scholarly journals The Effect of Foundation Flexibility on Probabilistic Seismic Performance of Plan-Asymmetric Buildings with Different Strength Distributions

2020 ◽  
Vol 2020 ◽  
pp. 1-23
Author(s):  
Sahar Mohammadzadeh Osalu ◽  
Hamzeh Shakib
Keyword(s):  
Seismic Performance ◽  
Limit State ◽  
Damage Index ◽  
Strength Distribution ◽  
Performance Level ◽  
Concrete Wall ◽  
Confidence Levels ◽  
Asymmetric Buildings ◽  
The Mean ◽  
Strength Distributions

In this research, the probabilistic seismic performance of asymmetric reinforced concrete wall-frame buildings with different strength distributions incorporating foundation flexibility effects is examined. By using probability-based performance evaluation approach, it is possible to provide a more accurate prediction of the different strength distribution effect on the seismic performance of asymmetric buildings and find the most efficient strength distribution for meeting each performance level. These efficient distributions can be adopted in the performance-based design of asymmetric buildings. For this purpose, first, the regression analysis and the concepts of efficiency and sufficiency were used to determine an optimal intensity measure (IM) for incremental dynamic analysis and evaluating the seismic response of the considered building models. Then, the proper magnitude of interstory drift capacity for this type of buildings in each limit state was estimated using the damage index concept. Finally, the effects of different strength distributions and the flexibility of foundation were studied on the seismic performance of the asymmetric buildings by investigating the mean annual frequencies of exceeding structural performance levels and confidence levels to satisfy performance objectives. It is concluded that irregular distributions of stiffness and strength in the plan of a building highly affect the seismic performance of buildings. Also, the results show that the optimum strength distribution is a function of the objective performance level and these optimum strength distributions are the same for both fixed- and flexible-base conditions. Meanwhile, the flexible effect of foundation increases the mean annual frequencies of exceedance within the range of 10% to 45% and significantly decreases the confidence levels in most cases.

Fatigue Reliability Functions in Semilogarithmic Coordinates

1991 ◽  
Author(s):  
Vladimir A. Avakov
Keyword(s):  
Fatigue Life ◽  
Coordinate System ◽  
Strength Distribution ◽  
Fatigue Reliability ◽  
Life Distribution ◽  
Similar Transformation ◽  
Asymptotic Type ◽  
Life Distributions ◽  
Strength Distributions

Abstract In the previous publication [2], the transformation between fatigue life and strength distribution was established using double-logarithmic coordinate system (lnN-lnS). Here, a similar transformation is established using a semi logarithmic (lnN-S) coordinate system. With the aid of the developed orthogonal relations, lognormal, Weibull and three-parameter logweibull life distributions have been transformed into normal, asymptotic type 1 of smallest value, and three-parameter Weibull strength distributions, respectively. This procedure may be applied to other types of fatigue life distribution.

Prediction of the Strength of Ceramic Tubular Components: Part II — Experimental Verification

1991 ◽  
Author(s):  
D. L. Shelleman ◽  
O. M. Jadaan ◽  
J. C. Conway ◽  
J. J. Mecholsky
Keyword(s):  
Silicon Carbide ◽  
Statistical Theory ◽  
Room Temperature ◽  
Strength Distribution ◽  
Ring Test ◽  
Stress Distributions ◽  
Pressure Test ◽  
Tubular Components ◽  
Tubular Specimens ◽  
Strength Distributions

Abstract The strength distribution of reaction bonded silicon carbide tubes that failed by internal pressurization was predicted from strength distributions obtained from simple laboratory test specimens at room temperature. The strength distributions of flexure bars, C-rings tested in tension, C-rings tested in compression, diametrally compressed O-rings, and internally pressurized short tubes were compared to the strength distribution of internally pressurized long tubes. The methodology involved application of Weibull statistical theory using elasticity theory to define the stress distributions in the simple specimens. The flexural specimens did not yield acceptable results, since they were ground prior to testing, thereby altering their flaw population in comparison with the processing induced flaw populations of the tubular specimens. However, the short tube internal pressure test, the c-ring tested in tension and the diametrally compressed o-ring test configurations yielded accurate predictions, since these specimens more accurately represent the strength limiting flaw population in the long tubes.

scholarly journals Lesões Músculo-Esqueléticas em Remadores de Competição

2015 ◽  
Vol 28 (4) ◽  
pp. 427 ◽  
Author(s):  
Francisco Bernardes ◽  
Alfredo Mendes-Castro ◽  
José Ramos ◽  
Ovídio Costa
Keyword(s):  
Statistical Analysis ◽  
Anatomical Location ◽  
Lumbar Region ◽  
Confidence Levels ◽  
Injury Occurrence ◽  
Parametric Statistics ◽  
The Mean ◽  
Occurrence Type ◽  
Location Type ◽  
Type Of Injury

<p><strong>Introduction:</strong> The objective of this study was the assessment of the injuries occurred over the competitive rowing lifetime of Portuguese senior rowers.<br /><strong>Material and Methods:</strong> We sent a questionnaire to all Portuguese senior rowers medalled in the national championships during the 2013-2014 season. We analysed biometric variables, anatomic location, type and circumstances of injury occurrence, type of treatment provided and time of inactivity. For statistical analysis we used parametric and non-parametric statistics with 95% confidence levels (p &lt; 0.05).<br /><strong>Results:</strong> The questionnaire was answered by 18 of the 18 female and 74 of the 77 male rowers. Females had significantly lower ages, heights and weights and rowed more often sculling boats (p &lt; 0.05). The number of years of practice, as well as the number of injuries per rower was similar, for both females and males. The mean age at the first injury was significantly lower in females (p &lt; 0.001), who also had more progressive lesions than acute ones, although not significantly. In both, the most frequent anatomical location and type of injury were the lumbar region and muscular pathology, with a higher occurrence in winter and spring, during land training. Females<br />sustained longer periods of inactivity, but not significantly.<br /><strong>Discussion:</strong> The results that were different from those reported by other authors may be related with differences in the studied populations or with other factors that need to be clarified.<br /><strong>Conclusion: </strong>The injuries sustained by the Portuguese competitive rowers, probably associated with a lower competitive exposure of our athletes, were less severe than those generally reported in the literature.</p>

