Digital Commons Network^™

The Current State Of Practice Of Building Information Modeling, Kevin P. Brooks

Masters Theses

Building Information Modeling (BIM) has become extremely prominent in the construction industry in the past twenty years. It serves as a digital repository that can, when used to its fullest potential, combine all aspects of designing, building, and managing a structure in one place, alongside all the data produced in those processes. The construction industry has to date struggled to increase productivity alongside similar fields, such as the manufacturing industry, though the construction industry generally has far more stakeholders on one project than the manufacturing industry. Further, building designs are becoming more complex while project schedules are becoming tighter. As …

The Effects Of Hurricane Wind Field Characteristics On Wind Blade Loads, Michael S. Tsai

Masters Theses

Over recent years, offshore wind energy has been growing around the world. This necessitates placing wind turbines directly in or near the oceans where hurricanes can be. Previous research has suggested that hurricane wind veer and direction change can have adverse loading effects on the turbine. Such effects can create damage to the blade or worsen existing ones. Currently, there is no known design standard for addressing wind veer and direction change specifically from hurricanes. Quantifying the loading contribution from these phenomena is not abundant either.

This thesis seeks to demonstrate a proposed procedure for defining design veer profiles and …

Post-Fire Damage Inspection Of Concrete Tunnel Structures, James Viglas

Masters Theses

In general, tunnels are designed with an abundance of safety regarding structural integrity, however, there can be uncertainty related to structural performance after a fire event. The residual condition of a tunnel after a fire is dependent on fire intensity and duration. The goal of this study is to correlate visual and material characteristics of structural and non-structural components of tunnels with fire temperature and exposure time. This can be further related to the residual capacity of structural members in a tunnel, providing insight into safety and overall functionality. Experimental results show that the visual response of materials with heat …

Correlation Between Laboratory Testing Results And In-Situ Sidewalk Scaling, Brian R. Shea

Masters Theses

Scaling tests aim to induce scaling behavior in concrete specimens similar to environmental conditions. The efficacy of laboratory tests’ ability to match environmental conditions is important to be able to evaluate the durability of concrete exposed to freeze-thaw cycles and de-icers. This study attempts to correlate results between two existing scaling test standards, ASTM C672 and the BNQ NQ 2621-900. The correlation is done via scaling evaluation including computer-based photogrammetric analysis, visual ratings, and cumulative mass loss measurements. Then a correlation between the laboratory testing and in-situ sidewalk panel specimens is made via visual ratings.

Comparison Of Scaling Performance Between Sidewalks Placed Using Hot And Cold Weather Concreting Procedures, Likhitha Rudraraju

Masters Theses

This study investigates the performance of concrete sidewalks placed using hot and cold weather concreting practices. The effect that curing methods, types of deicers, and supplementary cementitious material content have on the scaling resistance of concrete is examined in the laboratory and the field. After one winter, petrographic analysis was conducted on the cores from the sidewalk panels.

The results from field evaluation indicate that the concrete sidewalks placed using hot weather concreting showed better resistance against scaling than those placed using cold weather concreting. The results also suggest that the effect of curing method depends on the concreting procedure …

Wind-Wave Misalignment Effects On Multiline Anchor Systems For Floating Offshore Wind Turbines, Doron T. Rose

Masters Theses

Multiline anchors are a novel way to reduce the cost of arrays of floating offshore wind turbines (FOWTs), but their behavior is not yet fully understood. Through metocean characterization and dynamic simulations, this thesis investigates the effects of wind-wave misalignment on multiline anchor systems. Four coastal U.S. sites are characterized in order to develop IEC design load cases (DLCs) and analyze real-world misaligned conditions. Stonewall Bank, Oregon showed the highest 500-year extreme wave height, at 16.6 m, while Virginia Beach, Virginia showed the highest 500-year wind speed, at 56.8 m/s. Misalignment probability distributions, at all sites, are found to converge …

Measuring Accessibility To Food Services To Improve Public Health, Efthymia Kostopoulou

Masters Theses

Food accessibility has lately been of primary interest given its impact on public health outcomes. This thesis illustrates the gaps in food access by applying spatial analysis in Massachusetts accounting for a variety of demographic and socioeconomic factors. The number of grocery stores, farmers markets, and convenience stores within 1/4 and 1 mile of the Census tracts’ centroids are the two accessibility metrics used in the spatial analysis. In addition, a regression model is developed using the Gradient Boosting machine learning method to show the relationship between the socioeconomic factors and the number of grocery stores within 1 mile of …

Euplectella Aspergillum’S Natural Lattice Structure For Structural Design & Stability Landscape Of Thin Cylindrical Shells With Dimple Imperfections, Zoe Y. Sloane

