Civil and Environmental Engineering Commons^™

Modeling Of Size Effects In Metallic Samples Of Confined Volumes, Mohammadreza Yaghoobi

LSU Doctoral Dissertations

In material science, size effects is described as the variation of material properties as the sample size changes. In this dissertation, the size dependency of the material strength is addressed as size effects. The size effects underlying mechanisms depend on the nature of the considered material. In the case of crystalline metals, size effects in crystalline metals are governed by the dislocations, as the primary deformation mechanism, and their interactions with one another and other defects such as grain boundaries. In this dissertation, the size and strain rate effects of fcc metallic samples of confined volumes are investigated during the …

Vibration Control In Wind Turbines For Multi Hazards, Milad Rezaee

LSU Doctoral Dissertations

The increasing demand for reliable and clean energy with a low running cost, has developed wind energy harvesting industry in a fast rate during the past two decades, and has led to wind farms’ spreading in various regions with larger and taller wind turbines. Consequently, it is more likely that wind turbines are installed or planned to be installed in areas with higher possibility of natural multihazard. Therefore, flexible modern wind turbines are subjected to severe dynamic environmental loads. Generated excessive vibrations in the wind turbine’s structure due to these loads can have detrimental effects on energy production, structural lifecycle …

Characterization Of Dehalogenimonas Strains From A Louisiana Superfund Site That Reductively Dehalogenate Polychlorinated Alkanes, Trent Anthony Key

LSU Doctoral Dissertations

The research described in this dissertation was aimed at expanding understanding of the diversity and functional roles of microorganisms able to anaerobically transform chlorinated compounds. During the course of the research, a novel strictly anaerobic bacterial isolate originating from chlorinated solvent contaminated groundwater at a Superfund Site in south Louisiana (USA) was characterized. Phylogenetic analysis based on 16S rRNA gene sequencing placed the newly isolated strain, designated as NSZ-14 T, within the genus Dehalogenimonas but within a separate lineage from previously described species. Like previously described species within the genus Dehalogenimonas (i.e., D. lykanthroporepellens and D. alkenigignens), strain NSZ-14T was …

Characterization And Performance Of Eco And Crack-Free High-Performance Concrete For Sustainable Infrastructure, Iman Mehdipour

Doctoral Dissertations

"The main objective of this study is to develop, characterize, and validate the performance of a new class of environmentally friendly, economical, and crack-free high-performance concrete referred to as Eco and crack-free HPC that is proportioned with high content of recycle materials. Two classes of Eco-HPC are designed for: (I) pavement (Eco-Pave-Crete); and (II) bridge infrastructure (Eco-Bridge-Crete). Eco-HPC mixtures were designed to have relatively low binder content up to 350 kg/m³ and develop high resistance to shrinkage and superior durability. A stepwise mixture design methodology was proposed to: (i) optimize binder system and aggregate skeleton to optimize packing density …

Design And Performance Of Cost-Effective Ultra-High Performance Concrete For Prefabricated Elements, Weina Meng

Doctoral Dissertations

"This study presented in this thesis aims to: (1) develop a mixture design methodology for cost-effective ultra-high-performance concrete (UHPC) incorporating high volume of supplementary cementitious materials and conventional concrete and masonry sands; (2) developed UHPC with adapted rheology incorporating lightweight sand, hybrid fibers, and nanomaterials with improved properties; (3) design prefabricated UHPC panels with fiber-reinforced polymers (FRP) for enhanced flexural properties of stay-in-place panels made with optimized UHPC; and (4) explore potential applications of such UHPC elements. The proposed design methodology produced UHPC mixtures with 28-days compressive strengths higher than 125 and 168 MPa under standard water curing and 1-d …

Phytoforensics: Applications In Vapor Intrusion Assessment, Jordan Lee Wilson

Doctoral Dissertations

"Vapor intrusion (VI) occurs when contaminants in the vapor phase migrate in the shallow subsurface and enter buildings through cracks, seams, and gaps and has been recognized as a serious human-health threat as occupants are exposed to potentially harmful concentrations over long periods of time. The VI pathway has recently (2017) been identified as a primary exposure pathway and implemented into the Hazard Ranking System for inclusion on the Nation Priorities List. However, assessing VI and human exposure is not simple and current methods are time-, cost-, and labor-intensive; intrusive; and temporally and spatially variability. Trees are ideal candidates for …

Enhancing The Existing Microscopic Simulation Modeling Practice For Express Lane Facilities, Kelvin S. Machumu

UNF Graduate Theses and Dissertations

The implementation of managed lanes (MLs), also known as dynamically priced express lanes, to improve freeway traffic flow and personal throughput is on the rise. Congestion pricing is increasingly becoming a common strategy for congestion management, often requiring microscopic simulation during both planning and operational stages. VISSIM is a recognized microscopic simulation software used for analyzing the performance of managed lanes (MLs). This thesis addressed two important microscopic simulation issues that affect the evaluation results of MLs.

