Engineering Commons^™

Early-Age Hydration Studies Of Portland Cement, Fengjuan Liu

Electronic Theses and Dissertations

Our current knowledge on cement hydration during setting is based on the discrete observation of hydrated paste. An advanced micro/nano-level technique which can perform the in-situ observation on the continuous hydration of cement paste is demanded. In this study, Raman spectroscopy (RS) was chosen as such a method to continuously investigate wet pastes. The objective of this research is to explore the hydration process and microstructural development of fresh pastes with this technique. This research was conducted in three phases. First, the RS analysis was used to continuously observe the cement hydration from 20 minutes after mixing to 9 hours. …

Structural Health Monitoring Using Novel Sensing Technologies And Data Analysis Methods, Seyedmasoud Malekzadeh

Electronic Theses and Dissertations

The main objective of this research is to explore, investigate and develop the new data analysis techniques along with novel sensing technologies for structural health monitoring applications. The study has three main parts. First, a systematic comparative evaluation of some of the most common and promising methods is carried out along with a combined method proposed in this study for mitigating drawbacks of some of the techniques. Secondly, nonparametric methods are evaluated on a real life movable bridge. Finally, a hybrid approach for non-parametric and parametric method is proposed and demonstrated for more in depth understanding of the structural performance. …

Urban Expressway Safety And Efficiency Evaluation And Improvement Using Big Data, Qi Shi

Electronic Theses and Dissertations

In an age of data explosion, almost every aspect of social activities is impacted by the abundance of information. The information, characterized by alarming volume, velocity and variety, is often referred to as "Big Data". As one fundamental elements of human life, transportation also confronts the promises and challenges brought about by the Big Data era. Big Data in the transportation arena, enabled by the rapid popularization of Intelligent Transportation Systems (ITS) in the past few decades, are often collected continuously from different sources over vast geographical scale. Huge in size and rich in information, the seemingly disorganized data could …

Beneficial Utilization Of Municipal Solid Waste Incineration Ashes As Sustainable Road Construction Materials, Kazi Tasneem

Electronic Theses and Dissertations

Incineration of municipal solid waste (MSW) is common for energy recovery, and management of municipal solid waste incineration (MSWI) ashes has received a growing attention around the world. In the U.S., generation of MSW has increased up to 65% since 1980, to the current level of 251 million tons per year with 53.8% landfilled, 34.5% recycled and composted, and 11.7% incinerated with energy recovery. In the process of incineration, MSWI ash is being produced as byproducts; about 80 to 90% of the MSWI ash is bottom ash (BA) and 10 to 20% is fly ash (FA) by weight. The current …

Development Of Traffic Safety Zones And Integrating Macroscopic And Microscopic Safety Data Analytics For Novel Hot Zone Identification, Jaeyoung Lee

Electronic Theses and Dissertations

Traffic safety has been considered one of the most important issues in the transportation field. With consistent efforts of transportation engineers, Federal, State and local government officials, both fatalities and fatality rates from road traffic crashes in the United States have steadily declined from 2006 to 2011.Nevertheless, fatalities from traffic crashes slightly increased in 2012 (NHTSA, 2013). We lost 33,561 lives from road traffic crashes in the year 2012, and the road traffic crashes are still one of the leading causes of deaths, according to the Centers for Disease Control and Prevention (CDC). In recent years, efforts to incorporate traffic …

Uncertainty Treatment In Performance Based Seismic Assessment Of Typical Bridge Classes In United States, Mohammad Mehdizadeh

Electronic Theses and Dissertations

Bridge networks are expensive and complex infrastructures and are essential components of today's transportation systems. Despite the advancement in computer aided modeling and increasing the computational power which is increasing the accessibility for developing the fragility curves of bridges, the complexity of the problem and uncertainties involved in fragility analysis of the bridge structures in addition to difficulties in validating the results obtained from the analysis requires precaution in utilization of the results as a decision making tool. The main focus of this research is to address, study and treatment of uncertainties incorporated in various steps of performance based assessments …

Transferability And Calibration Of The Highway Safety Manual Performance Functions And Development Of New Models For Urban Four-Lane Divided Roads, Kaaf, Khalid Al

