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Articles 511 - 540 of 699

Full-Text Articles in Civil and Environmental Engineering

Performance Evaluation And Finite Element Analysis Of Fiber Reinforced Precast Concrete Underground Structures, Ashley Wilson Jan 2012

Performance Evaluation And Finite Element Analysis Of Fiber Reinforced Precast Concrete Underground Structures, Ashley Wilson

Civil Engineering Theses - Archive

This study aimed at evaluating the performance of BASF Synthetic and Steel fibers as alternative reinforcements in concrete pipes. A total of 93 synthetic fiber and 60 steel fiber reinforced pipes were produced and tested based on the ASTM C497 in order to have a benchmark for comparison with conventionally reinforced concrete pipes. Three production sites with different production equipment were used in different geographical locations in the United States. Standard ASTM C76 diameters of up to 36 in. with "Wall-B" and "Wall-C" were used in this study for both synthetic and steel fibers. Vertical and horizontal load-deformation plots for …

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Engineering Behavior Of Lime Treated High Sulfate Soils, Ahmed Hassan Mohamed Gaily Jan 2012

Engineering Behavior Of Lime Treated High Sulfate Soils, Ahmed Hassan Mohamed Gaily

Civil Engineering Theses - Archive

Regardless of increased knowledge and awareness of sulfate heave, the Texas Department of Transportation (TxDOT) continues to experience pavement failures during and immediately after construction on transportation infrastructures intended to last at least 20 years. Failures are predominantly observed in sites where high sulfate soils of 8,000 ppm or higher levels. Many of these failures are attributed to sulfate-induced heave where an expansive mineral called Ettringite is formed from calcium-based stabilizers (lime or cement) reacting with water, clay, and sulfates. The reactions responsible for Ettringite formation are extremely complex which make generalizations concerning the rate and magnitude of heaving in …

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Comparative Application Of Two Nanoparticles In Cement Mortar, Vinoth Mohanam Jan 2012

Comparative Application Of Two Nanoparticles In Cement Mortar, Vinoth Mohanam

Civil Engineering Theses - Archive

Carbon Nanotubes (CNTs) and Carbon Nanofibers (CNFs) are two of the most promising advanced materials in the construction industry due to their excellent material properties. In this study, their application in cement mortar is studied comparatively as possible choice for concrete repair. CNT and CNF have very high aspect ratio due to which the Van der Wal forces between the CNT and CNF tend to agglomerate; thus forming bundles. In order to achieve proper dispersion, ultrasonic energy was used to disperse the CNT and CNF in the aqueous solution. The mechanical properties such as compressive strength and flexural strength of …

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The Effects Of Climate, Soil, And Vegetation On The Design Of Water Balance Covers For Solid Waste Landfills In Texas, Salman Baig Jan 2012

The Effects Of Climate, Soil, And Vegetation On The Design Of Water Balance Covers For Solid Waste Landfills In Texas, Salman Baig

Civil Engineering Theses - Archive

The purpose of this study is to determine the effects of climate, soil, and vegetation on the design of water balance (WB) covers for solid waste landfills in Texas. This study was conducted using water balance software (UNSAT-H model) that considers unsaturated soil hydraulics and plant water uptake. To date, limited research has been conducted for WB covers in Texas. Texas is located in the central region of the United States and encounters approximately nine distinct 5 inch precipitation increments or ranges, unlike any other state in the United States. Texas includes various climate regions and is a favorable choice …

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Effect Of Saline Water On Landfill Gas Generation Of Municipal Solid Waste, Yogavathani Sivanesan Jan 2012

Effect Of Saline Water On Landfill Gas Generation Of Municipal Solid Waste, Yogavathani Sivanesan

Civil Engineering Theses - Archive

The Enhanced Leachate Recirculation (ELR) landfills operation results in rapid waste stabilization, waste decomposition and increased rate of gas generation. However, operating landfill as an ELR landfill requires availability of sufficient amount of fresh water in close proximity to the landfill facility. In coastal regions, where fresh water supplies may be scarce, available saline water may be considered for ELR operation. However, the effects of saline water on the decomposition solid waste and landfill gas generation are unknown and need to be investigated., The objectives of the current research are to investigate the effects of adding and/or recirculating saline water …

