Engineering Commons^™

Fracture Behavior Of Single Mason Sand Particles Under Uniaxial Compression, Thuy Thanh Trieu

Masters Theses

Tensile strength of granular materials under one-dimensional (1D) compression is often examined because granular materials fracture in many applications where the soil mass experience high compression stresses. Through methods such as 1D compression, three-dimensional (3-D) imaging, and discrete element modeling, researchers had determined that the Weibull distribution is a good model to represent the tensile strengths of granular material and the fracturing strength of granular materials is dependent on mineralogy, morphology, grain-size, loading rate, gradation, coordination number, and moisture content. Uniaxial compression experiments were performed on Mason sand particles retained between US sieve #10 (2 mm) and #20 (0.84 mm) …

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 …

Evaluation Of New England Bridges For Bat Roosting Including Methodology And Case Studies, Angela Berthaume

Masters Theses

Bats are known and documented to use bridge structures as roosts in various locations throughout the United States and abroad, but there is limited knowledge of how bats use bridges in New England. Significant population declines due to White-Nose Syndrome have resulted in several bat species being listed as state or federally threatened or endangered. If bats are using bridges as roosts, significant effort is required to ensure they are not disturbed or harmed during construction or maintenance work, requiring knowledge of assessment methods to identify likely roost locations in bridges. This thesis describes a two summer study evaluating the …

Evaluation Of The Hot Mix Asphalt Compactability Utilizing The Impact Compaction Method, Pawel Andrzej Polaczyk

Masters Theses

This study investigates possibility of utilizing an accelerometer to evaluate compactability of Hot Mix Asphalt compacted with an impact hammer. For over 50 years Marshall Asphalt Mix Design has been the principal choice for asphalt mix designers around the world. Although the United States has almost entirely moved to Superpave Mix Design, the rest of the world nations still choose the Marshall Method. The investigation was conducted with the accelerometer placed on the falling mass of the Marshall Hammer and acceleration data was stored and analyzed. Data obtained from the accelerometer was filtered and the asphalt mix response after each …

Particle Morphology And Its Influence On Friction And Dilatancy Of Sands, Karen Carmen Lee

Masters Theses

Particle morphology outlines the general analytical method used to describe soil particles’ structure and shape. The characteristics defining this term include sphericity, roundness, and surface texture. Particle morphology has a significant influence on sand behavior and consequently affects dilatancy and friction. Understanding the relationship between shear strength parameters and particle morphology answers fundamental questions about the mechanics of granular materials in general and has the potential to enhance the development of advanced constitutive models that describe granular materials’ behavior.

Many researchers have reported measurements for sphericity, roundness, and surface texture using both two-dimensional (2D) and three-dimensional (3D) images to analyze …

Implementing Online Updating To Complex Hysteresis Models In Real- Time Hybrid Simulation Using Constrained Unscented Kalman Filter, Bilal Ahmed Mohammed

Masters Theses

Although conventional experimental methods, such as quasi-static testing, shake table testing, etc., perform well to evaluate structural seismic performance necessary for modern seismic design, the quasi-static loading and/or reduced scale specimen used in shake table testing may not provide true dynamic responses of structural systems. To overcome these limitations, real-time hybrid simulation (RTHS) was developed, which is a combination of physical testing of the experimental substructure and analytical simulation of the numerical substructure. With the advancement of hybrid simulation, it is now possible to economically test large to full-scale specimens in laboratories at the real earthquake rate. Online model updating …

I. The High Strain Rate Response Of Hollow Sphere Steel Foam; Ii. The Dynamic Response Of An American Elm Tree, Ignacio Cetrangolo

Masters Theses

PART I

Hollow-sphere (HS) steel foam is a relatively new material whose cellular morphology and material properties qualify it as a metallic foam. This is an innovative foam-like material that exhibits high stiffness paired with low relative densities. Technological advancements in the past few decades have enabled the manufacturing of this material by a sintering process and, as a result, research has begun to accelerate as a multi-school collaboration effort for this particular work. Even though commercialization has been a challenge for metallic foams, it is imperative that researchers continue to prove and promote the advantages of metallic foams despite …

Extending Time Series Forecasting Methods Using Functional Principal Components Analysis, Isaac Michael Wagner-Muns

Masters Theses

"Traffic volume forecasts are used by many transportation analysis and management systems to better characterize and react to fluctuating traffic patterns. Most current forecasting methods do not take advantage of the underlying functional characteristics of the time series to make predictions. This paper presents a methodology that uses Functional Principal Components Analysis (FPCA) to create smooth and differentiable daily traffic forecasts. The methodology is validated with a data set of 1,813 days of 15 minute aggregated traffic volume time series. Both the FPCA based forecasts and the associated prediction intervals outperform traditional Seasonal Autoregressive Integrated Moving Average (SARIMA) based methods"--Abstract, …