Rural areas, which contain approximately 20% of the US population (49 million people) and 80% of the land area in the United States are fundamental to human well-being in both rural and urban areas. Within the United States, rural areas provide unique resources such as the infrastructure for food and bioenergy production as well as the transportation infrastructure from inland urban centers to ports. Despite this, little attention is paid to the unique challenges and opportunities these areas face with respect to building and maintaining civil infrastructure.
In this ten-week summer research program, students will work with faculty and graduate students in the Department of Civil Engineering to conduct research and contribute new knowledge to improve our understanding of how best to address the challenges facing rural environments. Through collaboration with industry partners, students will also be given opportunities to learn how infrastructure challenges are currently being addressed by the civil engineering industry.
Competitive stipend: $4,500
Suite-style room and meal plan
Travel expenses to and from Lincoln
Campus parking and/or bus pass
Full access to the Campus Recreation Center and campus library system
Managed Aquifer Recharge for Wastewater Management and Irrigation Supply.
Managed aquifer recharge (MAR) is a means of storing excess water in the subsurface for future use. In addition to storage benefits, managed recharge may also contribute to improved groundwater quality through in situ treatment of nutrients and organic contaminants during recharge. It can also provide a means for storage, treatment and use of agricultural wastewater for irrigation water supply. While large-scale engineered artificial recharge structures have been constructed in urban areas, little information is available on small farm-scale managed recharge systems. This project will quantify water quality benefits of farm-scale MAR basins, evaluate the potential for broad-scale adoption of low-cost farm-scale recharge, and compare management strategies to maximize recharge and contaminant treatment efficiency.
REU participants will have an opportunity to identify a specific research topic utilizing a farm-scale demonstration site or laboratory column studies. Current work on this project includes investigating the enhancement of insitu treatment from microbial denitrification through the addition of a slowly decomposing carbon source in the subsoil or comparison of passive versus active management strategies on both recharge rate and contaminant removal. Results of this project may increase the potential for adoption of farm-scale MAR, which could transform current agricultural wastewater management practices. The REU student working on this project will interact with students working on the constructed wetland project (described below) as the constructed wetlands could be used as a preliminary treatment step to improve wastewater quality prior to MAR, so as not to negative impact groundwater quality.
Connecting Refuse Truck Fuel Consumption and Tailpipe Emissions to Vehicle and Trip Characteristics
Fuel consumption and emissions are known to be correlated. Fuel consumption is also correlated with characteristics of traffic and roadways. For this project, fuel consumption, emissions, traffic, and roadway data were collected with various on-board sensors for refuse trucks with varying vehicle characteristics. These data will be analyzed through use of multivariate analysis. Results from this analysis should better define the relationship between emissions and fuel consumption in terms of vehicle trip characteristics.
Fuel consumption and emissions are known to be correlated. Fuel consumption is also correlated with characteristics of traffic and roadways. For this project, fuel consumption, emissions, traffic, and roadway data were collected with various on-board sensors for refuse trucks with varying vehicle characteristics. These data will be analyzed in a manner similar to that done by Evans et al (Evans, 1976) through use of multivariate analysis. While simplistic in its nature, the lack of knowledge regarding emissions and fuel consumption characteristics of solid waste collection vehicles suggests beginning with basic efforts to characterize fuel consumption and emissions as a function of vehicle and trip characteristics. The characteristics of interest include the truck specifications as well as vehicle speed, acceleration, distance traveled by functional type of roadway, idling time, stopped time (including idling time), travel time, and number of stops. Results from this analysis should better define the relationship between emissions and fuel consumption in terms of vehicle trip characteristics. It is expected that these results may then be used to help formulate operating strategies to help reduce fuel consumption. Reducing fuel consumption benefits the solid waste collection operator through cost savings and benefits society through reduced emissions.
Yong Rak Kim
Geotechnical and Materials Engineering
Innovative Design for Sustainable Roadway Mixtures Using Crop Residue Bio-Fibers Based on Multiscale Experiment-Simulation Approaches
New materials and mixture systems for civil engineering infrastructure must be developed to improve economics, performance and environmental sustainability. This project will investigate innovative additives for more sustainable bituminous roadways in rural areas. Among several potential additives, we will investigate physical and mechanical properties of bituminous mixtures that are transformed with biofibers.
