Civil and Environmental Engineering Commons^™

Dynamic Properties Of Railway Track And Its Components : A State-Of-The-Art Review, Sakdirat Kaewunruen, Alexander Remennikov

Faculty of Engineering - Papers (Archive)

Recent findings indicate one of major causes of damages, which is attributed to the resonant behaviours, in a railway track and its components. Basically, when a railway track is excited to generalised dynamic loading, the railway track deforms and then vibrates for certain duration. Dynamic responses of the railway track and its components are the key to evaluate the structural capacity of railway track and its components. If a dynamic loading resonates the railway track’s dynamic responses, its components tend to have the significant damage from excessive dynamic stresses. For example, a rail vibration could lead to defects in rails …

Impact Of Fire-Through And Misfire In Rectifier Valves On A Turbine Generator Neighboring To A Hvdc Inverter Station, Ming-Te Liang

Journal of Marine Science and Technology

The major purpose of this paper is the theoretical elucidation of the corrosion tube growth mechanism of mild steel occurred from the effect of pH value and oxygen corrosion at elevated pressure provided by Riggs et al. [6]. Based on the Nernst-Planck equation, continuity principle, Green's theorem, Stokes's theorem and the equation of Newton's second law of motion, the mechanism of corrosion tube development can be explained theoretically. The Bernoulli sum is contant at any cross-section of tubular corrosion product. The implication of the present results are theoretically enhanced the formation of corrosion tube mechanism.

Theoretical Elucidation On The Corrosion Tube Growth Mechanism Of Mild Steel In The Effect Of Ph On Oxygen Corrosion At Elevated Pressures, Ming-Te Liang

Journal of Marine Science and Technology

The major purpose of this paper is the theoretical elucidation of the corrosion tube growth mechanism of mild steel occurred from the effect of pH value and oxygen corrosion at elevated pressure provided by Riggs et al. [6]. Based on the Nernst-Planck equation, continuity principle, Green's theorem, Stokes's theorem and the equation of Newton's second law of motion, the mechanism of corrosion tube development can be explained theoretically. The Bernoulli sum is contant at any cross-section of tubular corrosion product. The implication of the present results are theoretically enhanced the formation of corrosion tube mechanism.

Assessment Of Ground Shaking In Ilan County, Taiwan, Hui-Mi Hsu, Sao-Jeng Chao, Howard Hwang

Journal of Marine Science and Technology

This paper presents an estimation of ground shaking intensity in the Ilan area caused by two scenario earthquakes. On the basis of seismic activity in the study area, the seismic zones, including Okinawa trough seismic zone section A and Suao-Hualien offshore seismic zone are established. The earthquakes occurring in these two zones are considered as the scenario earthquakes. The hundreds of boring logs are also collected and classified into three site classes as specified in the Taiwan Seismic Building Code. The intensity of ground shaking in the Ilan area caused by a scenario earthquake is then estimated by using an …

The Study Of Price Accept Threshold For The ??Lue Highway??Tour Of The North-East Region In Taiwan, Hung-Yen Chou, Jin-Long Lu, Chiang Fu

Journal of Marine Science and Technology

The “Blue Highway” in the NE region of Taiwan includes the tour itineraries of Keelung-Suao, Suao-Hualien and Keelung-Hualien, each with its individual oceanic scenic features and its potential corresponding onshore scenic spots. This study explores the relationship between the “Blue Highway” tour portfolios and price attributes to collect the preference recognition of the public concerning the NE region “Blue Highway” tour itineraries and prices with the stated preference method. The utility function of the discrete choice model assumes the impact effect among attributes to be in a linear relationship plus percentages. The price threshold model improves the assumption of this …

Case Study Of Wind-Resistant Design And Analysis Of High Mast Structures Based On Different Wind Codes, Ching-Wen Chien, Jing-Jong Jang

Journal of Marine Science and Technology

The high mast structure (HMS) has the characters of light weight and high cost efficiency. Therefore, it is widely used in the modern construction industry. It has a large the ratio of height (H) to least horizontal dimension (D) that makes it a particularly more slender and wind-sensitive than any other structures. Therefore, the purpose of this research is to develop the wind-resistant design (WRD) procedure for the slender, tapered support structures of HMS subjected to wind-induced excitation from vortex shedding and gust buffeting. This paper illustrates the theoretical basis and the analytical development of the WRD; including calculating gust …

The Manpower Supply Planning And Shift Setting For Mass Rapid Transit Carriage Maintenance In Short-Term Operations, Shangyao Yan, Chia-Hung Chen, Miawjane Chen

