Civil Engineering Commons^™

Effects Of The Antimicrobial Tylosin On The Microbial Community Structure Of An Anaerobic Sequencing Batch Reactor, Toshio Shimada, Xu Li, Julie L. Zilles, Eberhard Morgenroth, Lutgarde Raskin

Department of Civil and Environmental Engineering: Faculty Publications

The effects of the antimicrobial tylosin on a methanogenic microbial community were studied in a glucosefed laboratory-scale anaerobic sequencing batch reactor (ASBR) exposed to stepwise increases of tylosin (0, 1.67, and 167 mg/L). The microbial community structure was determined using quantitative fluorescence in situ hybridization (FISH) and phylogenetic analyses of bacterial 16S ribosomal RNA (rRNA) gene clone libraries of biomass samples. During the periods without tylosin addition and with an influent tylosin concentration of 1.67 mg/L, 16S rRNA gene sequences related to Syntrophobacter were detected and the relative abundance of Methanosaeta species was high. During the highest tylosin dose of …

Estimating Dilemma Zone Hazard Function At High Speed Isolated Intersection, Anuj Sharma, Darcy Bullock, Srinivas Peeta

Anuj Sharma Publications

The traditional surrogate measures of safety (like number of vehicles in dilemma zone) fail to quantify the risk of crash. Traffic conflict has been proposed as an improved surrogate measure of safety for operations at isolated intersections to quantify the risk. This paper develops a dilemma zone hazard function estimating procedure to obtain the probability of traffic conflict occurring. This approach is an extension of the current approach of dilemma zone boundaries to determine the risk of traffic conflict for an individual vehicle in the case of a dilemma zone incursion. Field data collected from the intersection of SR37 and …

Quantitative Comparison And Modeling Of Urban Storm Water Mass Loadings In The City Of Lincoln, Nebraska, Patrick R. Hartman

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The main goal of this study is to monitor, and then compare results related to the water quality and mass loadings of several constituents at two sites in Lincoln, Nebraska. Differences in water quality were assessed using matched-pair t-tests. Mass loadings were examined using cumulative mass plots, and a predictive model for total suspended solids (TSS) was developed at both sites using real-time data obtained from a USGS data probe. Statistical comparison tests were conducted on the collected water quality data to detect differences based on sample type (auto vs. grab) and sample location (Taylor Park vs. Colonial Hills) for …

Wim Based Live Load Model For Bridge Reliability, Marek Kozikowski

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Development of a valid live load model is essential for assessment of serviceability and safety of highway bridges. The current HL-93 load model is based on the Ontario truck measurements performed in 1975. Since that time truck loads have changed significantly. Therefore, the goal of this study is to analyze 2005-2007 Weigh-In-Motion (WIM) data and develop a new statistical live load model.

The analyzed WIM data includes 47,000,000 records obtained from different states. A special program was developed to calculate the maximum live load effect. Comparison of the old and new truck data showed that on average Ontario trucks are …

Live Load Models For Long Span Bridges, Marta Lutomirska

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

In the doctoral dissertation a live load model for long span structures was derived. The live load model is valid for spans between 600 ft and 5000 ft and it is intended to reflect current traffic patterns, quantities of trucks and their weights. The live load models available were developed for short and medium span bridges. Those models were not appropriate for long span bridges due to different types of structure and critical traffic patterns. Live load on long spans depends on traffic mix. One heavily overloaded truck does not have significant influence. Moreover, the continuous increase in the number …

Precast Post-Tensioned Segmental Pole System: U.S. Patent No. Us 6,851,231 B2, Maher K. Tadros, E. Terence Foster, Sherif A. Yehia, Audra L. Hansen

Department of Civil and Environmental Engineering: Faculty Publications

A precast post-tensioned segmental pole system capable of supporting a load is provided. The pole system includes a plurality of pole segments that use connectors and strands to anchor them together. The strands extend within a cavity formed in the pole segments and are external to the wall structure of the pole segments. The strands may be coupled between both of the pole segments, or be anchored to a connector. The connector includes an upper piece that is coupled to one pole segment, and a lower piece that is coupled to the other pole segment. Upper and lower pieces interlock …

Risk Mitigation For Highway And Railway Bridges, Andrzej S. Nowak, Marek Kozikowski,, Marta Lutomirska,

