The Experts below are selected from a list of 111 Experts worldwide ranked by ideXlab platform
Thomas Shantz - One of the best experts on this subject based on the ideXlab platform.
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shear wave velocity as Function of standard penetration test resistance and vertical effective stress at california bridge sites
Soil Dynamics and Earthquake Engineering, 2010Co-Authors: Scott J Brandenberg, Naresh Bellana, Thomas ShantzAbstract:Abstract Shear wave velocity, V s , is defined as a Statistical Function of SPT blow count, N 60 , and vertical effective stress, σ ′ v , using a data set collected at various California bridge sites. At each site, V s measurements were recorded by suspension logging in the same borehole in which N 60 was measured. Regression analysis was used to derive Statistical relations for sand, silt, and clay soil types. The relation between V s and N 60 is shown to depend strongly on σ ′ v since V s and N 60 normalize differently with overburden, which has been mostly omitted in previously published correlations. A random effects regression model is used to separate the error into intra- and inter-boring terms. Inter-boring errors are shown to depend weakly on geologic age. The average shear wave velocity in the upper 30 m, V s 30 , is computed directly from the suspension logs and compared with V s 30 ¯ computed from the Statistical relations. The relations are shown to provide unbiased estimates of V s 30 , with standard deviation of the error equal to the standard deviation of the inter-boring error term. Ground motion prediction equations require V s 30 as an input parameter, and the Statistical relations may be useful for estimating V s 30 at sites where only penetration resistance data are available. The proposed relations should not substitute for more accurate geophysical measurements when predicted ground motions are sensitive to the uncertainty in V s 30 , but may be useful for identifying whether geophysical measurements should be performed to better refine the V s 30 estimate.
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shear wave velocity as a Statistical Function of standard penetration test resistance and vertical effective stress at caltrans bridge sites 6 performing organization code
2010Co-Authors: Scott J Brandenberg, Naresh Bellana, Thomas ShantzAbstract:16. Abstract Shear wave velocity, Vs, is defined as a Statistical Function of SPT blow count, N60, and vertical effective stress, σv', using a data set collected at various California bridge sites. At each site, Vs measurements were recorded by suspension logging in the same borehole in which N60 was measured. Regression analysis was used to derive Statistical relations for sand, silt, and clay soil types. The relation between Vs and N60 is shown to depend strongly on σv', since Vs and N60 normalize differently with overburden, which has been mostly omitted in previously published correlations. A random effects regression model is used to separate the error into intra- and interboring terms. Interboring errors are shown to depend weakly on geologic age. The average shear wave velocity in the upper 30 m, Vs30, is computed directly from the suspension logs and compared with Vs30 computed from the Statistical relations. The relations are shown to provide unbiased estimates of Vs30, with standard deviation of the error equal to the standard deviation of the interboring error term. Ground motion prediction equations require Vs30 as an input parameter, and the Statistical relations may be useful for estimating Vs30 at sites where only penetration resistance data are available. The proposed relations should not substitute for more accurate geophysical measurements when predicted ground motions are sensitive to the uncertainty in Vs30, but may be useful for identifying whether geophysical measurements should be performed to better refine the Vs30 estimate.
Scott J Brandenberg - One of the best experts on this subject based on the ideXlab platform.
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shear wave velocity as Function of standard penetration test resistance and vertical effective stress at california bridge sites
Soil Dynamics and Earthquake Engineering, 2010Co-Authors: Scott J Brandenberg, Naresh Bellana, Thomas ShantzAbstract:Abstract Shear wave velocity, V s , is defined as a Statistical Function of SPT blow count, N 60 , and vertical effective stress, σ ′ v , using a data set collected at various California bridge sites. At each site, V s measurements were recorded by suspension logging in the same borehole in which N 60 was measured. Regression analysis was used to derive Statistical relations for sand, silt, and clay soil types. The relation between V s and N 60 is shown to depend strongly on σ ′ v since V s and N 60 normalize differently with overburden, which has been mostly omitted in previously published correlations. A random effects regression model is used to separate the error into intra- and inter-boring terms. Inter-boring errors are shown to depend weakly on geologic age. The average shear wave velocity in the upper 30 m, V s 30 , is computed directly from the suspension logs and compared with V s 30 ¯ computed from the Statistical relations. The relations are shown to provide unbiased estimates of V s 30 , with standard deviation of the error equal to the standard deviation of the inter-boring error term. Ground motion prediction equations require V s 30 as an input parameter, and the Statistical relations may be useful for estimating V s 30 at sites where only penetration resistance data are available. The proposed relations should not substitute for more accurate geophysical measurements when predicted ground motions are sensitive to the uncertainty in V s 30 , but may be useful for identifying whether geophysical measurements should be performed to better refine the V s 30 estimate.
