereas for deformation it is 29%

THE EFFECT OF PLACEMENT OF L-TYPE SHEAR WALLS IN RC STRUCTURES ON STRUCTURAL BEHAVIOR

2021 ◽  
Vol 0 (15) ◽  
pp. 0-0
Author(s):  
Muhammet Zeki ÖZYURT
Keyword(s):  
Reinforced Concrete ◽  
Natural Vibration ◽  
Shear Walls ◽  
Shear Wall ◽  
Structural Behavior ◽  
Structural System ◽  
Reinforced Concrete Structure ◽  
Vibration Period ◽  
Peak Displacement ◽  
Ground Floor

Aim: In this study; In this study, it was investigated how the symmetrical and different positions of the L-type shear walls on the floor plan affect the structural behavior in the reinforced concrete residential and office buildings with a symmetrical structural system. Method: In the study, three different carrier system types were created for a symmetrical reinforced concrete structure with 5 floors (ground floor + 4 normal floors), according to the shear wall layouts, and on a total of 12 different models (ground floor heights of 2.5 m, 3.0 m, 4.0 m and 5 m) was examined. Results: It was determined that as the ground floor height increased, the natural vibration period, soft floor irregularity coefficient and peak displacement value also increased in all models examined in the study. It has been observed that the natural vibration period is greater when the shear walls are located at the corners of the outer axles than if they are located in the middle of the outer axles and in the inner axles. It has been observed that in all cases of ground floor height, the number of soft floor irregularities in the corner shear wall layout model on the outer axes is approximately 0.2% higher than in the Type 2 situation. Conclusion: In this study, for the 5-storey reinforced concrete structures used for workplace and residential purposes, whose structural system is determined symmetrically so that torsional irregularity does not occur, the results obtained by changing the placement of L-section shear walls in the plan, drew attention to the fact that the position of the shear wall affects the structural behavior. For buildings with a ground floor height less than or equal to the normal floors, the most appropriate shear wall placement is when the shear walls are on the outer axes and in the corner. For buildings with a ground floor height higher than normal floors, the most appropriate shear wall placement takes place on the inner axes of the building.

Analysis on Influencing Factors of the Moment that Slider Begins to Slide for Sliding Base-Isolated System

2012 ◽  
Vol 166-169 ◽  
pp. 2713-2717
Author(s):  
Min Sun ◽  
Yu Guo Zhang ◽  
Yong Niu
Keyword(s):  
Friction Coefficient ◽  
Natural Vibration ◽  
Damping Ratio ◽  
Harmonic Excitation ◽  
Design Parameters ◽  
External Excitation ◽  
Vibration Period ◽  
Isolation Layer ◽  
The Moment ◽  
System Characteristics

The moment that isolation layer slider begins to slide has great effects on the whole system characteristics for sliding base-isolated system,and the moment plays a crucial role for the analysis of system energy and the confirmation of energy spectrum.Change rules of the moment that isolation layer slider begins to slide under the influence of the acting parameters and system’s design parameters,Taking two particle of plain sliding base-isolated system of building structure under harmonic excitation as the research object,are studied by using the numerical analysis method.The results show that the moment will be delayed if the friction coefficient of isolation layer or the natural vibration period of superstructure will be increased,and the moment will be advanced under the condition that the damping ratio of superstructure or external excitation which is exerted on structure being increased,while the mass ratio of isolation layer slider and superstructure has a very complex effect on the moment that isolation layer slider begins to slide,and the influence law relates to friction coefficient.

Asteroid and Comet Impact Speeds upon Mars: Significance for Panspermia and the Supply of Organics

1997 ◽  
Vol 161 ◽  
pp. 197-201 ◽  
Author(s):  
Duncan Steel
Keyword(s):  
Probability Distributions ◽  
Regions Of Interest ◽  
Significant Fraction ◽  
Organic Chemicals ◽  
Impact Speed ◽  
The Mean ◽  
The Impact

AbstractWhilst lithopanspermia depends upon massive impacts occurring at a speed above some limit, the intact delivery of organic chemicals or other volatiles to a planet requires the impact speed to be below some other limit such that a significant fraction of that material escapes destruction. Thus the two opposite ends of the impact speed distributions are the regions of interest in the bioastronomical context, whereas much modelling work on impacts delivers, or makes use of, only the mean speed. Here the probability distributions of impact speeds upon Mars are calculated for (i) the orbital distribution of known asteroids; and (ii) the expected distribution of near-parabolic cometary orbits. It is found that cometary impacts are far more likely to eject rocks from Mars (over 99 percent of the cometary impacts are at speeds above 20 km/sec, but at most 5 percent of the asteroidal impacts); paradoxically, the objects impacting at speeds low enough to make organic/volatile survival possible (the asteroids) are those which are depleted in such species.