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Identifying Issues Impacting Productivity Of Box Jacking Projects, Bhaumi Bhavan Chaurasia Jan 2012

Identifying Issues Impacting Productivity Of Box Jacking Projects, Bhaumi Bhavan Chaurasia

Civil Engineering Theses - Archive

Jacking is a trenchless construction technique used for installing underground pipeline system. Jacking method is more widely used for upgrading under capacity culverts and drainage structures under roads and railroad tracks. Also, this method is used for installing underground pipelines such as watermains, sewers etc.in populated and developed urban areas. In this method, culverts (segments) are installed through the ground from an entry shaft to an exit shaft. During the excavation and spoil removal processes, workers are required to be inside the pipe, this is essentially what separates pipe jacking trenchless construction method from microtunneling technology. The minimum recommended diameter …

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Effect Of Nano Zero Valent Iron On Degradation Of Municipal Solid Waste In Bioreactor Landfills, Meenakshi Gangopadhyay Jan 2012

Effect Of Nano Zero Valent Iron On Degradation Of Municipal Solid Waste In Bioreactor Landfills, Meenakshi Gangopadhyay

Civil Engineering Theses - Archive

Nanotechnology has substantial potential for reducing contamination, toxicity and overall human health hazards and environmental risks. In recent times, nano zero valent iron has proved to be effective in contaminant reduction and pollution control. Iron is an important micronutrient for the microbes involved in the anaerobic decomposition of solid waste in bioreactor landfills. Landfill leachate sometimes contains toxic compounds which nano zero valent iron has proven to be very effective in removing, particularly chlorinated organics, heavy metals, and odorous sulfides. Iron can also potentially increase landfill methane generation by removing long chain fatty acids and sulfides that inhibit methanogenesis.nZVI materials …

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An Investigation Of Pipe Jacking Loads In Trenchless Technology, Saeed Rahjoo Jan 2012

An Investigation Of Pipe Jacking Loads In Trenchless Technology, Saeed Rahjoo

Civil Engineering Theses - Archive

Pipe jacking is a trenchless technology method of installing pipes under existing facilities such as roads and railroads. Predicting jacking forces is important for planning, design, and construction phases of these projects. The jacking forces dictate shaft or pit locations, thrust block or backstop design, jacking equipment, use of intermediate jacking stations, and pipe bearing capacity. Calculating jacking forces depends on several site and project parameters such as soil and site conditions, lubrication, size of overcut, and steering corrections. Excessive jacking forces can damage the pipe and destabilize the drive shaft, which may stop project progress. There are different methods …

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Performance Of Large Diameter Polyvinyl Chloride (Pvc) Pipes In Water Applications, Pradip P. Deshmukh Jan 2012

Performance Of Large Diameter Polyvinyl Chloride (Pvc) Pipes In Water Applications, Pradip P. Deshmukh

Civil Engineering Theses - Archive

Polyvinyl chloride (PVC) pipes with diameters greater than 24" make up a small fraction of water utilities. Most of the research done on PVC pipes in water utilities focuses on diameters less than 24". Therefore, this thesis focuses on PVC water main pipelines with a diameter greater than 24" in an attempt to understand their performance in the water management facilities. This thesis had several objectives, such as to evaluate 24" and larger diameter PVC pipes in water transmission and distribution applications, calculate failure rate per hundred miles of PVC pipes at water utilities, categorize age of PVC pipelines with …

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Long-Term Performance Of Gfrp Reinforced Concrete Beams And Bars Subjected To Aggressive Environments, Yeonho Park Jan 2012

Long-Term Performance Of Gfrp Reinforced Concrete Beams And Bars Subjected To Aggressive Environments, Yeonho Park

