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Full-Text Articles in Engineering

Application Of Bayesian Networks To Integrity Management Of Energy Pipelines, Wei Xiang Dec 2019

Application Of Bayesian Networks To Integrity Management Of Energy Pipelines, Wei Xiang

Electronic Thesis and Dissertation Repository

Metal-loss corrosion and third-party damage (TPD) are the leading threats to the integrity of buried oil and natural gas pipelines. This thesis employs Bayesian networks (BNs) and non-parametric Bayesian networks (NPBNs) to deal with four issues with regard to the reliability-based management program of corrosion and TPD. The first study integrates the quantification of measurement errors of the ILI tools, corrosion growth modeling and reliability analysis in a single dynamic Bayesian network (DBN) model, and employs the parameter learning technique to learn the parameters of the DBN model from the ILI-reported and filed-measured corrosion depths. The second study develops the ...


Effects Of Building Scale Parameters On Pressure Equalization Capacity Of Roof Paver Systems, Matthew Sparks Aug 2019

Effects Of Building Scale Parameters On Pressure Equalization Capacity Of Roof Paver Systems, Matthew Sparks

Electronic Thesis and Dissertation Repository

Roof pavers are commonly installed with a cavity beneath the paver that develops an internal suction pressure. These cavity pressures reduce the net pressure felt by a roof paver subject to uplift. Paver-scale parameter effects are well-understood, in this study, the effects of changing building-scale parameters such as height, aspect ratio, afterbody length, small and large scale roof obstructions, and paver to roof size ratio on cavity pressures are investigated. To do so pressure measurements were taken at the University of Western Ontario’s Boundary Layer Wind Tunnel Laboratory on a modular flat roof building model at four different heights ...


Structural Optimization Of Cable-Stayed Bridges Considering The Action Of Permanent And Transitory Loads, Carolina Almeida Novaes Dos Santos Jun 2019

Structural Optimization Of Cable-Stayed Bridges Considering The Action Of Permanent And Transitory Loads, Carolina Almeida Novaes Dos Santos

Electronic Thesis and Dissertation Repository

Cable-stayed bridges are complex structures with several advantages such as aesthetical appeal, economic use of materials, and efficient construction method. Due to these advantages and the extensive knowledge gained from projects over the years, longer cable-stayed bridges are being constructed. As span lengths increase, structures become more flexible, which makes the accurate evaluation of wind loads critically important in the design of cable-stayed bridges. A large number of variables are involved in the design of cable-stayed bridges. Those include overall geometric dimensions, cross-sectional dimensions, number of stay-cables and pre-tensioning forces to be applied to the cables. Taking all variables into ...


Risk Analysis Of Natural Gas Distribution Pipelines With Respect To Third Party Damage, Joseph S. Santarelli Apr 2019

Risk Analysis Of Natural Gas Distribution Pipelines With Respect To Third Party Damage, Joseph S. Santarelli

Electronic Thesis and Dissertation Repository

The objective of this study is to develop a quantitative method of evaluating the risk of third party damage (TPD) on natural gas distribution pipelines using available industry data and practical engineering experience. A risk model for TPD of gas distribution pipelines is developed to allow for a more robust decision making process and better prioritization of the allocation of resources for operators of natural gas distribution pipelines. The model consists of likelihood and consequence classification procedures to estimate the severity of TPD events within an area.

The TPD model consists of a fault tree (FTA) model to estimate the ...


Full-Scale Measurements To Evaluate Single-Ply Metal Roof Performance Under Extreme Wind Loads, Mahshid Nasiri Mar 2019

Full-Scale Measurements To Evaluate Single-Ply Metal Roof Performance Under Extreme Wind Loads, Mahshid Nasiri

Electronic Thesis and Dissertation Repository

This study focused on assessing the performance of single-ply metal roofing system under high wind loads. Full-scale measurements were conducted at Insurance Research Lab for Better Homes at the University of Western Ontario, on a full-scale standing seam metal roof (SSMR) system in order to investigate the load sharing among the clip fasteners. A pressure loading approach was used for applying pressure distributions with spatial and time variation on the roof system as the induced loads on the clips were measured using installed load cells. The influence functions of clip reactions were measured. It was observed that the area of ...


