scholarly journals Component Combination Rules of Wind Load Effects of Building Structures

2020 ◽  
Vol 10 (24) ◽  
pp. 8775
Author(s):  
Haiwei Guan ◽  
Yuji Tian
Keyword(s):  
Extreme Values ◽  
Simulation Method ◽  
Wind Load ◽  
Combination Method ◽  
Wind Effect ◽  
Building Structures ◽  
Combination Rules ◽  
Load Effect ◽  
Mean Values ◽  
Standard Deviations

Under the action of the same wind azimuth, the extreme values of the wind load effect components of building structures are generated in the along-wind, cross-wind, vertical, and torsional directions. In designing the wind-resistant structure, the extreme values of effect components need to be combined to determine the internal force envelope values of members. Complete quadratic combination (CQC) and Turkstra combination rules are often used to determine the combination value of extreme values of wind effect components. The extreme probability distribution expressions of the CQC, and the Turkstra and approximate rules, are derived. The simplified combination Equations and combination coefficients of the CQC and Turkstra approximate rules are proposed in this paper. We use the combination Equations and Monte Carlo simulation method to analyze the accuracy of Turkstra and its approximate rules. The results show that the combination extreme is associated with the correlation coefficients, mean values, ratios of standard deviations, and fluctuating extremes of effect components. The errors between Turkstra and its approximate rules are small when load effect components show a positive correlation. The errors are largest when the standard deviations of components are equal. Our research results provide a theoretical basis for the combination method of wind load effect components of building structures.

scholarly journals A New Combination Method of Temperature and Vehicle Load Effects Based on SHM Data

2012 ◽  
Vol 5 ◽  
pp. 157-161 ◽  
Author(s):  
Zi Jian Wang ◽  
Rong Pan Hu ◽  
Shun Long Li
Keyword(s):  
Service Life ◽  
Extreme Values ◽  
Generalized Pareto Distribution ◽  
Rectangular Pulse ◽  
Combination Method ◽  
New Combination ◽  
Load Effect ◽  
Mean Values ◽  
Vehicle Load ◽  
Load Effects

When more than one load act on a structure, the combination of the load effects should be considered, especially for which are variant in time and in space. A new method to calculate the combination of two different loads effects as well as to predict the extreme value distributions in the subsequent service life is proposed. The loads discussed in this paper are two main loads acting on the cable-stayed bridge: the temperature and vehicle load, which can be modeled as rectangular pulse process and filtered Poisson process respectively. Firstly, truncated distributions of the two load effects are depicted using the monitoring data of Nanjing 3rd Yangtze River Bridge. The generalized Pareto distribution fits well to the upper tails of the vehicle load effect and the mean values of the temperature load effect in an hour follows a two weighted normal distribution. Then the combination of the two load effects as well as the prediction of extreme values in the subsequent service life can be calculated. In the end, the results obtained through the proposed method are compared with the observed value of the bridge.

scholarly journals Study on Partial Factor of Load for Reinforced Concrete Columns

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Zhengjie Cheng ◽  
Jitao Yao
Keyword(s):  
Structural Reliability ◽  
Design Method ◽  
Great Influence ◽  
Statistical Parameter ◽  
Simulation Method ◽  
Structure Design ◽  
Building Structures ◽  
Load Effect ◽  
Compression Members ◽  
Partial Factor

At present, the design method of components is still a partial factor design method, and the partial factor value is related to the load value. Because the partial factor has a great influence on the safety of engineering structure, it has been adjusted many times in the process of organization of the code. In order to be basically equivalent to European and American reliability standards and to conform to China’s national conditions and national policies, the Unified standard for reliability design of building structures is revised (i.e., the partial factor of permanent action and variable action was adjusted). Although the concept of factor of safety is commonly used in structure design practice to cover all the unexpected risks, there are some disadvantages to its direct use in structural reliability analysis. For example, the eccentricity of compression members is random, which will lead to the change in resistance parameters of compression members, rather than the fixed value specified in the code. However, the random variation in eccentricity is not considered in the code. So, in this paper, the partial factors of eccentrically loaded members are studied by considering the statistical parameter information of members with random eccentricity. This paper studies the partial factors of different types of components in different ratios of live load effect to dead load effect, and some recommendations are proposed to obtain safer designs. Finally, Monte Carlo simulation method is used to analyze the reliability of the eccentric member. The research results show that the value of partial factors of structure proposed in this paper is reasonable.

