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Articles 91 - 120 of 231
Full-Text Articles in Civil Engineering
Reactive Media For Chromium Reduction Under Alkaline Conditions For Use In Permeable Reactive Barriers, Sachin V. Apte
Reactive Media For Chromium Reduction Under Alkaline Conditions For Use In Permeable Reactive Barriers, Sachin V. Apte
Theses
The purpose of this study was to select the appropriate reactive media for chromate reduction to treat groundwater (high pH) with permeable reactive barriers. The study addresses groundwater contamination for three chromium refining sites located in Hudson County, New Jersey. The use of iron (Fe0) as a reactive medium was studied and found to be insufficient for use in permeable reactive barriers because of the high pH conditions of groundwater at these sites. Pyrite and iron (Fe0)-pyrite mixtures were studied as viable reactive media by considering their passivation kinetics, reductive capacities and solubility properties.
Column experiments …
Post-Cracking Tensile Properties Of Advanced Cementitious Materials And Ductility Of High Performance Concrete Beams, Wonsiri Punurai
Post-Cracking Tensile Properties Of Advanced Cementitious Materials And Ductility Of High Performance Concrete Beams, Wonsiri Punurai
Theses
In present direct tension tests, the complete stress-deformation curves, the resulting energy dissipated by damage, and the fracture energy of different types of cementitious composites, namely plain concrete, high strength concrete, normal fibrous concrete, high strength fibrous concrete, are studied and a ductility factor is calculated. It has been found that with the increasing strength of concrete due to the addition of the pozzoians such as silica fume and fly ash and when changing from normal strength to high strength, concrete ductility decreases. However, when fibers are combined with these matrices, concrete ductility increases. It is because of ductile steel …
Design And Engineering Of A Tensile Fabric Structure, Jairo Rios
Design And Engineering Of A Tensile Fabric Structure, Jairo Rios
Theses
Fabric structures are designed in an iterative process between architect and engineer, analysis input and output, and detail and patterning. There are three main steps in designing a fabric structure: shape finding, loading, and patterning/ detailing.
Shapefinding consists of finding the shape of the fabric where the fabric forces are in equilibrium. This type of structure is geometrically nonlinear which require iterative analysis to converge on a unique solution.
The loading of the structure is similar to that of any conventional structures. The departure is in the major effects that suction and ponding have on fabric surfaces.
Usually the details …
In Situ Enhancement Of Well Recovery By Pneumatic Media Injection, Michael Thomas Galbraith
In Situ Enhancement Of Well Recovery By Pneumatic Media Injection, Michael Thomas Galbraith
Theses
The objective of this thesis was to develop a new process for enhancing recovery wells at hazardous waste sites. The process, known as an extended radius well (ERW), involves injection of ceramic beads directly into groundwater plumes to create drainage paths for liquid contaminants. This is a variant of Pneumatic Fracturing, which is a patented in situ remediation process developed to increase permeability of soil and rock formations by injection of high pressure gas.
The research study comprised laboratory investigations, engineering scale tests, and a field pilot demonstration. The laboratory investigations examined the properties of several candidate media to determine …
Fluorescence Spectroscopy For The Characterization Of Humic And Fulvic Acids And Their Disinfection By-Products Formation Potential, Ishvinder H. Kochar
Fluorescence Spectroscopy For The Characterization Of Humic And Fulvic Acids And Their Disinfection By-Products Formation Potential, Ishvinder H. Kochar
Theses
Natural Organic Matter (NOM) plays a major role in the formation of undesirable organic by-products following disinfection/oxidation of drinking water. It is suspected that most precursors to disinfection by-products (DBPs) are humic although non-humic substances have not been studied and are suspected of also contributing to DBPs. NOM reacts with many of the disinfectants used to treat drinking water, such as chlorine, chioramine, and ozone, to form a variety of DBPs. Many of these DBPs have adverse health effects in humans (i.e. carcinogenic or mutagenic effects). The primary DBPs of concern include the trihalomethanes (THMs), haloacetic acids (HAAs), and haloacetonitrile …
Composite Columns, Magnar Berge
Composite Columns, Magnar Berge
Theses
The purpose of this thesis is to provide an introduction in the design of composite columns. The design methods according to AISC and Eurocode 4 are summarized and provide a procedure to design a composite column. In addition, equation are derived to determine the nominal flexural strength of typical composite cross-sections.