A Network Approach To Interdependent Infrastructure Resilience Assessment For Natural Hazards, Howard Tong Feb 2019

A Network Approach To Interdependent Infrastructure Resilience Assessment For Natural Hazards, Howard Tong

Electronic Thesis and Dissertation Repository

Natural disasters are increasingly costly to society as they disrupt basic infrastructure functions. Infrastructure managers face challenges from growing urbanization, climate change, and aging infrastructure. Infrastructure resilience is an emerging concept that has been suggested as a solution to this problem; however, it is not yet mature. This thesis proposes to extend an existing dynamic infrastructure resilience quantification methodology to include infrastructure growth capabilities while relaxing some of the original constraints. The methodology uses a complex networks approach to model infrastructure interdependencies that is applied to a case study in the City of Toronto using a newly developed web tool.


Quantification Of Uncertainties In Inline Inspection Data For Metal-Loss Corrosion On Energy Pipelines And Implications For Reliability Analysis, Tammeen Siraj Nov 2018

Quantification Of Uncertainties In Inline Inspection Data For Metal-Loss Corrosion On Energy Pipelines And Implications For Reliability Analysis, Tammeen Siraj

Electronic Thesis and Dissertation Repository

One of the major threats to the oil and gas transmission pipeline integrity is metal-loss corrosion. Pipeline operators periodically inspect the size of the metal loss corrosion in a pipeline using in-line inspection (ILI) tools to avoid pipe failure which may lead to severe consequences. To predict pipe failure efficiently, reliability-based corrosion management program is gaining popularity as it effectively incorporates all the uncertainties involved in the pipe failure prediction. The focus of the research reported in this thesis is to investigate the unaddressed issues in the reliability-based corrosion assessment to assist in better predicting pipe failure.

First, a methodology ...


Eco-Efficient Preplaced Recycled Aggregate Concrete Incorporating Recycled Tire Waste Rubber Granules And Steel Wire Fibre Reinforcement, Saud A. Alfayez Aug 2018

Eco-Efficient Preplaced Recycled Aggregate Concrete Incorporating Recycled Tire Waste Rubber Granules And Steel Wire Fibre Reinforcement, Saud A. Alfayez

Electronic Thesis and Dissertation Repository

With increasing world population and urbanization, the depletion of natural resources and generation of waste materials is becoming a considerable challenge. As the number of humans has exceeded 7 billion people, there are about 1.1 billion vehicles on the road, with 1.7 billion new tires produced and over 1 billion waste tires generated each year. In the USA, it was estimated in 2011 that 10% of scrap tires was being recycled into new products, and over 50% is being used for energy recovery, while the rest is being discarded into landfills or disposed. The proportion of tires disposed ...


Modeling Of Suspended Sediment Concentration Using Conventional And Machine Learning Approaches, In Thames River, Canada, Issam Mohamed Apr 2018

Modeling Of Suspended Sediment Concentration Using Conventional And Machine Learning Approaches, In Thames River, Canada, Issam Mohamed

Electronic Thesis and Dissertation Repository

Water resource management, planning, hydraulic design, environmental conservation, reservoir management and operation all require reliable information and data about Suspended Sediment Concentration (SSC). To predict such data, direct sampling and Sediment Rating Curves (SRC) are commonly utilized. Since direct sampling can be risky during extreme weather events and SRC cannot provide satisfactorily dependable results, engineers are trying to propose new precise fore-casting approaches. Various soft computing techniques have been applied to model different hydrological and environmental problems and have showed promising results in this regard. Although many studies have been performed to simulate the phenomena of SSC at numerous rivers ...


Experimental And Numerical Investigation Of Emulative Connections In Precast Concrete Walls, Mohamed Gamal Elsayed Feb 2018

Experimental And Numerical Investigation Of Emulative Connections In Precast Concrete Walls, Mohamed Gamal Elsayed

Electronic Thesis and Dissertation Repository

Grouted connections are widely used in the precast concrete construction. For instance, in precast concrete walls, they are used to connect assemblies of vertically stacked panels. The connection is comprised of a grout cylinder bound by a corrugated metallic duct, which is used to house a large diameter reinforcing bar bridging the horizontal gap of stacked panels. The connection is used to provide vertical continuity to the assembly, and to help resist tensile demands from in-plane bending. Current design guidelines consider such connections through a bar-in-concrete treatment, disregarding its composite nature and the confinement effect of the duct. This has ...


