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CEE @ Nebraska

Department of Civil and Environmental Engineering University of Nebraska–Lincoln Spring/Summer 2020

New College of Engineering building opening in Fall 2022

Page 22 UNL CEE professor Dr. Richard Wood is digitally mapping every millimeter of Robber’s Cave’s 5,000plus square feet, engravings and all.

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For Angelica Solomon, a member of the Winnebago Tribe of Nebraska and a UNL CEE graduate, a sobriquet earned as an infant has served as inspiration.

CONTENTS Letter from the Chair Page 2

Contributors Grace Panther

Shannon Bartelt-Hunt



Richard Wood

Mojdeh A. Pajouh



Xu Li

Ronald Faller



Ebrahim Mohammadi

Jennifer Schmidt-Rasumussen



Christine Wittich

Jinying Zhu



Chungwook Sim

Jiong Hu



Jongwan Eun

Sumit Jagdale


Special Thanks University Communications Troy Fedderson Scott Schrage Craig Chandler

Research: W-Beam Guardrail Systems Page 4 Student Spotlight: Francisco Garcia Page 7 CEE Student Org. News Page 8 Research: Monitoring Concrete Structures Page 10 Research: Gauging Water Quality Across Nebraska Page 12 Education: Playing in the Sand Page 18 Alumni Spotlight: Andres Torres Page 24 Retirement: Dr. Mohamed Dahab Page 25 New Faculty Page 26


Letter from the Chair


reetings from the Department of Civil and Environmental Engineering at the University of Nebraska-Lincoln. Like many institutions, we have had to adjust our teaching and research programs in response to the COVID-19 pandemic, but our department and college continue to grow. We welcomed five new faculty: Grace Panther, Tirthankar Roy, Congrui “Grace” Jin, Mojdeh Asadollahi Pajouh and Hamzeh Haghshenas to our faculty this year. The College of Engineering is embarking on an approximately $150 million project to renovate one building and construct two new buildings, which will be the future home of our departmental offices and many teaching and research labs. This issue of CEE@ Nebraska highlights the work of Ron Faller and the research faculty of Midwest Roadside Safety facility to develop the Midwest Guardrail System; a multidisciplinary study focusing on non-destructive evaluation of deterioration of concrete structures led by Jinying Zhu and Jiong Hu; and development of a citizen science program to collect water quality data across Nebraska. I’m also pleased to highlight the innovative educational programs developed in the department this year, including a new environmental engineering minor and an augmented reality sandbox for use in teaching visualization skills to our students. We are also pleased to bring you profiles of some of our outstanding students and alumni, including Andres Torres, a graduate alumnus of our master’s program who has held a number of leadership positions with Valmont Industries and currently serves as a member of the College of Engineering Advisory Board. We also recognize Mohamed Dahab, who retired from the department in 2019 after 36 years of service.

Dr. Shannon Bartelt-Hunt UNL CEE Chair sbartelt2@unl.edu

I want to thank the alumni, advisory board and friends of the department who have supported us through gifts and generous donations of their time to support our students and faculty. Our department continues to lead Nebraska and the nation in innovations in civil and environmental engineering infrastructure and transportation safety.














Minor in

Environmental Engineering Starting Fall 2020 at UNL CEE According to U.S. News rankings, Environmental Engineering is #3 in best engineering jobs with a median salary of $87,620 in 2018. Environmental engineering jobs are expected to increase by 5% between 2018-2028. Offering a minor in Environmental Engineering was a logical next step in growing the department. The new undergraduate minor in Environmental Engineering was approved by the Office of the Executive Vice Chancellor in winter of 2020.

The minor will be effective with the 2020-2021 academic year and will be offered on both the Omaha and Lincoln campuses. This new minor reflects the growing faculty expertise in the department. Additionally, it will enable the department to better serve our undergraduate students, employers, and external constituents. The primary student learning outcomes of the minor are to provide students with comprehensive exposure

to a broad range of environmental topics and to provide an understanding of the fundamental concepts of environmental engineering, including sustainability; water quality; water and wastewater treatment; air quality; and solid and hazardous waste management. The minor includes 18 hours of courses, including 9 hours of required courses and 9 hours of elective courses.




Guardrail Systems The Midwest Roadside Safety Facility (MwRSF) is a research organization at UNL that houses many faculty, postdoctoral researchers, graduate and undergraduate students from Civil and Environmental Engineering. The following is a research article prepared by MwRSF on the impact of a project they have been conducting for many years.


Article by Ronald Faller, Jennifer Schmidt-Rasmussen, Mojdeh A. Pajouh

or more than 60 years, W-beam guardrail systems have been the most common barrier system used to prevent drivers who run off the road from striking dangerous hazards. Conventional W-beam barriers were developed many years ago when the vehicle fleet was very different than it is today. As such, when these common barriers were crash tested using modern passenger vehicles, such as vans, sport-utility vehicles (SUVs), and pickup trucks, the guardrail systems would often result in vehicle instabilities, or rollover, as well as guardrail ruptures and vehicle penetration through the barrier system. Safety research on W-beam guardrail designs began in the early 1960s when the California Department of Transportation crash tested a W-beam guardrail system. This testing led to the development of a national standard for W-beam guardrail that incorporated a 27-in. top height mounting, 6-ft 3-in. post spacing, and 8-in. offset blocks. Wood offset blocks were used to offset the guardrail away from the front face of the vertical, soil-embedded, support posts, which reduced vehicle contact and snag