Electronic Theses and Dissertations

Many developing countries have witnessed fast and rapid growth in the last two decades due to the high development rate of economic activity in these countries. Many transportation projects have been constructed. In the same time both population growth and vehicle ownership rate increased; resulting in increasing levels of road crashes. Road traffic crashes in Gulf Cooperation Council (GCC) is considered a serious problem that has deep effects on GCC's population as well as on the national productivity through the loss of lives, injuries, property damage and the loss of valuable resources. From a recent statistical study of traffic crashes …

Role Of Force Resultants Interaction On Fiber Reinforced Concrete, Titchenda Chan

Electronic Theses and Dissertations

Ultra-high performance concrete (UHPC) is a recently developed concrete gaining a lot of interest worldwide, and a lot research has been conducted to determine its material properties. UHPC is known for its very high strength and high durability. Association Francaise de Genie Civil (AFGC) has defined UHPC as a concrete exhibiting compressive strength greater than 150 MPa (22 ksi). To utilize the full compressive strength of UHPC, complementary tension reinforcement is required. A recent research study to find light weight yet high strength alternative deck systems for Florida movable bridges demonstrated that a composite UHPC and high strength steel (HSS) …

Quantifying Ultra-High Performance Concrete Flexural System Mechanical Response, Yulin Xiao

Electronic Theses and Dissertations

The research and application of Ultra-high Performance Concrete (UHPC) has been developed significantly within the last 1-2 decades. Due to the specific property of high strength capacity, it is potential to be used in bridge deck system without shear reinforcement so that it provides even lighter self-weight of the deck. However, one of the shear component, dowel action, has not been adequately investigated in the past. In this dissertation, a particular test was designed and carried out to fully investigate the dowel action response, especially its contribution to shear resistance. In addition, research on serviceability and fatigue behaviors were expanded …

A New Multidimensional Psycho-Physical Framework For Modeling Car-Following In A Freeway Work Zone, Taylor Lochrane

Electronic Theses and Dissertations

As the United States continues to build and repair the ageing highway infrastructure, the bearing of freeway work zones will continue to impact the capacity. To predict the capacity of a freeway work zone, there are several tools available for engineers to evaluate these work zones but only microsimulation has the ability to simulate the driver behavior. One of the limitations of current car-following models is that they only account for one overall behavioral condition. This dissertation hypothesizes that drivers change their driving behavior as they drive through a freeway work zone compared to normal freeway conditions which has the …

Characterization Of Dynamic Structures Using Parametric And Non-Parametric System Identification Methods, Ayad Al Rumaithi

Electronic Theses and Dissertations

The effects of soil-foundation-structure (SFS) interaction and extreme loading on structural behaviors are important issues in structural dynamics. System identification is an important technique to characterize linear and nonlinear dynamic structures. The identification methods are usually classified into the parametric and non-parametric approaches based on how to model dynamic systems. The objective of this study is to characterize the dynamic behaviors of two realistic civil engineering structures in SFS configuration and subjected to impact loading by comparing different parametric and non-parametric identification results. First, SFS building models were studied to investigate the effects of the foundation types on the structural …

Measurements Of Fluvial Sediments Using A Single-Frequency Acoustic Attenuation System, Thomas Alexander Kajdan

Electronic Theses and Dissertations

Suspended sediments are a global-scale pollutant that threaten the integrity of our waterways and pose an environmental threat to many aquatic ecosystems. Innovative techniques are required to continuously monitor this pollutant. Ultrasonic acoustic measurements have the potential to improve the temporal resolution of fluvial sediment data. This work investigates the use of a prototype field grade single-frequency acoustic attenuation system that was developed at the National Center for Physical Acoustics (NCPA), located at the University of Mississippi. This field-deployable unit consists of two 20 MHz immersion transducers that are aligned in a "pitch-catch" configuration at a fixed distance of 18 …

Non-Hydrostatic Models For Wave Propagation, Breaking, And Run-Up, Zhangping Wei

Electronic Theses and Dissertations

This dissertation develops a series of non-hydrostatic pressure wave models based on the finite element free surface flow model, CCHE2D, for simulating propagation, breaking, and run-up of coastal wave processes. The first non-hydrostatic formulation presented in this dissertation directly introduces a non-hydrostatic pressure module into CCHE2D. An edge-based pressure allocation method is implemented, and a depth-integrated vertical momentum equation is introduced. The depth-integrated horizontal momentum equations are solved for a provisional velocity field, and then the non-hydrostatic pressure is obtained by satisfying the divergence-free velocity field condition, subsequently the velocity field is corrected by the non-hydrostatic pressure. Finally the free …