Mid-America Transportation Center: Final Reports and Technical Briefs

Performance of the transportation network strongly depends on the performance of bridges. Bridges constitute a vital part of the transportation infrastructure system and they are vulnerable to extreme events such as natural disasters (i.e., hurricanes, earthquakes, floods, major storms), as well as hazards stemming from negligence and improper maintenance, collisions (vessels and vehicles), intentional acts of vandalism, and terrorist attacks. These structures must be protected but the current approach to risk is not rational. Therefore, the objective of this project is to develop efficient risk analysis procedures for assessment of the actual safety reserve in highway and railway bridges. The …

Computer Aided Modeling Of Soil Mix Designs To Predict Characteristics And Properties Of Stabilized Road Bases, Charles W. Berryman Ph.D., Cpc, Wayne Jensen Ph.D., Tim Hensley P.E.

Mid-America Transportation Center: Final Reports and Technical Briefs

Considerable data exists for soils that were tested and documented, both for native properties and properties with pozzolan stabilization. While the data exists there was no database for the Nebraska Department of Roads to retrieve this data for predicting soil properties. The conventional methods used to determine soil properties, such as maximum laboratory density and optimum moisture content, were tedious, labor intensive and time consuming. When soil stabilization is involved, more time and efforts are needed to determine maximum laboratory density, optimum moisture content and optimum pozzolan content. The objective of this project was to develop a computerized model to …

Inspector’S Manual For Mechanically Stabilized Earth Walls, Wayne Jensen Ph.D.

Mid-America Transportation Center: Final Reports and Technical Briefs

The scope of the project is to develop a condition rating system, creation of an inspector's manual to reference during inspection or address any training for inspectors at the district level. The research project will develop a MSE wall condition rating system and incorporate this system into the database being developed and create training and reference manuals

Investigation And Mitigation Of Driver Confusion At Modern Roundabouts, Aemal Khattak, Ram Bishu, Karen Schurr, Gregory Mcknight

Mid-America Transportation Center: Final Reports and Technical Briefs

This research deals with two related issues: investigation and mitigation of roundabout elements that lead to driver confusion, and development of a flexible criteria matrix by which the Nebraska Department of Roads (NDOR) can evaluate arterial intersections to identify good candidates for conversion to roundabouts. The use of modern roundabouts along arterial roadways is relatively new in Nebraska. The first urban arterial roundabout was opened to traffic in June of 2002 at the intersection of 33rd and Sheridan Blvd in the City of Lincoln. Citizens and some professionals were somewhat skeptical of the capability of this roundabout to improve traffic …

Dynamic Evaluation Of New York State’S Aluminum Pedestrian Signal Pole System, Scott K. Rosenbaugh, Ronald K. Faller, Karla A. Lechtenberg, Robert W. Bielenberg, Dean L. Sicking, John D. Reid

Mid-America Transportation Center: Final Reports and Technical Briefs

The New York State Department of Transportation (NYSDOT) mounts pedestrian “hand/man” signals to aluminum

poles and uses frangible transformer bases to allow the system to break away. However, engineers at NYSDOT believed that the material properties of the aluminum poles themselves would allow the pedestrian signal poles to break away without the use of transformer bases. Elimination of the frangible transformer base would result in significant savings.

An aluminum pedestrian signal pole system was erected at the Valmont testing facility and tested with the Valmont- MwRSF/UNL pendulum with crushable nose in accordance with NCHRP Report No. 350 test designation no. …

Effects Of Aggregate Angularity On Mix Design Characteristics And Pavement Performance, Yong-Rak Kim, Leonardo T. Souza

Mid-America Transportation Center: Final Reports and Technical Briefs

This research targeted two primary purposes: to estimate current aggregate angularity test methods and to evaluate current aggregate angularity requirements in the Nebraska asphalt mixture/pavement specification. To meet the first research objective, various aggregate angularity tests were estimated with the same sets of aggregates and were compared by investigating their characteristics on testing repeatability, cost, testing time, workability, and sensitivity of test results. For the second objective, the effect of aggregate angularity on mixture performance was investigated by conducting laboratory performance tests (the uniaxial static creep test and the indirect tensile fracture energy test) of five mixes designed with different …