Civil Engineering Dissertations - Archive

The use of fiber-reinforced polymer (FRP) bars in reinforced concrete (RC) structures has emerged as an alternative to traditional steel reinforcement environments and other applications where steel has shown greater vulnerability. Although the number of analytical and experimental studies on RC beams with FRP reinforcement has increased in recent decades, its long term performance is still questioned in comparison to the traditional steel reinforcement. That is, long-term performance is a much recognized but less-mentioned topic in the field of the reinforced concrete with glass-FRP (GFRP) re-bars. There is a need to validate long-term performance of FRP reinforced concrete structures, and …

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Dynamic Bus Lane, Isaac F. Joskowicz Jan 2012

Dynamic Bus Lane, Isaac F. Joskowicz

Civil Engineering Dissertations - Archive

This dissertation documents the research conducted to investigate the feasibility of implementing a "Dynamic Bus Lane" (DBL) system on Westheimer Road in Houston, Texas, and to determine the particular conditions when the system could be applied to other arterial streets. The DBL system is a bus preferential system which would turn a normal traffic lane into a bus lane when a bus is approaching a bus stop at a major intersection. The bus would activate a dynamic message sign that would change the lane use from a normal traffic lane to a bus lane for the time when the bus …

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Qualitative Evaluation Of Transportation Construction Related Social Costs And Their Impacts On The Local Community, Amanda Ferguson Jan 2012

Qualitative Evaluation Of Transportation Construction Related Social Costs And Their Impacts On The Local Community, Amanda Ferguson

Civil Engineering Theses - Archive

Although construction is valuable after completion, it can cause many disturbances throughout the duration of the project. These negative impacts, such as economic losses and annoyances, which face the community surrounding a construction project, are referred to as social costs. They are the inconveniences that confront the general public and take many forms such as traffic delays and congestion, decreased revenue, increased accidents, and air and noise pollution. Social costs negatively affect the surrounding environment and everyday quality of life. Social costs are often not incorporated into construction design, planning or budgets. This can be attributed to the complexity of …

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Development Of A Flexible Pavement Design Procedure Based On The Mechanistic - Empirical Pavement Design Guide: A Case Study, Ali Qays Abdullah Jan 2012

Development Of A Flexible Pavement Design Procedure Based On The Mechanistic - Empirical Pavement Design Guide: A Case Study, Ali Qays Abdullah

Civil Engineering Dissertations - Archive

This research developed design tables of new flexible pavement structures for New York State Department of Transportation based on the Mechanistic Empirical Design Guide (MEPDG). The design tables were developed using the MEPDG software for Regions 1, 3, and 7 for Upstate part of New York State and for Regions 8, 10, and 11 for the Downstate part of New York State. The MEPDG software was used to run design cases for combinations of: climate conditions, traffic volume, subgrade soil stiffness (Mr) and pavement structures. The conditions that the MEPDG was used to run were: the road structures classified as …

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Application Of Ellipse For Horizontal Alignment, Farzin Maniei Jan 2012

Application Of Ellipse For Horizontal Alignment, Farzin Maniei

Civil Engineering Theses - Archive

In highway design, horizontal alignments provide directional transition of roadways. Three categories of horizontal transition curves are simple circular curves, compound circular curves, and spiral circular curves. Compound and spiral curves, as alternatives to a simple circular curve, are often more costly since they are longer in length and require additional right-of-way. These costs differences are amplified at higher design speed. This study presents calculations associated with using a single elliptical arc in lieu of compound or spiral curves in situations where the use of simple circular curves is not prudent due to driver safety and comfort considerations. The study …

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Performance Comparison Of High Density Polyethylene Pipe, Chandan Venkatesh Jan 2012

Performance Comparison Of High Density Polyethylene Pipe, Chandan Venkatesh

Civil Engineering Theses - Archive

The current and forecasted major challenge faced by water utilities is delivering potable water efficiently with minimum loss to end users. Water pipe failure has negative impact not only local communities but also on the nation's economy. The American Water Works Association (AWWA) has estimated that it will cost over $250 billion to replace and renew the nation's water pipes over the next 20 years. According to the 2009 American Society of Civil Engineers (ASCE) Report Card, seven billion gallons of water are lost in this country every day!Every pipe has unique properties with advantages and limitations. During a pipe's …

