Engineering Commons^™

Detection Of Deficiencies And Data Analysis Of Bridge Members With Deep Convolutional Neural Networks, Bennett Jackson

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

Concrete cracks and structural steel corrosion are two of the most common defects in bridges. Quantifying and classifying these defects provide bridge inspectors and engineers with valuable data for assessing deterioration levels. However, the bridge inspection process is typically a subjective, time intensive, and tedious task, as defects can be overlooked or in locations not easily accessible. Previous studies have investigated deep learning-based inspection methods, implementing popular models such as Mask R-CNN and U-Net. The architectures of these models offer certain advantages depending on the required task. This thesis aims to evaluate and compare Mask R-CNN and U-Net regarding their …

Breakaway Luminaire Pole Research, Jacob Conway

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

This document reports the efforts conducted to determine critical parameters and configurations for Manual for Assessing Safety Hardware 2016 (MASH) Test Level 3 (TL-3) compliant breakaway luminaire poles supported by slip bases, including identifying pole configurations with the potential to meet MASH TL-3 as well as recommending critical configurations for full-scale crash testing. A thorough literature review was conducted which included survey results collected from Midwest Pooled Fund state departments of transportation (DOTs), standard plans from state DOT’s, and past luminaire pole testing.

Numerical LS-DYNA models were developed for luminaire poles with 4-bolt slip base utilized by the Utah Department …

Performing Motorized-To-Non-Motorized Crash Analysis Using Multi-Model Lbs Traffic Data Calibrated Through Random Forest Models, Nicholas Aldridge

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

Traditionally, traffic prediction has been an engineering challenge due to insufficient quantities of data. In this thesis, the use of a new type of data called location-based service (LBS) data from StreetLight (StL) and a large database of multi-modal traffic counts are used to infer vehicle, pedestrian, and bicycle volumes on all road segments in Lincoln, Nebraska. Additional land use features are incorporated into the model from the EPA Smart Location Database (EPA-SLD). The use of random forest models provides strong measures of fit for all modes, with R² scores of 0.98 for both the bicycle and pedestrian modes …

Energy Dissipation Optimization For Circular Culverts, Chi Zhang

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

The principal goal of the current research is to develop and improve weir-based energy dissipator designs at the outlets of circular culverts. In the present case, we are interested in full-length weirs and staggered weirs. A review of related literature was completed and reported; a test facility was carefully designed and constructed to collect flow information in a basin downstream of a model broken-back circular culvert; instrumentation was installed to measure discharges, streamwise depths, and velocities. Both full-length and staggered weirs were tested over a range of discharges and tailwaters. The two types of weirs were subjected to two types …

Investigation And Modification Of Single-Post Aluminum Sign Supports For Mash Crashworthiness, Rodrigo Quintero

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

Traffic signs are used to display information to drivers and are one of the most commonly encountered roadside structures. Although they are a vital traffic control device, signs can pose a significant safety risk to errant drivers due to their extensive placement and proximity to the roadway. Therefore, traffic signs and their supports must be designed with crashworthiness in mind to reduce the likelihood of injury in the event of a vehicle impact. Prior to 2009, these systems were evaluated using the crash testing criteria found in the National Cooperative Highway Research Program (NCHRP) Report No. 350 [1]. Currently, they …

Integration Of Environmental Sustainability And Decision Making: Case Studies Of Civil Infrastructure, Sussan Moussavi

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

Sustainable development is important in the planning and design of critical civil infrastructure systems. However, decision making related to these systems currently lacks meaningful sustainability considerations. To fill this gap, this research explores the life cycle impacts of wastewater and energy infrastructure using case studies, life cycle assessment methodologies, and stakeholder discussions. Environmental and economic impacts, which are more commonly quantified, as well as more difficult to quantify societal factors, are explored. The goal of this research is to help inform decision making and facilitate the consideration of the three pillars of sustainability (e.g., economic, environmental, and social) during the …

Adaptation Of Concrete And Timber Bridge Railings For Low-Volume Traffic, Russell Masterson