Masters Theses

The first portion of this thesis assesses the structural application of a bracing design inspired by the deep-sea sponge, Euplectella Aspergillum. Many studies have investigated the natural strength found in the unique skeletal structure of this species. The braced design inspired by the sponge features square frames with two sets of cross-braces that are offset from the corners of each frame, creating a pattern of open and closed cells. This study reports the results of multiple Finite Element Analysis (FEA) computations that compare the described bracing pattern to a more common bracing design used in structural design. The designs …

Tall Timber In Denver: An Exploration Of New Forms In Large Scale Timber Architecture, Andrew P. Weuling

Masters Theses

Wood has been utilized by humans for thousands of years in the construction of our built environment. More recently, our expanded understanding of the material and the advancement of engineered wood have allowed us to use wood like never before. Concrete and steel, however, have emerged as the main materials used in large scale construction in the late 19^th and 20^th Centuries. As we are battling and searching for solutions to climate change, the importance of wood in large scale construction has increased as not only is its carbon intensity is lower than steel and concrete, but its …

Parametric Study Of Integral Abutment Bridge Using Finite Element Model, Asako Takeuchi

Masters Theses

A parametric study of single-span integral abutment bridge (IAB) was conducted using finite element analysis to explore the effects of various load conditions, bridge geometries, and soil properties. This study investigated the difference between the live load distribution of traditional jointed bridges and integral abutment bridges (IABs) under HL-93 truck component load. The results showed that AASHTO live load distribution factors (LLDFs) were overly conservative by up to 50% to use for IABs. LLDFs for IABs proposed by Dicleli and Erhan (2008) matched well for interior girder moment, but they were unconservative for exterior girder moment by up to 20% …

Post-Fire Assessment Of Concrete Tunnel Structures, Nicholas C. Menz

Masters Theses

Although concrete tunnel structures can lose strength and long-term durability due to fire, the literature on the remaining capacity of structures after fire events is very scattered, and no published post-fire inspection protocols specifically for concrete tunnel structures are available. This work aims to summarize and synthesize the current state of knowledge of the deleterious effects of fire on the residual condition of concrete tunnel structures and how the extent and degree of fire damage can be assessed. The scope of this work includes an extensive literature review, heat testing of some common tunnel elements, and residual strength testing of …

Utilizing Unmanned Aerial Vehicles (Uavs) For The Estimation Of Beam Corrosion Of Steel Bridge Girders, Gabrielle Pryor

Masters Theses

The transportation infrastructure in the United States is a complex system that is vital to the everyday operations of the country. Bridges are a significant asset of this network, with many of them approaching the end of their service life. Corrosion is a common cause of deterioration which ultimately results to structural deficiency for the aging bridges. The deterioration rate is a multi-aspect factor that makes bridge inspections crucial. However, the current bridge inspections are very costly and potentially unsafe for the involved personnel. To lower costs and increase safety, many state DOT’s and universities have decided to perform research …

School Bus Routing To Allow Later School Start Times, Rana Eslamifard

Masters Theses

School districts providing busing services for students who live too far to walk to school. In many districts a fleet of school buses is used in sequence to transport high school students, then middle school students, and then elementary school students. The result is that high school classes must start much earlier in the morning than the elementary school, and buses may traverse similar routes three times each morning and afternoon. In light of recent research on the benefits of later high school start times and the need to control transportation costs, school districts are seeking efficient school bus routing …

Modeling Of Electrical Grid Systems To Evaluate Sustainable Electricity Generation In Pakistan, Muhammad Mustafa Amjad

Masters Theses

Pakistan has always had a history of severe energy shortfalls, which rose up to an alarming 33% in 2013. This situation was countered by investments in the energy sector through the China Pakistan Economic Corridor (CPEC), which were unfortunately largely based on brown fuels. Although beneficial in the short term, these investments do not bode well for the climate scenario of Pakistan, with various parts of the country already having experienced temperatures rise of 1-3°C. To ensure that the current situation doesn’t exacerbate and is tackled in a timely manner, this research aims to examine how the untapped potential of …

Quantification Of Thermal Bridging Effects In Cold-Formed Steel Wall Assemblies, Divyansh Kapoor

Masters Theses

Thermal bridging can be defined as the phenomenon where a structural element spanning the building envelope acts like a thermal pathway which collects and moves energy (heat) from the interior to the exterior of the structure. CFS construction, due to the high thermal conductivity of steel with respect to its surrounding structural components and repetitive nature of framing, is highly prone to thermal bridging. Thermal bridging significantly alters the thermal performance of wall assemblies.

