scholarly journals Development of Deflection Prediction Model for Concrete Block Pavement Considering the Block Shapes and Construction Patterns

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Wuguang Lin ◽  
Yoon-ho Cho ◽  
In Tai Kim
Keyword(s):  
Prediction Model ◽  
Load Distribution ◽  
Structural Strength ◽  
Estimation Method ◽  
Fem Analysis ◽  
Concrete Block ◽  
The Other ◽  
Asphalt Pavements ◽  
Loading Test ◽  
Discrete Surface

Concrete block pavement (CBP) is distinct from typical concrete or asphalt pavements. It is built by using individual blocks with unique construction patterns forming a discrete surface layer to bear traffic loadings. The surface structure of CBP varies depending on the block shapes and construction patterns, so it is hard to apply a general equivalent elastic modulus estimation method to define the surface structural strength. In this study, FEM analysis and dynamic loading test were carried out to develop a deflection prediction model for CBP considering the block shapes and construction patterns. Based on the analysis results, it was found that block shapes did not have much effect on load distribution, whereas construction patterns did. By applying the deflection prediction model to the rutting model for CBP proposed by Sun, the herringbone bond pattern showed the best performance comparing with stretcher bond or basket weave bond pattern. As the load repetition increased to 1.2 million, the rutting depth of CBP constructed by herringbone bond pattern was 2 mm smaller than those constructed by the other two patterns.

Development of Deflection Prediction Model for Interlocking Concrete Block Pavements

2021 ◽  
pp. 036119812110513
Author(s):  
R. T. Arjun Siva Rathan ◽  
V. Sunitha
Keyword(s):  
Statistical Analysis ◽  
Prediction Model ◽  
Fem Analysis ◽  
Concrete Block ◽  
Primary Objective ◽  
Load Test ◽  
Beam Deflection ◽  
Laboratory Cost ◽  
Plate Load Test ◽  
Zigzag Shape

Interlocking concrete block pavement (ICBP) is one of the pavement types adopted worldwide, as it is economical and exhibits improved structural performance. The primary objective of the present study was to develop a deflection prediction model for ICBP considering the most influential parameters using the plate load test. The finite element method (FEM) based software PLAXIS was also employed to predict the plate load deflection to reduce laboratory cost and time. Statistical analysis was carried out to assure the identical deflection values between the laboratory plate load test and FEM analysis. Sensitivity analysis was performed to finalize the most significant parameters for developing the deflection prediction model using the Design Expert software. Two deflection models were predicted for zigzag shape blocks with two laying patterns: stretcher and herringbone. The model was developed in SPSS software by performing 1,680 trial experiments. The results from ANOVA statistical analysis proved that the developed model possessed a significant fit for a 95% confidence level. The predicted deflection model was validated using field deflection measurements obtained from four different roads using Benkelman beam deflection (BBD) and light weight deflectometer (LWD). Statistical two-tailed test results proved that the predicted deflection model was compatible with the observed field deflection value.

RELATIONS OF MOTOR ABILITY OF BALANCE AND SUCCESS OF PERFORMANCE OF GYMNASTICS ELEMENTS ON THE FLOOR EXERCISE

sportlogia ◽  
2021 ◽  
Vol 17 (1) ◽  
pp. 34-43
Author(s):  
Saša Jovanović ◽  
◽  
Snežana Bijelić ◽  
Adriana Ljubojević ◽  
Dalibor Fulurija ◽  
...  
Keyword(s):  
Physical Education ◽  
Prediction Model ◽  
Motor Skills ◽  
Predictive Value ◽  
Predictor Variable ◽  
The Other ◽  
Motor Ability ◽  
Training Methodology ◽  
Balance Ability ◽  
The Relationship

The purpose of this study is to investigate the relationship between motor ability for balance and the performance of selected gymnastic elements on the floor in students aged 7-8 years, to provide an overview of the current motor status of the respondents at this age, and to develop suggestions for possible changes in the curriculum at this age, and to develop suggestions for supplementing training methodology. Training of selected gymnastics elements was conducted on a sample of 42 subjects who had no previous experience in performing gymnastics elements during regular physical education classes, and the predictor variable was tested using four tests assessing motor balance ability. The tests assessing motor balance ability showed a statistically significant predictive value for the performance of all three gymnastics exercises. It is noticeable that the value of the prediction model increased the more complex an item was derived, indicating the complexity of the motor balance space and the high and stable level of the same in the subjects at the time of testing. Regarding the tests used, it can be noted that the test FLAM was significantly involved in the prediction of performance success in all three gymnastic elements, while the other two tests showed their predictive value in the execution of the hand stand. On the other hand, the study shows that the gymnastic elements used should be used in physical education classes to contribute to the promotion and development of all motor skills of students and as part of the preparation for the execution of more complex elements on the floor and apparatus in higher grades.

