Civil and Environmental Engineering Commons^™

Bus Arrival Time Prediction Using Stochastic Time Series And Markov Chains, Rajat Rajbhandari

Dissertations

Public transit agencies rely on disseminating accurate and reliable information to transit users to achieve higher service quality and attract more users. With the development of new technologies, the concept of providing users with reliable information about bus arrival times at bus stops has become increasingly attractive. Due to the fact that bus operation parameters and variables are highly stochastic, modeling prediction of bus travel and arrival times has become one of the many challenging tasks.

Stochastic time series and delay propagation models to predict bus arrival times using historical information were developed. Markov models were developed to predict propagation …

Uniaxial And Triaxial Behavior Of High Strength Concrete With And Without Steel Fibers, Xiaobin Lu

Dissertations

This study first presents an extensive experimental research program on the true uniaxial and triaxial compression behavior for both high strength concrete (HSC) and steel fiber reinforced high strength concrete (SFHSC). The experimental study mainly focuses on the octahedral shear stress strain relationship of those two types of concrete, which is adopted as the basis to develop a new incremental constitutive model. Emphasis is also put on the investigation of the variation of tangent Poisson's ratio under not only uniaxial but also triaxial stress conditions. The effect of cyclic loading on this parameter is also addressed.

According to this research, …

Development And Application Of Fractionation Procedure For Drinking Water Organic Matters, Yong Pu

Dissertations

USEPA mandates a control of disinfection by-products (DBPs) in finished drinking water and recommends reduction of natural organic matters (NOM), DBP precursors, to achieve this regulatory goal. Studies relating NOM with DBP include fractionation of water samples, characterization of collected organic fractions, fractions' formation potential tests, and jar or similar tests to remove NOM. This study discussed a current resin fractionation procedure on principle, procedure, and its efficiency when applied to water samples of low NOM (< 5mgIL). The primary objective of this research is to develop a fractionation procedure intended for water of low NOM by carefully applying mass balance concept through each fraction's fractionation and a selection of stable ion exchange resins. A new protocol was presented with triple columns of XAD-8 adsorption resin, one column of AG-MP-50 cationic resin, and another column of WA 10 weak anionic resin in sequence. This protocol was experimented and confirmed for its efficiency (±10% loss of mass) with samples from Canal Road (CR) and Raritan Millstone (RM) surface water treatment plants (WTPs) in central New Jersey. The second objective of this study is to develop a statistical model with a potential of online delineation of organic fractions of NOM. The resulting model based on samples of Passaic Valley Water Commission (PVWC) WTP in northern New Jersey was applied to predict organic fractions of samples from CR and RM plants. Paired T-test (paired t ratio 1.15 < t critical 2.02) indicated a good correlation between the predicted and actual fraction concentration. Finally, samples of Middlesex Water Company (MWC) were fractionated and Trihalomethane formation potential tests (THMFP) on collected fraction showed hydrophilic matters possessed a higher potential to produce TTHM in finished water than hydrophobic matter. Jar tests indicated while coagulation was effective in removing hydrophobic matter, it may not be optimum for removal of hydrophilic matter.

This study developed an accurate fractionation procedure for low NOM waters. It provided a better understanding of organic matter transformation at different treatment …

Tide-Influenced Contaminant Transport In Coastal Aquifers, Yong Peng

Dissertations

Coastal aquifers are distinguished from other aquifers because of tidal effects which cause complicated groundwater flow and contaminant transport phenomena in regions immediately adjacent to the coast. This study is designed to address the significance of tidal influence on contaminant transport by focusing on one-dimensional homogeneous coastal aquifers.

This study formulates a conceptual model and corresponding flow and transport equations, analyzes coastal boundary conditions, solves numerically the transport equation, and uses experiments to verify the numerical results.

