Transportation Engineering Commons^™

Optfill: A Tool For Infeasible Cycle-Free Gapfilling Of Stoichiometric Metabolic Models, Wheaton L. Schroeder, Rajib Saha

Mid-America Transportation Center: Final Reports and Technical Briefs

Stoichiometric metabolic modeling, particularly genome-scale models (GSMs), is now an indispens- able tool for systems biology. The model reconstruction process typically involves collecting informa- tion from public databases; however, incomplete systems knowledge leaves gaps in any reconstruc- tion. Current tools for addressing gaps use databases of biochemical functionalities to address gaps on a per-metabolite basis and can provide multiple solutions but cannot avoid thermodynami- cally infeasible cycles (TICs), invariably requiring lengthy manual curation. To address these limita- tions, this work introduces an optimization-based multi-step method named OptFill, which performs TIC-avoiding whole-model gapfilling. We applied OptFill to three fictional prokaryotic models …

Calibrating The Highway Capacity Manual Arterial Travel Time Reliability Model, Ernest Tufuor, Laurence Rilett, Li Zhao

Mid-America Transportation Center: Final Reports and Technical Briefs

The latest edition of the Highway Capacity Manual (HCM-6) includes, for the first time, a methodology for estimating and predicting the average travel time distribution (TTD) of urban streets. Travel time reliability (TTR) metrics can then be estimated from the TTD. The HCM-6 explicitly considers five key sources of travel time variability. A literature search showed no evidence that the HCM-6 TTR model has ever been calibrated with empirical travel time data. More importantly, previous research showed that the HCM-6 underestimated the empirical TTD variability by 70% on a testbed in Lincoln, Nebraska. In other words, the HCM-6 TTR metrics …

Analysis Of Component Errors In The Highway Capacity Manual Travel Time Reliability Estimations For Urban Streets, Ernest Tufuor, Laurence Rilett

Mid-America Transportation Center: Final Reports and Technical Briefs

The Highway Capacity Manual 6th edition (HCM6) includes a new methodology to estimate and predict the distribution of average travel times (TTD) for urban streets. The TTD can then be used to estimate travel time reliability (TTR) metrics. Previous research on a 0.5-mi testbed showed statistically significant differences between the HCM6 estimated TTD and the corresponding empirical TTD. The difference in average travel time was 4 s that, while statistically significant, is not important from a practical perspective. More importantly, the TTD variance was underestimated by 70%. In other words, the HCM6 results reflected a more reliable testbed than field …

An Integrated Computational And Experimental Study To Investigate Staphylococcus Aureus Metabolism, Mohammad Mazharul Islam, Vinai C. Thomas, Matthew Van Beek, Jong-Sam Ahn, Abdulelah A. Alqarzaee, Chunyi Zhou, Paul D. Fey, Kenneth W. Bayles, Rajib Saha

Mid-America Transportation Center: Final Reports and Technical Briefs

Staphylococcus aureus is a metabolically versatile pathogen that colonizes nearly all organs of the human body. A detailed and comprehensive knowledge of staphylococcal metabolism is essential to understand its pathogenesis. To this end, we have reconstructed and experimentally validated an updated and enhanced genome-scale metabolic model of S. aureus USA300_FPR3757. The model combined genome annotation data, reaction stoichiometry, and regulation information from biochemical databases and previous strain-specific models. Reactions in the model were checked and fixed to ensure chemical balance and thermodynamic consistency. To further refine the model, growth assessment of 1920 nonessential mutants from the Nebraska Transposon Mutant Library …

Development Of An Ndt Tool For In-Situ Assessment Of Prestress Loss, Bibo Zhong, Jinying Zhu, George Morcous

Nebraska Department of Transportation: Research Reports

The research objective is to develop a non-destructive testing (NDT) method to evaluate the prestress loss in prestressed concrete bridge girders using ultrasonic waves. The work principle is based on acoustoelastic effect - ultrasonic wave velocity varies with stress level in prestressed concrete. A self-reference test setup was proposed to measure wave velocity in two orthogonal directions (prestress and unstressed directions) in the girder. This setup will be able to reduce effects of material variation and temperature change.