Control of Grasp Stability in Humans Under Different Frictional Conditions During Multidigit Manipulation

1999 ◽  
Vol 82 (5) ◽  
pp. 2393-2405 ◽  
Author(s):  
Magnus K. O. Burstedt ◽  
J. Randall Flanagan ◽  
Roland S. Johansson
Keyword(s):  
Load Distribution ◽  
Safety Margin ◽  
Middle Finger ◽  
The Other ◽  
Surface Material ◽  
Tangential Load ◽  
Normal Forces ◽  
Grasp Stability ◽  
Contact Surfaces ◽  
Lift Off

Control of grasp stability under different frictional conditions has primarily been studied in manipulatory tasks involving two digits only. Recently we found that many of the principles for control of forces originally demonstrated for two-digit grasping also apply to various three-digit grasps. Here we examine the control of grasp stability in a multidigit task in which subjects used the tips of the thumb, index, and middle finger to lift an object. The grasp resembled those used when lifting a cylindrical object from above. The digits either all contacted the same surface material or one of the digits contacted a surface material that was more, or less, slippery than that contacted by the other two digits. The three-dimensional forces and torques applied by each digit and the contact positions were measured along with the position and orientation of the object. The distribution of forces among the digits strongly reflected constraints imposed by the geometric relationship between the object's center of mass and the contact surfaces. On top of this distribution, we observed changes in force coordination related to changes in the combination of surface materials. When all digits contacted the same surface material, the ratio between the normal force and tangential load ( F n: L ratio) was similar across digits and scaled to provide an adequate safety margin against slip. With different contact surfaces subjects adapted the F n: L ratios at the individual digits to the local friction with only small influences by the friction at the other two digits. They accomplished this by scaling the normal forces similarly at all digits and changing the distribution of load among the digits. The surface combination did not, however, influence digit position, tangential torque, or object tilting systematically. The change in load distribution, rather, resulted from interplay between these factors, and the nature of this interplay varied between trials. That is, subjects achieved grasp stability with various combinations of fingertip actions and appeared to exploit the many degrees of freedom offered by the multidigit grasp. The results extend previous findings based on two-digit tasks to multidigit tasks by showing that subjects adjust fingertip forces at each digit to the local friction. Moreover, our findings suggest that subjects adapted the load distribution to the current frictional condition by regulating the normal forces to allow slips to occur early in the lift task, prior to object lift-off.

scholarly journals A Bi-Level Weibull Model with Applications to Two Ordered Events

2020 ◽  
Vol 8 (2) ◽  
Author(s):  
Shuguang Song ◽  
Hanlin Liu ◽  
Mimi Zhang ◽  
Min Xie
Keyword(s):  
Maximum Likelihood ◽  
Estimation Method ◽  
Mixture Distribution ◽  
Likelihood Estimation ◽  
Random Variable ◽  
Weibull Model ◽  
Reliability Function ◽  
The Other ◽  
Regularity Conditions ◽  
Maximum Likelihood Estimation Method

In this paper, we propose and study a new bivariate Weibull model, called Bi-levelWeibullModel, which arises when one failure occurs after the other. Under some specific regularity conditions, the reliability function of the second event can be above the reliability function of the first event, and is always above the reliability function of the transformed first event, which is a univariate Weibull random variable. This model is motivated by a common physical feature that arises fromseveral real applications. The two marginal distributions are a Weibull distribution and a generalized three-parameter Weibull mixture distribution. Some useful properties of the model are derived, and we also present the maximum likelihood estimation method. A real example is provided to illustrate the application of the model.

scholarly journals A Study of the Diagnostic Accuracy of an Existing Multivariable Test to Predict Shoulder Dystocia

2019 ◽  
Vol 09 (03) ◽  
pp. e262-e267
Author(s):  
Henry Alexander Easley ◽  
Todd Michael Beste
Keyword(s):  
Diagnostic Accuracy ◽  
Prediction Model ◽  
Study Design ◽  
False Positive ◽  
False Positive Rate ◽  
Shoulder Dystocia ◽  
The Other ◽  
Predictive Values ◽  
Positive Rate ◽  
Sensitivity Specificity

Objectives To evaluate the diagnostic accuracy of a multivariable prediction model, the Shoulder Screen (Perigen, Inc.), and compare it with the American College of Obstetricians and Gynecologists (ACOG) guidelines to prevent harm from shoulder dystocia. Study Design The model was applied to two groups of 199 patients each who delivered during a 4-year period. One group experienced shoulder dystocia and the other group delivered without shoulder dystocia. The model's accuracy was analyzed. The performance of the model was compared with the ACOG guideline. Results The sensitivity, specificity, positive, and negative predictive values of the model were 23.1, 99.5, 97.9, and 56.4%, respectively. The sensitivity of the ACOG guideline was 10.1%. The false-positive rate of the model was 0.5%. The accuracy of the model was 61.3%. Conclusion A multivariable prediction model can predict shoulder dystocia and is more accurate than ACOG guidelines.

scholarly journals Prediction Model of Asphalt Content of Asphalt Mixture Based on Dielectric Properties

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Yanhui Zhong ◽  
Yilong Wang ◽  
Bei Zhang ◽  
Xiaolong Li ◽  
Songtao Li ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Prediction Model ◽  
Room Temperature ◽  
Asphalt Mixture ◽  
Aggregate Size ◽  
Asphalt Pavements ◽  
Test Results ◽  
Wide Range ◽  
Asphalt Content ◽  
Ground Penetrating