Condition Assessment Of Concrete Bridge Decks Using Ground And Airborne Infrared Thermography, Tarek Omar Feb 2018

Condition Assessment Of Concrete Bridge Decks Using Ground And Airborne Infrared Thermography, Tarek Omar

Electronic Thesis and Dissertation Repository

Applications of nondestructive testing (NDT) technologies have shown promise in assessing the condition of existing concrete bridges. Infrared thermography (IRT) has gradually gained wider acceptance as a NDT and evaluation tool in the civil engineering field. The high capability of IRT in detecting subsurface delamination, commercial availability of infrared cameras, lower cost compared with other technologies, speed of data collection, and remote sensing are some of the expected benefits of applying this technique in bridge deck inspection practices. The research conducted in this thesis aims at developing a rational condition assessment system for concrete bridge decks based on IRT technology ...


Bi-Directional Cyclic Behaviour And Liquefaction Analysis Of A Silica-Carbonate Sand, Keyvan Mirbaha Oct 2017

Bi-Directional Cyclic Behaviour And Liquefaction Analysis Of A Silica-Carbonate Sand, Keyvan Mirbaha

Electronic Thesis and Dissertation Repository

The cyclic behavior and liquefaction behavior of reconstituted samples of a local silica-carbonate sand are examined by performing monotonic and cyclic simple shear tests in addition to bender element shear wave velocity measurements. Shear wave velocity was found to vary with effective overburden stresses by an average power of 0.25. Maximum shear modulus (Gmax) was also computed from the shear wave velocity measurements and a correlation was developed between Gmax, effective stress and void ratio. Small strain and cyclic strain dependent shear modulus of the soil were determined, and shear modulus reduction curves were obtained. The results ...


Seismic Performance Of Steel Helical Piles, Moustafa K. El-Sawy Oct 2017

Seismic Performance Of Steel Helical Piles, Moustafa K. El-Sawy

Electronic Thesis and Dissertation Repository

Recent earthquakes have highlighted the need for safe and efficient construction of earthquake resilient structures. Meanwhile, helical piles are gaining popularity as a foundation for new structures and retrofitting solution for existing deficient foundations due to their immense advantages over conventional driven pile alternatives. In addition, helical pile foundations performed well in recent earthquakes, proving they can be a suitable foundation option in seismic regions. The objective of this thesis is to evaluate the seismic performance of helical piles by conducting full-scale shaking table tests and nonlinear three-dimensional numerical modeling using the computer program ABAQUS/Standard. The experimental setup involved ...


Pressure Equalization Of Wind-Induced Pressures On Residential Vinyl Siding Cladding In Full-Scale, Randy A. Van Straaten Aug 2017

Pressure Equalization Of Wind-Induced Pressures On Residential Vinyl Siding Cladding In Full-Scale, Randy A. Van Straaten

Electronic Thesis and Dissertation Repository

Residential vinyl siding cladding system failures have been observed in high wind events. North American vinyl siding design standards allow a 64% pressure equalization factor, which yield relatively low wind load resistance for these products. The allowance is based on testing, which is questioned based on the literature review. The modified discharge equation analytical model, developed by others, accurately predict extent of pressure equalization found in scaled wind tunnel measurements. The model provides value in informing testing standards, product design and forensic investigations. However, it has only been validated based on scaled wind tunnel testing which may present scaling effect ...


Estimation Of Turbulence Effects On Wind-Induced Suctions On The Roof Of A Low-Rise Building, Chieh-Hsun Wu Aug 2017

Estimation Of Turbulence Effects On Wind-Induced Suctions On The Roof Of A Low-Rise Building, Chieh-Hsun Wu

Electronic Thesis and Dissertation Repository

The effects of turbulence in the atmospheric boundary layer (ABL) on surface pressures of a typical low-rise building roof are investigated in this thesis. A 1/50 geometrically-scaled model of the Texas Tech University Wind Engineering Field Research Lab (WERFL) building model is used for pressure measurements in wind tunnel experiments. ABL wind turbulence intensities ranging from about 10% to 30%, and length scales ranging from 6 to 12 times of the building height (H) are generated. The effects of ABL turbulence on the mean roof pressures within the separated flow are explained from the time-averaged Navier-Stokes equations. The pressure ...