Steel Box System Monitoring Of N-2 Over I-80 Bridge, Atorod Azizinamini

Mid-America Transportation Center: Final Reports and Technical Briefs

The previously performed market analysis of bridge material in the range of short to medium span length indicates a declining trend for steel girders during the last two decades. The “simple for dead, continuous for live load” is a new method of bridge construction aiming at reducing the steel girder construction expenses and in essence enhancing the steel girders’ competitiveness in the short to medium span length bridges. This method of construction takes the advantage of the simple span construction as well as reduction of the forces in the bridge elements due to the continuous span behavior. The continuity of …

Moisture Sensitivity Of Hot Mix Asphalt (Hma) Mixtures In Nebraska – Phase Ii, Yong-Rak Kim, Hoki Ban, Ingryd Pinto

Mid-America Transportation Center: Final Reports and Technical Briefs

As a consequential effort to the previous NDOR research project (P564) on moisture damage, this report presents outcomes from this project incorporated with the previous project. Performance changes and fundamental material characteristics associated with moisture damage due to various anti-stripping additives in asphalt mixtures are studied through various experimental approaches and a numerical simulation. Three additives (i.e., one reference additive, hydrated lime, and two alternative additives: fly ash and cement) are investigated by adding them into two types of mixes (SP2 for low-traffic-volume roadways and SP5 for high-traffic-volume roadways) where two different asphalt binders (PG 64-22 for the SP2 mix …

Use Of Ground Penetrating Radar For Construction Quality Assurance Of Concrete Pavement, George Morcous Ph.D., Ece Erdogmus

Mid-America Transportation Center: Final Reports and Technical Briefs

Extracting concrete cores is the most common method for measuring the thickness of concrete pavement for construction quality control. Although this method provides a relatively accurate thickness measurement, it is destructive, labor intensive, and time consuming. Moreover, concrete cores are usually taken approximately every 750 ft, which may be inadequate for estimating the actual thickness profile of a pavement section; however extracting more cores would damage the pavement extensively and increase the labor cost and time excessively. Ground Penetrating Radar (GPR) is a well-established technique for subsurface exploration. Recently, GPR has been used for several transportation applications, such as measuring …

Application Of Ultra-High Performance Concrete To Bridge Girders, Maher K. Tadros Ph.D., P.E., George Morcous Ph.D.

Mid-America Transportation Center: Final Reports and Technical Briefs

Ultra-High Performance Concrete (UHPC) is a new class of concrete that has superior performance characteristics compared to conventional concrete. The enhanced strength and durability properties of UHPC are mainly due to optimized particle gradation that produces a very tightly packed mix, extremely low water to powder ratio, and use of steel fibers. The unique strength and durability properties of UHPC make it an attractive material for precast prestressed bridge girder construction. However, commercial UHPC mixes currently available in the US market cost about 10 times the cost of conventional concrete mixes, in addition to the need for special mixing and …

Dynamic Evaluation Of A Pinned Anchoring System For New York State’S Temporary Concrete Barriers, Christopher N. Howard, Cale J. Stolle, Karla A. Lechtenberg, Ronald K. Faller, John D. Reid, Dean L. Sicking

Mid-America Transportation Center: Final Reports and Technical Briefs

Temporary concrete barrier (TCB) systems are utilized in many circumstances, including for placement adjacent to vertical dropoffs. Free-standing TCB systems are known to have relatively large deflections when impacted, which may be undesirable when dealing with limited space behind the barrier (as seen on a bridge deck) or limited lane width in front of the barrier system. In order to allow TCB systems to be used in space-restricted locations, a variety of TCB stiffening options have been tested, including beam stiffening and pinning the barriers to the pavement. These pavement-pinning procedures have been considered time-consuming and may pose undue risk …

Effect Of Phase Countdown Timers On Queue Discharge Characteristics Under Heterogeneous Traffic Conditions, Anuj Sharma

Anuj Sharma Publications

Analysis of queue discharge characteristics at signalized intersections is a primary component of traffic signal analysis and design. On the basis of previous studies, mainly conducted in homogeneous traffic conditions, the discharge headway is assumed to be high at the start of green for the first few vehicles, mainly because of start-up lost times, and is also assumed to reach the minimum value by the fourth or fifth vehicle in the queue. The minimum headway is expected to continue until the end of the queue. However, this may not be the case under heterogeneous traffic conditions, such as those in …

Quantitative Rrna-Targeted Solution-Based Hybridization Assay Using Peptide Nucleic Acid Molecular Beacons, Xu Li, Eberhard Morgenroth, Lutgarde Raskin