The concept was first validated on small concrete specimens (cylinders and beams) in laboratory. A signal analysis algorithm was developed to reliably …

Corrigendum To “Heavy Metal Ion Detection On A Microspot Electrode Using An Optical Electrochemical Probe” [Electrochem. Commun. 86 (2018) 94–98], Santanu Roy, Abhijeet Prasad, Rahul Tevatia, Ravi Saraf

Mid-America Transportation Center: Final Reports and Technical Briefs

The authors regret to inform an error. Ravi F. Saraf of this pub- lication discloses financial interest in Vajra Instrument as its founder and President. In accordance with its Conflict of Interest policy, the University of Nebraska-Lincoln’s Conflict of Interest in Research Committee has determined that this must be disclosed. The authors would like to apologise for any inconvenience caused.

Feasibility Study Of Development Of Ultra-High Performance Concrete (Uhpc) For Highway Bridge Applications In Nebraska, Flavia Ribeiro Furtado De Mendonca, Mostafa Abo El-Khier, George Morcous, Jiong Hu

Nebraska Department of Transportation: Research Reports

Ultra-high performance concrete (UHPC) is a new class of concrete that has superior mechanical, durability, and workability properties that far exceed those of conventional concrete. To achieve these properties, a specific mix design with a very dense internal structure, fiber reinforcement, and low water-to-binder ratio (w/b) is commonly used. The goal of this research is to develop a non-proprietary UHPC mix with constituent materials that are readily available in the state of Nebraska for bridge construction applications. In developing this mix, the particle packing model is used, and an experimental study of the impact of various design parameters on the …

Evaluation Of Tie-Bar Anchoring Methods: Non-Shrink Grout Vs. Epoxy, Wally Heyen, Lieska Halsey, Tim Krason, Brandon Varilek, David Hansen

Nebraska Department of Transportation: Research Reports

Tie bars are epoxy coated steel bars that connect the longitudinal joints in concrete pavement. Tie bars prevent faulting and joint separation between lanes Tie bars can be placed into the plastic concrete or inserted after curing by drilling and anchoring with epoxy or non-shrink grout. The specification for the tie bars requires the use of a No. 5 bar, 18 inches long and shall meet ASTM A775 / A775M [1], Section 1020.The Nebraska Department of Transportation “Standard Specifications for Highway Construction,” (Section 603.03) requires contractors to mechanically insert tie bars into the face of pavements during construction. Tie bars …

Influence Of Curing Conditions On Concrete Specimens (Cylinders) In Hot And Cold Weather In The Field, Wally Heyen, Lieska Halsey, Tim Krason, David Hansen

Nebraska Department of Transportation: Research Reports

No abstract provided.

The Covid-19 Pandemic And Transportation Engineering, Chris Hendrickson,, Laurence Rilett

Department of Civil and Environmental Engineering: Faculty Publications

The COVID-19 pandemic has been an enormous global disruption with immense economic, environmental, and social impacts throughout the world. Only world wars and the flu pandemic of 1918 are comparable in the wide range of consequences, including fatalities, over a relatively short period of time. Unfortunately, we can expect other major disruptions to occur in the future. In this editorial, we intend to discern some lessons for the transportation engineering profession that can be learned from the current catastrophe that can help us prepare for future disruptions. We will ignore nontransportation aspects of the pandemic such as the development of …

Wastewater Treatment Fatty Acids For Biodiesel Production, Zachary Christman

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Wastewater scum is the thick oily substance that floats on top of the primary and secondary tanks within a wastewater treatment plant. Scum has a 30% to 60% lipid content making it an excellent resource for the biodiesel industry. Also the use of scum would reduce the cost of current management practices such as landfill disposal or incineration. In this article there is an overview of lipid byproducts currently being produced at wastewater treatment plants today. This is followed by a presentation showing a full length process for turning wastewater scum into biodiesel raw material.