One of the microscopic simulation issues that has not yet been addressed by previous studies is the required minimum managed lane routing decision …

Characterization Of Subgrade Resilient Modulus For Mepdg And The Effects On Pavement Rutting, Md Mostaqur Rahman

Theses and Dissertations

In 2008, the American Association of State Highway and Transportation Officials (AASHTO) released a modified pavement design method (i.e., the Mechanistic Empirical Pavement Design Guide (MEPDG)) based on Long Term Pavement Performance (LTPP) data from all over the United States. The MEPDG default design parameters developed from the LTPP database are expected to be significantly different than those for South Carolina material, traffic and weather conditions, thus the default design parameters may not be accurate for South Carolina. Therefore, the new pavement design method should be calibrated for South Carolina conditions by performing MEPDG local calibration.

Different input variables should …

Performance Assessment Of Hsrm Concrete Ties Through Finite Element Model Simulations, Adam I. Zeitouni

Theses and Dissertations

Concrete ties have become a promising alternative to timber ties for freight lines with increased curvature, high annual traffic, and large axle loads. They are also widely adopted in passenger lines. High strength (HS) concrete is the material of choice in the fabrication of prestressed concrete railroad ties. The higher strength of the concrete is directly related to higher values of the Elastic Modulus, thus increasing the rigidity of the material. The combination of increased strength, rigidity, and the material brittleness may lead to the development of high amplitude stresses with high gradients, which appears to be a common underlying …

Intermodal Network Design And Expansion For Freight Transportation, Fateme Fotuhiardakani

Theses and Dissertations

Over the last 50 years, international trade has grown considerably, and this growth has strained the global supply chains and their underlying support infrastructures. Consequently, shippers and receivers have to look for more efficient ways to transport their goods. In recent years, intermodal transport is becoming an increasingly attractive alternative to shippers, and this trend is likely to continue as governmental agencies are considering policies to induce a freight modal shift from road to intermodal to alleviate highway congestion and emissions. Intermodal freight transport involves using more than one mode, and thus, it is a more complex transport process. The …

A New Job Shop Heuristic Algorithm For Machine Scheduling Problems, Maryam Ehsaei, Duc T. Nguyen

Civil & Environmental Engineering Faculty Publications

The purpose of this research is to present a straightforward and relatively efficient method for solving scheduling problems. A new heuristic algorithm, with the objective of minimizing the makespan, is developed and presented in this paper for job shop scheduling problems (JSP). This method determines jobs’ orders for each machine. The assessment is based on the combination of dispatching rules e.g. the "Shortest Processing Time" of each operation, the "Earliest Due Date" of each job, the "Least Tardiness" of the operations in each sequence and the "First come First Serve" idea. Also, unlike most of the heuristic algorithms, due date …

Estimating Freeway Traffic Volume Using Shockwaves And Probe Vehicle Trajectory Data, Khairul Anuar, Mecit Cetin

Civil & Environmental Engineering Faculty Publications

Probe vehicle data are increasingly becoming the primary source of traffic data. In current practice, traffic volumes and speeds are collected from inductive loop or similar devices. As probe vehicle data become more widespread, it is imperative that methods are developed so that traffic state estimators like speed, density and flow can be derived from probe vehicle data as well. In this paper, a methodology to estimate traffic flow on a freeway based on probe vehicle trajectory data combined with traffic shockwave theory is proposed. In essence, probe vehicle trajectory can indicate the free-flowing and congested regimes. By using LWR …

Evaluation Of Red Rrfb Implementation At Freeway Off-Ramps And Its Effectiveness On Alleviating Wrong-Way Driving, Seckin Ozkul, Pei-Sung Lin

