Civil Engineering Commons^™

Reliability-Based Design And Acceptance Protocol For Driven Piles, Joseph Jabo

Graduate Theses and Dissertations

The current use of the Arkansas Standard Specifications for Highway Construction Manuals (2003, 2014) for driven pile foundations faces various limitations which result in designs of questionable reliability. These specifications are based on the Allowable Stress Design method (ASD), cover a wide range of uncertainties, do not take into account pile and soil types, and were developed for general use. To overcome these challenges it is deemed necessary to develop a new design and acceptance protocol for driven piles. This new protocol incorporates locally calibrated RLFD resistance factors for accounting for local design and construction experiences and practices, as well …

Microbial Community Shifts Caused By Changes In The Primary Oxidant At A Drinking Water Treatment Plant, Connie Marie Moloney

Graduate Theses and Dissertations

Microbial communities resistant to common oxidants can cause concerns for water treatment plants (WTPs). If a bacterium is not fully oxidized during disinfection, these species can impede upon filtration processes or seed biofilms in the distribution system. In an effort to minimize disinfection by-products (DBP's) that result from the reaction of chlorine (Cl2) with natural organic matter, water treatment plants have the option to change their primary oxidant to chlorine dioxide (ClO2). The following study examines the change in microbial communities during the sedimentation process under differing oxidation regimes, specifically chlorine (Cl2) and ClO2 at the local water treatment plant …

Field-Obtained Soil Water Characteristic Curves And Hydraulic Conductivity Functions, Elvis Ishimwe

Graduate Theses and Dissertations

A compacted clay liner (test pad) was constructed and instrumented with volumetric water content and soil matric potential sensors to determine soil water characteristic curves (SWCC) and hydraulic conductivity (k) functions. Specifically, the compacted clay liner was subjected to an infiltration cycle during a sealed double ring infiltrometer (SDRI) test followed by a drying cycle. After the drying cycle, Shelby tube samples were collected from the compacted clay liner and flexible wall permeability (FWP) tests were conducted on sub-samples to determine the saturated hydraulic conductivity. Moreover, two computer programs (RETC and UNSAT-H) were utilized to model the SWCCs and k-functions …

Dynamic Testing Of An Elevated Water Tank, Alexander Michael Font

Graduate Theses and Dissertations

The objective of this thesis was to identify the modal properties of a pedesphere type, elevated water tank under different operating conditions relating to the water level in the tank. The research that was conducted included both numerical and experimental components. The numerical components consisted of a simple hand calculation to identify the fundamental frequency as well as numerical computer models to identify the natural frequencies and mode shapes for the first three bending modes. The experimental components consisted of characterizing the vibration of the elevated water tank in its current environment through ambient vibration testing.

Multiple Reference Impact Testing Of Bridges Using A Network Of Low-Cost Dynamic Exciters, James David Lindsey

Graduate Theses and Dissertations

Multiple Reference Impact Testing (MRIT) is a form of Experimental Modal Analysis (EMA) that can be used to identify the dynamic properties of full-scale bridges. These dynamic properties include natural frequencies, mode shapes, damping ratios, modal scaling and modal flexibility. Since these system properties that are directly related to the mass and stiffness characteristics of a structure, impact test measurements can be used to quantitatively characterize condition of a structure. Over time, changes in the properties can be monitored and evaluated as indicators of damage or deterioration. Instrumented hammers and drop masses are typically used to perform MRIT by providing …

Assessment Of Nitrifying Bacteria In Massard Plant Using Molecular Tools, Jennifer Puanani Holmes-Smith

Civil Engineering Undergraduate Honors Theses

The discharge of nutrients (such as nitrogen and phosphorus) from wastewater treatment plants (WWTP) has become an increasingly important issue in the United States. Ammonia (NH3) is a common contaminant found in domestic wastewater and agricultural runoff. It can cause toxicity in fish if left untreated. The United States Environmental Protection Agency (EPA) recommends low national criteria for ammonia limits in freshwater. With these greater restrictions, ammonia-nitrogen limit compliance (5 mg/L) has become an issue at the Massard WWTP in Fort Smith, Arkansas. The purpose of this research is to assess the ammonia removal in the Massard WWTP in order …

