Engineering Commons^™

Effects Of Warm-Mix Asphalt Additives On Asphalt Mixture Characteristics And Pavement Performance, Jun Zhang

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

The primary objective of this research is to evaluate the feasibility of several WMA mixtures as potential asphalt paving mixtures for Nebraska pavements. To that end, three well-known WMA additives (i.e., Sasobit, Evotherm, and Advera synthetic zeolite) were evaluated. For a more realistic evaluation of the WMA approaches, trial pavement sections of the WMA mixtures and their HMA counterparts were implemented in Antelope County, Nebraska. More than one ton of field-mixed loose mixtures were collected at the time of paving and were transported to the NDOR and UNL laboratories to conduct comprehensive laboratory evaluations and pavement performance predictions of the …

Soil Behavior Under Blast Loading, Jichong An

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

Understanding the behavior of soil under blast loading is very important to engineers in mining, tunneling, and military construction. Due to the very complex structure of a soil mass it is very difficult to describe its constitutive relation, especially when it has different water contents and it is under blast loading conditions. New protective system designs subjected to blast loading need to be proved its validation prior to predict effect of explosive before implementation. Full-scale, buried explosive tests are costly. Finite element simulations play a significant role in the design of protective systems, for example a bottom platform of lightweight …

A Generalized Non-Parametric Approach For Uncertainty Evaluation In Travel Time Prediction Models, Bhaven Naik

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

A core component within Advanced Traveler Information Systems is travel time information because it is easily understood and perceived by travelers. However, the suggested travel time information should be based not only on historical and real-time conditions, but also on forecasted or “unknown” future conditions.

Existing research has focused primarily on developing models that forecast point estimates of the mean travel time that are in close comparison to their respective field values. There has been limited research on any insight into the reliability or uncertainty margin that exists around the forecasted point estimate. As well, these researches have a limitation …

Embedded Radio Frequency Identification Device License Plates For Roadside Use In Nebraska, Dwight L. Mosby Jr

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

The transportation industry has many stakeholders with different needs that work with advanced technologies. Radio Frequency Identification (RFID) is an emerging technology that is used to track inventory and it holds promise for the transportation industry. This research identifies how to evaluate transportation stakeholder requirements for RFID technologies using a tool described as the House of Quality (HOQ). This research investigates RFID’s ability to work in license plates and may provide infrastructure to support identifying RFID enabled commercial vehicles. This research considers variables that affect the performance of a RFID License Plate System that will use a scanner located at …

Characterization And Pollutant Loading Estimation For Highway Runoff In Omaha, Nebraska, Camilo Torres

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

Stormwater from roadways could have negative effects on the environment. Typical highway runoff pollutants include heavy metals, petroleum hydrocarbons, gasoline constituents, PAHs (polyaromatic hydrocarbons), oxygen demanding compounds measured as COD (chemical oxygen demand) and BOD (biochemical oxygen demand), and road salts.

The objectives of this research were: characterize the pollutants in roadway runoff and determine the effectiveness of the existing stormwater BMPs at the study site. To accomplish these objectives, eleven rainfall events were sampled from November 2008 through November 2010.

First flush and composite highway runoff samples were analyzed for heavy metals, anions, nutrients, particulates, BOD, COD, VOCs, and …

Constructability Testing Of Folded Plate Girders, Luke A. Glaser

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

A new steel girder bridge system was developed at the University of Nebraska. The innovative girder design is a box girder folded from a single steel plate that has a trapezoid shape with an opening on the bottom. The girder has application in short span bridges and accelerated construction situations. The structural performance of the girder requires investigation in all stages of a bridge’s lifecycle. This thesis contains descriptions and results from the first two tests from a series of tests developed to evaluate this new girder shape. The objective of these two tests was to investigate the constructability of …

Experimental Investigation Of Folded Plate Girders And Slab Joints Used In Modular Construction, Kyle A. Burner

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

The folded plate girder, a newly proposed bridge girder, is investigated through this thesis. The folded plate girder is cold bent out of a single sheet of steel. The cold bending eliminates the costly and inconsistent shop welds found in traditional girders. The folded plate girder is meant for application in short span bridges. The girder was subjected to an equivalent 75 year lifetime loading to investigate the fatigue performance.