on the lower, exposed region of the posts during the impact event. This common guardrail design provided acceptable safety performance for more than 30 years. As the vehicle fleet gradually changed, statistical analysis of W-beam guardrail crashes showed that pickup trucks versus conventional sedans were much more likely to roll over when impacting W-beam guardrail systems. Most full-size pickups and SUVs have a higher center-of-gravity (c.g.) than the standard four-door sedans used in prior full-scale crash testing programs. As a result, W-beam guardrails were unable to safely contain and redirect these higher c.g. vehicles during impacts at a high speed and high angle. Moreover, when additional layers of pavement were applied to a roadway, the effective height of the guardrail was significantly reduced. In order to avoid the need to raise guardrails after every pavement overlay project, transportation agencies needed a barrier design that could accommodate a reasonable reduction in height.

In 2000, the Midwest Roadside Safety Facility (MwRSF), recognized as a global leader in the development of crash-worthy safety structures, and the Midwest Pooled Fund Program, funded by numerous state departments of transportation (DOTs), initiated a comprehensive research study to develop a new guardrail system that would improve performance for higher c.g. vehicles, provide barrier height tolerances, and reduce the potential for W-beam rupture while maintaining acceptable performance for passenger cars. A great deal of effort was devoted to reconfiguring common, strong-post, W-beam guardrail systems by altering several design parameters, such as barrier height, post configuration (i.e., embedment depth), offset block size, and the location of rail splices. After many computer simulations and full-scale vehicle crash testing, a new W-beam guardrail system, called the Midwest Guardrail System (MGS), was developed at the University of Nebraska-Lincoln. The new design incorporated a 31-in. top rail height, 6-ft long guardrail posts with a reduced embedment

depth, increased depth of offset blocks from 8 in. to 12 in., and repositioned guardrail splices from post to midspan locations under the standard post spacing. First, an increased top rail mounting height allowed the barrier to better contain and redirect high c.g. passenger vehicles and allowed some installation height tolerance. Second, an increased offset block

“We believe that states should consider adopting 31-inch guardrail as their standard because these systems exhibit superior performance at little or no additional cost, which is a direct reflection of the 31-inch tall MGS.” - Federal Highway Administration

depth allowed the barrier to perform adequately for small car impacts with reduced snag risk on posts and improved the guardrail’s ability to safely contain and redirect high c.g. passenger vehicles by maintaining a higher rail height as the vehicle deflects the barrier backward. Third, a shifted location of the rail splice moved high, concentrated, bending stresses and shear stresses away from the weakest region of the rail where numerous bolt holes reduce the rail’s cross-sectional area. Finally, a raised rail height also reduced the post embedment by nearly 4 in., which improved post rotation in soil and the W-beam guardrail system’s ability to capture light trucks. Since 2002, numerous fullscale crash tests along with advanced computational simulations have been conducted on the MGS as well as on its many design variations. This new W-beam guardrail system provides increased safety performance



for impacts from higher c.g. vehicles. The MGS offers many variations to accommodate different conditions, including stiffened versions using reduced (half and quarter) post spacings and standard guardrail paired with a 6-in. high concrete curb, as well as installation on slopes, in long span applications to extend across culverts without attachment, connection to culvert structures via top slab, and with omitted posts. These variations are needed where space limitations and drainage considerations, such as culverts, do not allow for the installation of standard MGS with embedded posts. All full-scale vehicle crash tests were successfully performed in accordance with the current national transportation safety hardware standards, including the American Association of State Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (2009 and 2016 Editions), which both require crash testing with light and


heavy passenger vehicles at an impact speed of 62 mph and an impact angle of 25 degrees at the barrier’s most critical impact point. The Midwest Guardrail System has redefined the entire W-beam guardrail industry and comes highly recommended by the Federal Highway Administration: “We believe that States should consider adopting 31-inch guardrail as their standard because these systems exhibit superior performance at little or no additional cost which is a direct reflection of the 31-inch tall MGS.” Over the last 15 years, the MGS has been adopted across the United States and around the world with most state DOTs using the MGS as its standard guardrail system. This selection has been made easy; since, the MGS is a non-proprietary longitudinal barrier system. The MGS uses standard guardrail hardware and can be produced by all guardrail manufacturers.

In 2020, MwRSF researchers continue to work with state DOTs to meet day-to-day needs, improve guardrail systems to adapt to the needs of a changing vehicle fleet, and ensure the safety of the motoring public.

Student Spotlight Francisco Garcia

Transportation Research Board (TRB) Annual Conference 2020

I feel as though my TRB experience benefited me tremendously, especially since I was preparing to give my thesis defense later in the semester.