A Comparison And Evaluation Of Different Dynamic Characterization Approaches For Bridges, Juan Javier Torres Torres Goitia

Graduate Theses and Dissertations

The objective of this thesis was to compare different dynamic characterization approaches for full scale bridge structures to devise a rapid and reliable Structural Health Monitoring (SHM) program in the aftermath of a natural or manmade hazard. Present methods for structural condition evaluation of bridge structures rely heavily on on-site visual inspections of each structure by specially trained engineers and technicians. It has been proved in the literature that this current method is subjective, time consuming and manpower intensive, all of which are not suited for the critical conditions following a hazard event. This study focused on comparing three different …

Comparing Ferrous Chloride And Ferrous Sulfate As Secondary Coagulants At The Beaver Water District Drinking Water Treatment Plant, Jenny Doyle

Graduate Theses and Dissertations

In November 2012, the Beaver Water District (BWD) switched primary oxidants from free chlorine to chlorine dioxide (ClO2) to curb formation of trihalomethanes, a regulated group of organic disinfection byproducts (DBPs). Because ClO2 is reduced to chlorite (ClO2-), a regulated inorganic DBP, BWD incorporated ferrous salt into their coagulation regime to quench chlorite to chloride. In this study, two ferrous salts - ferrous chloride (FC) and ferrous sulfate (FS) - were compared as secondary coagulants in combination with alum, the primary coagulant. Ferrous salts were dosed stoichiometrically to reduce chlorite and alum was dosed at percentages (0-100%) relative to a …

Global Dynamic Characterization And Load Rating Of Bridge Structures Utilizing Economical Dynamic Excitation Devices, Eric Fernstrom

Graduate Theses and Dissertations

Experimental modal analysis (EMA) of bridges and other civil structures can be used to acquire quantitative data describing their condition, and enhance opportunities for structural health monitoring and related fields. The use of EMA on civil structures has been limited by the high cost of the excitation devices that are required for the best data quality. The objective of the research reported herein is to evaluate a low-cost excitation system for multiple-input, multiple-output (MIMO) EMA, enabling the production of accurate estimates of the global behavior of in-service bridges.

The prototype excitation system is composed of consumer entertainment devices, namely tactile …

The Investigation Of Cold-Mix Asphalt Creep Stiffness Testing Using Multiple Test Apparatuses And Gradations, Alexander Jackson

Graduate Theses and Dissertations

Many current methods of designing and testing Cold In-Place Recycled (CIR) asphalt are undesirable because they require large amounts of material and significant preparation. In an effort to lessen the cost and time of materials testing, this research utilizes several different methods of small scale testing of creep stiffness. These methods include using a Discovery Hybrid Rheometer (DHR) and a three point bending test to find the creep stiffness of emulsion based CIR. The new testing methods utilized samples on the scale of up to a hundredth the size of what the traditional methods of testing require. The two smaller …

The Characterization Of Foamed Asphalt Binders Using A Rotational Viscometer, John William Ryan

Graduate Theses and Dissertations

Foamed asphalt is a popular technic of vaporizing water into asphalt binder that falls under the umbrella term of warm-mix asphalt. In order to understand how to adjust mix designs for the use foamed asphalt, methods must be developed for characterizing different foamed asphalt binders. One way to characterize the asphalt binder is through viscosity testing using a rotational viscometer. The standard method of using a viscometer to measure the viscosity of asphalt binder is insufficient when dealing with foamed asphalts, so a new method has been created along with 4 metrics to analyze the data to characterize foamed asphalt …

Rapid Condition Assessment Of Bridges By Falling Weight Deflectometer, Jeremy David Rawn

