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Dynamic stability of fluid-conveying pipes on uniform or non-uniform elastic foundations
Title
Dynamic stability of fluid-conveying pipes on uniform or non-uniform elastic foundations.
Creator
Vittori, Pablo J., Florida Atlantic University, Elishakoff, Isaac, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
The dynamic behavior of straight cantilever pipes conveying fluid is studied, establishing the conditions of stability for systems, which are only limited to move in a 2D-plane. Internal friction of pipe and the effect of the surrounding fluid are neglected. A universal stability curve showing boundary between the stable and unstable behaviors is constructed by finding solution to equation of motion by exact and high-dimensional approximate methods. Based on the Boobnov-Galerkin method, the...
Show moreThe dynamic behavior of straight cantilever pipes conveying fluid is studied, establishing the conditions of stability for systems, which are only limited to move in a 2D-plane. Internal friction of pipe and the effect of the surrounding fluid are neglected. A universal stability curve showing boundary between the stable and unstable behaviors is constructed by finding solution to equation of motion by exact and high-dimensional approximate methods. Based on the Boobnov-Galerkin method, the critical velocities for the fluid are obtained by using both the eigenfunctions of a cantilever beam (beam functions), as well as the utilization of Duncan's functions. Stability of cantilever pipes with uniform and non-uniform elastic foundations of two types are considered and discussed. Special emphasis is placed on the investigation of the paradoxical behavior previously reported in the literature.
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Date Issued
2004
PURL
http://purl.flvc.org/fcla/dt/13167
Subject Headings
Strains and stresses, Structural dynamics, Structural stability, Fluid dynamics, Vibration
Format
Document (PDF)
Non-destructive evaluation of reinforced asphalt pavement built over soft organic soils
Title
Non-destructive evaluation of reinforced asphalt pavement built over soft organic soils.
Creator
Pohly, Daniel D., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
Abstract/Description
Research, tests and analysis are presented on several reinforcements placed in the asphalt overlay of a roadway built over soft organic soils. Non-destructive Evaluation (NDE) methods and statistical analysis were used to characterize the pavement before and after rehabilitative construction. Before reconstruction, falling weight deflectometer, rut and ride tests were conducted to evaluate the existing pavement and determine the statistical variability of critical site characteristics. Twenty...
Show moreResearch, tests and analysis are presented on several reinforcements placed in the asphalt overlay of a roadway built over soft organic soils. Non-destructive Evaluation (NDE) methods and statistical analysis were used to characterize the pavement before and after rehabilitative construction. Before reconstruction, falling weight deflectometer, rut and ride tests were conducted to evaluate the existing pavement and determine the statistical variability of critical site characteristics. Twenty-four 500ft. test sections were constructed on the roadway including sixteen reinforced asphalt and eight control sections at two test locations that possessed significantly different subsoil characteristics. NDE tests were repeated after reconstruction to characterize the improvements of the test sections. Test results were employed to quantify the stiffness properties of the pavement based on load-deflection data to evaluate the relative performance of the reinforced sections. Statistical analysis of the data showed the stiffness of the reinforced sections was consistently higher than the control sections.
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Date Issued
2009
PURL
http://purl.flvc.org/FAU/368253
Subject Headings
Soil remediation, Technological innovations, Structural stability, Design, Pavements, Performance, Management, Data processing, Structural analysis (Engineering)
Format
Document (PDF)
Stiffness characterization and life cycle analysis of reinforced asphalt pavements using falling weight deflectometer tests
Title
Stiffness characterization and life cycle analysis of reinforced asphalt pavements using falling weight deflectometer tests.
Creator
Lima-Arie, Alex., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
Abstract/Description
The western and northern parts of South Florida have shallow layers of organic and plastic soils under existing roads. These roads often exhibit large amount of cracking and distortion in a short period of time. Traditional repairs are often not practical due to high costs and extended construction time. In an effort to develop rehabilitation strategies that could be strictly applied to the surface layer, a pilot test site was selected along the alignment of SR 15/US 98 in northwest Palm...