Biofibers, which are locally available from abundant and inexpensive agricultural crop residues such as corn stover, have been shown to be effective engineering materials by improving reinforcing effects and stabilizing mechanisms within mixtures. The biofiber reinforced mixtures will be evaluated with multiscale experimental measurements and computational model simulations to identify core linkages between mixture component properties and performance and damage characteristics of entire mixtures. This multiscale experimental-computational approach will transform our understanding of the mechanisms of highly complicated mixtures that, in particular, presents inelastic-nonlinear-damage induced behavior. In this project, the REU participants involved will have an option to choose to investigate biofibers through either computational or experimental approaches. The REU participants working on this research project will interact with REU participants focusing on reliability and bridge design, as our focus on innovative materials research can be expanded to structural analysis and design efforts.
Dr. Xu Li
Constructed Wetlands for Agricultural Wastewater Reuse
Significant amounts of water are used in livestock production to cool and wash down animal facilities and remove animal wastes. Alternative water sources, such as storm water runoff from livestock facilities, have the potential to replace fresh water for use in livestock or crop production. Constructed wetlands (CWs) offer a potential means to treat these contaminated runoffs for reuse. Although CWs have been explored to treat urban runoff, a clear understanding of their applications in treating runoff from livestock facilities is lacking, particularly their efficiencies in removing contaminants beyond solids and nutrients (e.g., veterinary antibiotics and antibiotic resistant bacteria).
In this project, the REU participant will work with faculty and graduate student to construct pilot-scale surface flow CWs in a UNL greenhouse. Synthetic wastewater with a composition similar to those found in runoff from livestock facilities will be used as influent to the constructed wetland. Because plants play a vital role in the success of CWs, different plant species will be tested in the project, including cattails (Typha latifolia), a commonly used CW plant species, as well as other indigenous plants. The REU student will initially help the graduate student on maintaining the pilot-scale CWs in the greenhouse. Later in the program, the REU participant will have the flexibility to choose a certain aspect of the project to conduct a more in-depth study: e.g., independently monitoring the water quality in the effluent of the CWs as a function of influent quality or measuring the accumulation of various contaminants in the soil of the CWs over time. The REU participants of this project may closely work with REU student working on the graphene oxide water treatment project, as filtration is also an important mechanism to remove contaminants in CWs.
Dr. Yusong Li
Green storm water management system for rural communities
Although storm water management has traditionally focused only in urban area, increased attention is necessary for rural communities during agricultural development and urbanization. Urbanization results in a significant rise in the volume of storm water runoff due of the increase in impervious surfaces in cities which prevent the storm water from infiltrating the subsurface and reaching the water table. The runoff can also pick up contaminants, such as manure wastes and fertilizers, from the surfaces and eventually enter natural aquatic systems, hence polluting the impacting the ecosystems.
Engineered infiltration systems (EIS) are structures in urban areas that contain porous filtration media for the infiltration of stormwater to reduce the volume of surface runoff. Typically, the design of EIS focuses on the fast infiltration of stormwater, and the removal of contaminants in the stormwater was not always considered. For rural community sustainability, it is important to understand how EIS will promote the removal of contaminants. The research questions of this project include (1) how different porous media will promote contaminant removal in EIS, (2) how the intermittent nature of the storm events will influence contaminant removal in EIS.
Revisiting Reliability for Rural Bridges
: This project involves the development of “smart infrastructure” system(s) that capitalize on past health monitoring successes (e.g. bridges, buildings, pavements, intelligent transportation systems,) to effectively interpret and manipulate Big Data to eliminate bridge failures, increase structure durability, and save lives.
Successful development and deployment of smart infrastructure system(s) will drastically change the way transportation infrastructure is managed and how resources are allocated.In this research project, we will investigate which sensors and sensing systems are appropriate for smart infrastructure, what component and system models need to be developed, and how component and system degradation can be adequately addressed. The research project will incorporate sensor development and deployment and application of statistical and physical models to develop smart infrastructure systems that will be evaluated using laboratory and field testing. Sensor development will focus on producing innovative, advanced, low cost, integrated systems. Statistical models used will focus on development of smarter and faster algorithms that improve upon existing updating and prognosis tools and on enhanced, real-time integration of various data sets. Physical models will be used to predict system responses and the development of advanced, time-dependent constitutive relationships.
