Engineering Commons^™

Behavior And Strength Of Non-Prestressed And Prestressed Hillman Composite Beam Including Cfrp Retrofitting, Wajid Khan

Civil & Environmental Engineering Theses & Dissertations

The Hillman Composite Beam (HCB) is a recent innovation used for the first time in 2008 for a bridge construction in USA. It essentially consists of an FRP outer shell, concrete arch inside the shell and steel strands used to tie the two ends of the arch. Being new in the field, the behavior of HCB has not been thoroughly studied. This dissertation presents a study of the flexural behavior and strength of HCB up to the collapse as well as explores the influence of using carbon reinforced polymer (CFRP) retrofitting and prestressed steel for a further increase in HCB …

Dynamic Elasto-Plastic Behavior Of Steel Building Sub-Assemblage Including Cfrp Retrofitting Under Impact Load, Ali Mohammed Salih Aloosi

Civil & Environmental Engineering Theses & Dissertations

This dissertation presents the outcome of a theoretical and experimental study of the dynamic as well as the quasi-static elasto-plastic behavior of a steel building sub-assemblage including carbon fiber reinforced polymer (CFRP) retrofitting. The steel sub-assemblage consists of a beam-column attached to a pair of beams at its top end while its bottom end is fixed. An apparatus is constructed and used for conducting a series of experiments by applying a lateral impact load on the beam-column in the presence or absence of a static axial load. An innovative procedure for determining the shape of the forcing function caused by …

Efficient Domain Decomposition Algorithms And Applications In Transportation And Structural Engineering, Paul W. Johnson Iii

Civil & Environmental Engineering Theses & Dissertations

Domain decomposition is a divide-and-conquer strategy. In the first part of this dissertation, a new/simple/efficient domain decomposition partitioning algorithm is proposed to break a large domain into smaller sub-domains, in such a way as to minimize the number of system boundary nodes and to balance the work load for each sub-domain. This new domain decomposition algorithm is based on the network’s shortest path solution. Numerical results indicate that the new Shortest Distance Decomposition Algorithm outperformed the most widely used METIS algorithm in 21 out of 27 tested (transportation) examples. In the second part of this dissertation, another new/simple and highly …

Changing Trends In Wave Heights In The U.S. Mid-Atlantic Region, Hillary Lane

Civil & Environmental Engineering Theses & Dissertations

The pace and effects of climate change are an area of constant focus for coastal engineers as evolving patterns in the atmosphere worldwide affect the oceans and coasts on a regional and global scale. Surface waves respond to changing wind patterns both locally and from propagating swell, and the difficulty in predicting future wind patterns is well-established. Expectations that climate change will result in more frequent and intense coastal storms and consequently greater wave heights in the North Atlantic are still unrealized, and recent forecasts from a variety of atmosphere-ocean coupled global climate models instead predict decreasing wave heights through …

Global Sensitivity Analysis Of Mat Foundation Behavior By Using Finite Element Modeling, Yang Zhao

Civil & Environmental Engineering Theses & Dissertations

Mat foundation is used mostly for high-rise buildings and, since the demand for high- rise buildings is growing, having extensive understanding of mat foundation behavior leads us into more efficient structural design. Mat foundation behaviors are affected mostly by soil’s materials properties, foundation size, and thickness and loading conditions. In this study, the sensitivity of mat foundation structural responses to some of the design parameters are evaluated. Sobol decomposition, which is a variance-based technique, is used to perform the global sensitivity analysis. In this study, Patran, a finite element-based software, is used for modeling and simulations.

Approximate flexible method is …

Investigating The Relationship Between Latent Driving Patterns And Traffic Safety Using Smartphone-Based Mobile Sensor Data, Kenneth Wynne

Civil & Environmental Engineering Theses & Dissertations

Crash frequency modelling has been used in the past as an attempt to quantify the expected number of crashes occurring on a certain segment of roadway given a set of variables and factors describing the roadway segment and the traffic along that segment. These models are referred to as the Safety Performance Functions (SPFs) in the Highway Safety Manual (HSM). In past studies, these SPFs have focused primarily on roadway geometric information along with limited traffic exposure data such as traffic volume. Alternate data sources for probe vehicle data are increasingly available and this research sought to exploit this new …

Experimental And Predicted Behavior Of Frp Beam-Columns Including Retrofitting, Ali Al-Huazy