Show moreThe western and northern parts of South Florida have shallow layers of organic and plastic soils under existing roads. These roads often exhibit large amount of cracking and distortion in a short period of time. Traditional repairs are often not practical due to high costs and extended construction time. In an effort to develop rehabilitation strategies that could be strictly applied to the surface layer, a pilot test site was selected along the alignment of SR 15/US 98 in northwest Palm Beach County, where severe pavement distresses were observed due to the presence of thick organic layers. PaveTrac MT-1, GlasGrid 8501, PetroGrid 4582, and ARMI were used as promising asphalt reinforcing products in 24 experimental pavement sections, including 8 control sections without any reinforcement. A comprehensive field testing and monitoring program involving FWD, rut and ride quality measurements was conducted at the preconstruction, 6-month post-construction, and 18-month post-construction stages. Due to large variability in the sub-surface conditions, a statistics-based data analysis protocol was developed for performance evaluation and relative comparisons of the test sections and, in turn, reinforcing products. Post construction data from both 6 months and 18 months demonstrated that stiffness of reinforced sections were significantly higher than the control sections. Procedures were developed to identify and statistically quantify the benefits derived from the reinforcements only, so that the relative performance of various products could be monitored over time. Based on the field testing data available to date, a framework was developed in this study for the prediction of pavement life, which is essential for conducting a detailed Life Cycle Analysis
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Date Issued
2010
PURL
http://purl.flvc.org/FAU/2976446
Subject Headings
Structural analysis (Engineering), Pavements, Asphalt, Performance, Management, Structural stability, Design, Pavements, Live loads, Measurement
Format
Document (PDF)
Stability Analysis of Geosynthetic Reinforced MSW Landfill Slopes Considering Effects of Biodegradation and Extreme Wind Loading
Title
Stability Analysis of Geosynthetic Reinforced MSW Landfill Slopes Considering Effects of Biodegradation and Extreme Wind Loading.
Creator
Pant, Sharmila, Sobhan, Khaled, Florida Atlantic University, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
Abstract/Description
A numerical investigation was conducted to evaluate the geotechnical safety and slope stability of Municipal Solid Waste (MSW) landfills, considering the effects of geosynthetic reinforcements, biodegradation of the waste, and associated changes in material properties, and extreme wind force simulating hurricane conditions. Three different landfill slopes, 1:1, 1:2, and 1:3 having the height of 122m and width of 2134m, were analyzed using Limit Equilibrium Method (SLOPE/W) and Finite Element...
Show moreA numerical investigation was conducted to evaluate the geotechnical safety and slope stability of Municipal Solid Waste (MSW) landfills, considering the effects of geosynthetic reinforcements, biodegradation of the waste, and associated changes in material properties, and extreme wind force simulating hurricane conditions. Three different landfill slopes, 1:1, 1:2, and 1:3 having the height of 122m and width of 2134m, were analyzed using Limit Equilibrium Method (SLOPE/W) and Finite Element Modeling (ANSYS). Techniques developed in this study were used to analyze a case history involving a geogrid reinforced mixed landfill expansion located in Austria. It was found that few years after construction of the landfill, there is a significant decrease in the FS due to biodegradation. Extreme wind loading was also found to cause a substantial loss in the FS. The geosynthetic reinforcement increased the slope stability and approximately compensated for the damaging effects of biodegradation and wind loading.
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Date Issued
2016
PURL
http://purl.flvc.org/fau/fd/FA00004707, http://purl.flvc.org/fau/fd/FA00004707
Subject Headings
Engineering geology -- Mathematical models, Fills (Earthwork), Geogrids -- Performance, Geosynthetics, Reinforced soils, Retaining walls -- Performance, Sanitary landfills, Slopes (Soil mechanics) -- Stability, Soil stabilization, Structural analysis (Engineering)
Format
Document (PDF)
Cement stabilization of organic soils for controlling secondary compression behavior
Title
Cement stabilization of organic soils for controlling secondary compression behavior.
Creator
Ramirez, Juan., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
Abstract/Description
Western Palm Beach County, FL is characterized by thick deposits organic soils at shallow depths. Because of their high void ratio and compressibility, these soils undergo large primary consolidation followed by extended periods of secondary compression causing excessive premature structural distress. Although soil stabilization has been largely used with remarkable results in soft, expansive and non-organic soils, limited research and practice exist in the implementation with highly organic...
Show moreWestern Palm Beach County, FL is characterized by thick deposits organic soils at shallow depths. Because of their high void ratio and compressibility, these soils undergo large primary consolidation followed by extended periods of secondary compression causing excessive premature structural distress. Although soil stabilization has been largely used with remarkable results in soft, expansive and non-organic soils, limited research and practice exist in the implementation with highly organic soils. The main motivation of this research was to investigate the effects of cement stabilization on the compressibility behavior of organic rich soils, and develop mix design criteria for optimum cement contents necessary to induce the desired engineering behavior. This optimized mix design may provide guidelines for Deep Mixing Methods in organic soils.
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Date Issued
2009
PURL
http://purl.flvc.org/FAU/367760
Subject Headings
Soil consolidation, Measurement, Soils, Organic compound content, Soil remediation, Technological innovations, Concrete construction, Structural stability, Design
Format
Document (PDF)