CUTR Faculty Journal Publications

Wrong-way crashes are a major cause for safety concern along freeways and limited access facilities. This study investigated three different aspects of the use of Rectangular Rapid Flashing Beacons (RRFBs): 1) different settings of red RRFBs and their perceived effectiveness on reducing wrong-way driving based on a public opinion survey, 2) the effect of active red RRFBs on the behavior of drivers traveling on adjacent roadways via a before-and-after study, and 3) the effectiveness of red RRFBs on alleviating wrong-way driving on freeway off-ramps by analyzing the percentage of vehicles turning back after observing the red RRFB activation. Based on …

Improvement Assessment Of Bus Serviceability By Proposing Route Revision, Shahrzad Ainkeshavarzi, Hamed Soleimani

CUTR Faculty Journal Publications

Public transit is an essential part of a city’s transportation. An efficient transit system makes a city more sustainable by reducing the number of single occupancy vehicles leading to a reduction in emissions, energy consumption and less congestion on streets. Public serviceability is an important indicator to indicate how good a transit route is determined; however, it could change during the years since population density is variable. This study is intended to do a comparison between serviceability of a bus line in Memphis, Tennessee for one zip code area to point out the necessity of considering route revising in short-term …

Exploring Factors Contributing To Lane Changes During Left Turns On Quadruple Left-Turn Lanes At Signalized Intersections, Fulu Wei, Zhenyu Wang, Jian Lu

CUTR Faculty Journal Publications

Quadruple left-turn lanes are employed gradually at some major intersections in Jilin, China. At these intersections, frequent lane changes during left turns of vehicles can lead to vastly disordered traffic operations. In this study, the factors contributing to lane changes during left turn behaviors at quadruple left-turn lane intersections were interpreted based on a field survey. In total, data on 192 green intervals and 550 individual lane-change behaviors were collected in Changchun, Jilin Province. A lane-changing rate model was established to predict the rate of lane changes during left turns. In addition, an interval selection model was built to estimate …

How Bicycling Sharing System Usage Is Affected By Land Use And Urban Form: Analysis From System And User Perspectives, Ahmadreza Faghih-Imani, Naveen Eluru, Rajesh Paleti

Civil & Environmental Engineering Faculty Publications

There is a rapid growth of bicycle-sharing systems (BSS) around the world. Cities are supporting these systems as a more sustainable transport mode for short trips. Given the relatively recent adoption of BSS, there is substantial interest in understanding how these systems impact urban transportation. In this paper, we examine the functioning of the hugely successful New York City CitiBike system. We focus on the interaction of BSS with land-use and built environment attributes and the influence of weather condition and temporal characteristics on BSS usage. Towards this end, CitiBike system is analyzed along two dimensions: (1) at the system …

Spatiotemporal Distribution Of Eutrophication In Lake Tai As Affected By Wind, Wenhui Zhang, Qiujin Xu, Xixi Wang, Xiaozhen Hu, Cheng Wang, Yan Pang, Yanbin Hu, Yang Zhao, Xiao Zhao

Civil & Environmental Engineering Faculty Publications

One common hypothesis is that wind can affect concentrations of nutrients (i.e., nitrogen and phosphorus) and chlorophyll-a (Chl-a) in shallow lakes. However, the tests of this hypothesis have yet to be conclusive in existing literature. The objective of this study was to use long-term data to examine how wind direction and wind speed affect the spatiotemporal variations of total nitrogen (TN), total phosphorus (TP) and Chl-a in Lake Tai, a typical shallow lake located in east China. The results indicated that the concentrations of nutrients and Chl-a tended to decrease from the northwest to the southeast of Lake Tai, with …

Development Of Disaster Management In Turkey: From 1999 Kocaeli Earthquake To 2011 Van Earthquake, Mert Tolon, Kağan Cenk Mızrak

Civil Engineering Faculty Publications

The natural disasters that have occurred in Turkey are categorized as % 61 earthquakes, followed by landslides, floods, rock falls, fires and storms. Between the years of 1903 and 2000, there have been nearly 150 earthquakes in Turkey which led to damage and this is a challenge for Turkey. The management and plans of these natural disasters in Turkey were first developed in 1959. In 1999, with the magnitude of 7.4, The Kocaeli and Duzce earthquakes affected a region of Turkey that constitutes % 23 of the country’s population. After that, in 2000 necessary laws have been prepared and enacted. …