attended the 99th TRB Annual Conference in Washington DC from January 12th to January 16th to present my research titled: Integration of Artificial Neural Networks in Bridge Load Rating and Case Study Application. Presenting my work was an opportunity for me to get out my office setting and showcase what new developments have been made with my research. In summation, my work is focused on providing load rating engineers with a machine-learningbased tool that can determine whether a bridge needs to be load posted or not. This opportunity benefited me in two ways: practicing speaking about my work in front of an audience as well as receiving critical feedback about our methodology. As a graduate student, most of my time is spent working alone on my project and occasionally checking in with my advisor. Classwork is also mostly independent and not interpersonal. The first task was to create a presentation that would convey my work effectively. The

challenge was to be broad enough to cover the entire project and case study while not being too detailed about every single thing that we did. I think the tasks I performed before leaving for the conference helped me later this semester as I was preparing to defend my thesis. Another benefit from my attendance was to hear feedback as to what I am doing. Fortunately, my advisor and I were reassured that this is an interesting project that has the potential to help our local state agency engineers. In fact, three engineers approached me after the presentation to ask me to send them my presentation and related articles. It was very relieving to see the enthusiasm and support come from people other than my advisor. I was not looking forward to the questions portion of the presentation, however, I think that I answered the questions nearly as well as I could have. Besides my presentation, I attended many other lectern sessions and poster presentations. Many of the presentations were very technically

complicated, however, I engaged with poster presenters by asking them do describe their work. One of the most bizarre presentation topics I heard about is related to how drivers react to direct message signs that have been hacked to display obviously wrong information. The example they used in their surveys was a sign that read: “Construction Zone, Speed Up.” It turns out that a dangerously high number of motorists would follow the directions despite it not making any sense. My TRB experience has benefited me tremendously, especially since I was preparing to give my thesis defense later in the semester. Many engineering students don’t have the opportunity to present in front of peers very often. It’s critical for professionals to be able to stand in front of others and efficiently deliver presentations. I feel like I am still not a great presenter, but with practice and patience, I aspire to be able to give presentations excellently.



Omaha ASCE Stud The Omaha Campus ASCE student chapter strives to provide civil engineering students with the chance to establish connections with other students and engineering professionals, as well as provide opportunities to participate in various informative, social, and service events. I’d like to share a brief overview of some of the activities that our chapter is involved in.

Discover Engineering Days The CEE department has been actively engaged in K-12 outreach activities. Discover Engineering Days is an outreach program that the UNL College of Engineering organizes to introduce middle school students and their teachers to various fields of engineering. CEE faculty and graduate and undergraduate students hosted sessions at DED events in November 2019 and March 2020. More than 200 middle school students from around the state came to the CEE session and learned how civil engineers and environmental engineers can improve the infrastructure for the society through both presentations and hands-on activities. Another outreach activity that the CEE department participated in was the 3rd annual “Introduce a Girl to Engineering Day,” which is an event put on by a consortium of partners in Lincoln. CEE faculty and students hosted a table in the STEM playground where girls in grades 3-12 participated in hands-on activities about structures and water filtration.


One of our biggest endeavors continues to be the concrete canoe competition. For the 2019 competition we decided pay homage to our great state with the creation of the S.S. Cob, the largest lightweight concrete corn cob that has ever been created. Our team traveled to Missouri where we had a great time talking to all the other teams and showing off what Nebraska is made of. We are equally excited about our design this year and are looking forward to unveiling it at the regional competition. Back at home we also have numerous other events to promote student involvement. Our chapter participated in the college’s annual Engineer’s Week activities. This year we hosted an ‘Egg Drop’ competition, where students constructed devices that would protect an egg from breaking when dropped from a certain height. Several of our members also ran an event for E-week outreach. We showed middle schoolers several different types of dams and then had them construct their own out of various materials.


dent Chapter Additionally, our chapter continues to host monthly meetings with professional speakers who have experience in many areas of civil engineering. Our student chapter also maintains a good relationship with the ASCE Nebraska state section. Every year we collaborate with the state section on the ‘Truss Bustin’ event. High schoolers build balsa wood trusses and then bring them to our engineering building on campus. Once there we test how strong their trusses are and show them around the building and give them some insight into what it’s like to be an engineer. We also maintain involvement with the state section through social events with the younger member group, as well as promoting the monthly state section meetings that our members may attend.

CEE Graduate Students Association In November of 2017, I joined the Graduate Student Assembly (GSA) of the University of Nebraska-Lincoln (UNL) as an At-Large member. Before joining GSA, I had never seen 70 graduate students sitting around a table talking about serious issues specific to the graduate student community. There were two familiar faces from the department there, Noelle Mware, who was also a new at-large member of GSA and the other was Rami Ziara, who represented our department at the GSA for 2017-2018. Those of us involved in graduate student leadership decided that we should establish a departmental graduate student leadership organization. In our first meeting, we had a total of seven students. After talking about the visions and goals of the group, we brainstormed ideas about what can be done to improve the quality of our department from the perspective of us as grad students. We also wrote a preliminary constitution for the group to put on the RSOs website and asked the university for an official UNL email for the group. Our first planned activity was a social event that included food and a lot of fun activities, such as individual FIFA matches on Xbox, a charades tournament, and a Just Dance competition. In the summer of 2018, I was elected as the president for the 2018-2019 academic year but the nature of our group was teamwork, and the titles did not matter. Starting in August of 2018, we decided to build on some of the ideas we had from the previous

semester and add some new ideas. We typically held bi-weekly meetings on Tuesdays at 5:00 PM. We created social media accounts for the group on Facebook, Twitter, Instagram, and LinkedIn. We created our group’s webpage and started analyzing the department’s website for finding areas to improve. Our next step was coordinating the orientation for new graduate students of the department and changing the format. We designed it as a small social event with our graduate chair, and we held a panel of current grad students from different disciplines to share their thoughts and experiences in a Q/A format. We took pictures of the new graduate student to update their webpages on the department’s website. Our group inspired other departments of the college of engineering, such as mechanical engineering, to start similar groups for their graduate students. In January of 2019, due to the success of our groups at the departmental level, the college of engineering decided to form a similar group at the college level, calling it the graduate student advisory board (GeSAB) with representatives from each department. Moreover, the UNL GSA asked us to write a “Startup and Standard Operating Procedure” document for all the programs and departments in the university as a reference to follow. Although I am no longer a chapter officer, our group continues to improve the graduate experience of our students in the civil and environmental engineering department. - Shahab Karimifard