Civil & Environmental Engineering Theses & Dissertations

This thesis presents the outcome of a theoretical and experimental study of Fiber Reinforce Polymer (FRP) beam-columns with uniaxial bending and including retrofitting. The research involved the design and fabrication of a testing apparatus which was then used for a series of beam-column tests. Three different types of beam-column cross sections were used, namely, channel section, I-section, and square tube section. Six non-retrofitted beam-columns were tested in addition to two retrofitted ones. The members were subjected to an eccentric vertical load applied through a lever arm generating gradually increasing axial load and uniaxial bending moment up to the maximum load. …

Behavior And Strength Of Pultruded Frp I-Section Columns Including Uniaxial And Biaxial Bending, Emad M. Amin

Civil & Environmental Engineering Theses & Dissertations

This thesis presents the outcome of a study of the behavior and strength of pultruded glass fiber reinforced polymer (FRP) I-section columns including uniaxial and biaxial applied bending moments. Also included in the study is a critical assessment of ASCE-LRFD Pre-standard for pultruded FRP structures in view of the rigorous analysis presented herein. The theoretical solution is based on a system of three coupled differential equations of equilibrium combined with pinned flexural and torsional boundary conditions. Effects of induced warping due to second-order terms as well as initial out-of-straightness are accounted-for in the governing differential equations. Detailed investigations into the …

A Risk Assessment Of The Impacts Of Coastal Flooding And Sea Level Rise On The Existing And New Pump Stations 113, Norfolk, Va, David A. Pezza

Civil & Environmental Engineering Theses & Dissertations

The author assessed the risk to a wastewater pump station and a planned replacement located nearby due to coastal flooding and rising sea levels. The locations for the pump stations are in the Larchmont neighborhood by the Lafayette River tidal estuaries in Norfolk, Virginia. The Lafayette River is a tributary to the Elizabeth River, which flows to the Chesapeake Bay. The low-lying areas along the river are subject to coastal surges caused by tropical and extra-tropical storms that flood the bay.

The region is considered one of the urban areas most exposed to the accelerating rate of rising sea levels. …

Accuracy Comparison Of Numerical Integration Algorithms For Real-Time Hybrid Simulations, Ganesh Anant Reddy

Civil & Environmental Engineering Theses & Dissertations

The use of accurate numerical integration algorithms is one of the key factors for a successful real-time hybrid simulation (RTHS). In RTHSs, explicit integration algorithms are preferred more than implicit methods since all calculations need to be completed within a given time step during simulation. Explicit methods require the use of effective stiffness and damping for experimental substructures, which are incorporated into the calculation of the integration parameters. In general, those values that are greater than the expected stiffness and damping of the experimental substructure are used to ensure the stability of simulation. If a rate-dependent and nonlinear experimental substructure …

Characterizing Queue Dynamics At Signalized Intersections From Probe Vehicle Data, Semuel Yacob Recky Rompis

Civil & Environmental Engineering Theses & Dissertations

Probe vehicles instrumented with location-tracking technologies have become increasingly popular for collecting traffic flow data. While probe vehicle data have been used for estimating speeds and travel times, there has been limited research on predicting queuing dynamics from such data. In this research, a methodology is developed for identifying the travel lanes of the GPS-instrumented vehicles when they are standing in a queue at signalized intersections with multilane approaches. In particular, the proposed methodology exploits the unequal queue lengths across the lanes to infer the specific lanes the probe vehicles occupy. Various supervised and unsupervised clustering methods were developed and …

Inelastic Behavior And Strength Of Steel Beam-Columns With Applied Torsion, Mamadou Konate

Civil & Environmental Engineering Theses & Dissertations

This dissertation presents the outcome of an experimental and theoretical study of the inelastic behavior and strength of steel beam-columns with applied torsion. Although the international steel design specifications contain interaction relations for biaxially loaded beam-columns, the influence of applied torsion on such members has been completely ignored in the past. A series of hollow square section steel members are tested using an apparatus specially designed to apply torsion in the presence of an axial load and biaxial bending. The theoretical analysis involves formulation of a system of materially nonlinear differential equations and their solution based on a finite integral …

Analyzing Driver Behavior And Traffic Flow Breakdowns At The Hampton Roads Bridge Tunnel, Michelle L. Allen