The rapid detection of asphalt content in asphalt mixture is of great significance to the quality evaluation of asphalt pavement. Based on the dielectric properties of an asphalt mixture, the prediction model of asphalt content is deduced theoretically using three types of dielectric models: Lichtenecker-Rother (L-R) model, Rayleigh model, and Bottcher equation. Under the condition of laboratory mixing at room temperature (about 20–25°C), a dielectric test of asphalt mixture is conducted to verify the applicability of the model. The test results indicate that the dielectric constant of the asphalt mixture is inversely proportional to the asphalt content and directly proportional to the aggregate size of the mixture. Among the models, the Rayleigh model has a wide range of applications and exhibits a high accuracy, with an average relative error of only 1.86%. The results provide a theoretical basis for the nondestructive testing of asphalt pavements using ground-penetrating radar.

Tooth Root Stresses of Helical Gear Pairs With Unequal and Offset Face Widths

2011 ◽  
Author(s):  
Carlos H. Wink
Keyword(s):  
Load Distribution ◽  
Element Model ◽  
Helical Gear ◽  
The Other ◽  
Gear Pair ◽  
Tooth Root ◽  
Pair Member ◽  
Face Width ◽  
The Face ◽  
Root Stress

In this study, tooth root stresses of helical gear pairs with different combinations of face width increase and offsets were analyzed. Contact face width was kept constant. The variables studied were face width and gear faces offset. The well-known LDP – Load Distribution Program was used to calculate tooth root stresses using a finite element model. The results presented show that the face width increase and offset have a significant influence on tooth root stresses. In some cases, increasing face width of one gear pair member resulted in significant increase of tooth root stress of the other member. For gear pairs with unequal and offset face widths, tooth root stresses were mostly affected when face widths were increased to the same direction of the contact line travel direction.

scholarly journals Structural Health Monitoring and Interface Damage Detection for Infill Reinforced Concrete Walls in Seismic Retrofit of Reinforced Concrete Frames Using Piezoceramic-Based Transducers Under the Cyclic Loading

2019 ◽  
Vol 9 (2) ◽  
pp. 312 ◽  
Author(s):  
Wen-I Liao ◽  
Fu-Pei Hsiao ◽  
Chien-Kuo Chiu ◽  
Chin-En Ho
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Loading ◽  
Structural Health Monitoring ◽  
Health Monitoring ◽  
The Other ◽  
Structural Members ◽  
Interface Failure ◽  
Loading Test ◽  
Structural Health ◽  
Interface Damage

In this work, the piezoceramic-based transducers are used to perform the structural health monitoring (SHM) and interface damage detecting of non-ductile reinforced concrete (RC) frames retrofitted by post-installed RC walls. In order to develop the post-embedded piezoceramic-based transducers that can be used to identify interface failure or cracks between two structural members in retrofit construction, this work adopts the cyclic loading to test two specimens with post-embedded piezoceramic-based transducers (PPT). Since the failure of an interface between the post-installed wall and beam occurs, one of the specimens has damage in the foundation and existing boundary column and the other has damage in the top ends of column and wall. During the cyclic loading test, one transducer was used as an actuator to generate the stress waves and the other transducers were used as the sensors to detect the waves. In damaged specimens, the existence and locations of cracks and the interface damage can be detected by analyzing the wave response. Moreover, the severity of damage to the specimens can also be estimated. The experimental results indicate the effectiveness of the piezoceramic-based approach in the SHM and locating damage in shear-critical RC structural members under the seismic loading.

Study on the Drafting and Early-Warning of Temperature Double-Control Index of Different Sections & Periods of Concrete Block

2012 ◽  
Vol 188 ◽  
pp. 253-258
Author(s):  
Dong Sheng Shen ◽  
Yao Ying Huang ◽  
Yi Hong Zhou ◽  
Dan Dan Liu ◽  
Xiang Ze Gao
Keyword(s):  
Prediction Model ◽  
Probabilistic Method ◽  
Concrete Block ◽  
Arch Dam ◽  
Maximum Temperature ◽  
Measured Temperature ◽  
Dynamic Feedback ◽  
High Arch Dam ◽  
Concrete Blocks ◽  
Real Time Tracking

Although real-time tracking and feedback were carried out for the dam concrete construction process, there was still certain blindness in the construction units. The temperature double-control index, which is the allowable temperature and temperature gradient under typical age before concrete block reaching its maximum temperature, was proposed in this paper on the basis of the analysis of measured temperature process curves of concrete blocks. The probabilistic method was applied to draft the temperature double-control index of different sections and periods based on the measured temperature process curve of the poured block of a constructing extra-high arch dam in southwest China. Furthermore, the prediction model was also provided and applied in the dynamic feedback of new pouring block. It is demonstrated by the practice that the prediction model proposed in this paper has better pertinence and maneuverability for the construction units to control the maximum temperature of concrete block, i.e. the maximum temperature in high temperature season and in low temperature season are both controllable.

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