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Effect Of Stress And Suction Histories Dynamic Properties Of Statically Compacted Silty Sand, William Allan Douglas Jan 2012

Effect Of Stress And Suction Histories Dynamic Properties Of Statically Compacted Silty Sand, William Allan Douglas

Civil Engineering Theses - Archive

This paper is devoted to the analysis of the experimental study whose intent is to find the effect of the stress/suction history on the dynamic properties of silty sand subjected to small- to mid-strains. The practical application of this study includes determining the effect on soil stiffness properties of increased soil suction (transpiration of water) followed by loading induced by shallow foundations and vice versa. Small-strain stiffness properties such as shear modulus, material damping, and shear wave velocity, are important subsoil parameters for proper analysis and design of unsaturated earth structures subject to static and dynamic loading. Traditional soil testing …

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An Evaluation Of Failure Modes For Cast Iron And Ductile Iron Water Pipes, Ameya Brahmanand Paradkar Jan 2012

An Evaluation Of Failure Modes For Cast Iron And Ductile Iron Water Pipes, Ameya Brahmanand Paradkar

Civil Engineering Theses - Archive

The need to evaluate the performance of cast iron and ductile iron water pipes is of great importance since they are the most common pipe materials for water mains. The concern in the water industry is about the cost involved in repairs and replacement of water pipes due to failure. The rate of pipe failures increases as the design life ends and become a financial burden on the water industry. This thesis evaluates the failure modes for the two most used pipe materials for water mains in the United States which are cast iron and ductile iron pipes. A study …

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Development Of Traffic Inputs For The Mechanistic-Empirical Pavement Design Guide In New York State, Ferdous Intaj Jan 2012

Development Of Traffic Inputs For The Mechanistic-Empirical Pavement Design Guide In New York State, Ferdous Intaj

Civil Engineering Theses - Archive

Proper characterization of traffic data is a prerequisite for the determination of appropriate traffic inputs to Mechanistic-Empirical Pavement Design Guide (MEPDG). The development of proper traffic inputs helps reflect the traffic conditions over the life of pavement which would decrease the maintenance, repair and traffic disruptions and improve the traffic conditions of a road network.The objective of the study was to characterize the traffic data and suggest the site-specific, regional or state wide average values for traffic inputs to MEPDG for New York State. Vehicle class distribution (VCD), monthly distribution factors (MDF), hourly distribution factors (HDF), average number of axle …

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Selective Catalytic Reduction Of Nitric Oxide Over Cerium-Doped Activated Carbons, Annaprabha Athappan Jan 2012

Selective Catalytic Reduction Of Nitric Oxide Over Cerium-Doped Activated Carbons, Annaprabha Athappan

Civil Engineering Dissertations - Archive

Selective catalytic reduction (SCR) with ammonia for diesel engine NOx reduction using activated carbon (AC) was studied. Comparisons of unmodified and cerium-doped Granular Activated Carbon (GAC), Activated Carbon Fiber (ACF), and Multiwall Carbon Nanotubes (MWCNTs) were conducted. Physical and chemical properties and durability of the catalysts were examined using Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS), carbon hydrogen and nitrogen (CHN) analysis, X-ray Diffraction (XRD) analysis, Raman spectroscopy, X-ray Photoelectron spectroscopy (XPS), Thermo gravimetric analysis (TGA), Braunauer-Emmett-Teller (BET) surface area analysis and density analysis. Experiments were carried in a fixed bed column at various temperatures from 100º to 400º …

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Performance Of Prestressed Concrete Cylinder Pipe (Pccp) In Water Applilcations, Rahul Manda Jan 2012

Performance Of Prestressed Concrete Cylinder Pipe (Pccp) In Water Applilcations, Rahul Manda

Civil Engineering Theses - Archive

The analysis of water pipes failure data is of great importance as it has a significant impact society and the environment. These failures also have the overall impact on the financial burden on the water industry. This thesis evaluates the failure rate of Prestressed Concrete Cylinder Pipe (PCCP), which is one of the most conventional rigid pipes and are extensively used as the water and wastewater pipeline in the US and around the world. A statistical analysis of the failure rate based on the diameter size over multiple years will help in determining the performance of PCCP pipes. Also, the …

