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Missouri University of Science and Technology

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Articles 2221 - 2250 of 7869

Full-Text Articles in Civil and Environmental Engineering

High-Strength Selfconsolidating Concrete Girders Subjected To Elevated Compressive Fiber Stresses, Part 2: Structural Behavior, Jared E. Brewe, John J. Myers Jan 2011

High-Strength Selfconsolidating Concrete Girders Subjected To Elevated Compressive Fiber Stresses, Part 2: Structural Behavior, Jared E. Brewe, John J. Myers

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The design of prestressed concrete members is restricted by the requirement that the extreme compressive fiber stress at midspan be less than 60% of the concrete compressive strength at release of prestressing. the purported purpose of this limit is to provide serviceability performance, but it places unnecessary limits on the capability of the materials. for this research program, six prestressed concrete girders were produced with high-strength, self-consolidating concrete and subjected to elevated compressive fiber stress levels ranging from 65% to 84% of initial concrete compressive strength at release of prestressing. Part 1 of this series analyzed time-dependent prestress losses and …

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A Method For Calibration Of Speed-Flow Curves In Hcm 2010 And Determination Of Highway Capacity, Seyed Hadii Khazraee Khoshroozi Jan 2011

A Method For Calibration Of Speed-Flow Curves In Hcm 2010 And Determination Of Highway Capacity, Seyed Hadii Khazraee Khoshroozi

Masters Theses

"This study proposes a method for calibration of speed-flow curves in a format suggested by the Highway Capacity Manual (HCM) 2010 and applies it to two sites in Missouri: a work zone on I-44 around Pacific, and a basic freeway segment on I-270 in St. Louis. The three-regime model proposed is based on the two-regime (free-flow and transition) uncongested relationship suggested by the HCM 2010, complemented with a third regime representing congested conditions. Further, this study proposes a systematic approach based on regression analysis to determine capacity i.e., the break-point (intersection) between the transition and congested regimes. The proposed method …

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Laboratory Studies Of Compatibility Of Tamper Detection Materials With Improvised Explosive Device Crater Repairs, Levi Anthony Smith Jan 2011

Laboratory Studies Of Compatibility Of Tamper Detection Materials With Improvised Explosive Device Crater Repairs, Levi Anthony Smith

Masters Theses

"Past methods for road repairs of craters caused by improvised explosive devices (IEDs) on main supply routes (MSRs) and alternative supply routes (ASRs) in Iraq and Afghanistan have been problematic. Traditional temporary and permanent solutions have proven deficient by being easily penetrable or by exposing troops for long periods of time. The use of a pre-blended rapid hardening cementitious material for lED crater repair has solved issues such as quick placement of the repair and high strength of the repair within an hour of placement. However, there are still issues with IEDs being hidden in repairs tampered by or replicated …

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Towards Better Utilization Of Nexrad Data In Hydrology: An Overview Of Hydro-Nexrad, Witold F. Krajewski, Anton Kruger, James A. Smith, Ramon Lawrence, Charles Gunyon, Radoslaw Goska, Bong Chul Seo, Piotr Domaszczynski, Mary Lynn Baeck, Mohan K. Ramamurthy, Jeffrey Weber, A. Allen Bradley, Stephen A. Delgreco, Matthias Steiner Jan 2011

Towards Better Utilization Of Nexrad Data In Hydrology: An Overview Of Hydro-Nexrad, Witold F. Krajewski, Anton Kruger, James A. Smith, Ramon Lawrence, Charles Gunyon, Radoslaw Goska, Bong Chul Seo, Piotr Domaszczynski, Mary Lynn Baeck, Mohan K. Ramamurthy, Jeffrey Weber, A. Allen Bradley, Stephen A. Delgreco, Matthias Steiner

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

With a very modest investment in computer hardware and the open-source local data manager (LDM) software from University Corporation for Atmospheric Research (UCAR) Unidata Program Center, a researcher can receive a variety of NEXRAD Level III rainfall products and the unprocessed Level II data in real-time from most NEXRAD radars in the USA. Alternatively, one can receive such data from the National Climatic Data Center in Ashville, NC. Still, significant obstacles remain in order to unlock the full potential of the data. One set of obstacles is related to effective management of multi-terabyte datasets. A second set of obstacles, for …