Influence Of Crumbed Para Rubber Modifier In Aggregate Blend On Deformation Resistance Properties Of Hot Mix Asphalt, Hatthaphone Silimanotham

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research presents the influence of crumbed para rubber which is added into a portion of aggregate in hot mix asphalt (HMA) during the batch mixing process or called "Dry Process". The dry process has an advantage on its simplicity of quality inspection and less modification in the hot mix plant production process. This study has investigated the effects of adding crumbed para rubber particles on the engineering properties related to permanent deformation resistance of asphalt concrete. In this study, the asphalt mixture is prepared via Marshall Mix design, which contained with limestone and asphalt cement of Pen 60/70 at …

Multi-Layered Elastic Medium Under Axisymmetric Loading And Surface Energy Effects, Kanin Tarntira

Chulalongkorn University Theses and Dissertations (Chula ETD)

Multi-layered nano-scale structures have been found in a wide range of applications these days. Since the surface energy effect is presented at the nano-scale level, a novel calculation scheme is required to accurately capture the mechanical behaviors of such structures. In this study, a solution scheme for analysis of a multi-layered elastic medium with influence of surface energy effects subjected to axisymmetric loading by adopting Gurtin-Murdoch surface elasticity theory is presented. The standard Love's representation and Hankel integral transform are employed to derive the general solutions, and the obtained solutions are employed in the determination of the stiffness matrix for …

Factors Affecting Building Damage And People's Preparedness For Earthquake In Chiang Rai, Narongdej Intaratchaiyakit

Chulalongkorn University Theses and Dissertations (Chula ETD)

On May 5, 2014, an earthquake with a magnitude of 6.3 on the Richter scale occurred in Chiang Rai, Thailand. This earthquake was the strongest earthquake in Thailand at the Mae Lao District region. It also caused building damage and casualties. In this research, 277 participants living in village no.2 and village no.7 of Dong Mada, a sub-district at Mae Lao district in Chiang Rai, were selected. A questionnaire was used to interview these participants, and the data were analyzed by Chi-square, Fisher's exact test, a Mann-Whitney U test, and a Kruskal-Wallis test. The objective of this study was to …

Weakly Singular Boundary Integral Equation Method For Analysis Of Generalized T-Stresses Of Cracks In 3d Coupled-Field Media, Naruethep Sukulthanasorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

This thesis presents the development of a weakly singular boundary integral equation method for the analysis of the generalized T-stress of isolated cracks embedded in a coupled-field whole space. A pair of weak-form integral equations, one for crack-face generalized traction and the other for the gradient of the crack-face generalized displacement, is established in a general framework allowing various types of materials including elastic, piezoelectric, piezomagnetic and piezoelectromagnetic solids, general crack geometry and loading conditions to be handled in a unified fashion. In addition, the final governing integral equations contain only weakly singular kernels and this, as a result, renders …

An Application Of Geosynthetic Cementitious Composite Mat For Slope Stabilization, Phong Tan Ngo

Chulalongkorn University Theses and Dissertations (Chula ETD)

In recent years, soil erosion and slope instability caused by seepage and rainfall are major problems, especially in the mountain area. Many research studies have focused on finding a new technology or material to stabilize the soil slope. In this study, a novel material called geosynthetic cementitious composite mat (GCCM) is selected to study its performance on soil slope stabilization. A series of 1-g physical model tests and numerical simulation (Plaxis 2D) on sandy soil slopes stabilized with and without GCCM are performed under seepage condition. In addition, centrifuge modeling of soil slopes is performed under 25-g in seepage and …

Quantification Of Seismic Performance Factors For Circular Concrete-Filled Steel Tube Diagrid Structures, Nattanai Kuangmia

Chulalongkorn University Theses and Dissertations (Chula ETD)

In 21st century, diagrid structures become more popular lateral force-resisting systems for high-rise buildings world-wide. It consists of several grids of diagonal members on building perimeter serving as both lateral bracing and vertical-load carrying members. Since the diagrid structure is a relatively new type of lateral force-resisting system, current building codes do not explicitly provide the seismic performance factors (SPFs) for this system to use in design process. This thesis aims to determine appropriate SPFs for the diagrid structure incorporating circular concrete-filled steel tube to enable structural engineers to design this system according to seismic performance expected in building codes. …

Analysis Of Near Interface Cracks By Weakly Singular Boundary Integral Equation Method, Pisit Watanavit