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

Bridge railings are a safety feature to protect the traveling public by containing and redirecting errant vehicles during run-off-road (ROR) events. Most bridge railing design and evaluation efforts have focused on ROR crashes on high-volume roads. Bridge railings for low-volume roads can be designed for lower impact speeds, so railings designed for high-volume roads are unnecessarily robust for low-volume applications and can be optimized to reduce costs for bridge owners while still providing adequate safety. The aim of this research has been focused on improving the design of two low-volume bridge railing systems for use by the United States Department …

Three-Dimensional Structural Analysis Of Temple 16 And Rosalila At Copan Ruinas, Luis Tuarez

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

Temple 16 is an ancient Maya structure located at the heart of the Copán Ruinas Acropolis in Western Honduras. Temple 16 contains several earlier structures within it that were built on top of each other throughout Copán’s history. One of these earlier structures, Rosalila, is one of the most culturally significant structures within the Acropolis due to its preservation. An intricate series of archeological tunnels have been excavated throughout Temple 16 to allow for its study. However, significant cracking has been observed within Rosalila and several tunnels have experienced partial collapse. This not only poses a life safety issue for …

Safety And Operational Assessment Of Rural Free Right-Turn Ramp Intersections, Jonathon Camenzind

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

Free right-turn (FRT) ramps are alternative right-turn lane designs for intersecting highways. As of 2023, 79 FRT ramps exist at 68 rural highway intersections in Nebraska. FRT ramps may be located on three-legged or four-legged intersections and may be on the minor, the major, or both minor and major approaches of the same intersection.

This research compared the 68 rural FRT intersections to 24 similar non-FRT rural intersections to identify differences in crash frequency and crash rate and tested for statistical significance using a two-sample t-test. Crash data were obtained for the ten- year period of 2010-2019, with a focus …

Sustainable Revitalization Of Asphalt Pavements: An In-Depth Analysis Of Enhancing The Performance Of Asphalt Binder Through The Application Of Rheological And Molecular Dynamics Simulation Techniques, Muhammad Ahmad

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

Vegetable-based oils such as corn and soybean oil have triglycerides and fatty acids that allow them to be considered sustainable and effective recycling agents (RAs) for aged asphalt binder. However, there are concerns about their effect on the recycled asphalt binder's long-term performance, moisture damage resistance, and self-healing characteristics restoration. In this study, crude corn oil (CO) and crude soybean oil (SO) were used as RAs to restore the performance of a reclaimed asphalt binder (RAB) extracted from reclaimed asphalt pavement. The binder extracted from RAB was modified with a neat binder PG64-28 and RAs to restore the high-end performance …

Reducing Infiltration And Inflow In Small Collection Systems: Environmental, Economic, And Other Impacts, Andrew Hansen

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

Wastewater treatment facilities (WWTFs) and the collection systems (CSs) which feed them provide essential services to society by collecting sewage (aka wastewater), biologically treating it, and minimizing risks to human health as well as the impact of waste on the environment. However, as collection systems age, increasing infiltration and inflow (I/I) from groundwater and stormwater can negatively affect the system. I/I is often mitigated to reduce flow and eliminate other negative impacts to the system.

Ten total case studies, seven mechanical water resource recovery facilities (WRRFs) and three lagoon facilities, were examined for the environmental, economic, and other impacts/benefits from …

Assessing The Performance Of High-Rap Mixtures Incorporating Crude Vegetable Oils And An Antioxidant From Mechanical, Environmental, And Economic Perspectives, Nitish R. Bastola

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

Utilization of mixtures with high amounts of reclaimed asphalt pavement (RAP) in the pavement industry is limited because of the adverse effects of aged materials in recycled asphalt materials. To date, numerous approaches have been used to reduce the adversity of RAP in mixtures. One such approach is the use of recycling agents (RAs) from various sources, such as petroleum and bio-oil. However, the current need is to maximize the use of RAP by adopting a sustainable source of RAs. Therefore, this study uses two RAs based on vegetable oils (crude soybean oil and crude corn oil) with high-RAP mixtures …

Behavior Of Completely Automated Evapotranspiration Estimation (Eemetric), Atiqullah Atif

