Engineering Commons^™

The Impact Of Triclosan On The Spread Of Antibiotic Resistance In The Environment, Daniel E. Carey, Patrick J. Mcnamara

Civil and Environmental Engineering Faculty Research and Publications

Triclosan (TCS) is a commonly used antimicrobial agent that enters wastewater treatment plants (WWTPs) and the environment. An estimated 1.1 × 10⁵ to 4.2 × 10⁵ kg of TCS are discharged from these WWTPs per year in the United States. The abundance of TCS along with its antimicrobial properties have given rise to concern regarding its impact on antibiotic resistance in the environment. The objective of this review is to assess the state of knowledge regarding the impact of TCS on multidrug resistance in environmental settings, including engineered environments such as anaerobic digesters. Pure culture studies are reviewed …

Sustainable Design Of Buildings Using Semantic Bim And Semantic Web Services, Mehrdad Niknam, Saeed Karshenas

Civil and Environmental Engineering Faculty Research and Publications

In response to the growing concerns about climate change and the environment, sustainable design of buildings is increasingly demanded by building owners and users. However, fast evaluation of various design options and identification of the optimized design requires application of design analysis tools such as energy modeling, daylight simulations, and natural ventilation analysis software. Energy analysis requires access to distributed sources of information such as building element material properties provided by designers, mechanical equipment information provided by equipment manufacturers, weather data provided by weather reporting agencies, and energy cost data from energy providers. Gathering energy related information from different sources …

Earthmoving Productivity In Urban Bridge Construction, Seonghoon Kim, Yong Bai

Civil and Environmental Engineering Faculty Research and Publications

Earthmoving operations in urban bridge reconstruction projects are analyzed to identify significant factors that impact relatively low productivity. The research project was conducted in the urban interchange reconstruction of Interstate Highway 235 (I-235) in Des Moines, Iowa. By using observational studies and a statistical analysis method, the factors were identified, including match factor, number of passes, and loading cycle time per bucket. Number of truck, match factor, travel time, and hauling distance were identified as the unique factors for the off-site earthmoving project, while the start time and travel time were significant factors for the on-site project. This research also …

The Impact Of Capsid Proteins On Virus Removal And Inactivation During Water Treatment Processes, Brooke K. Mayer, Yu Yang, Daniel Gerrity, Morteza A. Abbaszadegan

Civil and Environmental Engineering Faculty Research and Publications

This study examined the effect of the amino acid composition of protein capsids on virus inactivation using ultraviolet (UV) irradiation and titanium dioxide photocatalysis, and physical removal via enhanced coagulation using ferric chloride. Although genomic damage is likely more extensive than protein damage for viruses treated using UV, proteins are still substantially degraded. All amino acids demonstrated significant correlations with UV susceptibility. The hydroxyl radicals produced during photocatalysis are considered nonspecific, but they likely cause greater overall damage to virus capsid proteins relative to the genome. Oxidizing chemicals, including hydroxyl radicals, preferentially degrade amino acids over nucleotides, and the amino …

The Role Of Shrinkage Strains Causing Early-Age Cracking In Cast-In-Place Concrete Bridge Decks, Tayyebeh Mohammadi, Baolin Wan, Christopher M. Foley

Civil and Environmental Engineering Faculty Research and Publications

Early-age cracking in cast-in-place reinforced concrete bridge decks is occurring more frequently now than three decades ago and principle factors that lead to early-age deck cracking are not fully understood. A finite element (FE) simulation methodology for assessing the role of shrinkage-induced strains in generating early-age bridge deck cracking is described. The simulations conducted indicate that drying shrinkage appears to be capable of causing transverse (and possibly longitudinal) bridge deck cracks as early as 9 to II days after bridge deck placement. The drying-shrinkage induced stresses would result in transverse cracking over interior pier supports in a typical bridge superstructure …

Introductory Editorial: Water Microbiology, Patrick J. Mcnamara, Mark J. Krzmarzick

Civil and Environmental Engineering Faculty Research and Publications

No abstract provided.

Quantifying Benefits Of Signal Timing Maintenance And Optimization Using Both Travel Time And Travel Time Reliability Measures, Howell Li, Steven M. Lavrenz, Christopher M. Day, Amanda Stevens, Darcy M. Bullock

Lyles School of Civil Engineering Faculty Publications

No abstract provided.

Indicators Of Reservoir Performance, Stefano Galelli

All ECSTATIC Materials

No abstract provided.

National Science Foundation Soil-Bentonite Cutoff Wall Award Abstract, Jeffrey C. Evans, Michael A. Malusis, Robert W. Jacob

NSF Soil-Bentonite Slurry Trench Cutoff Wall Documents

This award abstract describes the purpose of constructing a soil-bentonite cutoff wall as well as the tests that were performed to analyze the performance of the wall.