Department of Civil and Environmental Engineering: Faculty Publications

The potential of a solution-based hybridization assay using peptide nucleic acid (PNA) molecular beacon (MB) probes to quantify 16S rRNA of specific populations in RNA extracts of environmental samples was evaluated by designing PNA MB probes for the genera Dechloromonas and Dechlorosoma. In a kinetic study with 16S rRNA from pure cultures, the hybridization of PNA MB to target 16S rRNA exhibited a higher final hybridization signal and a lower apparent rate constant than the hybridizations to nontarget 16S rRNAs. A concentration of 10 mM NaCl in the hybridization buffer was found to be optimal for maximizing the difference between …

Application Of The Modified Log-Wake Law In Open-Channels, Junke Guo, Pierre Y. Julien

Department of Civil and Environmental Engineering: Faculty Publications

The modified log-wake law, which was developed for turbulent boundary layers and pipe flows, is extended to turbulent flows in open-channels. Turbulent velocity profiles in open-channels can be approximated with three components: (1) the law of the wall that results from the constant bed shear stress; (2) the law of the wake that reflects the effects of gravity, secondary currents and bed roughness; and (3) the cubic correction near the maximum velocity. A procedure to determine the four model parameters from velocity measurements while keeping κ = 0.41 is presented. The modified log-wake law compares very well with experimental data …

Implementing Scc Technology In Nebraska—All About Working Together, Mark D. Lafferty

Department of Civil and Environmental Engineering: Faculty Publications

In October 2001, Concrete Industries, Inc. (CI) was working with its admixture supplier to improve our form finish for precast concrete products. They brought us a new product and before long the concrete slump became a 26‐in. (660‐mm) diameter circle. Obviously, this generated a lot of excitement with our production personnel, but we also had to consider what it would take to get architects and engineers comfortable with using it.

Chemisorption Of Oxygen Onto Activated Carbon Can Enhance The Stability Of Biological Perchlorate Reduction In Fixed Bed Biofilm Reactors, Young Chul Choi, Xu Li, Lutgarde Raskin, Eberhard Morgenroth

Department of Civil and Environmental Engineering: Faculty Publications

Fixed bed biofilm reactors with granular activated carbon (GAC) or glass beads as support media were used to evaluate the influence of short-term (12 h) and long-term (23 days) increases of influent dissolved oxygen (DO) concentrations on biological perchlorate removal. The goal was to evaluate the extent by which chemisorption of oxygen to GAC can enhance the stability of biological perchlorate reduction. Baseline influent concentrations were 50 μg/L of perchlorate, 2 mg/L of acetate as C, and 1 mg/L of DO. Perchlorate removal in the glass bead reactor seized immediately after increasing influent DO concentrations from 1 to 4 mg/L …

Investigation Of Asphalt Pavement Analyzer Testing Program In Nebraska, Minki Hong, Yong-Rak Kim

Mid-America Transportation Center: Final Reports and Technical Briefs

The asphalt pavement analyzer (APA) has been widely used to evaluate hot-mix asphalt (HMA) rutting potential in mix design and quality control – quality assurance (QC-QA) applications, because the APA testing and its data analyses are relatively simple, rapid, and easy. However, as demonstrated in many studies and also experienced by the state of Nebraska, the APA testing is in question due to its high testing variability and a lack of sufficient correlation with actual filed performance. The primary objective of this research was to find critical materials and/or mixture design factors affecting APA test results so as to eventually …

Dynamic Impact Testing Of Crt Wood Posts In A Rigid Sleeve, Steven W. Arens, Ronald K. Faller, John R. Rohde, Karla A. Polivka

Mid-America Transportation Center: Final Reports and Technical Briefs

Dynamic impact testing was performed on 152-mm x 203-mm (6-in. x 8-in.) CRT wood posts placed in a rigid sleeve at various angles. A total of nine bogie tests were performed with three tests each at 0, 90, and 45 degree rotation angles relative to the strong axis of bending. For each bogie test, the raw acceleration data was obtained from accelerometers and was filtered. Then, force-displacement and energy-displacement graphs were plotted. Based on the results, the properties and strengths of the CRT wood posts at the different impact angles were determined. The results of this study will be the …