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Reaction Rates Of Ozone And Terpenes Adsorbed To Model Indoor Surfaces, M. Springs, J. R. Wells, Glenn Morrison Jan 2011

Reaction Rates Of Ozone And Terpenes Adsorbed To Model Indoor Surfaces, M. Springs, J. R. Wells, Glenn Morrison

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Reaction rates and reaction probabilities have been quantified on model indoor surfaces for the reaction of ozone with two monoterpenes (Δ3-carene and d-limonene). Molar surface loadings were obtained by performing breakthrough experiments in a plug-flow reactor (PFR) packed with beads of glass, polyvinylchloride or zirconium silicate. Reaction rates and probabilities were determined by equilibrating the PFR with both the terpene and the ozone and measuring the ozone consumption rate. to mimic typical indoor conditions, temperatures of 20, 25, and 30°C were used in both types of experiments along with a relative humidity ranging from 10% to 80%. the molar surface …

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"Long" Carbon Fiber Reinforced Concrete For Impact And Blast Resistance, Benjamin Paul Gliha Jan 2011

"Long" Carbon Fiber Reinforced Concrete For Impact And Blast Resistance, Benjamin Paul Gliha

Masters Theses

"One of the most commonly used materials for protective structures and construction is traditional reinforced concrete. However, in a blast, conventional reinforced concrete (RC) is susceptible to significant spalling (small to medium size chunks of concrete detaching from the original member). The force of the blast turns spalled concrete into projectiles, resulting in secondary fragmentation and the majority of loss of life. Furthermore, the concrete debris makes for difficult and uncertain footing. Both phenomena endanger personnel and complicate post-blast recovery efforts. A very promising but barely explored change to conventional RC construction is the addition of "long" carbon fibers (fibers …

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A Statewide Analysis Of Highway Safety In Arkansas, Uday R. R. Manepalli Jan 2011

A Statewide Analysis Of Highway Safety In Arkansas, Uday R. R. Manepalli

Masters Theses

"This research concentrated on two major aspects of highway safety analysis, hotspot identification and identification of crash contributing factors on highways. The objective of the first part of this thesis is to evaluate two crash frequency, three crash severity and two composite hotspot ranking methods. Based on the limitations of the existing hotspot identification methods (HSID), crash factor method (CFM), a crash severity based HSID method is proposed. A composite rank method (F 1) based on principal component analysis is also proposed. These methods are evaluated using three tests, the site consistency test, the method consistency test, and the total …

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Ozone And Terpene Reactions On Indoor Surfaces: Reaction Rates And Implications For Indoor Air Quality, Shi Shu Jan 2011

Ozone And Terpene Reactions On Indoor Surfaces: Reaction Rates And Implications For Indoor Air Quality, Shi Shu

Doctoral Dissertations

No abstract provided.

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Hardened Concrete Properties And Durability Assessment Of High Volume Fly Ash Concrete, Kyle Marie Marlay Jan 2011

Hardened Concrete Properties And Durability Assessment Of High Volume Fly Ash Concrete, Kyle Marie Marlay

Masters Theses

"Concrete is produced more than any other material in the world. Sustainable construction is extremely important in today's industry and fly ash is the leading material for sustainable concrete design. The addition of fly ash improves many fresh and hardened concrete properties. However, the slow hydration process associated with fly ash makes the use of the material in large amounts undesirable in conventional construction. This study evaluated the hardened concrete and durability performance of several high-volume fly ash (HVFA) concrete mixes. The various HVFA concrete mixes evaluated within this study consisted of 70 percent replacement of portland cement by weight …

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Influence Of Particle Size And Specimen Preparation On The Iowa Pore Index, Christopher Paul Davis Jan 2011

Influence Of Particle Size And Specimen Preparation On The Iowa Pore Index, Christopher Paul Davis