Reuse Of Cold Top Ex-Situ Vitrified Chromium Contaminated Soils In Hot Mix Asphalt Concrete, Gerald Charleston
Reuse Of Cold Top Ex-Situ Vitrified Chromium Contaminated Soils In Hot Mix Asphalt Concrete, Gerald Charleston
Theses
This research investigated the pilot scale feasibility of the remediation of chromium contaminated soil through cold top ex-situ vitrification and the reuse of the vitrified products as highway construction aggregates. There are more than two million tons of chromite ore residues from the chromate extraction manufacturing leftover in Hudson County, New Jersey. They contained both un-leached hexavalent and unoxidized trivalent chromium. Hexavalent chromium is well known as a group A human carcinogen. It is also considered an environmental and health hazard. Of the many ex- situ and in-situ physical, chemical, and biological treatment technologies for chromate production waste, the ability …
Fluorescence Spectroscopy For The Characterization Of Total Organic Carbon And Disinfection By-Product Formation, Matthew Brendan Washington
Fluorescence Spectroscopy For The Characterization Of Total Organic Carbon And Disinfection By-Product Formation, Matthew Brendan Washington
Theses
One of the concerns facing the drinking water industry is the formation of disinfection by-products (DBPs) during the disinfection stage of treatment. Organic DBPs form during the oxidation of the natural organic matter (NOM) found in natural waters by the application of a disinfectant, such as chlorine.
NOM is composed of two aggregate materials, humic and non-humic substances. It is unknown which portions of NOM react with the oxidant to form DBPs. Methods used to predict the formation of DBPs include total organic carbon (TOC) analysis and Trihalomethane Formation Potential (THMFP), which are time consuming and do not give specific …
Characteristics Of Recycled Plastics And Applications For Highway Appurtenances, Keith Macbain
Characteristics Of Recycled Plastics And Applications For Highway Appurtenances, Keith Macbain
Theses
Recycling is gaining widespread support in many communities as an environmentally acceptable solution to the management of solid waste. The success of these recycling programs depends largely on the development of high-value end use for the recycled products. This research involves an experimental and analytical study on the development of high-value, high-volume end uses for recycled plastic shapes. The experimental part includes material tests to determine mechanical properties of various recycled plastics. A constitutive model is proposed and verified that can be used in characterization of recycled plastics. Bending tests of recycled plastic beams were performed to assess strength, stiffness …
Analysis And Modeling Of Ultrasound Enhanced Soil Washing Process, Kamalavathany Rajaratnam
Analysis And Modeling Of Ultrasound Enhanced Soil Washing Process, Kamalavathany Rajaratnam
Theses
In this research, statistical analysis of data from ultrasound enhanced soil washing process was performed. The process was optimized using a statistical model. The model had four factors namely power, solvent:soil, surfactant, and dwell time as process variables. The percentage of removal efficiency was considered as the dependent variable. The results from two full and one partial factorial designs were analysed. Interactions up to third order were considered in the analysis, but the results from full factorial design showed that those of order higher than second had insignificant contributions to the removal of contaminants. Since the higher order interactions of …
Potential Effects Of Pneumatic Fracturing On Existing Structures And Utilities, Michael C. Canino
Potential Effects Of Pneumatic Fracturing On Existing Structures And Utilities, Michael C. Canino
Theses
This thesis develops a mathematical design model for predicting ground deformations resulting from pneumatic fracturing. Pneumatic fracturing is a patented process developed for the purpose of enhancing the in situ treatment and removal of hazardous contaminants from geologic formations. During pneumatic injections, measurable ground deformations are experienced both during and after the process. Safe application of pneumatic fracturing to contaminated plumes occurring beneath existing structures and utilities requires that the elastic deformation behavior of the geologic formation and overlying structures be quantified.
Data from five pneumatic fracturing sites were regressed to establish the characteristic polynomial describing the curvature of ground …
Relationship Between Precipitation, Surface Runoff, And Shallow Water-Table, Manoj Patel
Relationship Between Precipitation, Surface Runoff, And Shallow Water-Table, Manoj Patel
Theses
In this study, a model was developed to describe the relationship between precipitation, surface runoff, and shallow groundwater table in a watershed that is subjected to groundwater extraction and urbanization. Regression analysis of fourteen years (1976-1989) of time series data for precipitation, stream discharge, ground water elevation, and groundwater extraction yielded good correlation between these parameters.