Results of numerical and experimental studies conclude that tides can have a significant impact on contaminant transport, especially when under unconfined conditions, subject …

Modeling Contaminant Transport And Fate And Subsequent Impacts On Ecosystems, Ming Fan

Dissertations

Assessing risks associated with the release of metals into the environment and managing remedial activities requires simulation tools that depict speciation and risk with accurate mechanistic models and well-defined transport parameters. Such tools need to address the following processes: (1) aqueous speciation, (2) distribution mechanisms, (3) transport, and (4) ecological risk. The primary objective of this research is to develop a simulation tool that accounts for these processes. Speciation in the aqueous phase can be assessed with geochemical equilibrium models, such as MINEQL+. Furthermore, metal distribution can be addressed mechanistically. Studies with Pb sorption to amorphous aluminum (HAG), iron (HFO), …

Continuity Of Bridges Composed Of Simple-Span Precast Prestressed Concrete Girders Made Continuous, Libin Yin

Dissertations

Bridges composed of simple-span, precast, prestressed concrete girders made continuous via cast-in-place decks and diaphragms are continuous only for live loads and superimposed dead loads. The continuity diaphragms often crack due to time dependent effects in the girders. These cracks not only impair bridge ascetics and durability, but also reduce "degree of continuity". A related issue is that joint construction is time consuming and expensive due to reinforcement congestion. This dissertation presents a series of field tests, analytical studies, and laboratory experiments concerning the design and performance of this type of bridge.

Based on a survey of the state departments …

Development Of Dynamic Recursive Models For Freeway Travel Time Predictions, Xiaobo Liu

Dissertations

Traffic congestion has been a major problem in metropolitan areas, which is caused by either insufficient roadway capacity or unforesceable incidents. In order to promote the efficiency of the existing roadway networks and mitigate the impact of traffic congestion, the development of a sound prediction model for travel times is desirable.

A comprehensive literature review about existing prediction models was conducted by investigating the advantages, disadvantages, and limitations of each model. Based on the features and properties of previous models, the base models including exponential smoothing model (ESM), moving average model (MAM), and Kalman filtering model (KFM) are developed to …

Intercity Travel Demand : A Utility-Consistent Simultaneous Trip Generation And Mode Choice Model, Guilin Li

Dissertations

An intercity travel decision includes a complex set of subdecisions, such as when to travel, where to travel, which mode to choose, and others. The main focus of this dissertation is to examine trip frequency and mode choice of intercity non-business travel.

The objective of this study is to understand intercity travel behavior using disaggregate models. The proposed conceptual framework for intercity travel behavior leads to a nested logit/continuous choice model that is rigorously linked to the utility maximization theory. Compared to a traditional intercity travel demand model, the proposed model is utility consistent in that trip generation and mode …

The Use Of A Water Quality Model To Evaluate The Impacts Of Combined Sewer Overflows On The Lower Hudson River, Wen-Pin Shu

Dissertations

CSO discharges have long been recognized as a significant source of water pollution. While many sources of water pollution have been controlled over the past 20 years, CSOs continue to be a main environmental concern in several areas, especially in old cities. In the past, most CSO research focused on the CSO control processes, including floatables and suspended solids removal. Few studies have been conducted in the area of the impacts of CSO discharge on the receiving water quality. To achieve this purpose, a powerful water-modeling tool, WASP 6.1, is utilized in this study. The Lower Hudson River is selected …

A Conceptual Framework For Using Feedback Control Within Adaptive Traffic Control Systems, Renu Chhonkar

Dissertations

Existing adaptive traffic control strategies lack an effective evaluation procedure to check the performance of the control plan after implementation. In the absence of an effective evaluation procedure, errors introduced in the system such as inaccurate estimates of arrival flows, are carried forward in time and reduce the efficiency of the traffic flow algorithms as they assess prevalent traffic conditions. It is evident that the feed-forward nature of these systems cannot accurately update the estimated quantities, especially during oversaturated conditions.