Static And Dynamic Properties Of Controlled Low-Strength Materials Incorporating Treated Oil Sands Waste, Ahmed Mneina Aug 2017

Static And Dynamic Properties Of Controlled Low-Strength Materials Incorporating Treated Oil Sands Waste, Ahmed Mneina

Electronic Thesis and Dissertation Repository

Controlled Low-Strength Materials (CLSM) is a self-compacted self-leveling cementitious material with compressive strength of 8.3 MPa or less. It is used as an alternative of soil backfill materials in geotechnical and infrastructure applications. This study investigates the effects of incorporating treated oil sand wastes (TOSW) as a partial replacement of sand or fly ash on fresh and hardened properties of CLSM. In addition, the environmental impact of the proposed new mixtures was evaluated. The results show that CLSM mixtures incorporating TOSW had satisfied the limits and requirements of ACI committee 229 for CLSM with no environmental hazards. The incorporation ...


Tensile And Impact Behaviour Of Shape Memory Alloy Fibre Reinforced Engineered Cementitious Composites, Mohamed Ali El-Sayed Mahmoud Ali Jul 2017

Tensile And Impact Behaviour Of Shape Memory Alloy Fibre Reinforced Engineered Cementitious Composites, Mohamed Ali El-Sayed Mahmoud Ali

Electronic Thesis and Dissertation Repository

Extreme loading events such as impact, blast, and earthquakes have often led to partial or total collapse of structures, associated with economic and human life loss. Therefore, civil engineers have been seeking innovative materials and systems that would allow designing resilient and smart structures which can withstand such catastrophic events. Recently, engineered cementitious composites (ECC) and shape memory alloys (SMA) have emerged as strong contenders in the production of smart and resilient structural systems.

The aims of this study are to explore the possible synergy between ECC and SMA for developing a novel hybrid fibre-reinforced ECC incorporating randomly dispersed SMA ...


System Reliability Analyses And Optimal Maintenance Planning Of Corroding Pipelines, Changqing Gong Jul 2017

System Reliability Analyses And Optimal Maintenance Planning Of Corroding Pipelines, Changqing Gong

Electronic Thesis and Dissertation Repository

The failure of corroding pipeline joints may induce severe consequences. However, maintenance is expensive due to the cost of excavating and repairing a single joint and typically a significant number of joints that need repair. It is central to develop an optimal cost-effective maintenance strategy that balances cost and safety. A key component of the strategy is the reliability based condition evaluation of pipeline joints. The focus of the research reported in this thesis is therefore developing efficient reliability assessment methods for pipeline individual joints, and developing an optimal maintenance framework for the entire pipeline system.

First, efficient system reliability ...


Liquefaction Assessment Of Carbonate-Silica Silty Sands Using Energy, State Parameter And Shear Wave Velocity, Naemeh Naghavi Jul 2017

Liquefaction Assessment Of Carbonate-Silica Silty Sands Using Energy, State Parameter And Shear Wave Velocity, Naemeh Naghavi

Electronic Thesis and Dissertation Repository

The liquefaction behaviour and dynamic properties of reconstituted natural carbonate-silica silty sand samples were investigated in a series of monotonic and cyclic triaxial tests. The critical state parameters of the mixtures with different levels of fines were obtained through monotonic triaxial compression tests. Bender element tests were performed at the consolidation stage to characterize soil’s initial state and small strain properties. The results demonstrated that soil contraction capacity, liquefaction potential and undrained brittleness increase by increasing the state parameter. A general correlation between shear wave velocity and state parameter was established. The susceptibility and triggering of liquefaction under cyclic ...


Estimation Of Cavity Pressures In Air-Permeable, Multi-Layer Systems Using A Lumped-Leakage Approach, Rahul Prabhakaran Nair Sreedevi May 2017

Estimation Of Cavity Pressures In Air-Permeable, Multi-Layer Systems Using A Lumped-Leakage Approach, Rahul Prabhakaran Nair Sreedevi

Electronic Thesis and Dissertation Repository

For conventional buildings, the proper estimation of wind-induced pressures on the external façade, the roof surface, or the net pressures across elements like a canopy or parapet, which are exposed to wind on both sides, can be easily done using conventional wind tunnel tests. But in the case of air-permeable multi-layer systems, which have gaps or porosity in the external layer along with a cavity between the external and inner layers, the estimation of wind loading across the external layer or in the inner cavity by wind tunnel tests can be quite difficult due to practical difficulties in exactly simulating ...