In this project, the REU participant will assist with sensor development and deployment and will work with graduate students on the development of models using laboratory and field data. This project specifically addresses rural sustainability by providing a mechanism to reliability understand and quantify rural bridge condition in real time, thereby making those structures last longer and require less raw materials for their repair and replacement. Quantifying performance of raw materials used in the construction rural bridge networks via the development and deployment of the proposed “smart infrastructure” system helps establish how those materials can be more effectively managed and integrated into designs. This work is transformative, because the outcomes of this project will fundamentally change the way bridges, one of the most vital components in our transportation network, have been designed, implemented, assessed and managed. REU participants will be integrated into all aspects of the work, from understanding how models used to predict response under varying loads over varying timeframes are developed and updated to reflect changes in bridge “health,” to being actively involved with laboratory and field investigations of the response of single bridges and groups of bridges to simulated and actual demands.
Dr. John Sangster
Road Diets for Low Volume Roads
A road diet is the process of reducing capacity along a corridor, usually in the form of reducing the number of lanes, to prioritize secondary modes of travel or increase safety. The ongoing project, funded by the Nebraska Department of Roads (NDOR), includes case study analysis of three locations within NE where two-lane rural highways expand to four lanes as they pass through a town (population less than 12,000).
In these rural locations the four-lane section provides more capacity than is necessary, but creates a safety concern as left-turning vehicles are without a refuge area, and must wait to make their turn while sitting in a through lane. Restriping of the roadways can provide the needed refuge in the form of a two-way left turn lane, but rural residents are often hesitant to accept a reduction in roadway lanes, particularly given the need to pass high levels of truck traffic on rural highways, as well as the occasional farm combine traveling through town. The existing project includes traffic data collection and simulation to determine the anticipated impacts of a lane reduction on travel time.
The REU participant will work closely with the faculty and the graduate student conducting the study to extend and expand the analysis to incorporate additional concerns not currently included in the scope of work. Example expansions might include: assessing the effect of including commercial and residential driveways within the simulation; analyzing the size and frequency of traffic gaps with and without the road diet; and examining best practices for modeling two-way left turn lanes in traffic simulation environments. The initial work of the REU participant will be to conduct literature review on road diets, and to train on industry-standard traffic analysis software (Synchro and VISSIM) being used for the project. Literature review will focus on the limitations of what has yet been investigated regarding road diets, as well as the limitations of the analysis performed by the software applications used.
The REU participant will then play a key role in determining which extension analysis to pursue, and will work closely with the faculty and graduate student to perform the analysis. In addition to daily interaction with faculty and graduate students, REU participants within the transportation area will work in tandem, collaborating and reviewing each other’s ideas and work throughout the day.
Dr. John Sangster
Behavior of Drivers Newly Encountering Roundabouts.
Description: Single-lane roundabouts provide significant safety benefits over signalized intersections, and in low volume conditions, also provide significant travel time improvements. However, there is a hesitation to embrace this type of facility as a default option, especially by rural communities who do not yet have them. By understanding more about the ways in which driver behavior change as a population becomes more experienced with roundabouts, policy and decision makers can better prepare these communities with expectations on what will happen, and will be more successful at broadening the reach of this safe and efficient design.