Remediating Soil For Successful Vegetation Establishment Along Nebraska Highways, Shad Mills, Martha Mamo, Walt Schacht, Humberto Blanco-Canqui

Nebraska Department of Transportation: Research Reports

Vegetation along roadsides is important to prevent soil erosion, provide habitat, and filter water running off the road. Vegetation close to the pavement along highways in Nebraska does not readily establish and persist. It is thought that the sodium and bulk density are the driving factors behind the lack of vegetation. After a construction project the shoulder is seeded into the compacted soil, and during winter salts can accumulate in the soil because of deicing agents being used. The purpose of our study was to determine if the sodium and bulk density are the driving factors of the vegetation cover. …

Establishment Of Wildflower Islands To Enhance Roadside Health And Aesthetics, Walter Schacht, Judy Wu-Smart

Nebraska Department of Transportation: Research Reports

Wildflowers are crucial in the ecological function of the low-input roadside plant communities in terms of water andnutrient cycling, nutrient inputs such as nitrogen, total plant canopy cover, stand longevity, and provision of habitat for numerous small animals. Further, wildflowers provide critical foraging and nesting resources for birds, insects, and other wildlife. Unfortunately, habitat loss from agricultural and urban development has led to rapid population declines in wild bees and other pollinators across the US, thereby jeopardizing not only food production but also the sustainability of our natural landscapes (Kearns & Inouye, 1997). One way to mitigate wild bee decline …

Evaluation Of Reducing Cement Content In Ndor Class R Combined Aggregate Gradations, Miras Mamirov, Jiong Hu, Yong-Rak Kim

Nebraska Department of Transportation: Research Reports

The main objective of this research project was to achieve a cement reduction on Nebraska slip-form pavement concrete through aggregate particle packing optimization. A literature review was conducted to examine different aggregate optimization tools, quality control tests, and historical data of Nebraska Department of Transportation (NDOT) pavement mixtures. It was found that the Modified Toufar Model has good potential in optimizing particle packing and predicting packing degrees. The combined aggregate void content test was found to be useful to experimentally justify optimized aggregate gradations. The Box Test with a modified index and image analysis tool for surface void estimation was …

Long-Term Performance Evaluation Of Nudeck In Kearney East Bypass, George Morcous, Marc Maguire

Nebraska Department of Transportation: Research Reports

The Kearney East Bypass bridge is the first project that implements the newly developed precast concrete deck system (known as 2nd generation NUDECK). The new system consists of full-depth full-width precast prestressed concrete deck panels that are 12 ft (3.66 m) long each. The panels have covered shear pockets at 4 ft (1.22 m) spacing on each girder line to host clustered shear connectors that are adjustable in height. Narrow unreinforced transverse joints are used to eliminate the need for deck overlay. Also, deck panels are post-tensioned in the longitudinal direction using a new post-tensioning system that eliminates the need …

Standard Design For Nebraska County Bridges, Chungwook Sim, Jiong Hu, Maher K. Tadros, Alexander Bleyhl, David Gee

Nebraska Department of Transportation: Research Reports

Many county-owned bridges in Nebraska need replacement due to their structural deficiency. Most of the bridges needing replacement are in the 40 to 60 ft range. This span range lacks a standard design that fits Nebraska county practices in terms of speed and simplicity of construction. The current systems being used are (a) Precast 1 by 2 ft planks which can span up to 30 ft, (b) Cast-in-place slab bridges which can span up to 50 ft but require extensive field formwork, concrete placing, and curing, and are best when constructed in three-span units, and (c) Inverted tees which can …

Precast Concrete Deck-To-Girder Connection Using Uhpc, George Morcous, Mostafa Abo El-Khier

Nebraska Department of Transportation: Research Reports

The implementation of ultra-high-performance concrete (UHPC) in bridge construction has been growing rapidly in the last two decades due to its excellent mechanical properties, workability, and durability. This report presents a new UHPC connection between precast concrete deck panels and bridge girders that eliminates changes to the design and production of girder shear connectors commonly used in conventional cast-in-place concrete deck construction. In conventional construction, girder shear reinforcement or studs are extended into the cast-in-place concrete deck to transfer interface shear and create composite section. In the new connection, girder shear reinforcement or studs are kept underneath the deck panels, …

Development Of High-Performance Rapid Patching Materials For Pavement Repair, Gholami Shayan, Jiong Hu, Yong-Rak Kim