Sound Production Treatment for Acquired Apraxia of Speech: An Examination of Dosage in Relation to Probe Performance

2020 ◽  
pp. 1-16
Author(s):  
Julie L. Wambaugh ◽  
Lydia Kallhoff ◽  
Christina Nessler
Keyword(s):  
Retrospective Analysis ◽  
Sound Production ◽  
Apraxia Of Speech ◽  
Practice Schedule ◽  
Practice Schedules ◽  
Baseline Performance ◽  
The Mean ◽  
Number Of Treatment ◽  
The Impact

Purpose This study was designed to examine the association of dosage and effects of Sound Production Treatment (SPT) for acquired apraxia of speech. Method Treatment logs and probe data from 20 speakers with apraxia of speech and aphasia were submitted to a retrospective analysis. The number of treatment sessions and teaching episodes was examined relative to (a) change in articulation accuracy above baseline performance, (b) mastery of production, and (c) maintenance. The impact of practice schedule (SPT-Blocked vs. SPT-Random) was also examined. Results The average number of treatment sessions conducted prior to change was 5.4 for SPT-Blocked and 3.9 for SPT-Random. The mean number of teaching episodes preceding change was 334 for SPT-Blocked and 179 for SPT-Random. Mastery occurred within an average of 13.7 sessions (1,252 teaching episodes) and 12.4 sessions (1,082 teaching episodes) for SPT-Blocked and SPT-Random, respectively. Comparisons of dosage metric values across practice schedules did not reveal substantial differences. Significant negative correlations were found between follow-up probe performance and the dosage metrics. Conclusions Only a few treatment sessions were needed to achieve initial positive changes in articulation, with mastery occurring within 12–14 sessions for the majority of participants. Earlier occurrence of change or mastery was associated with better follow-up performance. Supplemental Material https://doi.org/10.23641/asha.12592190

Impact of changing rainfall conditions on surface and groundwater resources in an experimental watershed in Greece

2013 ◽  
Vol 12 (2) ◽  
pp. 119-125
Keyword(s):  
Groundwater Resources ◽  
Annual Runoff ◽  
Annual Rainfall ◽  
Rainfall Regime ◽  
Winter Rainfall ◽  
Rainfall Depth ◽  
Rainfall Volume ◽  
The Mean ◽  
Groundwater Reserves ◽  
The Impact

The present study concerns the impact of a change in the rainfall regime on surface and groundwater resources in an experimental watershed. The research is conducted in a gauged mountainous watershed (15.18 km2) that is located on the eastern side of Penteli Mountain, in the prefecture of Attica, Greece and the study period concerns the years from 2003 to 2008. The decrease in the annual rainfall depth during the last two hydrological years 2006-2007, 2007-2008 is 10% and 35%, respectively, in relation to the average of the previous years. In addition, the monthly distribution of rainfall is characterized by a distinct decrease in winter rainfall volume. The field measurements show that this change in rainfall conditions has a direct impact on the surface runoff of the watershed, as well as on the groundwater reserves. The mean annual runoff in the last two hydrological years has decreased by 56% and 75% in relation to the average of the previous years. Moreover, the groundwater level follows a declining trend and has dropped significantly in the last two years.

(Preprint)

2018 ◽  
Author(s):  
Natalia Banasik ◽  
Dariusz Jemielniak ◽  
Wojciech P?dzich
Keyword(s):  
Medical Condition ◽  
Extended Period ◽  
Well Being ◽  
Marginal Effect ◽  
Life Duration ◽  
Significant Difference ◽  
The Mean ◽  
Academic Teachers ◽  
Length Of Life ◽  
The Impact

BACKGROUND There have been mixed results of the studies checking whether prayers do actually extend the life duration of the people prayed for. Most studies on the topic included a small number of prayers and most of them focused on people already struggling with a medical condition. Intercessory prayer’s influence on health is of scholarly interest, yet it is unclear if its effect may be dependent on the number of prayers for a named individual received per annum. OBJECTIVE We sought to examine if there is a noticeable increased longevity effect of intercessory prayer for a named individual’s well-being, if he receives a very high number of prayers per annum for an extended period. METHODS We retrieved and conducted a statistical analysis of the data about the length of life for 857 Roman Catholic bishops, 500 Catholic priests, and 3038 male academics from the US, France, Italy, Poland, Brazil, and Mexico. We obtained information for these individuals who died between 1988 and 2018 from Wikidata, and conducted an observational cohort study. Bishops were chosen for the study, as they receive millions of individual prayers for well being, according to conservative estimates. RESULTS There was a main effect for occupation F(2, 4391) = 4.07, p = .017, ηp 2 = .002, with pairwise comparisons indicating significant differences between the mean life duration of bishops (M=30489) and of priests (M=29894), but none between the academic teachers (M=30147) and either of the other groups. A comparison analysis between bishops from the largest and the smallest dioceses showed no significant difference t(67.31)=1.61, p = .11. Our main outcome measure is covariance of the mean length of life in each of the categories: bishops, priests, academic teachers, controlled for nationality. CONCLUSIONS The first analysis proved that bishops live longer than priests, but due to a marginal effect size this result should be treated with caution. No difference was found between the mean length of life of bishops from the largest and the smallest dioceses. We found no difference between bishops and male academics. These results show that the impact of intercessory prayers on longevity is not observable.

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