scholarly journals A stochastic approach for the wind load effect on steel structures

2016 ◽  
Vol 69 (2) ◽  
pp. 137-145 ◽  
Author(s):  
Thiago Dias dos Santos ◽  
Gustavo Henrique Siqueira ◽  
Luiz Carlos Marcos Vieira Junior
Keyword(s):  
Steel Structures ◽  
Stochastic Approach ◽  
Wind Load ◽  
Load Effect

scholarly journals Between-Country Comparability of Clinical Chemistry Results: An International Quality Assessment Survey of 17 Analytes in Six European Countries through Existing National Schemes

1993 ◽  
Vol 30 (3) ◽  
pp. 304-314 ◽  
Author(s):  
R T P Jansen ◽  
D G Bullock ◽  
A Vassault ◽  
H Baadenhuijsen ◽  
A De Leenheer ◽  
...  
Keyword(s):  
The Netherlands ◽  
Quality Assessment ◽  
Mutual Recognition ◽  
Clinical Chemistry ◽  
Reference Method ◽  
European Countries ◽  
Mean Values ◽  
Related Data ◽  
Standard Deviations ◽  
The Uk

Two lyophilized control sera were distributed through seven national external quality assessment schemes in six European countries—Belgium, Switzerland, France, The Netherlands, Sweden and the United Kingdom—participated in the study. The results for 17 routine analytes were obtained from almost 5000 laboratories for the two sera. The organizers of the schemes were asked to process the results according to a common outlier removal procedure, and submit method-related data if available. The two sera were also distributed through the external/internal scheme of The Netherlands, and the within-laboratory standard deviations calculated in this scheme have been used in a scaling procedure for the external mean values and between-laboratory standard deviations of the participating countries. The results show remarkable agreement in the national mean values for practically all analytes, but considerable differences in the between-laboratory variation. Data from comparable method groups was obtained for 12 analytes from Belgium, France, The Netherlands and the UK. Though revealing some specific differences between methods and countries, the method-related data are generally in agreement with the all-method data. In this study reference method values were only available for cholesterol. The high degree of agreement found suggests, however, that mutual recognition of all-method mean values in national schemes could be acceptable, especially for analytes for which reliable reference methods are not available. The major element of variation is between-laboratory rather than between-country.

scholarly journals Time-Varying Wind Load Identification Based on Minimum-Variance Unbiased Estimation

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Huili Xue ◽  
Kun Lin ◽  
Yin Luo ◽  
Hongjun Liu
Keyword(s):  
Damping Ratio ◽  
Estimation Method ◽  
Minimum Variance ◽  
Wind Load ◽  
Ar Model ◽  
Unbiased Estimation ◽  
Recursive Identification ◽  
Time Varying ◽  
Building Structures ◽  
Shear Building

A minimum-variance unbiased estimation method is developed to identify the time-varying wind load from measured responses. The formula derivation of recursive identification equations is obtained in state space. The new approach can simultaneously estimate the entire wind load and the unknown structural responses only with limited measurement of structural acceleration response. The fluctuating wind speed process is investigated by the autoregressive (AR) model method in time series analysis. The accuracy and feasibility of the inverse approach are numerically investigated by identifying the wind load on a twenty-story shear building structure. The influences of the number and location of accelerometers are examined and discussed. In order to study the stability of the proposed method, the effects of the errors in crucial factors such as natural frequency and damping ratio are discussed through detailed parametric analysis. It can be found from the identification results that the proposed method can identify the wind load from limited measurement of acceleration responses with good accuracy and stability, indicating that it is an effective approach for estimating wind load on building structures.

MAXIMUM BREATHING CAPACITY AND VITAL CAPACITY OF MALE CHILDREN AND ADOLESCENTS

PEDIATRICS ◽  
1952 ◽  
Vol 9 (6) ◽  
pp. 659-670
Author(s):  
B. G. FERRIS ◽  
J. L. WHITTENBERGER ◽  
J. R. GALLAGHER
Keyword(s):  
Children And Adolescents ◽  
Surface Area ◽  
Body Surface Area ◽  
Body Surface ◽  
Vital Capacity ◽  
Normal Values ◽  
Mean Values ◽  
Single Attribute ◽  
Standard Deviations ◽  
The Individual

Expected mean values and a range of normal values (plus or minus two standard deviations) are presented for the vital capacity and the maximum breathing capacity of male children and adolescents. It is recommended that calculations of the above values be based upon four attributes (age, height, weight, and body surface area) rather than upon a prediction deriving from a single attribute (especially in the individual who does not have a standard height and weight for his age).