Hence, the objective of this research project was to quantify the magnitude of energy loss through cold-formed steel (CFS) stud wall assemblies at a component level …

Behavior Of Prestressed Concrete Bridges With Closure Pour Connections And Diaphragms, Gercelino Ramos

Masters Theses

Accelerated Bridge Construction (ABC) has gained substantial popularity in new bridge construction and bridge deck replacement because it offers innovative construction techniques that result in time and cost savings when compared to traditional bridge construction practice. One technology commonly implemented in ABC to effectively execute its projects is the use of prefabricated bridge components (precast/prestressed bridge components). Precast/prestressed bridge components are fabricated offsite or near the site and then connected on-site using small volume closure pour connections. Diaphragms are also commonly used to strengthen the connection between certain prefabricated components used in ABC, such as beam elements. Bridges containing closure …

The Promise Of Vr Headsets: Validation Of A Virtual Reality Headset-Based Driving Simulator For Measuring Drivers’ Hazard Anticipation Performance, Ganesh Pai Mangalore

Masters Theses

The objective of the current study is to evaluate the use of virtual reality (VR) headsets to measure driving performance. This is desirable because they are several orders of magnitude less expensive and, if validated, could greatly extend the powers of simulation. Out of several possible measures of performance that could be considered for evaluating VR headsets, the current study specifically examines drivers’ latent hazard anticipation behavior both because it has been linked to crashes and because it has been shown to be significantly poorer in young drivers compared to their experienced counterparts in traditional driving simulators and in open …

Sustainable Travel Incentives Optimization In Multimodal Networks, Hossein Ghafourian

Masters Theses

Tripod, an integrated bi-level transportation management system, is a smartphone application from the potential user’s point of view which would be instantly accessed prior to performing the trip. Since there are constantly several alternatives for any trip, Tripod considers a series and combination of various parameters, including departure time, mode and route, and rewards for each alternative with a number of redeemable points for goods and services called “Tokens”. The framework responsible for computing the optimized number of tokens awarded to the set of available alternatives in order to minimize the system-wide energy consumption under a constrained Token budget, is …

Modeling The Effect Of New Commuter Bus Service On Demand And The Impact On Ghg Emissions: Application To Greater Boston, Christopher Lyman

Masters Theses

The transportation sector is considered one of the major contributors to greenhouse gas (GHG) emissions in metropolitan areas, and any efforts to reduce these emissions requires strategic management of multiple transportation modes. This paper presents a method to identify opportunities to reduce GHG emissions by expanding commuter bus services and incentives to shift commuters from private cars to transit. The approach uses a nested multinomial logit model for mode choice in a region that includes driving alone, carpooling, walking, cycling, and using four possible transit modes (ferry, commuter rail, rapid transit and bus) by walk access or driving access. A …

Analysis Of Adhesive Anchorage Systems Under Extreme In-Service Temperature Conditions, Rachel Wang

Masters Theses

Adhesive anchorage systems have found widespread use in structural applications, including bridge widening, concrete repair and rehabilitation, and barrier retrofitting. Because these applications typically require adhesive anchorage systems to be installed outdoors, the effects of climate conditions and day-to-day temperature fluctuations on adhesive behavior and performance should be considered. The purpose of this thesis is to simulate pullout tests of adhesive anchorage systems for threaded rod and reinforcing bars and to emulate effects under various temperature conditions through the use of finite element analysis. Results from the finite element simulation are then compared to the physical tests conducted at UMass …

Performance Of Concrete Tunnel Systems Subject To Fault Displacement, Michael Morano

Masters Theses

A Finite Element Analysis (FEA) investigation of concrete tunnel systems traversing seismic faults is carried out to determine how to effectively mitigate the stresses induced in the liner when subject to fault displacement. A parametric study of various fault parameters, both in the damage zone and competent rock, is carried out to determine the site conditions which induce the most stress on the tunnel liner system. Results indicate that friction angle, cohesion, and elastic modulus of fault zones have varying effects on the stresses induced on the liner. The width of damage zone and expected displacements are also investigated and …

High Fidelity Modeling Of Cold-Formed Steel Single Lap Shear Screw Fastened Connections, Rita Kalo

Masters Theses

Cold-formed steel connections are commonly fastened using self-tapping self-drilling screws. The behavior of these connections can differ based on the screw manufacturer or the cold-formed steel product used, both of which have a large selection available for use in industry. Because of their popularity and the many possible variations of these connections, researchers have frequently tested screw connections to characterize their behavior. However, repeatedly conducting this type of experiment is time consuming and expensive. Therefore, the purpose of this work was to create finite element models that can successfully predict the behavior of single lap shear screw connections, a common …

Evaluating The Toxicity And Formation Of Halobenzoquinones In Point-Of-Use Chlorinated Drinking Water, Stephanie Hung

Masters Theses

Chlorine has effectively reduced the prevalence of waterborne diseases, however there are secondary consequences to this public health advancement. Disinfection byproducts (DBPs) are chemicals formed when chlorine reacts with natural organic matter (NOM) in water. A new class of DBPs, halobenzoquinones (HBQs), has recently been identified and data suggests it could be potentially carcinogenic and up to 1000 times more toxic than some regulated DBPs. So far, in vitro studies have assessed HBQ toxicity without taking into account its transformation in cell media into potentially less toxic compounds. This study evaluated the toxic effects of one HBQ, 2,6-DCBQ, and its …