This research is an attempt to develop a conceptual framework for the application of feedback control within the basic operation …

Issues Of Seismic Response And Retrofit For Critical Substation Equipment, Seyed Ali Hashemi Nezhad Ashrafi

Theses

This study focuses on means to reduce the seismic hazard for transformer-bushing systems and different issues of the response and rehabilitation of transformers. The primary means of seismic mitigation investigated is the use of the Friction Pendulum System (FPS) bearings to seismically isolate transformers. This is done by developing a finite element model representing the behavior of FPS bearings and implementing this model on to ADINA finite element package for further use in analytical studies. This model is used to study the behavior of isolated primary-secondary systems and the effects of parameters like different FPS radii or vertical excitations. Also …

Dynamic Multi-Ramp Metering Control With Simultaneous Perturbation Stochastic Approximation (Spsa), Jiangtao Luo

Dissertations

Ramp metering was proven to be a viable form of freeway traffic control strategy, which could eliminate, or at least reduce, freeway congestion. In this study, the development of ramp metering control strategies, models, and constraints (e.g., meter locations, ramp storage capacities, lower and upper bounds of ramp metering rates) are discussed in detail. The pre-timed and demand/capacity metering control strategies were first evaluated, while the potential metered ramps were determined. A Simultaneous Perturbation Stochastic Approximation (SPSA) algorithm is proposed to dynamically optimize multiple-ramp metering control by maximizing the total throughput subject to a number of constraints. The ramp metering …

Development Of A Multivariate Logistic Model To Predict Bicycle Route Safety In Urban Areas, Cheryl Allen-Munley

Dissertations

In response to the renewed appreciation of the benefits of bicycling to the environment and public health, public officials across the nation are working to establish new bicycle routes. During the past two decades, a number of methods have been endorsed for the selection of "suitable" bicycle routes. These methods are limited in that they do not explicitly address bicycle safety nor do they reflect urban conditions.

The purpose of this research is to develop an objective bicycle route safety rating model based on injury severity. The model development was conducted using a logistic transformation of Jersey City's bicycle crash …

Investigation Of An Integrated Regional Environmental Watershed Methodology, Marshall R. Boggio

Dissertations

Recent public awareness of the environment has placed increased emphasis on the health and current state of the regional watershed. The watershed has been defined as that area in which water flowing across and beneath a given land surface drains into a specific stream or river, ultimately flowing through a single point or outlet on that stream or river. Since the processes involved are many and are analyzed in the literature on an individual basis, the current investigation attempts a more holistic approach by suggesting a methodology that integrates all elements of the hydrologic cycle. The investigation utilizes the area …

The Consolidation Analysis Of A Clay Layer In The City Of Belem Do Para, Brazil, John Bezerra Jr.

Theses

In this study, an analysis was done on a particular clay layer found in the city of Belem do Para, Brazil. Various soil tests were conducted including a consolidation analysis. Data were gathered and analyzed in order to obtain a better understanding of how the soil responds under certain loading conditions. There have been no previous studies done on this material and so when it has been encountered in the field geotechnical engineers provide the safest, but not necessarily best design method possible. In the case of large buildings, piles are driven past this material to competent sand. There have …

Shape Finding Of Fabric Structures Using Grid Method, Armin Bischof

Theses

Fabric structures can span large distances with a very low self-weight, which makes them very efficient for covering huge areas. They have attractive shapes and an appealing architecture. These properties make them very popular and they are used in many different kinds of buildings. Airports, stadiums and halls are typical examples where the use fabric structures is often recommendable.

Fabric structures are built mainly out of fabric and cables; two structural members that can only take tension stresses. Therefore these structural members must be prestressed in such a way that their shape can carry all loads that might affect the …

Optimization Of Very Early Strength Concrete Mixes Using Maturity Method, Sun Punurai

Theses

Fast track concrete technology has been used over the past two decades for overnight highway repairs. Originally, fast track was concerned only with rapid strength gain and workability but little concern was paid to cost and durability of the concrete.

The purpose of this research study is to develop a current improved very early strength (VES) concrete mix, which was accepted by NJDOT in 1996. More than 50 concrete mixes were evaluated for strength, shrinkage, and curing rate (maturity), eventually leading to the development of an optimized VES concrete mix with improved performance characteristics.