Analysis of the data associated with groundwater recharge and discharge events that occurred in the watershed from 1976 to 1989 yielded a high correlation between the above cited parameters. Regression analysis utilized to predict monthly variations in groundwater elevations showed a fair correlation between …
Development Of A Fiber Optic Polarimetric Sensor For Concrete, Insang Lee
Development Of A Fiber Optic Polarimetric Sensor For Concrete, Insang Lee
Theses
Development of a fiber optic sensor for embedment in cementitious composites and measurement of displacements associated with the opening of microcracks is described. The sensor can be employed as a transducer for measurement of crack tip opening displacements during fracture tests. A polarization maintaining fiber is used as the sensing element, and transduction mechanism is similar to those of other polarimetric type based sensors. However, the deformation resolving power of the sensor is increased by way of increasing the effective length of the optical fiber. This is done by winding the optical fiber into a coil. A direct relationship between …
Nondestructive Dynamic Load Testing Of Bridges Using Strain Sensors, Suzanne Boland
Nondestructive Dynamic Load Testing Of Bridges Using Strain Sensors, Suzanne Boland
Theses
This thesis investigates the use of nondestructive bridge load testing utilizing strain sensing equipment. Nondestructive bridge load testing has not been used extensively due to lack of expertise and perceived high cost. It can, however, play a key role when an existing bridge needs to be evaluated. Since most evaluation techniques tend to be conservative, the results from such an evaluation may not represent the real properties of the structural members. The true properties of an existing bridge can be identified using the results from nondestructive static and dynamic load testing. The procedures used to identify a structure with the …
Fundamentals Of Adhesion Of Organic Compounds And Aqueous Cleaning Of Glass And Metal Surfaces : Applications In The Pharmaceutical And Chemical Industries, Michel J. De Ruijter
Fundamentals Of Adhesion Of Organic Compounds And Aqueous Cleaning Of Glass And Metal Surfaces : Applications In The Pharmaceutical And Chemical Industries, Michel J. De Ruijter
Theses
In this thesis we studied the physics and chemistry of the adhesion of various classes of organic compounds to glass and stainless steel surfaces, by using diagnostic aqueous cleaning solutions and other techniques. We defined the thermodynamic requirements for aqueous cleaning based on extensive experimental and theoretical work. Novel cleaning diagrams are introduced, based on electrostatic interactions between organic compounds and solid surfaces, to facilitate the design of aqueous cleaning systems. We studied the mass transfer parameters for selected situations. The electrochemical Pourbaix-diagrams were used to explain the effect of hydrogen peroxide added to aqueous solutions and to avoid corrosion …
Stress-Strain Behavior Of High Strength Concrete Cylinders, Danqing Chen
Stress-Strain Behavior Of High Strength Concrete Cylinders, Danqing Chen
Theses
Due to the recent development of high strength concrete in engineering and construction, it has become more important to study the behavior of materials in structures.
No results have been previously published in the literature regarding the influence of aspect ratio in plain high strength concrete cylinders on stress-strain behavior under uniaxial compression.Thus at present study, compression tests were conducted on 3x6 in., 3x9 in., and 3x12 in. plain high strength concrete cylinders to study their stress-strain behavior. Plain normal strength concrete cylinders were also tested and used for comparative study.
Based on the present investigations, attempting to obtain a …
Mechanical Behavior Of Polystyrene Foam Bead Lightweight Concrete, Hai-Ying Ni
Mechanical Behavior Of Polystyrene Foam Bead Lightweight Concrete, Hai-Ying Ni
Theses
This thesis is designed to investigate the effect of porosity on the mechanical properties (strength and modulus) of concrete, and to evaluate the effect of silica fume on the mechanical properties of the polystyrene foam bead lightweight concrete. In this research we made the lightweight concrete by using polystyrene foam beads as light weight aggregate and studied its mechanical properties in detail. Due to the near zero density and modulus of foam beads, we were able to consider it as "porosity". We could then control porosity in concrete by varying foam bead volume fraction.