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Effects Of Fiber Reinforced Polymer (Frp) Wrap On Reducing Chloride Penetration In Concrete, Gunther G. Garcia Jan 2012

Effects Of Fiber Reinforced Polymer (Frp) Wrap On Reducing Chloride Penetration In Concrete, Gunther G. Garcia

Civil Engineering Theses - Archive

The objective of this study was to investigate the effects of FRP wrap on reducing chloride penetration in concrete. It has been established that FRP wrap used to retrofit concrete structures offer a high resistance to chemical solutions. The ACI 318-11 Code allows for a reduction of clear cover depth if an equivalent clear cover depth can be establish. The FRP material used herein consisted of Tyfo SCH-41 and Tyfo SEH-51A composites fabricated from carbon and glass fibers, respectively. The wrapped FRP concrete specimens and control specimens without FRP wrap were tested according to ASTM C 1543 and ASTM C …

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Determining The Effectiveness Of Chlorine-Based Biofilm Control On The Friction Factors Of Large Diameter Pipelines In Raw Water, Shelly Stamler Hattan Jan 2012

Determining The Effectiveness Of Chlorine-Based Biofilm Control On The Friction Factors Of Large Diameter Pipelines In Raw Water, Shelly Stamler Hattan

Civil Engineering Theses - Archive

Large diameter transmission mains pumping raw water experience capacity loss during the summer months due to the growth of biofilm. The loss of capacity impacts power costs at a time when power is obtained at a premium. Biofilm growth varies with the seasons and varies along the length of the pipeline. Biofilm growth and decay directly impacts the friction factors. Future design work should consider a seasonal friction factor rather than an aged friction factor over time.The method of controlling biofilm is with the application of chloramines at the lake pump stations. This study compares the difference between little to …

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Water Permeability In Fiber Reinforced Plastic (Fpr)-Wrapped Concrete, Jyoti Ojha Jan 2012

Water Permeability In Fiber Reinforced Plastic (Fpr)-Wrapped Concrete, Jyoti Ojha

Civil Engineering Theses - Archive

A finite element analysis is performed using ANSYS software to analyze progress of water and its circulation in FRP wrapped concrete. This paper presents the modeling of water diffusion in FRP. Finite element programs do not usually employ issue permeability or diffusion. Therefore, diffusion of water in FRP is modeled by analogy with thermal conduction. A brief description of theoretical background is presented in the paper. The recommended FE modeling procedures are listed. Diffusion coefficient of Tyfo SCH 41S-1 obtained from an inspection report is used to analyze water permeably of FRP. Tyfo SCH 41S-1 is the most popular FRP …

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Resilient Moduli Properties Of Compacted Unsaturated Subgrade Materials, Pinit Ruttanaporamakul Jan 2012

Resilient Moduli Properties Of Compacted Unsaturated Subgrade Materials, Pinit Ruttanaporamakul

Civil Engineering Theses - Archive

According to the new Mechanistic Empirical Pavement Design Guide (MEPDG) and 1993 AASHTO flexible pavement design guide, Resilient Modulus (MR) has been used extensively as an important material property in structure design of pavement. The modulus is used as the primary input parameter to determine the stiffness parameters and constitutive behavior of pavement components. The system of pavement basically consists of the layers of surface, base, subbase (optional), and subgrade. The compacted subgrade soils supporting pavement structure are typically unsaturated with degrees of saturation varying from 75 to 90%. The effect of unsaturated soil behavior on the mechanical properties of …

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Productivity Analysis Of Box Jacking, Hossein Tavakoli Jan 2012

Productivity Analysis Of Box Jacking, Hossein Tavakoli

Civil Engineering Theses - Archive

Trenchless Technology (TT) offers methods to install utilities through the ground without damaging the surface. Box Jacking is a trenchless method for installation of prefabricated box and drainage structures without digging a trench. The concept of box jacking is similar to pipe jacking operations by first excavating an entry shaft, building the thrust block and concrete base, and setting jacking equipment. The process starts with pushing boxes while excavating at face, however, the movement of each box is achieved each time excavation at the shield is completed. Additionally, a pilot tube might be required in advance of box jacking operations. …