Graduate Theses and Dissertations

The objective of this thesis is to investigate the feasibility of using a Falling Weight Deflectometer (FWD) as an impact source to rapidly assess the condition of an in service bridge through the evaluation of its modal properties. Tests were conducted on two bridges, a Parker Pony Truss and a modern concrete deck on rolled steel beam bridge. Two full tests were performed on these structures with a hand held impact hammer and a falling weight deflectometer as sources for excitation. The advantage of using a FWD is that many transportation agencies already use these machines for pavement testing and …

Temperature Sensitivity Of Foamed Warm Mix Asphalt, Ryan Michael Hagedorn

Civil Engineering Undergraduate Honors Theses

Foamed warm mix asphalt (WMA) is a technology that is beginning to be utilized across the United States. Often, producers are placing foamed WMA at decreased temperatures without fully understanding the properties of this relatively new product. By studying the volumetric properties of laboratory produced foamed WMA, this study sought to better understand the temperature sensitivity of foamed WMA and the potential factors that contribute to this sensitivity. Two mix designs containing primarily limestone aggregate were tested using differing binder grades. It was determined that binder grade, binder source and potentially the inclusion of recycled asphalt pavement all influence how …

Dynamic Excitation Related Uncertainty In Ambient Vibration Testing Of A Truss Bridge, Ryan T. Dufour

Civil Engineering Undergraduate Honors Theses

The aging and deteriorating state of bridges in the US, along with the many limitations of the visual inspection data that is used for assessing and evaluating their condition, have provided motivation for research on experimental methods to quantitatively describe and evaluate their in-situ performance and condition. Ambient vibration testing is one such global characterization approach that has been widely explored due to its low cost and ease of implementation for in-service bridges. The testing is used to identify the modal properties of the structure, typically the natural frequencies, mode shapes, and damping ratios. Although ambient vibration testing has been …

Examination Of Nitrogen To Phosphorus Ratio In Nutrient Removal From Wastewater Through Chlorella Vulgaris, Courtney L. Hill

Civil Engineering Undergraduate Honors Theses

A need for phosphorus removal is becoming increasingly evident as some wastewater treatment plants struggle to meet wastewater effluent nutrient requirements. High nutrient levels in wastewater effluents have also caused ongoing tension between the state of Oklahoma and Arkansas regarding the pollution of the Illinois River. This research seeks to establish the relationship between nitrogen to phosphorus ratio in wastewater and the level of nutrient reduction using Chlorella vulgaris. Seed cultures of Chlorella vulgaris were added into solutions with various ratios of nitrate to phosphate representative of treated domestic wastewater and the removal of nitrogen and phosphorus were measured in …

Shear Capacity Of Prestressed Lightweight Self-Consolidating Concrete, Micah Alan Wyssmann

Civil Engineering Undergraduate Honors Theses

In prestressed members, self-consolidating concrete (SCC) has in some cases exhibited lower shear capacity than conventional concrete, which has been attributed to decreased aggregate interlock. However, little data is currently available to assess whether use of lightweight aggregate in prestressed SCC beams has further impact on aggregate interlock and shear strength. This study measured the shear capacity of six prestressed beams made from three different concrete mixtures: lightweight self-consolidating concrete (LWSCC) with expanded shale aggregate, LWSCC with expanded clay aggregate, and control normal weight SCC with limestone aggregate. Predicted shear capacities were determined based on current ACI Building Code and …

Evaluation Of The Effects Of Dynamic Excitation Characteristics On Ambient Vibration Test Results For A Multi-Girder Bridge, Gibran Santana

Civil Engineering Undergraduate Honors Theses

The bridge population in the US is currently aging and deteriorating rapidly. More than 30% of the bridges across the country have already exceeded their expected design life. Therefore, it is important to develop more timely, reliable and quantitative alternatives to the qualitative visual inspection approach that is currently used to evaluate these structures. One experimental approach that has been researched extensively for quantitatively characterize bridges is Ambient Vibration Testing (AVT) also known as Operational Modal Analysis (OMA). In this approach, the vibration responses of a structure due to unmeasured and uncontrolled ambient dynamic excitation are measured and analyzed to …