Wall Pressure Coefficients For Low- To High-Rise Buildings, Emilio S. Hong Mar 2017

Wall Pressure Coefficients For Low- To High-Rise Buildings, Emilio S. Hong

Electronic Thesis and Dissertation Repository

Currently, the design of wall cladding and components are based on provisions provided in building codes, such as ASCE 7 for the United States. These codes provide pressure coefficients based on the tributary area, position on the building and the building category. For ASCE 7, low-rise and high-rise buildings are separated by an artificial boundary at 60 ft. (18.2 m). The reasoning for this artificial boundary is unclear. This work investigates the wall pressure coefficients for various buildings, based on aspect ratios, motivated by the large differences in design pressure coefficients for low-rise and high-rise buildings.

For this study ...


Uncertainty Modeling In The Assessment Of Climate Change Impacts On Water Resources Management, Sohom Mandal Mar 2017

Uncertainty Modeling In The Assessment Of Climate Change Impacts On Water Resources Management, Sohom Mandal

Electronic Thesis and Dissertation Repository

Climate change has significant impacts on water resource systems. The objective of this study is to assess climate change impacts on water resource management. The methodology includes (a) the assessment of uncertainty introduced by choice of precipitation downscaling methods; (b) uncertainty assessment and quantification of the impact of climate change on projected streamflow; and (c) uncertainty in and impact of climate change on the management of reservoirs used for hydropower production. The assessment is conducted for two future time periods (2036 to 2065 and 2066 to 2095). The study area, Campbell River basin, British Columbia, Canada, consists of three reservoirs ...


Effects Of Turbulence On The Separating-Reattaching Flow Above Surface-Mounted, Three-Dimensional Bluff Bodies, Abul Fahad Akon Mar 2017

Effects Of Turbulence On The Separating-Reattaching Flow Above Surface-Mounted, Three-Dimensional Bluff Bodies, Abul Fahad Akon

Electronic Thesis and Dissertation Repository

Investigations of separated and reattaching flows over three-dimensional bluff bodies in turbulent boundary layers are important because of the large aerodynamic loads that these flows cause. For example, roofs of low-rise buildings are vulnerable to this kind of wind loading. Turbulence in the upstream flow affects the pressure distributions and the mean size of separation bubbles formed on bluff body surfaces. Whereas a number of studies have focussed on two-dimensional separation bubbles and surface pressures, a comprehensive understanding of the surface pressures and the separating-reattaching flows in relation to the turbulence in the incident boundary layers for surface-mounted, three-dimensional bluff ...


Numerical Modeling Of Tornado-Like Vortex And Its Interaction With Bluff- Bodies, Zoheb Nasir Feb 2017

Numerical Modeling Of Tornado-Like Vortex And Its Interaction With Bluff- Bodies, Zoheb Nasir

Electronic Thesis and Dissertation Repository

The study the flow structure of tornado-like vortices and their impact over engineering structures is important due to the extent of tornado induced fatalities and damages observed each year in North America and around the world. In the present study, a numerical modeling approach inspired by the WindEEE Dome and the modified version of Ward’s Tornado Simulator has been developed. Using a full-scale numerical simulator, tornadoes of different intensities have been simulated for different swirl ratio values to study flow structures in comparison with previous studies. The effect of topographic features on the tornado-like vortex has been investigated for ...


Investigation Of Grouted Dowel Connection For Precast Concrete Wall Construction, Douglas J. Provost-Smith Dec 2016

Investigation Of Grouted Dowel Connection For Precast Concrete Wall Construction, Douglas J. Provost-Smith

Electronic Thesis and Dissertation Repository

The grouted dowel connection is a simple and cost-effective connection used in many precast concrete structural systems. The required dowel length is currently designed as a regular bar in reinforced concrete, which underestimates the bond strength, thus resulting in excessive connection lengths. Furthermore, precast wall construction continues throughout cold weather, where in-situ heating of the grout used in the grouted dowel connections is usually conducted for short periods of time. Hence, early-age exposure to subfreezing conditions may affect the quality of the grout and subsequently the bond strength of the connection, which can compromise structural integrity.