The study has developed the new …

Shear Strengthening Of Rc Beams Using Carbon Fiber Reinforced Polymer Laminates, Zhichao Zhang

Dissertations

Shear failure is catastrophic and occurs usually without advanced warning, thus it is desirable that the beam fails in flexure rather than in shear. Many existing reinforced concrete (RC) members are found to be deficient in shear strength and need to be repaired. Deficiencies occur due to several reasons such as insufficient shear reinforcement or reduction in steel area due to corrosion, increased service load, and construction defects. Externally bonded reinforcement such as Carbon Fiber Reinforced Polymer (CFRP) provides an excellent solution in these situations.

In order to investigate the shear behavior of RC beams with externally bonded CFRP shear …

Hydrological And Geotechnical Investigation Of A Sparta, New Jersey Landslide, James Talerico

Theses

On August 13, 2000, a massive landslide occurred in Northern New Jersey following an extreme rainfall event during which 14.1 inches of precipitation fell locally during a 24-hour period. The slide, with an estimated volume of 22,000ft³, traveled up to 1,500ft in a short period. While landslides do occasionally occur along the coastal bluffs of the Atlantic Coastal Plain, slides of this magnitude are uncommon in the glacial soils of the New Jersey Highland section.

The investigation of this landslide was compiled through rainfall data and geotechnical data, which was used to determine the triggering mechanism of the …

Remediation Of Chromium Contaminated Soils With Colloidal Silica, Netnapid Yossapol

Dissertations

The low-viscosity stabilizer, colloidal silica, is extensively used as a grouting material in the construction of grout curtains. It has low viscosity and is non-toxic, which is suitable for injection to stabilize fine-grained soils. It is also applied as a stabilizer in the in-situ treatment of hazardous waste. Once the colloidal silica solution is injected into contaminated soil, it moves through the pores inside the soil matrix, initiating the stabilization process. The viscosity of the colloidal silica mixture increases while it moves until solidifications. This process is called gelation and results in the creation of a gel barrier around contaminated …

Probability Of A Hazardous Material Truck Accident In New Jersey, Mahesh Damodaran

Theses

Accident prediction modeling is a powerful tool for determining the frequency of accidents under certain circumstances. Nationwide, direct damages from highway hazardous material spills for the year 2000 were tallied at over $31billion. This thesis determines the probability of an accident involving hazardous materials on the roads of New Jersey. The methodology is based on a British predictive equation used by their Highways Agency to determine the probability of a hazardous spill over a section of a roadway. The parameters used by the British's Highways Agency, which is obtained from their accident data, were modified to reflect conditions that best …

Bi-Axially Loaded Slender Reinforced Concrete Columns Subjected To Sustained Loads, Song Gu

Dissertations

A generalized analytical approach is presented in this research to predict the behavior both of slender and short reinforced concrete columns under sustained biaxial eccentric load.

The present analysis proposes equations established at a cross section of a reinforced concrete column by combining force equilibrium, constitutive law, and compatibility conditions. The strain and curvature of each section and the deflection of the column can then be obtained and resolved.

The established creep computation models, recommended separately by American Concrete Institute (ACI) 209R-92 and the Comite' Euro-International du Be'ton (CEB)-FIP 1990 Model Code have been used to calculate creep and shrinkage …

Complete Stress-Strain Characteristics Of High Performance Concrete, Insang Lee

Dissertations

High performance concrete (HPQ has recently become a widely used concrete construction material for modem buildings, bridges, and pavements, etc. To produce such a better quality of concrete, chemical and mineral admixtures such as fly ash, slag cement, and silica fume, ground granulated blast furnace slag, as well as air-entraining agents are commonly used in the field construction. It has been found that high perforinance concrete can improve the workability, ultimate strength and durability of the concrete. However, the enhancement of ductility in concrete, and concrete structures as a whole is still inconclusive and needs more research. The ductility can …

A Bi-Level Programming Approach For The Shipper-Carrier Network Problem, Ya Wang

Dissertations

The Stackelberg game betweenshippers and carriers in an intermodal network is formulated as a bi-levelprogram. In this network, shippers make production, consumption, androuting decisions while carriers make pricing and routing decisions.The oligopolistic carrier pricing and routing problem, which comprisesthe upper level of the bi-level program, is formulated either as a nonlinearconstrained optimization problem or as a variational inequality problem,depending on whether the oligopolistic carriers choose to collude orcompete with each other in their pricing decision. The shippers' decisionbehavior is defined by the spatial price equilibrium principle. Forthe spatial price equilibrium problem, which is the lower level of thebi-level program, a …