Monitoring Concrete Structures

ASR concrete specimens conditioned in an environmental chamber at high humidity and temperature

Multidisciplinary study led by CEE faculty


lkali-silica reaction (ASR) is a chemical reaction that occurs in concrete and can lead to significant deterioration of many concrete structures. Although there has been considerable success towards minimizing the risk of ASR in new construction, diagnosis and evaluation of the extent of existing structures is a major challenge with relevance to the nuclear, transportation, and hydraulic sectors. Jinying Zhu and Jiong Hu, both associate professors in the CEE


Article by Jinying Zhu, Jiong Hu department, have spent the past few years developing novel techniques for non-destructive evaluation of ASR damage in concrete structures, particularly those in nuclear power plants. The faculty at UNL were joined by researchers at the University of South Carolina, University of Alabama, Georgia Institute of Technology, and Idaho National Laboratory in their multidisciplinary study sponsored by the U.S.,Department of Energy.

As part of this project, the team developed non-destructive monitoring techniques using ultrasonic waves and acoustic emission. The techniques were tested on small/medium concrete specimens in the laboratories at the Peter Kiewit Institute and validated on large-scale, realistic specimens at the University of Tennessee at Knoxville under the direction of Oak Ridge National Laboratory in Tennessee. “We have obtained many interesting findings so far,” Zhu said. “Initially

UNL team installed sensors for remote monitoring of large ASR specimens at University of Tennessee at Knoxville (UTK). (Left to right) Nolan Hayes (UTK), Hossein Arian Nejad, Hongbin Sun and Dr. Jinying Zhu

we planned to monitor the ultrasonic wave velocity change in concrete when deterioration develops, since we could measure the velocity with very high resolution. However, we noticed the temperature variation overshadows the effect of material deterioration in velocity measurement. Instead of making correction or compensation for temperature effect, we decided to use the temperature changes to drive the nonlinear response of the concrete material. This is a significant finding in the nonlinear non-destructive evaluation (NDE) field, because it

enables nonlinear NDE on large scale concrete structures.� These findings have recently been published in the Journal of Acoustical Society of American, with many more publications underway. The project involved several CEE graduate students, including Hongbin Sun, Hossein ArianNejad (graduated in 2019), Clayton Malone, and Yalei Tang, who have worked closely with Zhu, Hu, other university collaborators, and national laboratories.

The project has offered a unique opportunity for these students to engage in cutting-edge structural health monitoring research and has formed the basis of their theses and dissertations. As a result of his participation in this research and the novel techniques developed, Hongbin Sun has received an offer from the Oak Ridge National Laboratory to join as a Postdoctoral Fellow when he completes his Ph.D. at UNL.




Water Quality across


Shannon Bartelt-Hunt, professor of civil and environmental engineering, works with citizen scientists to conduct water tests for a program that started in 2018 to track water quality across the state. Text by Troy Fedderson


Photos by Craig Chandler


artelt-Hunt and her research team ask volunteers to test well water or surface water one time in Spring and Fall with a kit provided through the program. The goal is to measure nitrate, nitrite and phosphate in water statewide. Nitrate, nitrite and phosphate are all key components to fertile growing soil, but elevated levels in water can do harm. Elevated nitrates can cause disease in infants and pregnant women, and high levels of phosphorous can damage ecosystems. “The testing is easy and it’s realtime data for our citizen scientists,” Bartelt-Hunt said. “If they show that they’ve got elevated levels, we provide information for helping navigate the options to treat their water.” The data collected by this citizen science network will also be used

in research by Bartelt-Hunt and her partners from the College of Public Health at the University of Nebraska Medical Center and in the College of Information Science and Technology at the University of Nebraska at Omaha.

She and her colleagues have also demonstrated that citizen science is an accurate way to gather data. They published findings in the Journal of Environmental Science and Technology.

“Over time, we want to look at how water quality and adverse health effects — specifically pediatric cancers and birth defects — intersect; and we want to get a baseline of water quality in the state,” said BarteltHunt, who also serves as the Chair of the Department of Civil and Environmental Engineering.

“Citizen science is a powerful tool because it is a way to gather a large amount of data that we may not otherwise get access to and it also helps people feel connected to their communities and to the science.”

In 2018 and 2019, Nebraska citizens in 45 counties gathered 542 well water samples. Overall, 20 percent were found to have elevated nitrate levels. Bartelt-Hunt said the research they’re conducting wouldn’t be possible without the citizen science component.

- Dr. Bartelt-Hunt, Chair of the Department of Civil and Environmental Engineering

Originally published by Nebraska Today


Student Spotlight

A second-generation collegian, Angelica Solomon hopes to use her Nebraska Engineering degree to give back to Nebraska and the Winnebago community.