Water And Nutrient Reuse Within Closed Hydroponic Systems, Emerson Christie

Electronic Theses and Dissertations

Currently, little research exists on the maintenance of individual nutrient balance within the nutrient solutions of closed hydroponic systems and how this maintenance may result in reductions in water and nutrient consumption. In this study, a nutrient solution management procedure was developed to maintain outputs while minimizing inputs. Lactuca sativa (lettuce) crops were grown in six closed hydroponic systems utilizing the nutrient film technique. Electrical conductivity was used as the primary indicator of nutrient solution quality and determined if the nutrient solution was discarded and replaced (control systems) or restored (test systems). Restorations in test systems were made individually to …

Context-Aware Mobile Augmented Reality Visualization In Construction Engineering Education, Arezoo Shirazi

Electronic Theses and Dissertations

Recent studies suggest that the number of students pursuing science, technology, engineering, and mathematics (STEM) degrees has been generally decreasing. An extensive body of research cites the lack of motivation and engagement in the learning process as a major underlying reason of this decline. It has been discussed that if properly implemented, instructional technology can enhance student engagement and the quality of learning. Therefore, the main goal of this research is to implement and assess effectiveness of augmented reality (AR)-based pedagogical tools on student learning. For this purpose, two sets of experiments were designed and implemented in two different construction …

Applications Of Transit Signal Priority Technology For Transit Service, Frank Anthony Consoli

Electronic Theses and Dissertations

This research demonstrated the effectiveness of Transit Signal Priority (TSP) in improving bus corridor travel time in a simulated environment using real world data. TSP is a technology that provides preferential treatment to buses at signalized intersections. By considering different scenarios of activating bus signal priority when a bus is 3 or 5 minutes behind schedule, it was demonstrated that bus travel times improved significantly while there is little effect on delays for crossing street traffic. The case of providing signal priority for buses unconditionally resulted in significant crossing street delays for some signalized intersections with only minor improvement to …

Traffic Safety Assessment Of Different Toll Collection Systems On Expressways Using Multiple Analytical Techniques, Muamer Abuzwidah

Electronic Theses and Dissertations

Traffic safety has been considered one of the most important issues in the transportation field. Crashes have caused extensive human and economic losses. With the objective of reducing crash occurrence and alleviating crash injury severity, major efforts have been dedicated to reveal the hazardous factors that affect crash occurrence. With these consistent efforts, both fatalities and fatality rates from road traffic crashes in many countries have been steadily declining over the last ten years. Nevertheless, according to the World Health Organization, the world still lost 1.24 million lives from road traffic crashes in the year of 2013. And without action, …

Development And Validation Of The Structural Health Evaluation (SheTm) Program, Steven Worley

Electronic Theses and Dissertations

No abstract provided.

Geotextile Tubes And Their Application To Dewatering, Kevin R. Morgan

Electronic Theses and Dissertations

Geotextile tubes are a proven cost-effective technology offering speed, efficiency, and minimal impact to the environment for dewatering of sediment or sludge from dredging operations. Common applications include: removal of solids from municipal water and waste water treatment, agricultural remediation, marine dredging operations, construction dewatering, and beach preservation and protection. Geotextile tubes are manufactured in a variety of configurations.

Geotextile tubes are used for a wide variety of environmental applications including dewatering and slurry containment. One of the most important design aspects of the tubes themselves is the ability to be flexible and expand and hold form under high pressure …

Evaluation Of Long Term Effects Of Erosion Due To Groin Placement In The Northern Yucatan Peninsula, Andrew V. Mahfood

Electronic Theses and Dissertations

This thesis documents the results of a study conducted to evaluate the long term effects of groin placement on beach re-nourishment and beach restoration in the Yucatan peninsula. The study includes the evaluation of six control points located on Chelem beach in Yucatan, Mexico, very close to the Progreso pier. The control points were set up in an active groin field to record data on the re-nourishment project covering the Chelem beach area. These erosion control groins were constructed as part of an experimental project to see how the adopted U.S. Army Corps of Engineers guidelines, for installing groins, affected …