When roundabouts are first installed, some percentage of drivers initially change their route to avoid it. Among drivers that do use the roundabout, some are hesitant to enter the circulating lane, and the capacity is significantly reduced until drivers are more familiar with the use of the facility. Although it is difficult to schedule a research study to coincide with the construction of a roundabout in an area previously devoid of them, there exists a site in Lincoln, NE where one is in close proximity to a high school parking lot, which would allow researchers to analyze how the behavior of new drivers in a roundabout differs from average (experienced) drivers. This pilot study seeks to develop analysis methods to assess driver behavior entering a roundabout. The capacity of an approach to a roundabout is controlled by the conflicting circulating flow passing by the entrance, with calculations using parameters of follow-up headway and gap acceptance to determine how many vehicles per hour are likely to be able to pass through. The initial work of the REU participant will be to conduct literature review on roundabout capacity, follow-up headway, and gap acceptance. The REU participant would then work in conjunction with the faculty advisor to design an experiment to collect data on driver behavior at the roundabout location. The pilot study would include preliminary analysis of behavior for average drivers, providing proof of concept for the data collection and reduction method proposed. In addition to the daily interaction with faculty and graduate students, REU participants within the transportation area will work in tandem, collaborating and reviewing each other’s ideas and work throughout the day
Dr. John Sangster
Safety Versus Access on Rural Highways
Median-divided rural highways have intersections with minor roads that are two-way stop controlled throughout the less populated areas of Nebraska. These crossings of a high-speed road with a low-volume crossing street pose severe safety concerns, as drivers pulling out sometimes misjudge the time available for their maneuver, leading to the types of automobile accidents with the worst outcomes.
This pilot study proposes to examine the potential for replacing the standard intersection design at these locations with a restricted crossing u-turn facility, prohibiting left- and through-movements from the side road, and providing a u-turn location downstream from the main crossing.
The initial work of the REU participant will be to conduct literature review on the geometric design of restricted crossing u-turns, as well as the safety and operational impacts of implementing this design. Of particular interest will be the median size required to implement this design, which will have the most significant impact on the cost effectiveness of this solution at a given location. A case study analysis of Highway 2 between Lincoln and Nebraska City within the state of Nebraska will be done, assessing the number of locations were this solution might be implemented. Peak hour traffic counts will be conducted for a single exemplary location, and industry-standard traffic simulation software (VISSIM) will be used to assess the operational impacts of implementing this design. The Highway Safety Manual procedures will be used to assess crash impact factors as a measure of potential safety improvements.
The REU participant will work with the faculty advisor and graduate students to develop a sample cost estimate per location to implement the proposed design. Ultimately, the goal of the research will be to integrate the operations, safety, and cost information to make recommendations on when to implement restricted crossing u-turn facilities for two-way stop controlled intersections on high-speed rural highways. In addition to the daily interaction with faculty and graduate students, REU participants within the transportation area will work in tandem, collaborating and reviewing each other’s ideas and work throughout the day.
Dr. Joshua Steelman
Revisiting Reliability for Rural Bridges
Service life is a prominent contemporary topic in US bridge management (TRB 2015). Rural settings present distinct service life challenges from those typically addressed at a national scale. Rural bridges are not as susceptible as urban bridges to corrosive deterioration accelerated by de-icing chemicals, but many rural bridges were designed and constructed to support loads of lower magnitude and different configuration than are currently required. Fundamental questions arise regarding whether rural bridges can safely carry vehicles and implements outside the scope of the original design assumptions, and further, what is “safe.
Sustainable management of bridge networks is particularly significant for rural infrastructure, where construction activities become increasingly costly with greater distance from large population centers and associated manufacturing capabilities if a bridge is deemed insufficient and in need of retrofitting or replacement.
This project represents a transformative shift in bridge infrastructure management and rationally extends service life by transitioning toward a performance-based paradigm. Performance-based structural engineering aims to provide appropriate degrees of safety through probabilistic assessment of  structural demands,  the capacity of the structure to resist those demands, and  selected performance objectives (e.g. minor damage / slight permanent deformation vs major damage / incipient collapse).
This project dovetails with the Better Bridges with Big Data project, leveraging data obtained from mining, sensing, and structural health monitoring. Extensive, rich data improves understanding of loads applied to rural structures and the in-situ response of structures to the imposed loads. Loading characteristics for uniquely rural considerations, such as farm equipment and agricultural freight, will be incorporated into an evaluation and decision-making framework, allowing service lives to be extended while maintaining safety and meeting strategic performance objectives. REU participants will be integrated into on-going research (acquisition and processing of data, developing probabilistic models, developing computational structural models, performing reliability analyses, correlating structure and loading parameters to likelihood of performance outcomes).
Participants will also possess autonomy to select particular aspects of the research upon which to focus creative and critically investigative energies, overseen by faculty and graduate mentors.