Masters Theses

"This study was performed in order to identify a size correction that would allow aggregate of different sizes, other than the standard 1/2-3/4-inch fraction, to be used in the Iowa Pore Index (IPI) test. This size correction would allow for the IPI to be determined for aggregate gradations of material that have a nominal maximum size (NMS) smaller than 3/4-inch. The interest in a size correction for the IPI developed from its use in a Durability Factor (DF) estimation equation. The estimation equation was developed with the use of 19 different DF from Missouri aggregate sources, where eight aggregates had …

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Bond Strength Of High-Volume Fly Ash Concrete, Michael Hayse Wolfe Jan 2011

Bond Strength Of High-Volume Fly Ash Concrete, Michael Hayse Wolfe

Masters Theses

"Concrete is the most consumed man-made material in the world. Unfortunately, due to the production of cement, concrete has a large carbon footprint. Replacement of cement with fly ash, an industrial waste product, offers a sustainable alternative. The goal of this research was to explore the feasibility of using high-volume fly ash (HVFA) concrete for structural applications by testing the material's reinforcement bond properties. A series of pull-out tests and beam splice tests were performed on specimens with a 70 percent fly ash replacement of cement and then compared to identical tests performed on control specimens cast from a 100 …

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Driven Pile Load Test Data For Load And Resistance Factor Design In Missouri, Joseph Ronson Cravens Jan 2011

Driven Pile Load Test Data For Load And Resistance Factor Design In Missouri, Joseph Ronson Cravens

Masters Theses

"The Missouri Department of Transportation (MoDOT) has recently migrated from allowable stress design (ASD) to load and resistance factor design (LRFD) of driven piles. This transition was initiated when the Federal Highway Administration (FHWA) issued a policy stating that all new bridge designs shall be designed in accordance with the American Association of State Highway and Transportation Officials (AASHTO) LRFD Bridge Design Specifications to eliminate the difference in design methodologies for bridge superstructures and bridge substructures. However, the resistance factors for driven piles specified in the AASHTO LRFD specifications are based on nationwide pile data, consisting of a wide range …

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Evaluation Of The Orientation Of 90⁰ And 180⁰ Reinforcing Bar Hooks, Nichole Lynn Podhorsky Jan 2011

Evaluation Of The Orientation Of 90⁰ And 180⁰ Reinforcing Bar Hooks, Nichole Lynn Podhorsky

Masters Theses

"This thesis describes test results of a study initiated to evaluate the potential influence of hook tilt angle of standard reinforcing hooks on the bond strength of concrete. The topic of the evaluation of the orientation of 90 and 180 degree reinforcing bar hooks in concrete members was identified by the Concrete Reinforcing Steel Institute (CRSI) as high-priority for the reinforcing steel industry. In this test program, a series of single bar and multiple bar specimens were designed and tested to examine bar behavior and potential group effects that may exist in wide flexural members with multiple bars, such as …

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Ozone Uptake Rates And Secondary Product Emissions Of Green Building Materials, Seth Paul Lamble Jan 2011

Ozone Uptake Rates And Secondary Product Emissions Of Green Building Materials, Seth Paul Lamble

Masters Theses

"Building materials considered "green" were tested for their ability to remove ozone and their potential to generate undesirable byproducts such as aldehydes. Three types of ceiling tile were tested, along with seven flooring materials and eight wall materials. These materials were selected based on "green" criteria. For several this means they were recycled or produced from renewable resources. Others were designed to be low emitting, or due to their composition were likely to be low emitting. Ozone deposition velocities ranged from 0.25 m h-1 for a type of resilient linoleum type flooring to 8.23 m h-1 for a clay based …

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Installation And Performance Evaluation Of Coaxial Cable Sensors For Crack And Corrosion Detection, Iana Muchaidze Jan 2011

Installation And Performance Evaluation Of Coaxial Cable Sensors For Crack And Corrosion Detection, Iana Muchaidze