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

Evapotranspiration (ET) is the second-largest component in the water balance equation, globally consuming 70% of the earth’s annual precipitation. Accurate and consistent estimation of ET is essential for ensuring water resources sustainability, proper management, planning, and regulations of water resources. Though a 100% accurate estimation of ET may not be feasible with the current technology, there are proven techniques that give us estimates of ET we can heavily rely on. Mapping Evapotranspiration at High Resolution with Internalized Calibration (METRIC) is a widely used surface energy balance model that produces relatively accurate ET maps utilizing remote sensing data and requires skilled …

Experimental And Numerical Study: Sheet Pile Abutment Systems For Water–Crossing Bridges, Hung Phi Van

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

Sheet piles are geotechnical-structural elements with interlocking edges together that are driven into the ground to deliver soil retention and excavation support. Steel sheet pile walls are widely used for retaining walls, riverbank protection, seawalls, cofferdams, etc. In Nebraska, sheet pile walls prevent scouring and protect backfill for bridge abutment systems. While sheet piling is not designed and applied to resist vertical load, several recent studies attempted to investigate whether sheet piles could be employed for axial load bearing. Many projects from Europe and some in the U.S. have utilized the axial load-bearing capacity of sheet piles in bridge abutment …

Empirical Fragility Functions And Numerical Parametric Study For Buckling Of Steel Grain Bins Under High Wind Loads, Andrew Ruder

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

While rural infrastructure is critical to the agricultural industry, it has been historically more susceptible to damage and slower to recover following natural disasters than its urban and suburban counterparts. This has been made evident most recently by the events of the August 10, 2020, derecho in which rural regions in Iowa were among the hardest hit areas with sustained windspeeds exceeding 120 mph. Among the most frequently damaged structures in this event were corrugated steel grain bins, which farmers and co-ops use to dry and store certain commodities. Unlike most other critical structures, steel grain bins are not designed …

Evaluation Of Swelling Pressure And Shear Strength Of Inorganic Microfiber-Reinforced Bentonite For The Engineered Barrier System, Jose Maria Ferdinand Victoria Calaunan

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

Nowadays, the permanent disposal of high-level radioactive waste materials has been a primary concern in several countries. The deep geological repository, being the preferred disposal method across the globe, utilizes a network of engineered barriers to prevent the radioactive material from spreading throughout the facility and harming the natural environment. Part of this engineered barrier system (EBS) is the buffer material, which essential function is holding the radioactive waste-containing canister in place. However, the potential generation of desiccation cracks in this buffer material is imminent due to the heat emitted from the radioactive waste. Knowing the capability of inorganic fibers …

Measuring Acoustic Nonlinearity Of Elastic Materials Using Thermal Modulation Of Ultrasonic Waves, Bibo Zhong

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

Nonlinear acoustic techniques have been used to determine the nonlinear properties of materials. Existing methods either require complex equipment to measure absolute nonlinear coefficients or can only be used on laboratory-sized specimens. A recently developed thermal modulation method addresses the limitations of existing methods, but further theoretical analysis and validation are required.

In this dissertation, theoretical analyses were first conducted to study the mechanically and thermally induced acoustoelastic effect. Beginning with the wave equation, the relationship of the ultrasonic wave velocity with respect to mechanical strain and the thermal strain was derived in detail. These analyses provided theoretical support for …

Efficiency Of Bank Filtration In The Removal Of Cyanotoxins Under Different Levels Of Nutrients, Luke Walkenhorst

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

Harmful Algal Blooms (HABs) are an increasing concern not only in Nebraska, but across the world. Increasing global temperatures in conjunction with overuse of synthetic fertilizers are leading causes to the increasing frequency and concern of HABs. In the present work, the effectiveness of simulated bank filtration (BF), as an economical water treatment option, to remove cyanotoxins under different levels of nutrients (nitrates and phosphates) was investigated. Vertical flow-through columns pre-acclimated with two levels of nutrients (e.g., nitrate and phosphate—10 vs. 50 mg/L) were exposed to two different levels of cyanotoxins (10 vs. 75 μg/L). Results from the study confirmed …

Data-Driven Prioritization And Empirical Predictions For Bridge Scour In Nebraska, Awgku Ahmad Hashim Awg Bolhasan

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

The effect of scour at the bridge substructure results in an increase in the vulnerability of the overall bridge stability. Previous studies have found that current guidelines are often overly-conservative with respect to scour. This project aims to provide guidance on hydraulic modeling parameters and reasonable scour estimates specific to Nebraska conditions. This will enable engineers to assess bridge sites for scour more precisely for efficient and effective design and countermeasures.