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shear wave velocity as a Statistical Function of standard penetration test resistance and vertical effective stress at caltrans bridge sites 6 performing organization code
2010Co-Authors: Scott J Brandenberg, Naresh Bellana, Thomas ShantzAbstract:16. Abstract Shear wave velocity, Vs, is defined as a Statistical Function of SPT blow count, N60, and vertical effective stress, σv', using a data set collected at various California bridge sites. At each site, Vs measurements were recorded by suspension logging in the same borehole in which N60 was measured. Regression analysis was used to derive Statistical relations for sand, silt, and clay soil types. The relation between Vs and N60 is shown to depend strongly on σv', since Vs and N60 normalize differently with overburden, which has been mostly omitted in previously published correlations. A random effects regression model is used to separate the error into intra- and interboring terms. Interboring errors are shown to depend weakly on geologic age. The average shear wave velocity in the upper 30 m, Vs30, is computed directly from the suspension logs and compared with Vs30 computed from the Statistical relations. The relations are shown to provide unbiased estimates of Vs30, with standard deviation of the error equal to the standard deviation of the interboring error term. Ground motion prediction equations require Vs30 as an input parameter, and the Statistical relations may be useful for estimating Vs30 at sites where only penetration resistance data are available. The proposed relations should not substitute for more accurate geophysical measurements when predicted ground motions are sensitive to the uncertainty in Vs30, but may be useful for identifying whether geophysical measurements should be performed to better refine the Vs30 estimate.
Bowen Zheng - One of the best experts on this subject based on the ideXlab platform.
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numerical studies on the failure process of heterogeneous brittle rocks or rock like materials under uniaxial compression
Materials, 2017Co-Authors: Shengwen Qi, Bowen ZhengAbstract:In rocks or rock-like materials, the constituents, e.g. quartz, calcite and biotite, as well as the microdefects have considerably different mechanical properties that make such materials heterogeneous at different degrees. The failure of materials subjected to external loads is a cracking process accompanied with stress redistribution due to material heterogeneity. However, the latter cannot be observed from the experiments in laboratory directly. In this study, the cracking and stress features during uniaxial compression process are numerically studied based on a presented approach. A plastic strain dependent strength model is implemented into the continuous numerical tool—Fast Lagrangian Analysis of Continua in three Dimensions (FLAC3D), and the Gaussian Statistical Function is adopted to depict the heterogeneity of mechanical parameters including elastic modulus, friction angle, cohesion and tensile strength. The mean parameter μ and the coefficient of variance (hcv, the ratio of mean parameter to standard deviation) in the Function are used to define the mean value and heterogeneity degree of the parameters, respectively. The results show that this numerical approach can perfectly capture the general features of brittle materials including fracturing process, AE events as well as stress-strain curves. Furthermore, the local stress disturbance is analyzed and the crack initiation stress threshold is identified based on the AE events process and stress-strain curves. It is shown that the stress concentration always appears in the undamaged elements near the boundary of damaged sites. The peak stress and crack initiation stress are both heterogeneity dependent, i.e., a linear relation exists between the two stress thresholds and hcv. The range of hcv is suggested as 0.12 to 0.21 for most rocks. The stress concentration degree is represented by a stress concentration factor and found also heterogeneity dominant. Finally, it is found that there exists a consistent tendency between the local stress difference and the AE events process.
Awad M - One of the best experts on this subject based on the ideXlab platform.
