Civil Engineering Master's Theses

Support vector machine for structural abnormality detection

David Michael Vines-Cavanaugh — Fri, 12 Apr 2013 09:29:08 PDT

The United States is suffering from an aging civil infrastructure crisis; among the solutions are research and development of sensor-based monitoring and abnormality detection technologies. This thesis contributes to this area by investigating an abnormality detection strategy that relies on a pattern classification technique known as two-class Support Vector Machine (SVM).Input for the classifier is vibration data from sensors on a structure, and the output is a classification of this data into one of two classes. For example, class-1 could indicate that a structure is healthy, and class-2 could indicate a specific type of abnormality. Multi-class classification, i.e. the ability...

Construction smart forms: an application of information technology to reduce waste by increasing interoperability

Babak Jalalzadeh Fard — Wed, 10 Apr 2013 11:45:57 PDT

The subject of this thesis is Construction Smart Forms. The idea is based on the fact that a large amount of data in a construction project is alphanumerical and is gathered by fillable forms. Building Information Modeling (BIM) has made major improvements in data interoperability for geometrical data and 3D models. But for expanding its reach to contain all information shared in a construction project during its lifetime, and beyond, it needs to provide standards and solutions for all the data shared in the projects. eXtensible Markup Language (XML) is the most recognized tool for data sharing in Information Technology...

A meta-heuristic approach for assessment of automobile related policies, and their impact on CO2 emissions

Leila Pourzahedi — Mon, 04 Mar 2013 07:26:38 PST

After the 1997 Kyoto Protocol, governments are becoming more wary of the effects of Green House Gases (GHGs) on the climate, and are trying to control and reduce their country's share by various means. From Cap-and-Trade programs, to introducing hybrid and plug-in vehicles, and creating standards for every source of pollution, they are trying to limit these emissions from every aspect possible. One of the pollution sources with a great deal of contribution to the total GHGs emitted is the transportation sector. Setting policies and regulations is one effective way to limit the share of these sources. In United States,...

Examination of linear projection techniques for mitigation of environmental effects in vibration based damage detection

Salma Mozaffari Kojidi — Thu, 28 Feb 2013 12:31:04 PST

Both environmental variations and damage produce changes in structural properties and this makes the detection of small damage from vibration signals difficult. Techniques to improve damage detection under fluctuating environmental conditions based on projecting the data in directions where the variance from environmental changes is the smallest have been proposed; three of these are: Principal Component Analysis (PCA), Factor Analysis (FA), and Missing Data Analysis (MDA). A question that arises is under which conditions these techniques are appropriate. Indeed, in the limiting case where one knows the probability density of the feature vector projections cannot lead to improved performance. It...

Transit signal priority with three-point advanced prediction: case study of Beacon Street, Brookline, MA

Hangjue Li — Tue, 26 Feb 2013 13:21:38 PST

This thesis proposes a traffic signal control algorithm for transit priority based on advanced detection. For each traffic signal, approaching transit vehicles are detected at three points. The two closest points are just before and just after the transit stop preceding the subject signal; the third and most distant point is just after the second preceding transit stop. At each detection point, adjustments to the signal cycle are made in order to increase the chance that the train arrives during a (future) green period. Adjustments at the earlier detection points include shortening or lengthening signal phases, and assume that further...

Exploring mechanisms of P content heterogeneity in cultured phytoplankton using agent based modeling

Neil Fredrick — Thu, 14 Feb 2013 07:59:45 PST

There can be significant intraspecific individual-level heterogeneity in the internal P content of phytoplankton, which can affect population-level behaviors, including the growth rate. There are several mechanisms that can create this heterogeneity, including biological variability in states and behavior. Here we use modeling to explore the contribution of various mechanisms to the heterogeneity in phytoplankton grown in a laboratory culture. An agent-based model simulates individual cells and their nutrient content. Heterogeneity is introduced by randomizing states (e.g. P content) and parameters (e.g. maximum uptake rate) of daughter cells at division. The model was calibrated to observations of internal P content...

Pavement macrotexture monitoring through sound generated by the tire-pavement interaction

Vitaliy Victorovich Saykin — Tue, 05 Jun 2012 12:22:47 PDT

Safe roads require pavement surfaces that provide adequate friction to tires, helping to bring vehicles to a complete stop in a timely manner that avoids accidents. The current manual methods of evaluating surface friction of roads and bridges are not only dangerous for the inspectors and motorists on the road but they are also very time-consuming and subject to inspector's judgment. This thesis confirms the possibility of monitoring friction of pavement through pavement macrotexture from acoustic measurements underneath the body of a moving vehicle. Currently, macrotexture is quantified by a Mean Texture Depth (MTD) index. In the present work, MTD...