Four sites were surveyed for scour changes between the period of December 9, 2020, to April 20, 2021. At these four sites, overland and bathymetry survey data were collected. …

Evaluation Of An Equivalent Mean Grain Size Diameter To Rationally Predict The Erodibility Of Fine Riverbed Soils In Nebraska, Basil Abualshar

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

The erosion of riverbed soils under the bridges is one of the major reasons that cause bridge closure or failure leading to a significant effect on the local economy. One of the commonly used methods to predict the erosion rate of soils is the excess shear stress method, which is based on two parameters describing the erodibility behavior; the erodibility coefficient and the critical shear stress. On the other hand, studies showed that the mean grain size diameter D₅₀ could be correlated to the erosion resistance of soils, usually for cohesionless soils but not for cohesive soils. It is …

Development Of A Next-Generation Non-Proprietary Portable Concrete Barrier, Riley Ruskamp

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

Portable concrete barriers (PCBs) are segmented barriers made of precast concrete units that are connected by various load-bearing hardware. PCBs are typically used to shield work zones by redirecting errant vehicles upon impact with the barrier system. Most commonly-available PCBs have demonstrated performance issues arising from the sloped face of the barrier, which encourages vehicles to pitch and roll during impact, potentially resulting in vehicle rollover. Concerns also exist regarding the large dynamic deflections exhibited by these systems that can encroach upon the protected work zone or require anchoring to prevent large displacements. In addition to these concerns, the American …

Risk Assessment Of Hazardous Material Transportation For Small And Tribal Communities, Harrison Redepenning

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

By and large transportation of hazardous materials (HazMat) across the US is increasing, with truck transportation as the most common method of transport. Smaller communities (population <5,000) and Native American communities often lack the economic and political influence to quantify the dangers that HazMat incidents present to the immediate and surrounding areas. Lack of such information is an impediment to adequate preparedness in cases of HazMat incidents. This research focuses on assessing the vulnerability of small and tribal communities in Nebraska to the impacts of highway HazMat incidents. This was done by estimating the expected number and type of HazMat incidents per population in each community. Additionally, statistical analysis was conducted on actual HazMat incidents to determine if small and Native American communities experience a higher rate of incidents per population and per HazMat VMT than large and other small communities respectively. For per population, it was found small versus large is statistically significant while Native American versus other small communities was not significant. For per HazMat VMT, neither comparison was found to be statistically significant. In estimated HazMat incidents, actual HazMat incidents per population, and actual HazMat incidents per HazMat VMT, small communities had higher mean values than their large counterparts. Communities on Native American reservation land experienced a higher estimated and lower actual HazMat incident rate per population than other small communities. For actual HazMat incidents per VMT, Native American communities had a higher rate than other small communities.

Advisor: Aemal Khattak

A Physical Model Of Deadmans Run, Quinn Brandt

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

A physical model of Deadmans Run and a pair of railroad bridges was constructed to assess the impacts of the bridges on flood flows. Lower Platte South Natural Resources District is planning a series of improvements to Deadmans Run to improve flood conveyance capacity and remove approximately 500 homes and businesses from the floodplain. The rail bridges are located less than a mile from the confluence of Deadmans Run and Salt Creek, meaning the bridges present a significant bottleneck to the planned improvements. The physical model was used to characterize the drag effects caused by the bridges, which was used …

Experimental And Numerical Analysis Of Soil-Geosynthetic Composite For A Geosynthetic-Reinforced Roadway System, Daniel Robertson