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psychological and social variables associated with the thinking and creativity of students in secondary education comparative study between general education students and technical education
Journal of Environmental Sciences-china, 2018Co-Authors: Hassan M S M, Al Ateeq A M, Yousif M, Awad MAbstract:The study aimed to identify the psychological and social variables related to the thinking and creativity of secondary school students. The study relied on the descriptive approach to comparison and analysis and the tools that were relied upon in this study. The first tool The Torrance test of creative thinking (Figure 2b) The second tool Maslow test for the sense of security for adolescents and adolescents Third, the quality of life standard has reached 400 students, divided into 200 technical education, 100 of whom are males and 100 females, and 200 of them are general education, 100 of whom are males and 100 females. Between 15 and 18 years old. The results of the study were based on a number of psychological, behavioral, human and environmental theories and creative theories. The results showed that there were differences between secondary and technical education students in creative thinking. The average number of students in secondary education (131.375), the average of technical education students (113.185) (3.493) at a significant level (0.05), which is therefore a Statistical Function. Hence, we can say that there are differences between students of secondary education and students of technical education in creative thinking for the benefit of secondary school students. Technical Education. The results showed that there were differences between rural students and city students in creative thinking. The average number of rural students (148.305) and the average number of students in the city (96.255) and the value of "T" (11.321) at a significant level (0.05) We can say that there are differences between rural students and city students in creative thinking for rural students, as the average rural students are larger than average city students. The results showed that there were differences between males and females in the post-creative thinking, where the average females (144.35), the mean males (100.21) and the value of T. (9.194) at a significant level (0.05), which is thus a Statistical Function, That there are differences between males and females in the post-creative thinking for the benefit of females, as the average female has been greater than the average male.
Naresh Bellana - One of the best experts on this subject based on the ideXlab platform.
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shear wave velocity as Function of standard penetration test resistance and vertical effective stress at california bridge sites
Soil Dynamics and Earthquake Engineering, 2010Co-Authors: Scott J Brandenberg, Naresh Bellana, Thomas ShantzAbstract:Abstract Shear wave velocity, V s , is defined as a Statistical Function of SPT blow count, N 60 , and vertical effective stress, σ ′ v , using a data set collected at various California bridge sites. At each site, V s measurements were recorded by suspension logging in the same borehole in which N 60 was measured. Regression analysis was used to derive Statistical relations for sand, silt, and clay soil types. The relation between V s and N 60 is shown to depend strongly on σ ′ v since V s and N 60 normalize differently with overburden, which has been mostly omitted in previously published correlations. A random effects regression model is used to separate the error into intra- and inter-boring terms. Inter-boring errors are shown to depend weakly on geologic age. The average shear wave velocity in the upper 30 m, V s 30 , is computed directly from the suspension logs and compared with V s 30 ¯ computed from the Statistical relations. The relations are shown to provide unbiased estimates of V s 30 , with standard deviation of the error equal to the standard deviation of the inter-boring error term. Ground motion prediction equations require V s 30 as an input parameter, and the Statistical relations may be useful for estimating V s 30 at sites where only penetration resistance data are available. The proposed relations should not substitute for more accurate geophysical measurements when predicted ground motions are sensitive to the uncertainty in V s 30 , but may be useful for identifying whether geophysical measurements should be performed to better refine the V s 30 estimate.
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shear wave velocity as a Statistical Function of standard penetration test resistance and vertical effective stress at caltrans bridge sites 6 performing organization code
2010Co-Authors: Scott J Brandenberg, Naresh Bellana, Thomas ShantzAbstract:16. Abstract Shear wave velocity, Vs, is defined as a Statistical Function of SPT blow count, N60, and vertical effective stress, σv', using a data set collected at various California bridge sites. At each site, Vs measurements were recorded by suspension logging in the same borehole in which N60 was measured. Regression analysis was used to derive Statistical relations for sand, silt, and clay soil types. The relation between Vs and N60 is shown to depend strongly on σv', since Vs and N60 normalize differently with overburden, which has been mostly omitted in previously published correlations. A random effects regression model is used to separate the error into intra- and interboring terms. Interboring errors are shown to depend weakly on geologic age. The average shear wave velocity in the upper 30 m, Vs30, is computed directly from the suspension logs and compared with Vs30 computed from the Statistical relations. The relations are shown to provide unbiased estimates of Vs30, with standard deviation of the error equal to the standard deviation of the interboring error term. Ground motion prediction equations require Vs30 as an input parameter, and the Statistical relations may be useful for estimating Vs30 at sites where only penetration resistance data are available. The proposed relations should not substitute for more accurate geophysical measurements when predicted ground motions are sensitive to the uncertainty in Vs30, but may be useful for identifying whether geophysical measurements should be performed to better refine the Vs30 estimate.