Civil & Environmental Engineering Theses & Dissertations

The Hampton Roads Bridge Tunnel (HRBT) is a major link for activity in Hampton Roads. The eastbound direction also suffers from congestion during both morning and peak hours. During these periods of congestion, the flow rate varies in regards to the location of the congestion. This study focuses on investigating driver behavior during these different conditions and briefly investigates the cost of delay due to the different capacities. To accomplish this, per vehicle record data (PVR) is used. This data, collected at the exit of the tunnel, provides information on arrival time, speed, lane location, vehicle class, and time headway. …

Effective Cfrp Retrofitting Schemes For Prestressed Concrete Beams, Herish Abdullah Hussein

Civil & Environmental Engineering Theses & Dissertations

This thesis presents a detailed theoretical study of a number of retrofitting schemes for prestressed concrete beams using carbon fiber reinforced polymer (CFRP) sheets to increase flexural strength and ductility. A simply-supported beam subjected to a gradually increasing uniformly distributed load is adopted for the study with a variety of CFRP retrofiring schemes. Three different types of beam cross sections are included for quantifying the influence of CFRP retrofitting when used in high compression regions in addition to CFRP use in high tension areas. To achieve this goal, nonlinear moment curvature relations are developed and coupled with a finite-difference solution …

Feasibility Of Mainstream Nitrite Oxidizing Bacteria Out-Selection And Anammox Polishing For Enhanced Nitrogen Removal, Pusker Raj Regmi

Civil & Environmental Engineering Theses & Dissertations

Short-cut nitrogen removal avoids nitrite oxidation to nitrate by nitrite oxidizing bacteria (NOB) and allows a) reduction of formed nitrite to nitrogen gas via heterotrophic denitrification and/or b) oxidation of remaining ammonia with formed nitrite to nitrogen gas via anaerobic ammonia oxidation (anammox). The precondition for achieving shortcut nitrogen removal is suppression of NOB, which is favored by warm and high ammonia strength conditions found in internally generated ammonia-rich waste streams through anaerobic digestion of waste solids referred to as sidestreams or reject water. The discovery of anammox bacteria in the mid-1990s, which are capable of transforming NH₄+ …

Stormwater Infrastructure Optimization On Conjunctive Improvements, Mohammad Hussin Shar

Civil & Environmental Engineering Theses & Dissertations

The studied drainage system is located in the downtown of the City of Newport News, in a basin known as Anderson Park. The drainage system collects and conveys rainfall runoffs to the system outfall located at the shoreline of the Hampton Roads body of water, which is located south of the study area. The aim of this study is to analyze the area's drainage system, determine maximum capacities, identify system deficiencies and generate the most possible, practical and economical solution for fixing the system deficiencies.

After collecting all of required data, the drainage system was modeled and calibrated using the …

Dimensionless Criteria For Selecting Tidally-Influenced Advective-Dispersive Desalination Brine Mixing Plume Characterization Models, Alireza Shahvari

Civil & Environmental Engineering Theses & Dissertations

The very nature of requirements for implementing a desalination process is highly spatial due to the need to secure both a source for the operation and sink for brine dilution. Thus, the applicable coastal location is bound to natural tidal mixing characteristics and subjected to a near- or a far-field availability for source and sink. Mixing characteristics of coastal waters are very different from one point to another due to the spatiotemporal tidal characteristic in loco in a manner that it can vary from being highly advective to completely dispersive dominant. Once a location is identified, estimation of corresponding water …

An Investigation Of Pavement Distress Variables On Crash Outcomes Using Hierarchical Generalized Linear Regression Modeling, Robert Alan Morgan

Civil & Environmental Engineering Theses & Dissertations

Previous macro-level studies show that the condition of the pavement is associated with roadway safety. However, this premise has not been examined on a micro-level using detailed pavement distress variables (PDVs). The main focus of this research will be to expand the use of the PDV data to further understand the safety risks associated with the type of pavement and each individual PDV by analyzing the likelihood of having a rear-end and/or injurious crash, given that a crash occurs.