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

The present research conducted tests to evaluate the reinforcing performance of geosynthetics including three geogrids (GG1, GG2, and GG3) and one geotextile (GT) for three different soil types – sand, clay, and red shale. All geosynthetics showed great improvement under the lowest confining pressure. The report concluded that between the Large-Scale Direct Shear test, the Large-Scale Pullout Box, and the FLAC simulation, the three geogrids showed the greatest improvement when conducted with sand. The sand could withstand a much greater normal pressure than either clay or red shale. The biaxial geogrids, GG1 and GG3, had ideal results for lower stress …

Performance Of Concrete With Different Cement Finenesses And Nano-Activators, Brandon Faltin

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

The excessive shrinkage in modern concrete is the result of the construction industry in its quest to complete the job as soon as possible. In order to accomplish this, the fineness of cement was increased significantly in recent decades for a faster rate of strength gain. To combat the cement fineness and reverse the trend of shrinkage, the usage of coarse cements and nanoparticles should be strongly considered. The coarse cement is used to reduce the shrinkage of concrete, while the nanoparticle increases the early strength, alleviating the original concerns of reduced early strength when using coarse cement.

Work in …

Estimation Of Methane Emissions From Beef Cattle Manure In Nebraska, Noe Hernandez

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

The emission of methane from livestock production contributes to climate change. Cattle manure accounts for one-third of the total methane emission over the lifecycle of beef and dairy production and represents an opportunity to lower the environmental footprint of the beef industry. While models have been developed to estimate methane emissions from manure under certain types of manure storage methods, there is a lack of a user-friendly interface that agricultural or environmental engineers can use to estimate the methane emission from manure for specific regions. Therefore, the goal of this study was to build an interface to estimate methane emissions …

Detecting And Evaluating Cracks On Aging Concrete Members With Deep Convolutional Neural Networks, Brendan Barnes

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

Cracks in concrete structures are evaluated through a timely and subjective manual inspection. The location of cracks is often recorded in an inspection report where some cracks are measured. Although measurements or locations may not be necessary for all cracks observed in concrete members, if quantitative data can be gathered in an autonomous way, allowing measurement data to be used in tracking changes in spatial and temporal scales, this quantitative data can provide useful information not yet captured in the manual inspection process. This thesis aims to construct an image-based crack detection and evaluation pipeline that can assist health monitoring …

Application Of Biochar As Beneficial Additive In Concrete, Temirlan Barissov

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

Biochar is a high-carbon solid material produced via thermal decomposition of organic biomass in a low-oxygen environment. Characterized with high water retention properties and high alkalinity, biochar is generally used for soil amendment and fertilization purposes. This study is intended to explore the feasibility of using biochar as a beneficial additive of the most used manmade material, concrete. Literature review revealed several studies where biochar was successfully implemented as an additive in concrete. The beneficial influence of biochar on the mechanical characteristics of concrete is based on nucleation and densification effects. However, the internal microstructure, porosity and chemical composition of …

Modeling Watershed Sensitivity To Climate Change In Systems Affected By Discharge Of Mine Tailings, Johnette C. Shockley

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

For more than a century, a large volume of gold-mining tailings was deposited in Whitewood Creek and the Belle Fourche River, tributaries to the Cheyenne River in western South Dakota. Much of it still remains, and field and historical evidence indicates continued remobilization of tailings-containing alluvium in these bedrock-dominated channels. Both long-term, natural fluctuations in climate and anthropogenically driven changes can impact regional precipitation, temperature, hydrologic patterns, and ecosystem functions. Such changes have the potential to affect both the transport and distribution of arsenic-laden sediments and mechanical erosion that can undermine the stability of channel-bed and overbank material.

This study …

Probabilistic Seismic Vulnerability Assessment Of Freestanding Historic Monuments, Marie E. Wagner

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

Seismic events can cause significant damage to structures, especially to freestanding structures which are not fixed to the ground and are free to rock independently. This thesis will study the response of freestanding statues and monuments to ground motions and develop probabilistic models for overturning, in order to assist in retrofitting and repair efforts. To do this, single and dual block system models were created with a variety of sizes, aspect ratios, and asymmetries, then subjected to several historic ground motions to determine whether they overturn using three-dimensional distinct element analysis as a result of rocking, sliding or twisting in …