Determination of Basic Wind Velocity for Wind Load-Governed Limit State

2019 ◽  
Author(s):  
Ji Hyeon Kim ◽  
Hae-Sung Lee
Keyword(s):  
Wind Velocity ◽  
Reliability Index ◽  
General Procedure ◽  
Limit State ◽  
Wind Load ◽  
Wind Pressure ◽  
Load Factor ◽  
Load Effect ◽  
Design Life ◽  
Target Reliability Index

<p>This paper proposes a general procedure for evaluating a nominal value of wind velocity for a wind load- governed limit state to secure a target reliability index during the design life of a structure. The nominal value of wind velocity, referred to as a basic wind velocity, and wind load factor should be determined so that the factored wind load effect secures a target reliability index for a wind load-governed limit state. In this study, the analytical form of the return period of the basic wind velocity is expressed as a function of the target reliability index, wind load factor, and statistical parameters of wind pressure, which are derived as linear functions of the coefficient of wind velocity. The proposed approach is applied to the Korean Highway Bridge Design Code-Cable supported Bridge, which specifies the design life of a structure as 100- and 200-year.</p>

Determination of Menthol in Cigarette Tobacco Filler

1967 ◽  
Vol 50 (4) ◽  
pp. 770-773
Author(s):  
Charles L Tucker ◽  
C L Ogg
Keyword(s):  
Chromatographic Method ◽  
Colorimetric Method ◽  
Cigarette Tobacco ◽  
Mean Values ◽  
Accuracy And Precision ◽  
Standard Deviations ◽  
Gas Chromatographic Method

Abstract A gas chromatographic and a colorimetric method for determining menthol in cigarette tobacco filler were studied collaboratively by 15 laboratories. No statistically significant differences were found in the precisions within or between laboratories. There were no significant differences between mean values for the two methods for any of the samples. Trends toward higher mean values for the colorimetric method and lower within-laboratory standard deviations for the gas chromatographic method were noted. Remarks by collaborators suggest that the accuracy and precision of the colorimetric method may be improved, and further studies are recommended.

scholarly journals Drought Stress Detection in Juvenile Oilseed Rape Using Hyperspectral Imaging with a Focus on Spectra Variability

2020 ◽  
Vol 12 (20) ◽  
pp. 3462
Author(s):  
Wiktor R. Żelazny ◽  
Jan Lukáš
Keyword(s):  
Drought Stress ◽  
Hyperspectral Imaging ◽  
Oilseed Rape ◽  
Treatment Effects ◽  
Vegetation Index ◽  
Principal Component ◽  
Hyperspectral Data ◽  
Stress Detection ◽  
Mean Values ◽  
Standard Deviations

Hyperspectral imaging (HSI) has been gaining recognition as a promising proximal and remote sensing technique for crop drought stress detection. A modelling approach accounting for the treatment effects on the stress indicators’ standard deviations was applied to proximal images of oilseed rape—a crop subjected to various HSI studies, with the exception of drought. The aim of the present study was to determine the spectral responses of two cultivars, ‘Cadeli’ and ‘Viking’, representing distinctive water management strategies, to three types of watering regimes. Hyperspectral data cubes were acquired at the leaf level using a 2D frame camera. The influence of the experimental factors on the extent of leaf discolorations, vegetation index values, and principal component scores was investigated using Bayesian linear models. Clear treatment effects were obtained primarily for the vegetation indexes with respect to the watering regimes. The mean values of RGI, MTCI, RNDVI, and GI responded to the difference between the well-watered and water-deprived plants. The RGI index excelled among them in terms of effect strengths, which amounted to −0.96[−2.21,0.21] and −0.71[−1.97,0.49] units for each cultivar. A consistent increase in the multiple index standard deviations, especially RGI, PSRI, TCARI, and TCARI/OSAVI, was associated with worsening of the hydric regime. These increases were captured not only for the dry treatment but also for the plants subjected to regeneration after a drought episode, particularly by PSRI (a multiplicative effect of 0.33[0.16,0.68] for ‘Cadeli’). This result suggests a higher sensitivity of the vegetation index variability measures relative to the means in the context of the oilseed rape drought stress diagnosis and justifies the application of HSI to capture these effects. RGI is an index deserving additional scrutiny in future studies, as both its mean and standard deviation were affected by the watering regimes.

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