Developments in cost estimating and scheduling in bim technology

Xinan Jiang — Fri, 27 Apr 2012 11:51:48 PDT

Building Information Modeling (BIM) is an emerging technology in Architecture, Engineering, and Construction (AEC) industry. BIM is a computable representation of building and its related information, which provides a virtual view of the objects in the building with physical geometry (2D or 3D) and other functional parameters. Compared to parametric models in CAD, the object-based parametric models in BIM represent the objects by both physical and functional parameters. Diverse BIM tools such as Autodesk Revit Architecture™, ArchiCAD™, Bentley Architecture™, etc. have been widely adopted within AEC industry in design/modeling, construction energy analysis, clash detection, construction scheduling and cost estimating.

In...

Adsorption behavior of naphthalene onto organoclay in aqueous solution

Mansoureh Norouzi Rad — Tue, 24 Apr 2012 12:03:00 PDT

The adsorption properties of naphthalene, as a representative Polycyclic Aromatic Hydrocarbon (PAH), from its aqueous solution onto organoclay are evaluated and are compared with adsoprtion properties of napthalene on sediments. The organoclay is a representative of Reactive Core Mat (RCM) while the sediments are collected from an actual Superfund site interest at Neponset River, Milton, MA. The adsorption experiments are conducted in batch series using a saturated napthalene solution with concentration of 34 ppm. Adsorption kinetic tests are conducted to measure equilibrium time and to define the appropriate adsorption kinetics models. Once the equilibrium time is determined, isotherm experiments are...

An experimental examination of mass perturbation strategies to mode normalization in a plate

Matthew Maddalo — Thu, 16 Feb 2012 11:07:09 PST

In modal identification, there are often practical applications where input forces cannot be determined, and output-only analysis must be implemented. A limitation of output-only identification is that the scaling which connects eigenvectors to the input-output response of the system is unknown. One particular strategy to obtain this normalization involves introducing a known perturbation to the system in question - typically a change in mass. Existing techniques operate under the assumption that the eigenvectors of the system are real, meaning that the system is undamped or classically damped. Although this often provides a reasonable approximation, it is never strictly true. In...

Chemical changes and performance of iron-electrolysis for groundwater remediation

Ali Ciblak — Wed, 15 Feb 2012 06:04:03 PST

Sustainable and effective technologies are required for remediation of contaminated groundwater. Iron electrolysis is a promising technology, which uses natural and low-cost materials, to enhance remediation of groundwater contaminated with chlorinated solvents.

A two-stage experimental program is conducted to evaluate chemical changes induced by iron electrolysis and its potential for enhanced electrochemical transformation of trichloroethylene (TCE). The first stage includes evaluation of changes in electrolyte pH, redox potential, and conductivity due to iron electrolysis in batch and sand-packed flow-through columns. The controlled variables selected for batch experiments include anode material (inert or iron), background electrolyte composition, electric current and polarity...

Impact-echo modeling and imaging techniques

David Charles Abramo — Fri, 27 Jan 2012 13:56:52 PST

Deteriorating infrastructure across the United States is an issue that is commonly referred to in today's society, yet there still remains a question about the level of severity. One of the most relied upon infrastructure components are the thousands of bridges that are essential to everyday life. A common structural component among all bridges is the reinforced concrete bridge deck. Internal air pockets and voids can develop over time with no knowledge of their existence. Among the available condition assessments for bridge decks is a technique noted as impact-echo (IE), a common non-destructive evaluation (NDE) system. This method utilizes mechanical...

Optimal sequencing of traffic streams at a signalized junction

Parham Tavakolian — Tue, 10 Jan 2012 09:22:45 PST

At a signalized intersection, efficiency can be gained by running compatible traffic streams in parallel, while incompatible streams run in series. In an intersection with an asymmetric clearance times, some sequences require less clearance time than others. In a simple intersection with a limited number of sequences, finding the optimal sequence is trivial. However in a complex intersection with a large number of traffic streams or unusual geometry, the optimal sequence is not obvious, and the number of possible sequences can be too large to check manually. An optimal sequence increases intersection capacity and minimizes delay by allowing an intersection...