Journal of Marine Science and Technology

An effective carriage maintenance plan cannot only reduce the mass rapid transit system operating costs, but is also directly related to its safety and schedule punctuality. Traditionally, the arrangement of the carriage maintenance manpower supply has been based on staff experience, and has been performed manually following simple rules. This is not only time-consuming but often ineffective. Therefore, in this research, we incorporate flexible management strategies, different combinations of principles, and the related operating constraints, to develop a basic carriage maintenance manpower supply plan model. Furthermore, we construct an integrated model by modifying the basic model, which can help an …

Dynamic Design Guidelines For Prestressed Concrete Sleepers, Alexander Remennikov, Martin H. Murray, Sakdirat Kaewunruen

Faculty of Engineering - Papers (Archive)

Current design philosophy, outlined in AS 1085.14, is based on the analysis of permissible stresses resulting from quasi-static wheel loads and essentially the static response of concrete sleepers. In general, cracking can incur when the bottom fibre stress is larger than tensile strength of concrete. Premature cracking of prestressed concrete sleepers has been detected in railway tracks. The major cause of cracking is the infrequent but high-magnitude wheel loads produced by a small percentage of “out-of-round” wheels or railhead surface defects, which are crudely accounted for in AS 1085.14 by a single load factor. Based on the current design method, …

Evaluación Probabilística De La Amenaza Sísmica Regional Para Tunja, Gladys Patricia Molina Molina

Ingeniería Civil

El presente trabajo contiene la evaluación probabilística de la amenaza sísmica para la Ciudad de Tunja, que está ubicada en la cordillera Oriental colombiana a los 05º32’07” de latitud Norte y 73º22’04” de longitud oeste. Tunja se encuentra en un área propensa a la actividad sísmica; en la zona se desarrollan varios sistemas de fallas activas. Según datos históricos, en los últimos 500 años la sismicidad de Tunja y su área cercana ha sido destacada. Esta investigación se desarrolló siguiendo los procedimientos de Hanks y Cornell (1994) que permite estimar las aceleraciones pico esperadas para periodos de retorno de 475, …

Development Of High Performance Precast/Prestressed Bridge Girders, Amin K. Akhnoukh

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

Demand continues to increase for bridges with long spans and shallow depths. Due to safety concerns, four-span overpasses are being replaced with two span overpasses to avoid placement of piers near the highway shoulders. In the meantime, the bridge profile is restricted due to existing businesses nearby. Thus, nearly the same superstructure depth must be used for double the span length. This dissertation focuses on topics aiming at providing precast prestressed concrete girders with the shallowest possible depth for a given span. It forms parts of larger projects conducted by the University of Nebraska for the Nebraska Department of Roads …

Assessing Water Quality Modeling In Subtropical Regions Based On A Case Study Of The Aguamilpa Reservoir, Oliver Obregon

Theses and Dissertations

The shortage of water in Mexico has made public and private institutions look at reservoirs as an alternative solution for present and future water supply. However, eighty percent of the existing reservoirs in Mexico are contaminated at some level, many severely. Water quality models are water-management tools used to diagnose water quality problems and the impact of various environmental conditions. They can be effective in assessing various measures of remediation leading to improved water quality. In most of the cases such water quality models have been successfully applied in reservoirs located in temperate climates. However, the use of water quality …

Green Roofs For A Green Town: Possibilities Of Green Roof Implementation In The Town Of Normal, Lindsey Sihau, '09

Outstanding Senior Seminar Papers

Green roofs have been growing in popularity throughout the world. Scientists have been studying them since the 1980’s. This research project reviews the literature regarding both the benefits and barriers to green roof construction and management. Policies around the nation are then examined and analyzed. Suggestions are made regarding possible additions to the local Stormwater Management Policy that would emphasize the importance of sustainable building techniques such as green roofs, and hopefully offer incentive to their implementation.

Integrated Science Assessment For Oxides Of Nitrogen And Sulfur – Ecological Criteria, United States Environmental Protection Agency

United States Environmental Protection Agency: Staff Publications

This Integrated Science Assessment (ISA) is a synthesis and evaluation of the most policy-relevant science that forms the scientific foundation for the review of the secondary (welfare-based) national ambient air quality standards (NAAQS) for oxides of nitrogen (NO_x) and oxides of sulfur (SO_x). The Clean Air Act definition of welfare effects includes, but is not limited to, effects on soils, water, wildlife, vegetation, visibility, weather, and climate, as well as effects on man-made materials, economic values, and personal comfort and well-being. The current secondary NAAQS for SO_x, set in 1973, is a 3-hour average …

Effective Medium Equations For Chemotaxis In Porous Media, Francisco J. Valdes-Parada, Mark L. Porter, K. Narayanaswamy, Roseanne Ford, Brian D. Wood

Francisco J. Valdes-Parada

Biodegradation is an important mechanism for contaminant reduction in groundwater environments; in fact, in-situ bioremediation and bioaugmentation methods represent alternatives to traditional methods such as pump-and-treat. Chemotaxis has shown to enhance bacterial transport toward or away from concentration gradients of chemical species in laboratory experiments and can signifficantly increase contaminant flux undergoing degradation at the interfaces of lowand high-permeability regions. In this work, the method of volume averaging is used to upscale the microscale description of chemotactic microbial transport in order to obtain the corresponding macroscale equations for bacteria and the attractant. As a first apprach, cellular growth/death and consumption …

Separation Of Time Scales For Transient Dispersion, Mark L. Porter, Francisco J. Valdes-Parada, Brian D. Wood

Francisco J. Valdes-Parada

No abstract provided.