Masters Theses

"Even under service loads, reinforced concrete (RC) structures can develop cracks that result in excessive deflection of the structures and provide passages for moisture to corrode steel reinforcement. It is thus critical to develop a simple, cost-effective tool for real-time crack monitoring and associated corrosion detection that may affect the engineering maintenance of RC structures. The objectives of this study include: (1) to develop a die-cut manufacturing process of coaxial cables with spiral outer conductors, (2) to quantify the sensing properties of a miniaturized topology-based crack sensor, (3) to investigate the effectiveness of various sensor installation procedures in RC applications, …

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Categorization And Experimental Evaluation Of Anchorage Systems For Fiber-Reinforced Polymer Laminates Bonded To Reinforced Concrete Structures, Stephen V. Grelle Jan 2011

Categorization And Experimental Evaluation Of Anchorage Systems For Fiber-Reinforced Polymer Laminates Bonded To Reinforced Concrete Structures, Stephen V. Grelle

Masters Theses

"While externally-bonded fiber-reinforced polymer (FRP) composites are commonly used for the strengthening of structurally deficient reinforced concrete (RC) members, the topic of anchoring FRP to concrete to achieve higher design strengths has not been addressed. Many innovative systems have been developed to anchor FRP to concrete, but the research involving these anchorage systems is not centralized and is therefore difficult to access. Additionally, systematic testing procedures for evaluating the strength of an anchorage system have not been widely used. To aid in the organization of anchorage system research and facilitate a better understanding of anchorage system behavior, a categorization system …

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Development And Testing Of Chemically-Based Self-Consolidating Concrete, Mark Daniel Ezzell Jan 2011

Development And Testing Of Chemically-Based Self-Consolidating Concrete, Mark Daniel Ezzell

Masters Theses

"Self-consolidating concrete (SCC) possesses several characteristics that can benefit the concrete construction industry including accelerated construction, a reduction in labor and equipment, and a reduction in construction noise through eliminating or reducing the need to vibrate the concrete. However, SCC has some potential downsides. These problems can usually be attributed to higher paste content, higher fines content, rounder aggregate, and higher water to cement (w/c) ratios used to increase the flow of the concrete. The goal of this research project was to develop a SCC that had improved material properties through the use of chemical admixtures instead of modifications to …

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Micropile Response To Combined Loading, Kyle Allen Kershaw Jan 2011

Micropile Response To Combined Loading, Kyle Allen Kershaw

Doctoral Dissertations

"The familiarity and acceptance of micropiles by engineers, contractors, and owners has greatly expanded in recent years such that they are routinely considered on many projects. However, research regarding the behavior of micropiles has lagged behind. The goal of this research project was to address some of the fundamental gaps that were not addressed in engineering practice and require further study and testing. Specifically, this research studied the behavior of micropile foundations subjected to simultaneous axial and lateral (combined) loading, including an assessment of the impact of axial load on lateral behavior of micropiles. This research project consisted of three …

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Hilbert Transform Applications In Signal Analysis And Non-Parametric Identification Of Linear And Nonlinear Systems, Zuocai Wang Jan 2011

Hilbert Transform Applications In Signal Analysis And Non-Parametric Identification Of Linear And Nonlinear Systems, Zuocai Wang

Doctoral Dissertations

"Hilbert Huang Transform faces several challenges in dealing with closely-spaced frequency components, short-time and weak disturbances, and interrelationships between two time-varying modes of nonlinear vibration due to its mixed mode problem associated with empirical mode decomposition (EMD). To address these challenges, analytical mode decomposition (AMD) based on Hilbert Transform is proposed and developed for an adaptive data analysis of both stationary and non-stationary responses. With a suite of predetermined bisecting frequencies, AMD can analytically extract the individual components of a structural response between any two bisecting frequencies and function like an adaptive bandpass filter that can deal with frequency-modulated responses …

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Postcyclic Behavior Of Low-Plasticity Silt, Shuying Wang Jan 2011