Solomon Discovers Her ‘Great Voice’ at Nebraska U Text by Troy Fedderson Photos by Craig Chandler


ngelica Solomon, a member of the Winnebago Tribe of Nebraska and a Nebraska Engineering graduate, is inspired by a sobriquet she earned as an infant, propelling her to step up, take on challenges and leadership roles that will extend beyond college. “When I around 3-months-old, I was given the Native American name Ma nè gì waho pì winga, or Great Voice Woman Who Walks This Earth,” Solomon said. “As I was growing up, it made me feel like I really had some big shoes to fill. It felt daunting. But, it led me to the decision to use my voice and advocate for everyone I could — especially fellow Natives.” A transfer from the University of New Mexico, Solomon tapped into that voice through student involvement at the University of Nebraska–Lincoln. Her primary outlet came from serving as president and treasurer with UNITE, a student-led organization for Native Americans. She also joined Lambda Theta Nu, a Latina sorority; worked as a peer mentor with the Office of Academic Success and Intercultural Services; volunteered to serve as a role model through the YWCA’s SMART Girls program; helped families plan house construction through Bluestone Homes, a subsidiary of Ho-Chunk Inc., an economic development company based in Winnebago; and landed an internship with Olsson, a Lincoln-based engineering firm.



The daughter of two college graduates — including her mother, a Husker alumna who earned a psychology degree — Solomon was pushed to seek higher education. That background helped Solomon buck national statistics that show only 17% of Native American students continue their education after high school, compared to 60% of the entire U.S. population. When she walks across the stage during Nebraska commencement exercises on Dec. 21, Solomon will be among the 10% of Native Americans who earn a bachelor’s degree. “This is so important to me because of the statistics,” Solomon said. “While we have the ability to succeed, Natives really don’t go to college. Too many of us don’t have anyone to look up to or someone to push us to earn the degree. “My hope is to use this degree to give back to my tribe — both as a role model to students and as a professional engineer.”


Names — from those given by parents to nicknames earned via adventures with friends — can be weighty things. Her love for the field grew from being challenged by a fifth-grade math teacher and through exposure in high school coursework. It specifically took root following a project in which she used computer-aided design software to design a shed. “That project was when I learned what civil engineering is, and that I loved it,” Solomon said. “From that point on, I’d walk down the street, imagining that I was taking off layers of each building, exploring how it may have been constructed.” A challenging final project two years ago in an Intro to Structures course led by Joshua Steelman cemented Solomon’s desire to seek a civil engineering focus in structural analysis. She has continued to build upon that career foundation in the classroom and professionally, earning the Olsson internship and molding it into a fulltime, post-graduation job.

As an intern, she worked with a professional civil engineering team on nine government projects revolving around bridge design, improvements and replacements. Her contributions include documenting and quantifying materials needed to build five bridge projects, calculating design details from weld sizes to rebar tension specs, and developing a pedestrian bridge concept drawing. She will join Olsson as an assistant bridge engineer in the coming weeks. The new post will include some of her duties as an intern while expanding responsibilities, which will include seeing projects through to completion. Solomon credits her success on campus to the staff of the Office of Academic Success and Intercultural Services; Steelman; Moises Padilla, director of the Nebraska College Preparatory Academy; Amanda Ponce, a former university employee who served as a UNITE adviser and sorority founder; and friends and family.

“I wouldn’t have gotten through college without the relationships I developed on campus, especially those from back in the OASIS lounge space,” Solomon said. “I’d recommend that space to any student who doesn’t have someone to look up to. There are so many amazing people there who challenge you to have tough, but good, conversations.” Post-graduation, Solomon hopes to continue using her voice, expanding her education by eventually seeking a graduate degree, developing professional contacts and expertise, and increasing her interactions with Native American students while fostering relationships within the Winnebago community.

changes unless someone is made to feel uncomfortable. Nothing changes unless we make ourselves uncomfortable.’ “That’s been an inspiration to me through college and will keep driving me in my career. It’s also my motivation for going back home and giving back when I can, helping do a few things that are needed to make some needed changes for my community.”

Troy Fedderson tfedderson@unl.edu

Craig Chandler cchandler2@unl.edu

Originally published by Nebraska Today

“Frank LaMere came to talk to UNITE one time — he has since died, but he was always one who spoke with a big voice for the tribe,” Solomon said. “He was famous for saying, ‘Nothing



Playing Sand in the

Design and Implementation of an Augmented Reality Sandbox for Civil and Environmental Engineering

Article by Grace Panther, Ebrahim Mohammadi, Richard Wood


isualization is a crucial component of engineering. The ability to conceptualize real and imagined spatial relationships, including being able to mentally visualize, organize, manipulate, and reason about these relationships is foundational to most sub-disciplines within the department.

landscape. The augmented reality Sandbox platform consists of three main parts: (1) a depth camera that generates a stream of depth images, (2) a computer that processes the depth image streams, and (3) a projector that projects the topographical contours and colors on a box filled with sculptable sand.

Additionally, it is well documented that well developed spatial skills are a better predictor of success in engineering degree attainment compared to other testing measures, including mathematics. Visualization skills are also malleable, and their development could assist in increasing diversity and retention in engineering. The Sandboxes were adopted to assist instructors in demonstrating threedimensional (3D) constructs in an active, hands-on learning environment.