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Assessment And Rating Of Mechanically Stabilized Earth Walls, Noel Janacek Jan 2012

Assessment And Rating Of Mechanically Stabilized Earth Walls, Noel Janacek

Civil Engineering Theses - Archive

Mechanically stabilized earth (MSE) walls have been increasingly utilized in the United States since 1972 and in Texas since 1979. MSE walls provide earth retention for commercial, industrial and transportation projects throughout Texas. Within the transportation industry, the traditional design life of MSE walls is 75 years, with new projects requiring 100 year design life. The millions of square feet of existing MSE walls are generally less than half of the anticipated design life, making identifying and assessing the existing wall inventory a significant asset management component for optimizing maintenance expenditures. This thesis proposes and applies a system that assesses …

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Resilient Properties Of Unsaturated Base Materials, Ranjan Kumar Rout Jan 2012

Resilient Properties Of Unsaturated Base Materials, Ranjan Kumar Rout

Civil Engineering Theses - Archive

A pavement system basically consists of a surface layer, a base course, a subbase (optional) and the subgrade. As per MEPDG and 1993 AASHTO flexible pavement design guide Resilient Modulus (MR) is used as the primary input parameter to determine the stiffness parameters and the constitutive behavior of pavement components, such as subgrade and unbound bases. Generally, pavements are constructed on compacted soils that are typically unsaturated with degrees of saturation varying from 75 to 90%. The main focus of this research is to determine the effect of matric suction on the resilient moduli property of the base materials. The …

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Design Of Controlled Low Strength Material For Bedding And Backfilling Using High Plasticity Clay, Anil Kumar Raavi Jan 2012

Design Of Controlled Low Strength Material For Bedding And Backfilling Using High Plasticity Clay, Anil Kumar Raavi

Civil Engineering Theses - Archive

Flowable fill or Controlled Low Strength Material (CLSM) is a self-compacted cementitious material used in the field in the place of compacted fill. It is also known as unshrinkable fill, controlled density fill, flowable mortar, plastic-soil cement, soil-cement slurry, and others. The advantages of this material include lesser soil settlements, elimination of compaction, and lower costs when compared to chemically treated and compacted subsoils. CLSMs have a wide range of applications such as using them as a backfill, bedding material, trench filling material, void filling material, bridge abutment and embankment materials and also in pavement bases. Current research is aimed …

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Selecting A Shaft/Pit Construction Method For Trenchless Technology, Bassam Abusad Jan 2012

Selecting A Shaft/Pit Construction Method For Trenchless Technology, Bassam Abusad

Civil Engineering Theses - Archive

The word shaft describes a vertical access point that is created by excavating, vertical boring, or blasting required before the start of tunneling or boring operations. Most trenchless technologies require entry shafts and exit shafts and in some cases and intermediate shaft Trenchless technologies are methods used for the construction and rehabilitation of underground utility pipes. Since pits and shafts are excavated below the ground surface level, Occupational Safety and Health Administration (OSHA) rules and regulations are enforced for the safety of the workers. The focus of this research is to describe shaft and pit construction methods as applied to …

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Comparison Of Measured And Predicted Response Of Six Mnroad Asphalt Test Sections, Veni Valli Nagarajan Jan 2012

Comparison Of Measured And Predicted Response Of Six Mnroad Asphalt Test Sections, Veni Valli Nagarajan

Civil Engineering Theses - Archive

The study, sponsored by MnRoad, aimed to compare the measured and predicted values of strains and stresses for six cells 33, 34, 35, 77, 78 and 79 of the third MnRoad experiments. Cells 33, 34 and 35 were constructed for studying the polyphosphoric acid study while cells 77, 78 and 79 for the fly-ash stabilization study, during 2007. Each cell is instrumented with three transverse strain gauges and three longitudinal strain gauges at the bottom of HMA layer while three pressure cells were located at the top of the subgrade layer to measure vertical compressive stress.The FWD deflection data collected …

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