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Full-Text Articles in Engineering

Behavior Of Prestressed Concrete Bridges With Closure Pour Connections And Diaphragms, Gercelino Ramos Oct 2019

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 …


Finite Element Simulation Of Bonded And Mechanically Anchored Shear Interfaces Of Externally Applied Frp Sheets To Concrete And Wood-Concrete Composites, Alaa Al-Sammari Jul 2019

Finite Element Simulation Of Bonded And Mechanically Anchored Shear Interfaces Of Externally Applied Frp Sheets To Concrete And Wood-Concrete Composites, Alaa Al-Sammari

Doctoral Dissertations

Composite construction is prevalent in advanced structural systems where components of different materials are combined in the same structure to improve the performance of strong and economic structural sections. Maintaining continuity between the different structural components to produce monolithic structural behavior is challenging because of differences in the mechanical properties of these materials in terms of stiffness, strength, and ductility. The different components of the composite section are typically joined using adhesives and/or mechanical anchors to produce partial or full composite action. This dissertation discusses two types of shear interfaces intended to result in structural composite behavior. The first type …


Northeastern Species In Hybrid Cross Laminated Timber, Hamid Kaboli Jul 2019

Northeastern Species In Hybrid Cross Laminated Timber, Hamid Kaboli

Doctoral Dissertations

Known in the building industry throughout the world, Cross Laminated Timber (CLT) is a massive timber building material with outstanding structural, fire, and seismic properties. CLT is a cost-competitive, sustainable construction material is a good candidate as a substitute material for concrete, masonry, and steel, in mid-rise and high-rise buildings. CLT is perpendicular layers of dimensional lumbers usually laminated together and forming a massive structural panel. This dissertation explores the viability of utilizing Massachusetts grown Eastern Hemlock and Eastern White Pine in CLT panels as pure or in conjunction with other high-value wood products. 59% of Massachusetts’ lands are covered …


Evaluation Of The Effect Of Bottom Bar Splice Location On Performance Of Beams In Reinforced Concrete Perimeter Frames, Jorge Rivera Cruz Jul 2019

Evaluation Of The Effect Of Bottom Bar Splice Location On Performance Of Beams In Reinforced Concrete Perimeter Frames, Jorge Rivera Cruz

Doctoral Dissertations

The American Concrete Institute (ACI) Building Code Requirements for Structural Concrete and Commentary (ACI 318-14) indirectly accounts for resistance to progressive collapse by providing requirements for structural integrity in concrete structures. ACI 318-14 structural integrity requirements are intended to provide alternate load paths so that progressive collapse is avoided in the event of the unintended loss of an interior support. ACI 318-14 §9.7.7.5 requires that splices of structural integrity reinforcement be designed as Class B splices near mid-span for top reinforcement and near the support for bottom reinforcement. However, ACI 318-14 does not provide a clear definition for the support …


Mechanical Performance Of Structural Systems With Missing Members: From Buildings To Architected Materials, Panagiotis Pantidis Jul 2019

Mechanical Performance Of Structural Systems With Missing Members: From Buildings To Architected Materials, Panagiotis Pantidis

Doctoral Dissertations

Structural systems are potentially subjected to damage initiating scenarios throughout the course of their service time. Depending on the nature and extent of the damaging event, they may experience significant reduction or even complete loss of their mechanical performance. This dissertation delves into the mechanics of structural systems under the notion of missing members from their domain, investigating types of structural systems: a) multi-story steel framed buildings, and b) materials with a truss-lattice microstructure. Part I of the dissertation investigates the performance of multi-story steel framed buildings under a column removal scenario, developing an analytical framework for their quasi-static robustness …


A Multiline Anchor Concept For Floating Offshore Wind Turbines, Casey Fontana Mar 2019

A Multiline Anchor Concept For Floating Offshore Wind Turbines, Casey Fontana

Doctoral Dissertations

Floating offshore wind turbines (FOWTs) hold great potential for the renewable energy industry, but capital costs remain high. In efforts to increase FOWT substructure efficiency and reduce costs, this thesis investigates a novel multiline anchor concept in which FOWTs share anchors instead of being moored separately. The goal of this thesis is to evaluate the force dynamics, design, and potential cost reduction of the system. Anchor forces are simulated using the NREL 5 MW reference turbine and OC4-DeepCwind semisubmersible platform, and multiline anchor force is computed as the vector sum of the contributing mooring line tensions. The use of a …


Performance Of Concrete Tunnel Systems Subject To Fault Displacement, Michael Morano Mar 2019

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 Mar 2019

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 …


Nonlinear Fastener-Based Modeling Of Cold-Formed Steel Shear Walls Under Lateral Loads, Fani Derveni Jan 2019

Nonlinear Fastener-Based Modeling Of Cold-Formed Steel Shear Walls Under Lateral Loads, Fani Derveni

Structural Engineering Masters Projects

As cold-formed steel (CFS) has increasingly been used in low- and mid-rise construction across United States, it becomes necessary to capture and evaluate its lateral response in both, sub-system/member level and system level. The main lateral resisting system in cold-formed steel construction is shear walls; shear walls are the focus of this work. In particular, the present study aims to shed light on the response of wood sheathed coldformed steel (CFS) shear walls exposed to earthquake events through nonlinear high fidelity fastener-based modeling. The numerical approach is fastener-oriented including nonlinear experimental-determined connector elements for steel-to-sheathing connections, orthotropic oriented strand board …