Sample crash data and PDV data from the Commonwealth of Virginia for the years 2007 and 2008 were used to produce …

The Role Of Proximity In Reducing Auto Travel: Using Vmt To Identify Key Locations For Development, From Downtown To The Exurbs, Robert B. Case

Civil & Environmental Engineering Theses & Dissertations

The purpose of this dissertation is to discover the VMT impact of each level of proximity in order to help government identify key locations for housing development, and thereby lower VMT and reduce dependence on foreign oil. By discovering the VMT impact of each level of proximity, this dissertation provides a) the first known means of calculating the proximity-based VMT benefit of subject locations by individual proximity level, and b) the new finding that it is likely that high VMT benefit can be achieved at moderate proximity levels acceptable to many households, enabling representative governments to be politically successful while …

Watershed-Scale Hybrid Stochastic-Deterministic Modeling Framework And Diffused Sources Superpositioning, Ruby Juvah Damalie

Civil & Environmental Engineering Theses & Dissertations

Predicting hydrologic system behavior is imperative to planning and management of water resources. The study developed an integrated hybrid stochastic and deterministic framework to improve prediction accuracy for overland flow and diffused sources in a watershed. The methodology includes sampling input parameters at system level and contribution of nonpoint source from hydrologically disconnected areas (heretofore referred to as system-level approach and superpositioning respectively). System-level approach includes the integration of a topography-based sampling grid generalized linear model developed by the study and Monte Carlo methods. The superpositioning method adopts in-stream water quality equation for overland flow pollution estimation.

The system-level approach …

Thermo-Elasto-Plastic Behavior Of Biaxially Loaded Steel Beam-Columns Inducing Those From World Trade Center Towers, Yanhong Zhao

Civil & Environmental Engineering Theses & Dissertations

An experimental and theoretical investigation into the behavior of biaxially loaded steel beam-columns is conducted including the effects of high temperature. Systems of materially nonlinear differential equations of beam-column equilibrium are first formulated for both ambient and high temperature conditions. An iterative finite integral procedure is formulated and programmed to solve the governing differential equations. To check the validity of the theoretically predicted behavior and strength of the beam-columns, a series of forty-two laboratory tests are conducted at both ambient and high temperature up to 950°F. Upon achieving a good agreement between the predicted beam-column behavior and that observed in …

Exploring Travel And Activity Behavior In Transit-Oriented Developments: Insights Into Transportation Benefits And Travel Demand Modelling, Sanghoon Son

Civil & Environmental Engineering Theses & Dissertations

As a sustainable urban development and transportation planning strategy, researchers and planners are increasingly interested in transit-oriented development (TOD). By integrating transit system and neighborhood design, TOD aims to provide a livable environment that is alternative mode friendly, higher density, and mixed-use to residents and workers in the vicinity of transit stations. Despite the recent growing interest in TOE), however, transportation benefits of TOD are not well quantified and characteristics of TOD are not adequately reflected in travel demand models.

This dissertation contributes to understanding of the travel and activity behavior by comprehensively exploring them in the context of TOD. …

Biaxial Bending And Lateral-Torsional Instability Of Imperfect Frp I-Beams Including Effects Of Retrofitting, Jodi Marie Knorowski

Civil & Environmental Engineering Theses & Dissertations

This thesis presents the outcome of a theoretical and experimental study of the behavior of Fiber Reinforced Polymer (FRP) I-beams susceptible to lateral-torsional instability or when subjected to biaxial bending. Laboratory experiments involved application of vertical and horizontal static loads to a 4 x 4 x ¼ in. I-beam with various lengths, and the resulting displacement, twist, and strain were recorded. In the vertical direction, the beam was loaded from different reference load heights with respect to the shear center of the beam. The governing biaxial flexure and torsion differential equations were modified to account for the presence of initial …

Efficient Stand-Alone Generalized Inverse Algorithms And Software For Engineering/Sciences Applications: Research And Education, Subhash Chandra Bose S V Kadiam

Civil & Environmental Engineering Theses & Dissertations

Efficient numerical procedures for finding the generalized (or pseudo) inverse of a general (square/rectangle, symmetrical/unsymmetrical, non-singular/singular, real/complex numbers) matrix and solving systems of Simultaneous Linear Equations (SLE) are formulated and explained. The developed procedures and its associated computer software (under MATLAB computer environment) have been based on "special Cholesky factorization schemes" (for a singular matrix), the generalized inverse of the matrix product, and were further enhanced by the Domain Decomposition (DD) formulation.