The rebar detail used in the closure region between adjacent slabs has been investigated in the past by the NCHRP 12-68 project. This thesis will proposes a hooked rebar detail …

A Needs Assessment Of Highway Stakeholders Of An At–Grade Highway–Railroad Intersection In Lincoln, Nebraska, Ryan Haas

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

The University of Nebraska-Lincoln has deployed a data collection test bed along a rail

corridor in the City of Lincoln. The test bed spans about 2.5 miles along the corridor

which parallels Cornhusker Highway, with the focus placed on the Adams Street

highway rail grade crossing (HRGC). The test bed currently has some data-collecting

capabilities, but the possibility exists that there is additional data that could be useful to

various users of the rail crossings.

To gauge these possible unmet data needs of highway stakeholders, a needs

assessment was carried out by the author. A comprehensive literature review was done …

Impact Of Bottom Flange Confinement Reinforcement On Performance Of Prestressed Concrete Bridge Girders, Quinton Patzlaff

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

For many years AASHTO provided no recommendation to state DOT’s on bottom flange confinement reinforcement for their bridge superstructures. The 1996 edition of AASHTO Standard Specification for Highway Bridges stated that nominal reinforcement be placed to enclose the prestressing steel from the end of the girder for at least a distance equal to the girder’s height. A few years later the 2004 AASHTO LRFD Bridge Design Specification changed the distance over which the confinement was to be distributed from 1.0h to 1.5h, and gave minimum requirements for the amount of steel to be used, No.3 bars, and their maximum spacing, …

Time-Dependent Scour Depth Under Bridge-Submerged Flow, Yuan Zhai

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

Failure of bridges due to local scour has motivated many investigators to explore the reasons of scouring and to give the prediction of the scour depth. But most scour prediction equations only address non-pressure-flow situations. Little research has been dedicated to another destructive scour, submerged-flow bridge scour (pressure flow scour) which can cause significant damages to bridges when partially or totally submerged during a large flood.

This thesis is specifically focused on the experimental study for time-dependent scour depth under bridge-submerged flow. The experiments were conducted in a self contained re-circulating tilting flume where two uniform sediment sizes and one …

Use Of Passive Samplers To Evaluate Pharmaceutical Fate In Surface Waters, Delshawn L. Brown

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

Emerging contaminants have been of importance in recent water research. Wastewater treatment plants (WWTPs) have proved ineffective at handling present-day antibiotic loads from hospital and municipal sources. Kolpin et al. (2002) performed a study that identified pharmaceuticals in numerous waters downstream from effluent discharge. Though present in trace levels, concern has been raised regarding pharmaceutical persistence in natural environments. In the present study, uptake rates were quantified in the laboratory for 25 pharmaceutical compounds using Polar Organic Chemical Integrative Samplers (POCIS). Twenty new uptake rates were determined for compounds that have no previously reported literature values. POCIS was also used …

Computational And Experimental Characterization Of Bituminous Composites Based On Experimentally Determined Properties Of Constituents, Pravat Karki

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

The stiffness of asphalt concrete mixtures is characterized in terms of the dynamic modulus for designing the thickness of flexible pavements. The dynamic modulus value of asphalt concrete is either determined experimentally or predicted by using empirical, semi-empirical, analytical or computational micromechanics models. This study proposes to use a computational micromechanics model to predict the dynamic modulus of asphalt concrete mixtures based on the experimentally determined properties of the constituents in the heterogeneous microstructure. The model defines asphalt concrete mixtures as the composites of two different homogeneous isotropic components – the viscoelastic fine aggregate matrix phase and the elastic aggregate …

Quantitative Comparison And Modeling Of Urban Storm Water Mass Loadings In The City Of Lincoln, Nebraska, Patrick R. Hartman

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

QUANTITATIVE ANALYSIS AND MODELING OF URBAN STORM WATER MASS LOADINGS IN THE CITY OF LINCOLN, NEBRASKA

Patrick Ryan Hartman, M. S. University of Nebraska, 2010

Advisors: Bruce I. Dvorak, David M Admiraal

The main goal of this study is to monitor, and then compare results related to the water quality and mass loadings of several constituents at two sites in Lincoln, NE. Differences in water quality were assessed using matched-pair t-tests. Mass loadings were examined using cumulative mass plots, and a predictive model for total suspended solids (TSS) was developed at both sites using real-time data obtained from a USGS …