Creating A National Nonmotorized Traffic Count Archive: Process And Progress, Krista Nordback, Kristin A. Tufte, Morgan Harvey, Nathan Mcneil, Elizabeth Stolz, Jolene Liu

Civil and Environmental Engineering Faculty Publications and Presentations

Robust bicycle and pedestrian data on a national scale would help promote effective planning and engineering of walking and bicycling facilities, build the evidence-based case for funding such projects, and dispel notions that walking and cycling are not occurring. To organize and promote the collection of nonmotorized traffic data, a team of transportation professionals and computer scientists is creating a national bicycle and pedestrian count archive. This archive will enable data sharing by centralizing continuous and short-duration traffic counts in a publicly available online archive. Although other archives exist, this will be the first archive that will be national in …

Flowability And Density Characteristics Of Controlled Low Strength Material (Clsm) Using Native High Plasticity Clay, Anand J. Puppala, Bhaskar Chittoori, Anil Raavi

Civil Engineering Faculty Publications and Presentations

In pipeline construction projects when high plastic clayey soils are encountered in the excavated trench material, they are typically landfilled and better quality materials are imported from outside quarry sources for use as bedding and haunch zone materials. This practice has detrimental environmental and cost impacts; therefore, an efficient reutilization of this high plastic excavated material to produce controlled low strength materials (CLSMs) to use as bedding and haunch zone materials will have major sustainability benefits. As a part of an on-going research study, novel CLSM mix designs were developed by utilizing native high plastic clayey soils from the excavated …

Uncertainty Considerations In Calibration And Validation Of Hydrologic And Water Quality Models, J. Hernandez

Civil Engineering Faculty Publications and Presentations

Hydrologic and water quality models (HWQMs) are increasingly used to support decisions on various environmental issues and policy directions for present and future scenarios, at scales varying from watershed to continental levels. Uncertainty associated with such models may affect the ability of the models to accurately evaluate the response of complex systems, leading to misguided assessments and risk management decisions. Current well-known HWQMs contain numerous input parameters, many of which are not known with certainty, and in other cases model users can hardly recognize the genesis of uncertainty. Uncertainty in data, model structure, and model parameters can propagate throughout model …

Lidar Scanning With Supplementary Uav Captured Images For Structural Inspections, Richard L. Wood, Mohammad Ebrahim Mohammadi

Department of Civil and Environmental Engineering: Faculty Publications

Structural assessment using remote sensing technologies can be performed efficiently and effectively using such technologies as LiDAR (light detection and ranging). LiDAR can be employed for various structural assessments, such as as-built conditions for a newly constructed facility, routine inspection during its service life, or structural collapse evaluation after a natural hazard or extreme event. However, the main disadvantage of LiDAR is that it is a line-of-sight technology that can result in significant occlusions. Architectural or structural components can be partially or fully occluded by another object with respect to the location of the laser scanner. Supplemental photogrammetry techniques, such …

Stethoscope-Based Detection Of Detorqued Bolts Using Impact-Induced Acoustic Emissions, Joe Guarino, Robert Hamilton

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Results of a preliminary study investigating a simple method for detecting looseness in bolted fasteners of a steel structure are presented. Extensive research by many investigators demonstrates that the frequency response of a bolted structural member changes when one or more bolts are loosened. A simple and effective method for detecting looseness can be applied to bolted joints, using inexpensive and commonly-available equipment and software. The difference between spectrograms associated with tight and loose bolts is clearly apparent due to the presence of a tell-tale mode when one or more bolts are loosened. Further, a striking difference can be elucidated …

Interfacial Bond Between Reinforcing Fibers And Calcium Sulfoaluminate Cements: Fiber Pullout Characteristics, Robert B. Jewell, Kamyar C. Mahboub, Thomas L. Robl, Arne C. Bathke

Civil Engineering Faculty Publications

The results of an experimental investigation on the influence of the interfacial bond of reinforcing fibers embedded in a calcium sulfoaluminate matrix on the fiber-pullout peak load and energy consumption are presented. Bonding at the fiber-matrix interface plays an important role in controlling the mechanical performance of cementitious composites—in particular, composites formed from sulfate-based systems (calcium sulfoaluminate [CSA] cements), as opposed to the silicate systems found in portland cement. Various types of fibers were selected, including polyvinyl alcohol (PVA), polypropylene, and copper-coated steel. The fibers were embedded in three different matrixes: two sulfate-based cements including one commercially available CSA cement …

An Investigation Into Bacterial Contamination In An Urban Nebraska Stream Using Microbial Source Tracking, Allison R. Speicher

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

High levels of fecal bacteria in surface waters are a public health concern due to the enteric illnesses caused by primary contact with these waters. Shortcomings in the current fecal indicator bacteria (FIB) monitoring approach and the ubiquity of pathogen-impaired water bodies has led to the development of microbial source tracking (MST), a molecular tool that can identify potential fecal contamination sources. In this study we use a bacterial community based approach examining the V4 region of the 16S rRNA gene to elucidate sources of fecal bacteria in Antelope Creek, an urban creek in Lincoln Nebraska.