Nebraska Department of Transportation: Research Reports

Concrete pavements exhibiting severe distresses which require patching are commonly observed in the concrete pavement in Nebraska. Due to the requirements of opening pavement to traffic after placing the rapid patching materials, it is essential for that concrete to achieve high early strength. To ensure this, a high cement content and chloride-based accelerators are currently used in the Nebraska Department of Transportation (NDOT) Portland cement-based rapid-patching materials. Besides its associated high cost, high cement content tends to result in a less stable mix with high shrinkage, high heat of hydration, and high cracking potential. In addition, using chloride-based accelerators has …

Condition Assessment Of Bridge Decks With Asphalt Overlay, Sepehr Pashoutani, Jinying Zhu

Nebraska Department of Transportation: Research Reports

Ground penetrating RADAR (GPR) is a widely used nondestructive testing (NDT) method for bridge deck evaluation. However, the current GPR signal and data processing software and algorithms are not able to provide comprehensive information about bridge deck condition. Although the original objective of this research project was to develop GPR analysis algorithms for condition assessment of bridge decks with asphalt overlay, the scope of work has been expanded to concrete bridge decks with or without overlays.

In this study, the research team developed a complete GPR analysis procedure that includes the following components: 1) obtain zero-time for GPR reflection at …

The Application Of Gray-Scale Level-Set Method In Segmentation Of Concrete Deck Delamination Using Infrared Images, Chongsheng Cheng, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Conventional nondestructive delamination detection of concrete pavements through thermography is often based on temperature contrasts between delaminated and sound areas. Non-uniform backgrounds caused by the environmental conditions are often challenging for contrast-based methods to robustly differentiate the delaminated areas from the sound areas. Instead of focusing on the temperature contrast, this study proposes a temperature gradient-based level set method (LSM) to detect boundaries for delamination segmentations. A modified edge indicator function is developed to represent the normalized temperature gradient of a thermal image. The experimental study was conducted to evaluate its applicability and stability for boundary detection in terms of …

Investigation Of Dsr Test Methods To Determine Binder Low Temperature Properties, Kommidi Santosh, Yong-Rak Kim

Nebraska Department of Transportation: Research Reports

The low temperature rheology of bituminous binders is of great interest because low temperature cracking is one of the primary asphalt pavement failure modes observed in cold-climate places such as Nebraska. Low temperature binder characterization/grading has been primarily conducted using the bending beam rheometer (BBR), while the dynamic shear rheometer (DSR) can alternatively be used to characterize the low temperature properties of binders with the recent advancement of DSR equipment that can cover a wide range of testing temperatures. This study investigates alternative testing-analysis methods using the DSR to determine low temperature asphalt binder properties that have been measured by …

Performance Evaluation Of Inverted Tee (It) Bridge System, Garrett P. Martindale, Daniel Watson, Antony Mohsen Kamal Masoud Kodsy, Mostafa Abo El-Khier, Richard L. Wood, George Morcous

Nebraska Department of Transportation: Research Reports

The Inverted Tee (IT) girder bridge system was originally developed in 1996 by the University of Nebraska–Lincoln (UNL) researchers and Nebraska Department of Transportation (NDOT) engineers. This bridge system currently accounts for over 110 bridges in Nebraska used for both state highways and local county roads. Extensive longitudinal and transverse deck cracking have been observed and noted in numerous bridge inspection reports. Since the IT girder bridge system is relatively new, limited data and knowledge exist on its structural performance and behavior. This study evaluates the IT girder bridge system by conducting twenty field observations as well as recording accelerometer, …

Biomethane Production From Distillery Wastewater, Zachary Christman

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Distillery wastewater treatment is a great ecological problem, for example, India produces 2.7 billion liters of alcohol that results in 40 billion liters of wastewater. However, this material can be seen as a resource since 11 million cubic meters of biogas at 60% methane could be produced in addition to cleaning the water. The distillery has two options of what to do with the biogas. The first is to use the biogas to fuel the distillery making the production plant more energy efficient and removing some of the need to buy natural gas. The other is to upgrade the biogas …

Restricted Crossings On Rural Highways, John Sangster, Tim Adams

Nebraska Department of Transportation: Research Reports

This study examines the potential for replacing the standard intersection design at two-way stop control (TWSC) and all- way stop control (AWSC) intersections along rural highways with a roundabout or a restricted crossing u-turn (RCUT) facility. The geometry of the RCUT design prohibits left and through movements from the side road, and provides a u-turn location downstream from the main crossing. This type of facility has been implemented for rural highways extensively in both Maryland and North Carolina, as well as in limited cases in many other states such as Minnesota and Missouri, with the potential to serve as a …