Análisis De La Influencia Del Refuerzo Transversal En El Confinamiento De Columnas De Sección Circular Y Rectangular Modeladas A Escala Reducida, Jhony Armando Sanchez Sierra

Ingeniería Civil

No abstract provided.

Fatigue Risks In The Connections Of Sign Support Structures: Phase 1, Christopher Foley, Baolin Wan, Mathew Weglarz, Matthew Hellenthal, Jordan Komp, Andrew Smith, Joseph Schmidt

Transportation Reports with the Wisconsin Department of Transportation

Wisconsin sought to assess the risk of fatigue-induced fracture in its existing sign support structures designed before the latest AASHTO specifications that included fatigue design. A framework for assessing fatigue-induced fracture risk is developed and detailed synthesis of fatigue testing of connections is conducted. Statistical analysis of tests conducted since 1970 is made and models for characterizing uncertainty in the fatigue life of these connections are proposed. Recommendations regarding further fatigue testing (specimen configuration, number and stress range) are given. Statistical models for wind speed and direction are developed using historical records obtained through the National Climatic Data Center for …

Detection Of Voids In Prestressed Concrete Bridges Using Thermal Imaging And Ground-Penetrating Radar, David G. Pollock, Kenneth J. Dupuis, Benjamin Lacour, Karl R. Olsen

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Thermal imaging and ground-penetrating radar was conducted on concrete specimens with simulated air voids. For the thermal imaging inspections, six concrete specimens were constructed during the month of June 2007 to simulate the walls of post-tensioned box girder bridges. The objective was to detect simulated air voids within grouted post-tensioning ducts, thus locating areas where the post-tensioning steel strands are vulnerable to corrosion. The most important deduction taken from these inspections was that PT-ducts and simulated voids were more detectable in the 20 cm (8 in.) thick specimens than in the 30 cm (12 in.) thick specimens. While inspections of …

Multiple Radar Data Merging In Hydro-Nexrad, Witold F. Krajewski, Bong Chul Seo, Anton Kruger, Piotr Domaszczynski, Gabriele Villarini, James A. Smith

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The Hydro-NEXRAD merging algorithms include two options: (1) data-based merging; and (2) product-based merging. Data-based merging algorithm takes volume scan reflectivity data from all radars involved through preprocessing algorithm that performs volume data quality control, interpolates data to synchronize temporal scale between individual radars, and finally combines data onto a common geographic grid. Reflectivity values for a given location are assigned by a weighting function with respect to the distance from the radar. This single reflectivity field is then converted to rainfall amounts using a user-requested standard approach. In product-based merging algorithm reflectivity data from multiple radars are all converted …

New Consolidation Of Emission And Processing For Air Quality Modeling Assessment In Asia, Yuan Du

Masters Theses

Gridded Asian emission input with fine resolutions for regional photochemical air quality modeling is absent from current studies. A new top-down emission process based on GIS-FORTRAN program has been developed in this study to consolidate the current available regional emissions in Asia and provide model-ready emission input with more flexibility. The INTEX-B anthropogenic emission inventory in 2006 integrated with biogenic from GEIA, as well as biomass burning and ship emissions from TRACE-P has been adopted as the top-level emissions, which are then spatially allocated into grid-cell level by our GIS application. The spatial allocation factors generated for this process are …

Experimental And Modeling Studies For Optimizing Flocculant-Aided Sediment Retention Ponds, Byung Joon Lee

All Dissertations

Attempts to control sediment-containing runoff and associated water quality problems have involved the establishment of many small to medium sediment retention ponds and the injection of nonionic and anionic polyacrylamide (PAM) flocculants to enhance colloid removal. However, to date use has been driven more by practicing engineers and trial-and-error approaches than by logical and consistent design approaches. Therefore, the purpose of this research was to optimize colloidal clay removal in PAM-aided sediment retention ponds by applying experimental and theoretical methodologies.
Initially, simple measurement techniques for the molecular weight (MW) and charge density (CD) of various PAMs were tested and their …

Quantitative Rrna-Targeted Solution-Based Hybridization Assay Using Peptide Nucleic Acid Molecular Beacons, Xu Li, Eberhard Morgenroth, Lutgarde Raskin