Postcyclic Behavior Of Low-Plasticity Silt, Shuying Wang

Doctoral Dissertations

"Liquefaction of low-plasticity silt has been reported during earthquakes in the recent past. Excess pore pressure builds up due to the dynamic loading and then dissipates. The postcyclic behavior of low-plasticity silt was investigated in this research for materials obtained from the Mississippi River Valley. The experimental program involved specimen preparation using a slurry consolidation approach. A special technique was developed for specimen movement, reducing the testing program time by half. Both static and cyclic triaxial tests were conducted to confirm the ability to prepare replica specimens. In order to characterize the monotonic behavior, triaxial tests were conducted to determine …

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Phytoforensic Tools: Directional Uptake Of Chlorinated Solvents, Matthew Alan Limmer Jan 2011

Phytoforensic Tools: Directional Uptake Of Chlorinated Solvents, Matthew Alan Limmer

Masters Theses

"Trees have been used to locate contaminated soil and groundwater, augmenting traditional methods, such as well drilling, that are time-consuming and expensive. In the past decade, plant sampling has gained acceptance as a reliable method for site screening. In this new field of phytoforensics, research efforts focus on developing quicker, more accurate and more informative sampling and analysis methods for measuring contaminant concentrations in trees. These phytoforensic tools are a novel approach to site assessments, potentially reducing cost while more effectively locating contaminated groundwater. This thesis evolved from field data suggesting azimuthal concentrations in tree trunks may reflect the corresponding …

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Leaching Characteristics Of Inorganic Contaminants From Coal Fly Ash, Tingzhi Su Jan 2011

Leaching Characteristics Of Inorganic Contaminants From Coal Fly Ash, Tingzhi Su

Doctoral Dissertations

"Leaching of trace elements raises environmental concerns in coal fly ash disposal and reuse. US EPA is in the process of creating the first national rule on coal ash management. However, due to the complexity of coal fly ash composition, the leaching characteristics of trace elements are not well understood. Meanwhile, driven by the tightening emission regulations, new types of coal fly ashes are continuously generated as a result of the technological evolution at coal energy industry. The changing landscape highlights the needs for a comprehensive database to assess the leaching characteristics of different types of coal fly ashes, evaluation …

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Evaluation Of Hydraulic Efficiency Of Disinfection Systems Based On Residence Time Distribution Curves, Jordan M. Wilson, Subhas K. Venayagamoorthy Dec 2010

Evaluation Of Hydraulic Efficiency Of Disinfection Systems Based On Residence Time Distribution Curves, Jordan M. Wilson, Subhas K. Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Hydraulic efficiency is a vital component in evaluating the disinfection capability of a contact system. Current practice evaluates these systems based upon the theoretical detention time (TDT) and the rising limb of the residence time distribution (RTD) curve. This evaluation methodology is expected because most systems are built based on TDT under a "black box" approach to disinfection system design. Within recent years, the proliferation of computational fluid dynamics (CFD) has allowed a more insightful approach to disinfection system design and analysis. Research presented in this study using CFD models and physical tracer studies shows that evaluation methods based upon …

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Product Technical Information, Steel Stud Manufacturers Association Dec 2010

Product Technical Information, Steel Stud Manufacturers Association

CCFSS Library (1939 - present)

No abstract provided.

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Evaluation Of Compacted Silt Characteristics By Ultrasonic Pulse Velocity Testing, Desislava Z. Slavova, David M. Weidinger, Adam F. Sevi, Louis Ge Dec 2010

Evaluation Of Compacted Silt Characteristics By Ultrasonic Pulse Velocity Testing, Desislava Z. Slavova, David M. Weidinger, Adam F. Sevi, Louis Ge

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Unintrusive measurement of field modulus and moisture content of roadway subgrade and fill materials greatly enhances field control during construction. Establishing a measurement method in a laboratory setting provides an initial assessment of a tool's possible usefulness in the field. an ultrasonic test system was used in this research in order to determine the wave velocities of cylindrical soil specimens in a laboratory setting in support of a Briaud Compactive Device (BCD) research project. the BCD is a non-destructive test method that can quickly determine soil modulus both in the laboratory and the field. Cylindrical soil samples of silt were …