Performance and psychometric properties of lupus impact tracker in assessing patient-reported outcomes in pediatric lupus: Report from a pilot study

Lupus ◽  
2020 ◽  
Vol 29 (13) ◽  
pp. 1781-1789
Author(s):  
Suhas K Ganguli ◽  
Joyce S Hui-Yuen ◽  
Meenakshi Jolly ◽  
Jane Cerise ◽  
Barbara Anne Eberhard
Keyword(s):  
Systemic Lupus Erythematosus ◽  
Pilot Study ◽  
Disease Activity ◽  
Lupus Erythematosus ◽  
Patient Reported Outcomes ◽  
Laboratory Data ◽  
Damage Index ◽  
Systemic Lupus ◽  
Patient Reported ◽  
The Mean

Objective To evaluate the reliability, validity, feasibility and psychometric performance of the Lupus Impact Tracker (LIT) as a patient reported outcome (PRO) measure tool in pediatric systemic lupus erythematosus (pSLE). Methods This is a prospective, observational, pilot study where patients aged between 12 and 25 years, fulfilling the 1997 ACR classification criteria for SLE, were enrolled. Over 3 consecutive, routine, clinical visits, the patients completed the LIT alongside the Patient-Reported Outcomes Measurement Information System-Short Forms (PROMIS-SFs), Childhood Health Assessment Questionnaire (CHAQ). Rheumatologists completed the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) and the Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC-ACR) Damage Index. Demographic, clinical and laboratory data were also collected. Results Of 46 patients enrolled, 38 patients completed 2 visits and 31 completed all 3 visits. Seventy-eight percent were female, 33% African American, 28% Asian, 15% Caucasian and 17% Hispanic. The mean (SD) age was 17.2 (2.7) years, with a mean (SD) disease duration of 4.6 (3.1) years. The mean (SD) SLEDAI-2K at enrollment was 3.54 (2.96). In the 38 patients who completed two or more visits, intra-class correlation coefficient and Cronbach alpha were calculated to be 0.70 and 0.91 respectively, signifying good reliability of LIT. The LIT showed positive correlation with CHAQ-Disability Index and majority of the PROMIS-SFs parameters. Construct validity was established against clinical disease activity (SLEDAI-2K). Conclusion The preliminary results indicate that the LIT is a reliable and valid instrument to capture PRO in p-SLE. Prospective validation with a larger, multicenter cohort is the next step.

Consideration and Propagation of Ground Motion Selection Epistemic Uncertainties to Seismic Performance Metrics

2018 ◽  
Vol 34 (2) ◽  
pp. 587-610 ◽  
Author(s):  
Karim Tarbali ◽  
Brendon A. Bradley ◽  
Jack W. Baker
Keyword(s):  
Seismic Hazard ◽  
Seismic Response ◽  
Ground Motion ◽  
Seismic Performance ◽  
Performance Metrics ◽  
Epistemic Uncertainty ◽  
Seismic Demand ◽  
Intensity Measures ◽  
Ground Motion Selection ◽  
The Mean

This paper investigates various approaches to propagate the effect of epistemic uncertainty in seismic hazard and ground motion selection to seismic performance metrics. Specifically, three approaches with different levels of rigor are presented for establishing the conditional distribution of intensity measures considered for ground motion selection, selecting ground motion ensembles, and performing nonlinear response history analyses (RHAs) to probabilistically characterize seismic response. The mean and distribution of the seismic demand hazard is used as the principal means to compare the various results. An example application illustrates that, for seismic demand levels significantly below the collapse limit, epistemic uncertainty in seismic response resulting from ground motion selection can generally be considered as small relative to the uncertainty in the seismic hazard itself. In contrast, uncertainty resulting from ground motion selection appreciably increases the uncertainty in the seismic demand hazard for near-collapse demand levels.

Seismic Damage Assessment of Regular Gravity Design Buildings

2013 ◽  
Vol 569-570 ◽  
pp. 294-301
Author(s):  
Caterina Negulescu ◽  
Kushan K. Wijesundara ◽  
Evelyne Foerster
Keyword(s):  
Damage Assessment ◽  
Failure Modes ◽  
Limit State ◽  
Damage Index ◽  
Ductile Failure ◽  
Ultimate Limit State ◽  
Natural Period ◽  
Damage Indices ◽  
Seismic Damage Assessment ◽  
Assessment Results

During the past earthquakes, different low ductile failure modes are observed in the gravity design structures and thus, the most of existing damage indices may fail to assess the damage of gravity design structures accurately in referring to the two main performance levels: immediate occupancy and ultimate limit state. Therefore, this study investigates the possible damage indices for the damage assessment of gravity design frames. For this purpose, among the existing damage indices in the literature, this study considers the inter-story drift and the natural period based damage indices. In addition, two new damage indices based on the wavelet based energy and the dominant inelastic period of a building are also considered in this study. Furthermore, the damage assessment results from the four damage indices for three gravity design buildings are compared and discussed. From the comparison, linear correlations between the inter-storey drift based damage index and the wavelet energy based index, and dominant inelastic period based damage index are observed. Finally, this study concludes based on the observations that no significant effects of number of inelastic cycles to the damage assessment results for low ductile structures. However, this study also highlights the effects of number of inelastic cycles to the damage for medium and high ductile structures.

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