Department of Civil and Environmental Engineering: Faculty Publications

The potential of a solution-based hybridization assay using peptide nucleic acid (PNA) molecular beacon (MB) probes to quantify 16S rRNA of specific populations in RNA extracts of environmental samples was evaluated by designing PNA MB probes for the genera Dechloromonas and Dechlorosoma. In a kinetic study with 16S rRNA from pure cultures, the hybridization of PNA MB to target 16S rRNA exhibited a higher final hybridization signal and a lower apparent rate constant than the hybridizations to nontarget 16S rRNAs. A concentration of 10 mM NaCl in the hybridization buffer was found to be optimal for maximizing the difference between …

How Can We Best Manage Freeway Congestion?, Robert Bertini, Christopher Monsere

TREC Project Briefs

Researchers from Portland State University evaluate Oregon’s Implementation of System-Wide Adaptive Ramp Metering (SWARM).

Optimal Maintenance Crew Composition And Enhancement Of Crew Productivity, Robert Schober

All Theses

The South Carolina Department of Transportation (SCDOT) dedicates a large portion of its budget and other resources to the maintenance of the State's transportation infrastructure. In order to maximize the efficiency and productivity of the State's highway maintenance workforce, the SCDOT partnered with Clemson University to research the performance of these maintenance crews. The goal of this research is to identify optimal crew compositions, if possible, and to suggest potential crew productivity enhancement methods.
Data was collected from the SCDOT Highway Maintenance Management System (HMMS) and crew rankings were developed based on several pre-determined performance criteria. These rankings were then …

The North American Transportation Security Center, Steven Douglas Kreis, Michael M. Barclay

Kentucky Transportation Center Research Report

No abstract provided.

P-M Characteristics Of Reinforced Concrete Sections, Paul Johnson

All Theses

This manuscript presents two parametric studies which were performed to evaluate a provision which originated in the 1994 Uniform Building Code (UBC). This provision states that if gravity-induced axial loads carried by a reinforced concrete member are greater than 35% of the pure axial load-carrying capacity (Po) of that member, then the member cannot be used as part of the lateral force resisting system (LRFS). Along with the UBC provision, the Structural Engineers Association of California's (SEAOC) Blue Book states that the value of 0.35Po corresponds to the level of axial load representing a balanced state of strain, i.e., the …

Investigation Of The Merging Of Two Axisymmetric Turbulent Jets, Jeffrey Smith

All Theses

A study was done to determine the converging distance of two axisymmetric turbulent jets and to compare the experimental results with the Reichardt hypothesis. This experiment consisted of measuring the velocity profiles of the two jets and manipulating the momentum ratio between the jets. Through testing, it was determined that the Reichardt hypothesis while efficient, over predicts the converging distance of the jets by up to 25% in some cases.
An Acoustic Doppler Velocimeter (ADV) was used to take measurements across the path of the jets and monitored the velocity and the turbulent kinetic energy. After observing the velocity profiles, …

Analysis Of Speed-Related Crashes Using Event Data Recorder Data, Swathi Korpu

All Theses

Safety in general is defined as 'the absence of unintended harm to living creatures or inanimate objects' (Evans, 2004). Traffic safety is measured in terms of motor vehicle crashes. A crash is an unplanned event which results in either fatality, or injury or property damage. Of all the factors that contribute to a crash, speed is a major issue, as more than 31 percent of all fatal crashes involve speeding (NHTSA, 2007). The speed-safety relationship can be determined by knowing the effect of speed on the frequency and severity of crashes. The relationship between speed and frequency of crashes is …

Air Demand In Free Flowing Gated Conduits, David Peter Oveson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A physical experimental setup of a circular, gated closed conduit was built at the Utah Water Research Laboratory (UWRL). Setup configurations were modified and data were measured to aid in the study of physical variables on air demand. It was determined that gate opening, gate and water surface roughness, and conduit length all were significant variables on the air demand measured through the conduit air vent. It was also determined that no noticeable air velocity profile existed above the air-water interface. A linear relationship was found between the air flow rate to water flow rate ratio (air-demand ratio) and head-to-gate …

Analysis Of Effectiveness Of Bridges With Partial Isolation, Wenying Hu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A special class of seismically isolated bridges shares a common feature in that both ends of the superstructure are restrained and isolators over the columns of bridge uncouple the superstructure from the ground motions. They are defined as partial isolation bridges. From measured acceleration responses, effectiveness of full seismic isolation had been confirmed widely. However, the seismic isolation behavior in the partial isolation has not been widely observed.

The effectiveness of partial isolation is evaluated in this study. The static design procedures for linear and nonlinear partially isolated bridges are developed. Results from the static analysis of linear and nonlinear …