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Design Charts For Retaining Walls In Seismic Areas, Yingwei Wu, Shamsher Prakash Dec 2010

Design Charts For Retaining Walls In Seismic Areas, Yingwei Wu, Shamsher Prakash

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Retaining walls have failed either by sliding away from the backfill or due to combined action of sliding and rocking displacements, during earthquakes. Performance based design of the retaining walls in seismic areas must account for the likely displacements, in addition to calculating the usual factors of safety against failure in bearing, sliding and overturning. a realistic model for estimating dynamic displacement has been developed, which accounts for the combined action of sliding and rocking and takes into consideration, non-linear soil stiffness in sliding, and rocking, geometrical and material damping in sliding, and rocking, and coupling effects. This model was …

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Cold-Formed Steel Framing Seismic Design Optimization Phase 1a: Seismic Equivalency Parameter Evaluation, American Iron And Steel Institute Nov 2010

Cold-Formed Steel Framing Seismic Design Optimization Phase 1a: Seismic Equivalency Parameter Evaluation, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

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Web-Based Intelligent Computational Argumentation Based Conflict Resolution In Air Traffic Management, Xiaoqing Frank Liu, Ravi Santosh Arvapally, Hojong Baik, Rubal Wanchoo Nov 2010

Web-Based Intelligent Computational Argumentation Based Conflict Resolution In Air Traffic Management, Xiaoqing Frank Liu, Ravi Santosh Arvapally, Hojong Baik, Rubal Wanchoo

Computer Science Faculty Research & Creative Works

Collaborative decision making (CDM) is a process of reaching consensus on a potential solution of an issue through the evaluation of the different possible alternatives. the web-Based intelligent computational argumentation system allows concerned stakeholders to post their arguments on different alternatives, assign weights and priorities to the arguments and reach the most favorable alternative using fuzzy intelligent techniques over the Internet. Exchange of information among the stakeholders improves the collaboration and drives towards the collective intelligence. in this paper, we show how our tool facilitates resolution of conflicts in air traffic management. It could enhance the Ground Delay Program (GDP) …

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Seismic Performance Of Square Rc Bridge Columns Under Combined Loading Including Torsion With Low Shear, Q. Li, Abdeldjelil Belarbi, S. S. Prakash Nov 2010

Seismic Performance Of Square Rc Bridge Columns Under Combined Loading Including Torsion With Low Shear, Q. Li, Abdeldjelil Belarbi, S. S. Prakash

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

During earthquake excitations, reinforced concrete bridge columns can be subjected to a combination of axial load, shear force, flexural moments, and torsional moments. the torsional moment can be much more significant in columns of bridges that are skewed, curved, have unequal spans, or unequal column heights. Combined loading including torsion can result in complex flexural and shear failure of these bridge columns. This paper presents an experimental study on the seismic behavior of square reinforced concrete columns under combined cyclic flexural and torsional moments. the columns in this study were designed with an aspect ratio of six and tested under …

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Structural Health Monitoring Of Reinforced Concrete Columns Subjected To Reversed Cyclic Loading Using Innovative Smart Aggregates, Yashar Moslehy, Haichang Gu, Abdeljalil Belarbi, Y. L. Mo, Gangbing Song Nov 2010

Structural Health Monitoring Of Reinforced Concrete Columns Subjected To Reversed Cyclic Loading Using Innovative Smart Aggregates, Yashar Moslehy, Haichang Gu, Abdeljalil Belarbi, Y. L. Mo, Gangbing Song

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Structural health monitoring is an important issue for the maintenance of large-scale civil infrastructure, especially for bridge columns. in this paper, an innovative piezoceramic-Based approach is developed for the structural health monitoring of reinforced concrete columns. an innovative piezoceramic-Based device, smart aggregate, is utilized as a transducer for health monitoring purposes. to investigate the seismic behavior of RC bridge columns, structural health monitoring tests were performed on two bridge columns under combined reversed cyclic loading at Missouri University of Science and Technology. Experimental results show that the proposed smart aggregate-Based approach successfully evaluated the health status of concrete columns during …

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