Pavement Quality Indicators Study, Wayne Jensen Ph.D., Cody Kluver

Mid-America Transportation Center: Final Reports and Technical Briefs

The Nebraska Department of Roads (NDOR) conducts annual examinations of the Nebraska’s interstate and federal high-way pavements. During these examinations, numerous indicators of pavement quality are measured directly or are com-piled from parameters recorded by a vehicle passing over the pavement section. Parameters are documented and analyzed for each one-tenth mile segment. A number of pavement sections where innovative features have been incorporated were selected by the NDOR for comparison to nearby conventional pavement sections. This study used data recorded by the NDOR as well as field observations to develop a comparison between two pavement sections, one with innovative fea-tures …

Assimilating Remote Sensing-Based Et Into Swap Model For Improved Estimation Of Hydrological Predictions, Baburao Kamble, Ayse Kilic

Department of Civil and Environmental Engineering: Faculty Publications

An agro-hydrological simulation model is useful for agriculture monitoring and Remote Sensing provides useful information over large area. Combining both information by data assimilation is used in agro-hydrological modeling and predictions, where multiple remotely sensed data, ground measurement data and model forecast routinely combined in operational mapping procedures. Remote sensing cannot observe input parameters of agro-hydrological models directly. A method to estimate input parameters of such model from Remote Sensing using data assimilation has been proposed by Ines [2002] using the SWAP (Soil, Water, Atmosphere and Plant) model. A Genetic Algorithm (GA) loaded stochastic physically based soil-water-atmosphere-plant model (SWAP) was …

Performance Requirements And Evaluation Procedures For Advance Wide Area Detectors, Anuj Sharma, Matthew Harding, Brad Giles, Darcy M. Bullock, James R. Sturdevant, Srinivas Peeta

Department of Civil and Environmental Engineering: Faculty Publications

Dilemma zone protection ideally requires the exact position and speed of all the vehicles approaching the intersection. However, point detectors, typically used to protect vehicle incursion into the dilemma zone, only provide binary information about the presence or absence of a vehicle at a fixed point in space. The information regarding position and speed of the vehicle in subsequent time steps is extrapolated. The extrapolation error increases with the increase in projection time. Wide area detector (WAD) overcomes this drawback by tracking each vehicle at all times until they move out of range. Such a detector has the potential to …

Field Evaluation Of Alternative Real-Time Methods For Estimating Approach Delay At Signalized Intersections, Anuj Sharma, Darcy M. Bullock

Department of Civil and Environmental Engineering: Faculty Publications

Vehicle delay at a signalized intersection is among the widely used performance measures of efficiency at a signalized intersection. The Highway Capacity Manual (HCM) uses this performance measure to report the level of service at a signalized intersection. This performance measure is also used to estimate travel time along the arterials. With the advent of technological advances in the field of vehicle detection, real-time measurement of delay at a signalized intersection has become economically and computationally feasible. This paper compares three emerging techniques for estimating approach delay: an Input Output technique (IO), a Hybrid technique, and the HCM delay equation. …

Buffer Law And Transitional Roughness Effect In Turbulent Open-Channel Flows, Junke Guo, Pierre Y. Julien

Department of Civil and Environmental Engineering: Faculty Publications

A novel and complete velocity profile law is presented for turbulent open channel flows. The law embeds the linear law in the viscous sublayer; the quartic law due to turbulent bursting that must satisfy instantaneous mass conservation, the modified log-wake law in the outer region and the effects of wall roughness. Specifically, an arctangent law smoothly connects the linear law with the log law of the wall. Combining the arctangent law with the modified log-wake law, a continuous velocity profile is proposed for smooth boundary conditions. A complete velocity profile is obtained after subtracting a new roughness function. Finally, the …

Effects Of Aggregates On Properties And Performance Of Mastics And Superpave Hot Mix Asphalt Mixtures, Francisco Aragão

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Superpave, a set of advancements in testing devices and specifications for asphalt binders and mixtures, was limited to address the effects of aggregates. Because aggregates represent around 95% in mass of the asphalt mixtures, it is important to understand how these materials affect properties and performance of such mixtures. This research focus on how different types and contents of aggregates affect properties of mastics and asphalt mixtures, and their performance considering the viscoelastic nature of the asphalt material.

Five different types of aggregates and hydrated lime were used for sample fabrication together with two different binders. Several different tests were …