In this thesis, full-scale ...


Development Of Design Loads For Transmission Line Structures Subjected To Downbursts Using Aero-Elastic Testing And Numerical Modeling, Amal Elawady Dec 2016

Development Of Design Loads For Transmission Line Structures Subjected To Downbursts Using Aero-Elastic Testing And Numerical Modeling, Amal Elawady

Electronic Thesis and Dissertation Repository

The failure of transmission line structures due to severe High Intensity Wind (HIW) events is one of the major problems facing the electrical utility companies in various places around the globe including Canada. An extensive research program focusing on this problem started about fifteen years ago at The University of Western Ontario (UWO). In this Thesis, two major milestones are achieved leading to the advancement of the knowledge in this field. The first milestone is conducting, for the first time, a test on an aero-elastic model of a multi-span transmission system under reduced–scale simulated downbursts. The first objective of ...


Behavior Of Fire-Exposed Rc Frames Before And After Jacketing, M. Monir M. Ajan Alhadid Oct 2016

Behavior Of Fire-Exposed Rc Frames Before And After Jacketing, M. Monir M. Ajan Alhadid

Electronic Thesis and Dissertation Repository

Analysis and design of fire-exposed Reinforced Concrete (RC) frames before and after jacketing with concrete layers are commonly performed using prescriptive methods that rely on the concept of fire rating. These methods were developed based on empirical results on individual RC members subjected to certain fire conditions. In typical fire scenarios, the residual capacity, stiffness and thermal deformations affects not only the local performance of each fire-exposed member, but also the load redistribution and global behavior of the entire frame. In terms of fire safety, the philosophy of the new building codes considers objective-based design as an alternative of the ...


Foundation Effects Of Trees Under Wind Loads, Padmavathi Venkata Sagi Oct 2016

Foundation Effects Of Trees Under Wind Loads, Padmavathi Venkata Sagi

Electronic Thesis and Dissertation Repository

Winching tests were conducted on a mature 24-year-old Norway spruce tree. The tree was instrumented with strain gauges along the root structure and tilt sensors along the tree stem and was winched to failure. Tracked tree-root system response to failure load and the material properties of the tree-root-soil system were used to examine the applicability of simple engineering principles to tree stability analysis. Tree stability was studied using the principles of Winkler foundation model for the first time. In order to study the very complex windthrow phenomenon, a novel experimental technique was used. Tree saplings with complete structural root systems ...


Numerical Studies For Improving Fracture Toughness Resistance Curve Testing Using Single-Edge (Notched) Tension Specimens, Yifan Huang Sep 2016

Numerical Studies For Improving Fracture Toughness Resistance Curve Testing Using Single-Edge (Notched) Tension Specimens, Yifan Huang

Electronic Thesis and Dissertation Repository

The fracture toughness resistance curve, i.e. the J-integral resistance curve (J-R curve) or the crack tip opening displacement resistance (CTOD-R) curves, is widely used in the integrity assessment and strain-based design of energy pipelines with respect to planar defects (i.e. cracks). This thesis deals with issues related to the experimental determination of the J(CTOD)-R curves using the newly-developed single-edge (notched) tension (SE(T)) specimens. In the first study, the plastic geometry factor, i.e. the ηpl factor, used to evaluate J in a J-R curve test based on the SE(T ...


Innovating Two-Stage Concrete With Improved Rheological, Mechanical And Durability Properties, Manal F. Najjar Sep 2016

Innovating Two-Stage Concrete With Improved Rheological, Mechanical And Durability Properties, Manal F. Najjar

Electronic Thesis and Dissertation Repository

Two-stage concrete (TSC), also known as preplaced aggregate concrete, is a special type of concrete that is produced using a unique procedure which differs from that of conventional concrete. TSC is distinguished by its high coarse aggregate content and exceptional placement technique, whereby aggregates are first pre-placed in the mold then injected with a special grout. The preplacement of aggregates saves substantial energy since only the grout needs mechanical mixing; the grout is self-leveling and needs no vibration and no mechanical compaction. However, TSC applications are still limited despite substantial advancement of modern concrete technology. Therefore, there is a need ...