We hypothesized that sediment …

First Steps In Developing Cement-Based Batteries To Power Cathodic Protection Of Embedded Steel In Concrete, Niall Holmes, Aimee Byrne, Brian Norton

Articles

This paper presents the first steps in developing innovative cement-based batteries to power cathodic protection in reinforced concrete structures. Initial electrical outputs of 1.55V and 23mA have been found to be sufficient to polarise prescribed corrosion currents of 20mA per m2 of embedded steel. Cathodic protection is a well-developed and powerful technique to limit the effects of steel reinforcement corrosion. However, as it requires an electrical supply day and night, it is often powered by non-environmentally friendly diesel generators or connected to the electrical grid. This paper focuses on increasing the ionic conductivity of the solution in the cement pores, …

Structural Properties Of Concrete Materials Containing Roadcem, Niall Holmes

Articles

This paper presents findings from a preliminary study to assess the structural and material properties of a nonstandard, concrete type mix containing RoadCem, a traditional soil stabilising additive. Two different mixes determined the effect of adding RoadCem in terms of compressive and flexural strengths, breaking strain, thermal expansion and contraction behaviour, permeability using a falling head, and Young’s modulus. RoadCem is a fine powder containing alkali metals and synthetic zeolites which are complemented with a complex activator. RoadCem modifies the dynamics and chemistry of cement hydration by enhancing the crystallisation process and forming longer needle crystalline structures. It reduces the …

Nonlinear Analysis Of Isotropic Slab Bridges Under Extreme Traffic Loading, Donya Hajializadeh, A. Salam Al-Sabah, Eugene J. Obrien, Debra F. Laefer, Bernard Enright

Articles

Probabilistic analysis of traffic loading on a bridge traditionally involves an extrapolation from measured or simulated load effects to a characteristic maximum value. In recent years, Long Run Simulation, whereby thousands of years of traffic are simulated, has allowed researchers to gain new insights into the nature of the traffic scenarios that govern at the limit state. For example, mobile cranes and low-loaders, sometimes accompanied by a common articulated truck, have been shown to govern in most cases. In this paper, the extreme loading scenarios identified in the Long Run Simulation are applied to a non-linear, two-dimensional (2D) plate finite …

Spatial Time-Dependent Reliability Analysis Of Reinforced Concrete Slab Bridges Subject To Realistic Traffic Loading, Donya Hajializadeh, Mark Stewart, Bernard Enright, Eugene J. Obrien

Articles

Resistance and loads are often correlated in time and space. The paper assesses the influence of these correlations on structural reliability/probability of failure for a typical two-lane RC slab bridge under realistic traffic loading. Spatial variables for structural resistance are cover and concrete compressive strength, which in turn affect the strength and chloride-induced corrosion of RC elements. Random variables include pit depth and model error. Correlation of weights between trucks in adjacent lanes and inter-vehicle gaps are also included and are calibrated against Weigh-In-Motion (WIM) data. Reliability analysis of deteriorating bridges needs to incorporate uncertainties associated with parameters governing the …

Identifying And Modelling Permit Trucks For Bridge Loading, Bernard Enright, Eugene J. Obrien, Cathal Leahy

Articles

Accurate estimates of characteristic traffic load effects are essential in order to optimize bridge safety assessment. Permit trucks dominate the extreme upper tail of the truck loading distribution and as a result need careful examination. This paper proposes rules for filtering these trucks from Weigh-In-Motion data for both the US and Europe. The importance of these trucks in critical bridge loading events is then examined for both regions. A Monte Carlo traffic simulation model is developed which focuses on the accurate simulation of permit trucks.