In addition to topographical maps, the platform can also simulate rainfall and water flows based on

An augmented reality Sandbox is a 3D interactive tool that projects topographical maps using contour lines and colors based on the real-time shape of the special shapeable sand that is designed by the user-designed


“It is well documented that well developed spatial skills are a better predictor of success in engineering degree attainment compared to other testing measures, including mathematics. Visualization skills are also malleable, and their development could assist in increasing diversity and retention in engineering.�

The Sandboxes that were designed for use within the Civil and Environmental Engineering curriculum will allow instructors to create hands-on demonstrations of topographic maps, surveying/geomatics, watersheds, and water resources. Instructors will use the Sandboxes in courses like Geometric Control Systems, Water Resources Engineering, and Water Resources Development. Students in the Geometric Control Systems course demonstrated a significant interest in using the augmented reality Sandbox, gained an understanding how the platform works, and what real-world models can be simulated with the platform. In addition, the augmented reality Sandbox helps them to learn about topographical maps, profiles, and sections that are vastly used in civil engineering-related projects.

I found that it was one of the best and most helpful experiments we had done because by using it we could easily see the contour lines projecting on the sand and also we could move the sand around and create different landforms. I found it extremely interesting and helpful.

- Pooja Rajeev, CIVE 221. (Student)

The augmented sandbox provided students with a hands-on approach to learn about contour lines, gradient, and other topographic subjects in a simplistic and easy to follow manner.

A second sandbox was also created for dedicated use on the Omaha campus to support instructional activities. The Sandboxes have been designed to be portable and can be used in outreach activities in addition to their use with Civil and Environmental Engineering students. For the Spring of 2020, additional exercises were developed and the scope of the lab exercises was planned to be expanded by engaging students in creating a 3D surface with various gradients by interpreting the

provided topographical maps without any real-time projection feedback and then assessing the created 3D surfaces based on real-time feedback. This is done to develop skills in evaluating topographical maps.

designed topography, which expands its application to topics beyond topographical visualizations. In the fall of 2019, the first Sandbox was designed and assembled on the Lincoln campus. The Sandbox was tested with students in the Geometric Control Systems course, where they created a 3D surface that contained regions with different gradients with the assistance of the real-time feedback of the Sandbox. Moreover, the students then assessed the constructed surface qualitatively through developing the profile plots of the selected regions with different and various gradients.

- Dylan Downes, CIVE 221. (Student)



As bits of Robber’s Cave history fade to folklore, the thousands of engravings that crowd its Dakota sandstone walls like graffiti are likewise disintegrating, imperceptibly but inevitably, into miniature dunes at the base of the walls.


Laser scanning leads to 3D rendering of Robber’s Cave Text by Scott Schrage Photos by Craig Chandler A first-of-its-kind project funded by History Nebraska and coordinated by the University of Nebraska–Lincoln’s Richard Wood is preserving those voices by digitally mapping every millimeter of the cave’s 5,000-plus square feet, engravings and all.

Wood and several Nebraska students have produced a 3D rendering of Robber’s Cave using light detection and ranging, or lidar, which fires near-infrared laser beams at a surface, measures the time they need to reflect and return from that surface, then calculates the distance to a given point.

By repeating the process at 92 locations throughout the cave to generate a 3D cloud of points — 3.1 billion of them — Wood’s team has managed to capture each contour of the cave’s uneven terrain, branching tunnels and multi-level architecture.

This is the largest data collection my research group has ever done. - Dr. Richard Wood

These walls can talk — echoing more than a century of visits from those who have carved names and symbols and faces with finger or stick or knife — but some of the distant voices are nearing whispers.



When it dries and shrinks, the surface of the walls becomes brittle. So if you have people down there even just walking by, the shaking of the ground will cause enough friction to just pop it off.

- John Rissetto Preservation Archaeologist History Nebraska

“This is the largest data collection my research group has ever done,” said the assistant professor of civil and environmental engineering, whose team used two portable scanners to map the cave over roughly 30 hours in September. Some aspects and areas proved especially tricky, Wood said. Getting representative averages of the tunnels’ widths entailed digitally chopping them into more-cylindrical sections that could be measured more objectively. Mapping two vertical shafts, one of which acts as a de facto well, required a specialized tripod that lessened the otherwise-extreme angles at which the scanner fired its beams. Scanning a chamber that houses bats meant contending with protective screens and the dim red lights designed to accommodate its nocturnal residents. “It actually was a fun challenge,” said Wood, who got plenty of help from doctoral student Yijun Liao, undergraduate student Dylan Downes


and postdoctoral researcher M. Ebrahim Mohammadi. The resulting 3D rendering will help History Nebraska make the case for adding Robber’s Cave to the National Register of Historic Places, said David Calease, who helps coordinate such efforts for the state agency. To Calease’s knowledge, the Robber’s Cave application ranks as the first to include a detailed digital rendering among its nomination materials. “In most nominations, it’s, ‘We’re going to photograph this, that and the other,’” Calease said. “But with a place like this, it’s very difficult. You can take a picture, but it’s really hard to get that feel and understanding from it. This is such a unique place that we needed to do something different to really capture it.” The scanning also represents a more general effort to digitally preserve the current state of the cave amid the subtle ravages of humidity, temperature and time.