Test matrices from different fields of applications have been chosen, tested and compared with other existing algorithms. The results of the numerical tests have indicated that the developed …

Demand Responsive Signal Control Strategy (Drsc) Incorporating Queue Length Information In Real-Time Signal Control, Rahul Rajbhara

Civil & Environmental Engineering Theses & Dissertations

Most of the existing vehicle detection systems, namely inductive loops, video cameras etc. are incapable of measuring the queue lengths at signalized intersections. However, with the advent of modern technology, newer detection methods such as probe vehicles equipped with wireless communications (Connected Vehicles), particularly under the Vehicle Infrastructure Integration [52), and radar detection currently provide this capability [53). This thesis presents a Demand Responsive Signal Control Strategy (termed as DRSC) for an isolated signalized intersection. The control strategy incorporates real-time queue length information (obtained from probe vehicles) into the signal control logic. Demand based maximum green time for each upcoming/new …

Static And Impact Load Response Of Reinforced Concrete Beams And Slabs With Nsm-Cfrp Retrofitting, Nakul Ramanna-Sanjeevaiah

Civil & Environmental Engineering Theses & Dissertations

The use of Near-Surface Mounted Carbon Fiber Reinforced Polymer (NSM-CFRP) reinforcement such as carbon FRP strips holds a high potential for increasing the flexural strength of reinforced concrete members. In comparison to externally bonded CFRP laminates, NSM-CFRP reinforcement approach has several advantages. The main advantages include increased stiffness and strength, better bonding, the possibility of anchoring the reinforcement into adjacent members, and minimal installation time. Thus, the structural engineers worldwide are developing a considerable interest in practical applications of the NSM-CFRP reinforcement technique. A considerable amount of research is still needed in order to fully benefit from this method not …

Evaluation Of Hydraulic Conductivity Of Non Aqueous Phase Liquids In Partially Saturated Soils, Chijioke Ekeleme Akamiro

Civil & Environmental Engineering Theses & Dissertations

This study seeks to investigate a problem of predicting the hydraulic conductivity of NAPLs in partially saturated soils and to relate the hydraulic conductivity to basic soil parameters that are either easy to determine or are in wide use. To evaluate hydraulic conductivity in partially saturated soils, previous researchers have focused on flow geometry, soil and chemical properties, etc. used in CHEMFLO program by Nofziger et al., (1989) and saturation equations by such authors as Van Genutchen (1980) and Brooks and Corey (1964). Among those, the soil-water characteristic curve (SWCC) is the most widely used constitutive relations for unsaturated soils …

Analysis Of Primary-Secondary Incident Events On Urban Freeways, Hongbing Zhang

Civil & Environmental Engineering Theses & Dissertations

The objective of this study is to understand the nature of primary and secondary traffic incidents, assess their impacts and explore the implications in traffic operations, safety, and planning. To achieve the objective, a queue-based secondary incident identification method was developed and applied based on detailed incident, traffic and geometric data sets from Hampton Roads, Virginia. This identification method can overcome the limitations in earlier studies and identify secondary incidents in both road directions. An innovative event categorization defines the term "primary-secondary incident event", as one characterized by a primary incident and one or more associated secondary incidents in both …

Spatial Analysis Of Travel Behavior And Response To Traveler Information, Xin Wang

Civil & Environmental Engineering Theses & Dissertations

Transportation planners have long recognized that it is urgent to integrate emerging spatial analysis with travel behavior studies. A clearer understanding of the spatial interactions among travelers and the complex environment they face has the potential to reap benefits of the ongoing technologies of travel behavior, spatial analysis and Advanced Traveler Information Systems (ATIS).

Considering that spatial patterns have been overlooked in the literature of travel behavior and ATIS, the main objective of this research is to use robust methods of spatial analysis to enhance the understanding of how the associations between traveler decisions, built environment and socio-demographic characteristics are …

Integrating Probe Vehicles And Stationary Detector Data To Construct Accurate Cumulative Curves To Study Bottlenecks, Khairul Azfi Anuar

Civil & Environmental Engineering Theses & Dissertations

Advancements in sensors technologies have given researchers and practitioners access to an immense amount of traffic data from multiple types of sensors. However, because of the diversity of the data types, developing a relationship between the different data sources can be challenging. To further complicate the issue, the presence of error or noise makes it difficult to infer any reliable conclusions from the data. To develop a relationship between different data sources, a new methodology is proposed in this thesis for fusing stationary detector data and probe vehicle data to construct an accurate cumulative curve. To remove or to reduce …