Evaluating The Impact Of Double-Parked Freight Deliveries On Signalized Arterial Control Delay Using Analytical Models And Simulation, Aaron J. Keegan

Masters Theses

Freight deliveries on signalized urban streets are known to cause lane blockages during delivery. Traffic congestion associated with urban freight deliveries has gained increasing attention recently as traffic engineers and planners are tasked with finding solutions to manage increasing demand more sustainably with limited road capacity. The goal of this research is to evaluate two models for quantifying the capacity and signalized control delay effects of a lane-blocking freight delivery on an urban arterial. The two methods are: an All-or-Nothing model similar to methodology used in the Highway Capacity Manual 6^th Edition, and a Detailed model consistent with kinematic …

All-Red Clearance Intervals For Use In The Left-Turn Application Of Flashing Yellow Arrows, Francis Tainter

Masters Theses

With the advancement of implementation for a novel traffic control device, the Flashing Yellow Arrow (FYA), agencies across the country have continually sought strategies to improve intersection operations and safety, specifically with respect to the left-turn application. More so, permissive left-turn intervals have been communicated to drivers using several traffic signal indications; however, most frequently these phases are represented through the circular green (CG) ball and more recently, the FYA. Previous research in this area determined that the FYA indication produced the most effective communication of permissive left-turns. Further, this previous research led to the inclusion of the FYA in …

Impact Of S-Curve On Speed In A Modern Roundabout, Akshaey Sabhanayagam

Masters Theses

According to the US Department of Transportation, around 20 people die on a daily basis in a signalized intersection, with most of these resulting from angle or head-on collisions. The US-DoT’s Federal Highway Administration (FHWA) has identified modern roundabout intersections to be substantially safer than signalized intersections, due in part to the reduction in conflict points from 32 in a traditional signalized intersection to 8 in a modern roundabout. Despite the increased adoption of modern roundabouts across the US, there are a number of specific design elements for which the direct impact they have on operational and safety related performance …

Reward Allocation For Maximizing Energy Savings In A Transportation System, Adewale O. Oduwole

Masters Theses

Transportation has a major impact on our society and environment, contributing 70% of U.S petroleum use, 28% of U.S. greenhouse gas (GHG) emissions, over 34,000 fatalities and 2.2 million injuries in 2013. Punitive approaches to used to tackle environmental issues in the transportation sector, such as congestion pricing have been well documented, although the use of incentives or rewards lags behind in comparison. In addition to the use of more fuel-efficient, alternate energy vehicles and various other energy reduction strategies; energy consumption can be lowered through incentivizing alternative modes of transportation. This paper focused on modifying travelers’ behavior by providing …

Driver Understanding Of The Flashing Yellow Arrow And Dynamic No Turn On Red Sign For Right Turn Applications, Elizabeth Casola

Masters Theses

Since their introduction to the 2009 Edition of the Manual on Uniform Traffic Control Devices, flashing yellow arrows (FYA) have had significant success in communicating the permissive turn message. While widely used for the permissive left turn maneuver, agencies recently have been utilizing flashing yellow arrows for the use with right turn applications as drivers interact with crossing pedestrians. As pedestrian conflicts are a concern during the permissive green phase, there is additional worry for the potential interaction between a pedestrian and vehicle turning right on red. This research explores the existing driver comprehension of permissive right turns during both …

Performance Of Adhesive And Cementitious Anchorage Systems, Mirna Mendoza

Masters Theses

Post-installed anchoring systems are used extensively in Massachusetts Department of Transportation (MassDOT) projects due their ease of attachment to existing structures. However, recommendations on materials from various manufacturers are currently lacking for certain situations such as long-term tension loading. The purpose of the investigation presented in this thesis was to provide guidance on the use of anchoring systems to MassDOT. This research project evaluated the behavior of adhesive and cementitious bonded anchoring systems per the Stress-versus-Time-to-Failure approach found in the provisional standard AASHTO TP-84 in order to provide recommendations pertaining to the test method. Supplemental short-term anchor pullout tests were …

Development Of High Early-Strength Concrete For Accelerated Bridge Construction Closure Pour Connections, Stephanie Castine

Masters Theses

Accelerated bridge construction (ABC) has become a popular alternative to using traditional construction techniques in new bridge construction and existing bridge deck replacement because of the reduction of time spent in field activities. A key feature of bridges built using ABC techniques is the extensive use of prefabricated components. Prefabricated components are joined in the field using small volume closure pours involving high performance materials (steel and concrete) to ensure adequate transfer of forces between components. To date, the materials developed for closure pours have been based on proprietary components, so a need has arisen for development of mixes that …