When humidity rises, moisture can work its way between layers of the sandstone, with even slight temperature fluctuations then driving expansion and contraction. Over time, that heaving eventually weakens the bonds among layers and primes the sandstone to flake off. “When it dries and shrinks, the surface of the walls becomes brittle,” said John Rissetto, a preservation archaeologist with History Nebraska. “So if you have people down there even just walking by, the shaking of the ground will cause enough friction to just pop it off. “As (this) continues, it’s going to decrease the depth of the engravings to the point where they’re no longer going to be visible.” Those engravings and other markings help tell the tale of the cave, which began as a naturally occurring but shallow formation that was expanded into a storage cavern in 1869 by the owners of Nebraska’s

first brewing company, Pioneers Brewery. Unconfirmed, often dubious reports boast of historic visitors: an injured Jesse James, slaves escaping to freedom via the Underground Railroad, Chuck Norris. But former owner Ed Scarborough Jr. did treat one of the cave’s tunnels as a shooting range in the 1970s, explaining the bullet holes that pepper its walls. Fraternities, sororities, church groups, literary societies and other organizations did hold initiation ceremonies in the cave. Bands played there. People partied and played craps there. And many left evidence in the form of names, Greek letters, hearts, peace signs or other symbols not fit for print. “A lot of people we talked to in Lincoln said, ‘Oh, yeah, I used to hang out there when I was younger,’ or, ‘I remember visiting with friends of mine,’” Rissetto said of the cave, which remains open for tours. “It

is part of Lincoln’s history among a specific generation.” The sheer number of engravings scrawled into the walls can almost overwhelm the eyes, which Rissetto said should make the digital rendering of Robber’s Cave especially valuable for those looking to unearth more of its history. Making the 3D rendering publicly available online, as the team eventually hopes to do, might also help drive tourism to the site when visiting Lincoln for a Husker football game or staying with relatives during the holidays, Rissetto said. “It’s the same way that the Statue of Liberty and the Eiffel Tower are also in 3D on the web, and people still go to those all the time,” he said. “It’s just another interesting way to entice people to find these places and visit them. It’s part of a supplement, but it’s not a substitute.”

Regardless of the verdict, Rissetto and Calease said History Nebraska hopes to continue collaborating with Wood’s team on future applications and other projects. Rissetto cited Chimney Rock as another Nebraska signature that, bearing the constant brunt of the elements, could benefit from the digital preservation of a lidar scan. The group said it foresees a future in which lidar-based renderings become common components of both National Register nominations and historical documentation more broadly.

Troy Fedderson tfedderson@unl.edu Craig Chandler cchandler2@unl.edu


Alumni Spotlight Andres Torres M.S. Civil Engineering, 2005 UNL CEE

I will never forget my experience as a student especially the trust and support I received from faculty and staff, particularly Dr. Jones, that contributed to making my dreams become a reality.


n 2001, I graduated with a bachelor’s degree in Civil Engineering from the National University of Colombia (Bogota, Colombia) and shortly thereafter made the decision to travel to the United States to learn English. I enrolled in the ESL program at the University of Nebraska-Omaha (UNO) for the Fall 2001 semester. My goal at that time was to learn English and return to Colombia. But in Spring 2002, Dr. Libby Jones offered me a summer job working in the transportation lab with the Intelligent Transportation Systems Van in UNL’s Civil Engineering Department. I accepted the position. My primary responsibility was to conduct traffic studies and collect data, but I may have had more fun driving the van, washing it, and even changing the oil! That summer, I was offered a graduate assistantship with the Civil Engineering Department which allowed me to pursue a Master’s of Science in Engineering at UNL. I completed the degree in Spring 2005.


Soon after graduation, I received a job offer from Valmont Industries (Valley, NE) to serve as a Structural Design Engineer within their International Division. In this role, I designed tubular steel structures manufactured at Valmont’s facilities around the globe. The structures were installed in over 25 countries and used to support transmission and distribution lines, highway lighting, sports lighting, and traffic lights. After receiving my Professional Engineer License in 2008, I enrolled in the MBA program at UNO which I completed in 2013.

while having a minimum visual impact to urban areas.

My role at Valmont has changed and evolved over the years. I have also served as a Project Engineer, Project Manager, and Business Director. I have trained and managed engineers, managed non-technical aspects of projects, and led sales and commercial activities in Latin America. I am currently working with Valmont’s Product Development Team helping to develop disguised structures which will allow cellphone providers to expand wireless network coverage

My studies laid the groundwork for a very interesting and fulfilling career path; one that I never dreamed of while working in the transportation lab during that summer of 2002. I will never forget my experience as a student especially the trust and support I received from faculty and staff, particularly Dr. Jones, that contributed to making my dreams become a reality.

The University of Nebraska not only gave me the technical knowledge that I needed to become an Engineer, but also helped me to develop other important skills in leadership, teamwork, and problem solving, which I use on a daily basis in my work. Starting with English classes, then an Engineering Degree, and finally an MBA, my studies at the University of Nebraska provided me with a solid foundation.

News Dr. Mohamed Dahab Emeritus Professor, UNL CEE

Dr. Dahab taught a wide range of coursework, advised over 30 graduate students, and served as author or co-author on over 40 peer-reviewed journal articles. He will be remembered as a wonderful mentor and advocate, who has positively impacted so many lives.