Chulalongkorn University Theses and Dissertations (Chula ETD)

This thesis presents a weakly singular boundary integral equation method for analysis of sub-interface cracks in a three-dimensional, linearly elastic, multi-material domain. The formulation is established in a general framework allowing finite bodies, general material anisotropy and loading conditions, arbitrarily shaped cracks, and curved material interface to be treated. A system of integral equations governing the unknown data on the boundary, the crack surface and the material interface are established using a pair of weakly singular, weak-form displacement and traction integral equations and the continuity along the material interface. A symmetric Galerkin boundary element method together with the standard finite …

Contact Problems With Surface Stress Effects, Supakorn Tirapat

Chulalongkorn University Theses and Dissertations (Chula ETD)

This dissertation presents a theoretical study of contact problems with consideration of surface energy effects by adopting a complete Gurtin-Murdoch theory of surface elasticity. The fundamental solution of a layered elastic half-space subjected to axisymmetric surface loading is obtained by using Love's representation and the Hankel integral transform. The analytical solutions for both displacement and stress fields are expressed in terms of semi-infinite integrals, which can be accurately evaluated by employing a numerical quadrature scheme. The obtained solutions are employed as the required influence functions in the investigation of axisymmetric indentation on a layered elastic medium with frictionless and adhesive …

Seismic Effects Of Cornice Projection In Masonry-Infill Reinforced Concrete Buildings In Bhutan, Tek Nath Kararia

Chulalongkorn University Theses and Dissertations (Chula ETD)

Bhutan is located in utmost active seismic zone in the belt of the Himalayan region. However, there is a prevailing architectural requirement of cornice projections away from the perimeter columns at each floor proportional to the floor level to increase floor area and retain Bhutanese architectural style. This irregular projection with thick solid brick walls resting at the edge of cantilever projection affects the structural response during a strong earthquake. To date, there is not adequate investigation on the effects of such cornice projection on seismic performance of buildings. In this study, Nonlinear Response History Analysis (NLRHA) using vertical ground …

Life-Cycle Reliability Assessment Of Existing Rc Bridge Structures Under Multiple Hazards Using Inspection Data, Thanapol Yanweerasak

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study presented a novel methodology to estimate the life-cycle reliability of existing reinforced concrete (RC) corroded bridges under multiple hazards. The life-cycle reliability of a bridge girder under traffic load and airborne chloride hazards was compared with that of a bridge pier under seismic ground motion and airborne chloride hazards. When predicting the life-cycle reliability of existing RC corroded bridges, inspection results could be used to estimate the current material corrosion level. Random variables associated with the estimation of time-variant steel weight loss will be updated to be consistent with the given inspection results by using Sequential Monte Carlo …

Performance And Internal Environment Of Partial Nitrification-Entrapped Cells Under Changes In Cell-To-Matrix Ratio And Substrate Concentrations, Pattaraporn Kunapongkiti

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this study, partial nitrification performance was investigated in entrapped cell-based reactors prepared using phosphorylated polyvinyl alcohol gel (PPVA) and operated using oxygen limiting strategy. The study was divided into three main parts: 1) to investigate the community of nitrite-oxidizing bacteria (NOB) in the reactors operated at different bulk dissolved oxygen (DO) concentrations, 2) to investigate the effect of cell-to-matrix ratio (1% and 4%) on partial nitrification performance of the entrapped-cell-based reactors and to observe internal environment, microbial community, and microbial localization within the gel matrix during long-term operation of the reactors, and 3) to study effect of ammonia and …

Roles Of Dissimilatory Nitrate Reduction To Ammonium In Biological Nitrogen Removal System, Pokchat Chutivisut

Chulalongkorn University Theses and Dissertations (Chula ETD)

Biological nitrogen removal system is a wastewater treatment process that normally utilizes nitrification-denitrification to convert nitrogen wastes to unharmful gaseous products. However, apart from these two pathways, dissimilatory nitrate reduction to ammonium (DNRA) can also compete with denitrification for nitrate and yield ammonium waste as the end product. The aim of this research is to extend knowledge on the DNRA pathway, including the study on its occurrence and microorganisms responsible for the process. To observe the presence of DNRA, microbial sludge from aquacultures which utilized biological nitrogen removal processes was applied to examine the pathway of DNRA in these systems. …