Civil and Environmental Engineering Commons^™

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 …

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 …