r. Mohamed Dahab retired from the Department of Civil and Environmental Engineering in summer 2019, after 36 years of dedicated service to the department. He was born and raised in Tripoli, Libya and came to the United States as a young international student. Dr. Dahab earned his B.S. in Civil Engineering from the University of Iowa and his M.S. and Ph.D. degrees in Environmental Engineering from Iowa State University. In 1983, he accepted a position at the University of Nebraska-Lincoln as an Assistant Professor. He was promoted to full professor in 1995 and served as Chair of the Department from 1999 to 2009. Dr. Dahab taught a wide range of coursework, ranging from the required junior-level courses, seniorlevel water/wastewater and solidwaste courses, capstone design, and the graduate-level courses related to biological wastewater treatment. His research and practice interests

are in sustainable systems for environmental and water quality management including biological treatment, nutrient removal, biosolids management, bio-energy recovery, and in the use of natural systems for wastewater treatment. Dr. Dahab has advised over 30 graduate students, and served as the author or co-author on over 40 peer-reviewed journal articles. He has been very active in professional organizations, including in the Nebraska Water Environment Association (serving through all of the officer positions) and then in the Water Environment Federation, culminating in serving as President in 2006-2007. He served on the Nebraska Environmental Quality Council and on the Stockholm International Water Institute Scientific Program Committee. Dr. Dahab has served as faculty advisor to student groups such as Chi Epsilon and ASCE Student Chapter. He was engaged with environmental

engineering programs in Austria, Brazil, Egypt, Hungary, Korea, Libya, Malaysia, MĂŠxico, Saudi Arabia, and Spain. Dr. Dahab is a Fellow in both the American Society of Civil Engineers (ASCE) and the Water Environment Federation (WEF), and is a licensed professional engineer in Iowa and Nebraska. A retirement reception was held for Dr. Dahab in Fall 2019. Many colleagues and former students attended the event. Dr. Dahab plans to spend time traveling and visiting family in his retirement years. He will be remembered as a wonderful mentor and advocate, who has positively impacted so many lives.



Dr. Mojdeh Pajouh Research Assistant Professor Midwest Roadside Safety Facility Dr. Mojdeh Pajouh joined the Department of Civil and Environmental Engineering, Midwest Roadside Safety Facility at the University of Nebraska-Lincoln as a research assistant professor in January 2020. Her research interests include design of crash-worthy transportation infrastructure through computational modeling and full-scale testing, dynamic soil-structure interaction, security engineering, as well as

engineering education. She holds a Ph.D. from Texas A&M University in Geotechnical Engineering, and a M.Sc. in Structural-Earthquake Engineering from Tehran Polytechnic. Prior to her new appointment, Dr. Pajouh worked for the University of Nevada, Las Vegas as assistant professor. She is a registered Professional Engineer in the State of Texas, and a member of Transportation Research Board (TRB) Committee on Geotechnical Site Characterization.

Dr. Hamzeh Haghshenas Research Assistant Professor Dr. Hamzeh Haghshenas joined the Department of Civil and Environmental Engineering at the University of Nebraska-Lincoln (UNL) as a research assistant professor in 2020. Dr. Haghshenas received a B.S. degree in Civil and Environmental Engineering(2006)and the M.S. in Transportation and Highway Design (2011) from Iran, followed by the M.S. in Mechanical Engineering

Dr. Tirthankar Roy

Assistant Professor Water Resources Engineering


Dr. Tirthankar Roy joined the Department of Civil and Environmental Engineering at the University of Nebraska-Lincoln (UNL) in the fall of 2019. He was a Postdoc in the Department of Civil and Environmental Engineering at Princeton University (2017-2019). He holds a Ph.D. in Hydrology from the University of Arizona (2017), an M.Tech. in Civil Engineering from the Indian Institute of Technology Kanpur (2012), and a B.Tech. in

Agricultural Engineering from Bidhan Chandra Krishi Viswavidyalaya, India. During his M.Tech., he received the DAAD Scholarship to work on his thesis at Technische Universität Dresden, Germany. He is an Early Career Committee member at the International Association of Hydrological Sciences (IAHS). His research interests include satellite remote sensing applications in hydrology, hydrologic extremes, catchment hydrology, landatmospheric interactions, statistics and machine learning, water resources management, water and health, and socio-hydrology.

Dr. Congrui Jin Assistant Professor Geotechnical and Materials Engineering Dr. Congrui Jin joined the Department of Civil and Environmental Engineering at the University of Nebraska-Lincoln (UNL) in the spring of 2020. She received her Ph.D. degree in Mechanical Engineering with a minor degree in Applied Mathematics from Cornell University. She was then a postdoctoral fellow at the Department of Civil Engineering at Northwestern University. Prior to joining University of and Applied Mechanics(2017) and a Ph.D. in Geotechnical and Materials Engineering(2018) from UNL. He had been working for Nebraska Department of Transportation (NDOT) as a materials and research engineer before rejoining UNL. Dr. Haghshenas’ research interests include multi-scale/multi-aspect characterization of infrastructure materials, mechanistic analysis and design of pavements, and infrastructure sustainability.


Nebraska-Lincoln, she was an assistant professor at the Department of Mechanical Engineering at State University of New York at Binghamton. Her research contribution is documented in more than 40 peer-reviewed journal publications, two book chapters and one book. Her research interest is in the broad area of theoretical and applied mechanics motivated by practical applications in additively manufactured materials, geological materials, and construction materials used in our infrastructure system.

New Faculty Dr. Grace Panther

Assistant Professor Engineering Education

Dr. Grace Panther joined the Department of Civil and Environmental Engineering as an assistant professor in August 2019. Dr. Panther conducts discipline based educational research in engineering. Her research interests include the role of 3D spatial skills in the development and success of engineering students, inclusivity issues within teamwork, and the knowledge practices of practicing engineers. She completed her B.S. in Environmental Sciences,

M.S. and Ph.D. in Environmental Engineering at Oregon State University. Prior to her new faculty appointment, Dr. Panther worked as a post-doctoral researcher in the Department of Engineering Education at the University of Cincinnati.


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The College of Engineering, Department of Civil and Environmental Engineering

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