In our experiments we used the …
The Influence Of Hydrodynamics And Particle Size On The Rejection Properties Of Ultrafiltration Membranes, Usama M. Shahin
The Influence Of Hydrodynamics And Particle Size On The Rejection Properties Of Ultrafiltration Membranes, Usama M. Shahin
Theses
A mathematical model based on the flow hydrodynamics is developed to calculate the treatment efficiency of ultrafiltration process. This model relates the treatment efficiency with the consideration of both fixed parameters and variable parameters. The fixed parameters are function of the intrinsic rejection coefficient, diffusion coefficient, and viscosity whereas the variable parameters can be related to the fluid velocity, volume flux, and cartridge dimensions. The model has been examined by solutions with solutes that have different molecular weights. The experimental data fits the proposed mathematical model very closely suggesting its suitability to evaluate the rejection efficiency in ultrafiltration. As such …
Geotechnical Characterization Of Water Treatment Plant Residuals, Zhengyuan Xia
Geotechnical Characterization Of Water Treatment Plant Residuals, Zhengyuan Xia
Theses
Evaluation of engineering properties of water treatment plant (WTP) residuals is a critical part in predicting their behaviors in monofills. In this study, ten WTP residual samples were collected from ten water treatment plants across the United States. Their general chemical/physical and geotechnical properties including liquid and plastic limits, compaction) shear strength, permeability and durability characteristics were determined.
It was observed that the geotechnical properties of WTP residuals are influenced by various factors such as mineral particle composition, organic content, type and amount of chemical additives) and time of aging, etc. Based on this study, the behavior of WTP residual …
Design, Construction, And Operation Of Water Treatment Plant Residual Monofills, Haitao Bian
Design, Construction, And Operation Of Water Treatment Plant Residual Monofills, Haitao Bian
Theses
Due to the stringent environmental regulations, landfilling becomes the most viable option for ultimate disposal of water treatment plant (WTP) residues. At present, most states apply the regulations for municipal solid waste (MSW) landfills to the landfilling of WTP residues. This is too stringent since the WTP residues are not hazardous. Therefore, development of suitable criteria for WTP residual monofills is necessary and urgent.
A set of environmental and geotechnical experiments was conducted to characterize WTP residues. It can be concluded that very little leachate will be produced and migration of leachate is unlikely. Also it was noted that insignificant …
Attachment Systems For Curtain Wall Construction And Maintenance Requirements, Peter S. Donaghy
Attachment Systems For Curtain Wall Construction And Maintenance Requirements, Peter S. Donaghy
Theses
Curtain Wall construction has become a familiar and widely used method for enclosing structures. Since the 1950's this type of enclosure has become increasingly the most popular choice of Designers and Builders. During this period of development, however, acceptable and uniform building standards have not evolved to create adequate quality control.
This thesis investigates some of the design requirements of Curtain Walls, in particular the attachment system, and the maintenance costs that are directly related to the attachment system and the consequences of such failures.
Fracture Of Cementitious Composites, Sira Tindukasiri
Fracture Of Cementitious Composites, Sira Tindukasiri
Theses
Studies in fracture mechanics of concrete use a testing setup which tends to include unacceptably large errors in deflection measurements. Recent work reported by Kim [3] has proposed a new testing setup to eliminate these errors and consequently produce better determinations of fracture parameters.
The error which occurs most frequently is in the measurement of the load-line deflection. Until recently, the way this measurement has been made, using a dial gauge or LVDT (Linear Variable Differential Transformer) to measure the deformation between the center of the specimen and the frame, includes the crushing of the concrete surface at the supports …
Behavior Of R/C Columns Under Nonproportional Variations In Axial And Lateral Loads, Kaniz Fatema Ahsan
Behavior Of R/C Columns Under Nonproportional Variations In Axial And Lateral Loads, Kaniz Fatema Ahsan
Theses
The study on the behavior of reinforced concrete columns subjected to the motion of earthquake suggests that the structure may experience nonproportional variations in axial and lateral forces. In order to assess the capacity of a reinforced concrete structure under nonproportional loadings, an analytical model is developed using the fiber modeling technique.
The method is based on detailed analytical description of the geometry and material properties used in evaluating the behavior of the critical regions rather than a simplified and predefined set of hysteresis rules. The present study has two principal components of investigation. First, the analyses are done at …
The Collapse Of The Cypress Viaduct During The Loma Prieta Earthquake Of October 17, 1989, Mohamed M. Eid
The Collapse Of The Cypress Viaduct During The Loma Prieta Earthquake Of October 17, 1989, Mohamed M. Eid
Theses
The Loma Prieta earthquake of October 17, 1989 in California was one of the most disastrous earthquakes in U.S history. It caused damage to commercial, residential, and industrial structures, transportation and utilities.