Assessing The Impact Of Game Day Schedule And Opponents On Travel Patterns And Route Choice Using Big Data Analytics, Anuj Sharma, Vesal Ahsani

Nebraska Department of Transportation: Research Reports

The transportation system is crucial for transferring people and goods from point A to point B. However, its reliability can be decreased by unanticipated congestion resulting from planned special events. For example, sporting events collect large crowds of people at specific venues on game days and disrupt normal traffic patterns.

The goal of this study was to understand issues related to road traffic management during major sporting events by using widely available INRIX data to compare travel patterns and behaviors on game days against those on normal days. A comprehensive analysis was conducted on the impact of all Nebraska Cornhuskers …

Asphalt Binder Laboratory Short-Term Aging, Hamzeh Haghshenas, Robert C. Rea

Nebraska Department of Transportation: Research Reports

The Rolling Thin Film Oven (RTFO) is widely used to simulate asphalt binder short-term aging. However, there is a general interest to improve the current short-term aging protocol especially for reducing the aging time. Besides, there are some doubts about the capability of RTFO in the simulation of aging of highly polymer modified asphalt binders which is mainly due to improper dispersion of such binders in the bottles during rotating and creeping of highly viscous binder out of the bottles during rotation. This work addresses the effect of time, temperature, airflow rate, and weight of asphalt binder on the laboratory …

Restricted Crossing U-Turns At Rural Intersections, Timothy Adams

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

This study examines the potential for replacing the standard intersection design at two-way stop control (TWSC) and all-way stop control (AWSC) intersections along rural highways with a roundabout or a restricted crossing u-turn (RCUT) facility. The geometry of the RCUT design prohibits left and through movements from the side road, and provides a u-turn location downstream from the main crossing. This type of facility has been implemented for rural highways extensively in other states and has the potential to serve as a cost-effective solution to improve roadway safety within Nebraska.

Comparative analysis is conducted for three site locations (Humphrey, Madison, …

Unl-Cc Outdoor Education Center Master Plan, Marie Wagner

Honors Program: Senior Projects (Public)

The following report contains the work done by the group Griswold Engineering in completion of the Senior Design requirements for Civil Engineering and the Honors Requirements of the Project Manager. As the project manager, my job was to organize the project as a whole and to work alongside the Structural Engineer on the project. One of the main problems to overcome was the division of labor amongst the group. The project was originally conceived as a group project with one project manager and five other students to serve as the project engineers in each subdiscipline. Since this group only had …

Civil Engineering Design Of Cornhusker Council's Outdoor Education Center, Kelly Weiler

Honors Program: Senior Projects (Public)

A team of geotechnical, structural, hydraulic, environmental, and transportation experts collaborated to provide engineering solutions to the Cornhusker Council in an effort to solve the current problems facing their Outdoor Education Center. This results of this project provided the structural design of three bridges on the property, transportation plans for two parking lots and roadway design, geotechnical recommendations for soil testing and erosion prevention, and an environmental and hydraulic analysis of the property. A major challenge in the design of this project is the consideration of the dangers and regulations that accompany the floodway and floodplain regions on site. Various …

34-Inch Tall Three Beam Transition To Concrete Buttress, Scott Rosenbaugh, Wyatt Fallet, Ronald K. Faller, Robert W. Bielenberg, Jennifer Schmidt

Nebraska Department of Transportation: Research Reports

Roadway resurfacing and overlay projects effectively reduce the height of roadside barriers placed adjacent to the roadway, which can negatively affect their crashworthiness. More recently, bridge rails and concrete barriers have been installed with slightly increased heights to account for future overlays. However, adjacent guardrails and approach transitions have not yet been modified to account for overlays. The objective of this project was to develop an increased-height, approach guardrail transition (AGT) to be crashworthy both before and after roadway overlays of up to 3 in. (76 mm).

A 34-in. (864-mm) tall, thrie beam transition was designed such that the system …