Effects Of Posttensioning Slippage On 2-Way Spanning Concrete Slabs, Niall Holmes, Eoin Byrne

Articles

This paper investigates the effect of improper posttensioning of a 2-way spanning concrete slab subject to a central point load. Due to plate slippage alone, the support conditions only offered a 1-way spanning action which could have led to premature failure with dangerous consequences. Posttensioning can strengthen a flat slab against punching shear by controlling deflections and cracking under service loads compared with traditional punching shear reinforcing methods leading to more slender structures and economic solutions for longer spans. However, if the method is not properly applied, these thinner floor plates can fail in a brittle and sudden manner by …

A Direct Demand Model Of Departure Time And Mode For Intercity Passenger Trips, Fatemeh Nazari, Seyedehsan Seyedabrishami, Amir Reza Mamdoohi

Civil Engineering Faculty Publications and Presentations

Travel demand is well announced as a crucial component of transportation planning. This paper aims to develop a direct demand model, denoting a more acceptable abstraction of reality, for intercity passengers in daily work and leisure trips in Tehran province. The model utilizes combined estimation across the data source, collected in 2011, of travelers originating from the city of Tehran and heading toward two destination clusters: intra-province and inter-province. The paper sketches a way to predict simultaneous choice of departure time and travel mode under the influence of zonal (origin, destination, and residence), individual and household socio-demographic, and trip-related variables. …

A Level-Of-Service Model For Protected Bike Lanes, Nick Foster, Christopher Monsere, Jennifer Dill, Kelly Clifton

Civil and Environmental Engineering Faculty Publications and Presentations

Several methods exist for quantifying the quality of service provided by a roadway from a bicyclist’s perspective; however, many of these models do not consider physically protected bike lanes and, of those that do, none is based on empirical data from the US. This is problematic as engineers, planners, and elected officials are increasingly looking to objective performance measures to help guide transportation project design and funding prioritization decisions. This paper addresses this gap by presenting a cumulative logistic model to predict user comfort on protected bike lanes developed from data collected during in-person video surveys. The surveys were conducted …

Dynamic Ventilation And Power Output Of Urban Bicyclists, Alexander Y. Bigazzi, Miguel A. Figliozzi

Civil and Environmental Engineering Faculty Publications and Presentations

Bicyclist intake of air pollutants is linked to physical exertion levels, ventilation rates, and exposure concentrations. Whereas exposure concentrations have been widely studied in transportation environments, there is relatively scant research linking on-road ventilation with travel conditions and exertion levels. This paper investigates relationships among power output, heart rate, and ventilation rate for urban bicyclists. Heart rate and ventilation rate were measured on-road and combined with power output estimates from a bicycle power model. Dynamic ventilation rates increased by 0.4-0.8% per watt of power output, with a mean lag of 0.8 minutes. The use of physiology (ventilation) monitoring straps and …

Design Of Piles In Liquefied Soils For Combined Inertial And Kinematic Demands, Arash Khosravifar, J. Ugalde, T. Travasarou

Civil and Environmental Engineering Faculty Publications and Presentations

The design of piles penetrating liquefiable soils poses a number of challenges, including 1) accounting for the effects of liquefaction on lateral soil springs (p-y), 2) estimating liquefaction-induced kinematic demands (lateral spreading displacements) including pile-pinning effects, and 3) combining the effects of inertial demands from superstructure and kinematic demands from liquefied ground. This paper illustrates two approaches to address the above questions: A) a simplified decoupled approach adopting equivalent static analysis (ESA), and B) a detailed, coupled approach adopting nonlinear dynamic analyses (NDA). These approaches are presented through example projects showing the limitations and the potential conservatism associated with the …

Is Service-Learning Worth It?: A Mixed-Methods Study Of Faculty’S Service-Learning Experiences, Joan M. Blakey, Shirley Theriot, Mary Cazzell, Melanie L. Sattler

Civil Engineering Faculty Publications

Service-learning benefits students, communities, institutions of higher learning, and faculty. Most studies have focused on the impact of service-learning on students; however, there is a dearth of mixed-methods research examining faculty use of service-learning. Using a two-phase, exploratory, mixed-methods design, the purpose of this study was to understand the factors that influenced 24 faculty fellows’ engagement with service-learning. The qualitative component examined four faculty’s in-depth experiences with service-learning to understand the meaning they assigned to those experiences and to identify key themes that affected engagement. The quantitative phase of the study explored the extent to which 20 additional faculty fellows’ …

Counting And Classification Of Highway Vehicles By Regression Analysis, Mingpei Liang, Xinyu Huang, Chung-Hao Chen, Alade Tokuta

Electrical & Computer Engineering Faculty Publications

In this paper, we describe a novel algorithm that counts and classifies highway vehicles based on regression analysis. This algorithm requires no explicit segmentation or tracking of individual vehicles, which is usually an important part of many existing algorithms. Therefore, this algorithm is particularly useful when there are severe occlusions or vehicle resolution is low, in which extracted features are highly unreliable. There are mainly two contributions in our proposed algorithm. First, a warping method is developed to detect the foreground segments that contain unclassified vehicles. The common used modeling and tracking (e.g., Kalman filtering) of individual vehicles are not …