Impact Of Truck Regulation And 65mph Speed Limit On Truck Accidents In New Jersey, Rajat G. Rajbhandari

Theses

The state of New Jersey enacted two regulations with significant importance to the highway operations: 65 mph speed limit and truck restriction on the National Network. The speed limit of 65mph was used on limited sections of interstate system highways with an objective to reduce energy consumption by vehicles and truck restriction was used on the interstate system and other state highway system to reduce large truck accidents and thereby increase truck safety. In this research, the safety impacts of these two regulations on truck crashes were studied.

The research focused on monthly truck crashes along the highway sections where …

Seismic Response Of Transformer Bushing Systems And Their Rehabilitation Using Frictional Pendulum System, Selahattin Ersoy

Dissertations

This thesis is concerned with the performance of electric power transformers and their attachments under earthquake loading. It begins with the description of the transformers, attached bushings, and some typical examples of substation failures in earthquake loading. This is followed by the development of finite element model of three different sizes of transformers. Finite element models consist of several thousand degrees of freedom and they are basic to this thesis. Some of the major findings from these models are utilized to derive a simplified model of a portion of a substation, The frictional pendulum system (a base isolation method) is …

Inelastic Seismic Behavior Of Stiffening Systems : Multi-Span Simply-Supported (Msss) Bridges, Alireza Yazdani-Motlagh

Dissertations

Stiffening behavior can result from interaction between a structure (base system) and its surrounding environment as in the MSSS bridge soil-structure interaction. In this study, three MSSS bridge cases are parametrically analyzed and their dynamic characteristics and behavior are presented and discussed. Later, for investigating stiffening behavior, a simplified stiffening model is introduced and an extensive parametric study with more than 367,000 analyzed cases is performed. In the parametric study, different stiffening parameters (i.e., stiffness, strength, gap size, and mass), 41 strong motion records, and several damage criteria are considered and effects of the stiffening parameters variations on the dynamic …

Shear Behavior Of Reinforced Concrete Deep Beams Strengthened With Cfrp Laminates, Jon Erik Moren

Theses

Considerable research has been performed using CFRP plates bonded to normal reinforced concrete beams, the objective being to improve shear and flexural strength. However, very few tests have been performed on reinforced concrete deep beams with CFRP as shear reinforcement. The purpose of this experiment is to investigate the behavior of the deep beam in shear with various arrangements of Sika CarboDur laminates bonded to the sides. The beams were designed to be shear deficient with stirrups omitted, except at the supports and directly under the load. In total eight beams were tested, four with one-point loading and four with …

Mechanical Properties And Stress-Strain Behavior Of High Performance Concrete Under Uniaxial Compression, Pornchai Jiratatprasot

Theses

Many recent innovations in advanced concrete materials technology have made it possible to produce concrete with exceptional performance characteristics. High performance concrete (HPQ is defined as concrete that meets special performance and uniformity requirements that cannot always be achieved routinely by using conventional materials and normal mixing, placing, and curing practices. The importance of HPC to structural engineering is unquestionable. However, HPC is a relatively new material. Some results of research on conventional concrete are not entirely applicable. In this experiment, the main mechanical properties of HPC including compressive strength, modulus of elasticity, and Poisson's ratio were investigated and compared …

Fractionation & Segregation Of Suspended Particles Using Acoustic And Flow Fields, Nazhat Aboobaker

Dissertations

The fractionation of particles by size or by density has many applications in a variety of technologies. Decontamination and separation of fine sediments is useful in treating sediments. The application of acoustic standing wave fields for the fractionation and segregation of suspended particles was studied.

The above technology was implemented at the bench scale by building a Plexiglas chamber. Two ultrasound transducers were fixed to opposite sides of the chamber to generate the acoustic standing wave field. The technology was evaluated using silica dioxide (Si02) (1-5 ~tm) and silicon carbide (SiQ (5-20 ~tm) particle suspensions in deionized water. Due to …