This study includes investigations about the Cypress Viaduct collapse re?ported by:
- California Governor's Board of Inquiry [4].
- National Institute of Standards and Technology (NEL) W.
- 3The Author.
Investigators in the first report concluded that the collapse was due to horizontal ground motion. In the second one, it was due to the vertical ground motion.
In the author's investigation, a detailed static and dynamic analyses are performed to determine …
Three-Dimensional Beam-Columns, Mohammad Hassan Shams
Three-Dimensional Beam-Columns, Mohammad Hassan Shams
Theses
This thesis explores several special cases of three-dimensional beam-columns and suggests that the method of finite differences can be used when a solution of general case is required. The thesis begins with a review of the three-dimensional beam-column equations and then shows how these equations can be used to generate the member stiffness matrix for the nonlinear analysis of three-dimensional frames. Examples are included which discuss the differences between the analytical and numerical solutions.
Frictional Resistance Of Geotextiles, Md. Khairul Alam
Frictional Resistance Of Geotextiles, Md. Khairul Alam
Theses
The pullout resistance of geotextiles was examined using pullout tests. A suitable wooden box with large (2 ft x 2 ft x 4 ft) dimensions was used to avoid the effect of boundary and to simulate field conditions. Two types of failure patterns were observed. For shallow embedment (<3 ft), geotextile produced a movement of the surrounding mass of sand in the shape of an inverted cone due to interlocking friction between geotextile and sand particles. The cone angle decreases with increase in depth of embedment. For embedment equal to or greater than 3 ft., no sand cone developed and the failure occurred along the interface of geotextile and sand. For 1 ft. surcharge, the increase in the pullout resistance due to combined horizontal and vertical embedment was about 30 %.
Bridge Deterioration Models, Christopher R.H. Howard
Bridge Deterioration Models, Christopher R.H. Howard
Theses
The deteriorated condition of America's bridges raises the need for a proper and optimal method of bridge management, from the conceptual stage through the construction stage, and throughout the useful life of our bridges. State agencies need to expand their data collection process so as to include additional information pertinent to the formulation of a credible system. This is critical in order to accommodate increased research efforts to investigate the behavioral pattern/s of the nations bridges and to eventually optimize bridge management systems. This thesis looks at the bridge deterioration model as a vital tool in realizing more effective bridge …
Response Characteristics Of Inelastic Single Degree Of Freedom Systems Subjected To Intraplate Earthquakes, Linda C. Jones
Response Characteristics Of Inelastic Single Degree Of Freedom Systems Subjected To Intraplate Earthquakes, Linda C. Jones
Theses
Within recorded, although not recent, history, there have been several large magnitude earthquakes in the Eastern and Central United States and the need to provide measures to protect from potential damage is recognized by the engineering community. Since there are inherent differences between earthquakes that occur along tectonic plate boundaries, interplate, and those that occur within the plate boundaries, intraplate, it is important to understand how these differences impact structural design. A parametric study of single degree of freedom systems subjected to various recorded and artificial ground motions was performed to identify the variations in response characteristics.
It was found …
Stability And Durability Of Large Aggregate Asphalt Concrete, Rais A. Khan
Stability And Durability Of Large Aggregate Asphalt Concrete, Rais A. Khan
Theses
There are many factors which affect the properties of asphalt concrete and one of these is a maximum aggregate size used in the mix. In this study of the effect of maximum aggregate size on Marshall stability, flow and durability of asphalt aggregate mixtures is investigated.
Two different mixes having gradations with maximum aggregate sizes of 3/4 and 1-1/2 inches were considered. The optimum asphalt content for mix having 3/4 inch maximum aggregate size, was determined by the standard Marshall procedure. The optimum asphalt content for the mix having 1-1/2 inch maximum aggregate size, was estimated based on thickness of …
Strength And Fragility Of Concrete, Kang-Qun Shao
Strength And Fragility Of Concrete, Kang-Qun Shao
Theses
It is known that both strength and fragility are two of the most important properties in concrete. In this research, theories of Chemistry, Physical Chemistry of Surfaces, Thermodynamics and Fracture Mechanics are used to study the relationships between the macromechanical behavior of concrete and the microstructure in concrete. The objectives of this research are therefore to find some effective ways to explain theoretically why the concrete is so brittle (fragile) and how to increase its strength or to decrease its fragility. Based on the present studies, an equation is formulated to calculate the coefficient of the fragility (or brittleness) of …