Evaluating steel-reinforced concrete bridge decks using ground-penetrating radar: models for deterioration

Christopher Franklin Wright — Tue, 11 Oct 2011 07:49:14 PDT

Lack of regular maintenance programs for infrastructure systems in the United States has created a sizeable financial gap between available and required funds to keep these essential systems in good condition. Asset management strategies are being employed to ensure the most efficient use of available funds. Bridges, and their decks in particular, are components of the infrastructure system that are well suited for management by these systems due to their accessibility and general uniformity. Essential to successful bridge management is knowledge of the current state of the bridge network as well as the ability to forecast future states. Several nondestructive...

Use of bioaccumulation test results to evaluate treatment efficacy of a reactive core mat on contaminated subaqueous sediments

Sara Michelle Barbuto — Fri, 07 Oct 2011 07:29:12 PDT

A multi-stage research approach was developed to assess the ability of an organoclay-based reactive core mat (RCM) to prevent the breakthrough and uptake of hydrophobic organic contaminants by overlying biota. Through sorption to this organoclay layer, the RCM offers the potential to sequester contaminants as well as provide a stable foundation for clean overlying sediment. In the field the RCM is covered by a 10 cm layer of clean sand to provide stability for the RCM and also to provide substrate for biota regeneration. Bench-scale testing of the RCM was performed in the Integrated Contaminated Sediment Testing Apparatus Column (ICSTAC),...

Implementing integrated delivery principles while addressing risk management obstacles

Douglas James Erickson — Wed, 01 Jun 2011 06:53:41 PDT

New technologies are changing the way construction projects are delivered. Advances in technologies such as building information modeling (BIM) have challenged owners, designers, and construction teams to develop innovative means for procuring services required for the construction of a variety of projects. One of the delivery methods currently being used on building and infrastructure projects throughout the world, primarily in Australia, is a method known as Integrated Project Delivery (IPD). IPD is a project delivery approach that aims to harness inter-party collaboration to add project value. Two fundamental goals of IPD are to increase productivity and decrease waste born from...

A new coupled consolidation and contaminant transport device to test a reactive core mat for remediation of contaminated, subaqueous sediments

Dogus Meric — Wed, 16 Feb 2011 07:20:22 PST

This thesis describes a laboratory testing program to assess the efficacy of a reactive core mat (RCM) for the remediation of contaminated, subaqueous sediments. The RCM is a 1.25 cm (0.5 in) thick sheet that consists of a reactive layer confined within geotextile filtering layers. The reactive layer is composed of needle-punched fabric impregnated with one or more reactive and/or adsorbing materials (e.g., organoclay, activated carbon, etc.) depending on the contaminant and aqueous environment type. To test the efficiency of the RCM, a new bench scale testing device was designed and fabricated, the Integrated Contaminated Sediment Testing Column Apparatus (ICSTAC),that...

Inducing and imaging partial degree of saturation in laboratory sand specimens

Seda Gokyer — Tue, 22 Jun 2010 09:59:10 PDT

As a critical failure induced by earthquakes, liquefaction has been investigated intensively to evaluate its potential occurrence and prevention. Even though significant advancements have been made in developing and implementing liquefaction mitigation measures, they are often too costly or not suitable for existing structures. Recent research at Northeastern University has demonstrated the benefits of inducing partial degree of saturation (IPS) in preventing the occurrence of liquefaction.

The research reported in this thesis proposes a new technique for inducing partial degree of saturation by the introduction of gas bubbles. The proposed technique utilizes a commercially available chemical compound which reacts with...

A Monte Carlo based method for the dynamic performance analysis of tall buildings under turbulent wind loading

Marra Ann Smith — Tue, 25 May 2010 08:09:13 PDT

The current state of the practice for the design of tall buildings, subjected to wind hazards, is prescriptive based (i.e., ASCE 7-05). However, the concept of using a non-prescriptive methodology, which would allow for design beyond the code criteria, seems preferable in the context of tall buildings from an economic point of view. This type of approach to design is referred to as performance-based engineering (PBE).

This thesis presents a procedure for the calculation of the dynamic response of tall buildings, using Monte Carlo (MC) integration methods, as a first attempt at a performance assessment. The proposed MC numerical procedure...

The impact of mixing on the chloramination process

William Christopher Copithorne — Fri, 18 Dec 2009 08:15:08 PST

Interest in chloramination treatment for potable water has increased in recent years with the advent of more stringent drinking water requirements as a result of chloramines ability to form stable chlorine residuals and minimal disinfection byproducts. However, many utilities which have switched to chloramination for secondary disinfection have reported problems upon the start-up of their new systems. It is believed that these issues may be the result of inadequate mixing. A previous study by Jain (2007) identified an optimum mixing intensity for adequate chloramination by completing bench scale experiments on a standard jar test apparatus. This study was limited to...