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Application Of Wavelet Analysis And Random Field In Integrity Management Of Pipelines Containing Dents And Corrosions, Junxiong Lin

Electronic Thesis and Dissertation Repository

Metal loss corrosions and dents are two major threats to the integrity of oil and natural gas pipelines. In the pipeline industry, the Fitness-For-Service (FFS) assessment is commonly employed for pipelines containing these defects. However, FFS assessment usually assumes that a defect has a simple shape, and such a simplification may significantly affect the accuracy of the assessment. Therefore, retaining the actual shapes of defects and incorporating them into the FFS assessment can improve assessment accuracy. The main objective of the present thesis is to extract key information about the sizes, directions, and shapes of corrosions and dents from the …

Parametric Analysis And Enhancement Of The Burst Capacity Model For Composite-Repaired Corroded Pipelines, Rodrigo Silva Silva-Santisteban

Electronic Thesis and Dissertation Repository

One of the main causes of pipeline failures is corrosion, which leads to a localized loss of the pipe wall thickness and hence compromises the capacity of the pipeline. Composite repair is a method to rehabilitate corroded pipelines. Design codes such as ASME PCC-2 are commonly used to design the repair thickness. As the predictive accuracy to determine the burst capacity of a composite repaired pipeline with existing models is generally poor, the main objective of the present thesis is to provide insights on the parameters that affect the burst capacity and propose improvements to the prediction of burst capacity …

Towards Smart And Cost-Effective Bridge Infrastructure Monitoring Systems, Premjeet Singh

Electronic Thesis and Dissertation Repository

Bridge health monitoring (BHM) has recently gained significant interest worldwide in the inspection and maintenance of aging bridge infrastructure in the era of climate change and adverse weather conditions. However, extensive datasets resulting from these monitoring systems require appropriate tools to diagnose the data systematically under various operating conditions of bridges, leading to expensive and time intensive BHM strategies. To mitigate this challenge, a smart and cost-effective bridge infrastructure management system is of paramount need in today’s world. This thesis aims to develop a suite of cost-effective bridge management strategies by employing limited and mobile sensing technology and addressing their …

Experimental Evaluation Of Abl And Downburst Wind Loads On An Elevated Building, Kate Current

Electronic Thesis and Dissertation Repository

Elevated low-rise buildings are vulnerable to cladding damage underneath the structure due to extreme winds and the absence of proper wind loading codes and standards such as the National Building Code of Canada (NBCC). The space between the ground and the horizontal base surface of an elevated structure affects its aerodynamics differently compared to a ground-mounted structure. Despite the widespread use of elevated low-rise buildings, there is still limited understanding of the wind interaction across building surfaces for different stilt heights and wind types. This research aims to evaluate the impact of atmospheric boundary layer (ABL) and downburst wind loads …

Simplified Modeling Of Bonded Prestressed High Strength Concrete Girders During Fire Exposure, Yi Mao

Electronic Thesis and Dissertation Repository

To evaluate the behavior of structures exposed to fire and estimate their structural fire resistance, engineers need design tools to overcome the complexities associated with structural analysis during fire exposure. These complexities include the uneven distribution of temperature within the structural elements and the deterioration in material properties. The current study introduces a simplified numerical model to evaluate the flexural behavior of bonded prestressed high-strength concrete sections exposed to fire. The model starts by predicting the temperature distribution within a structural element using 2-D finite difference analysis. It then uses one-dimensional sectional analysis to estimate the section behavior. The numerical …

A Computational Framework For Aerodynamic And Aeroelastic Modeling Of Wind Loads On Tall Buildings, Abiy Fantaye Melaku

Electronic Thesis and Dissertation Repository

Driven by the burgeoning growth of computing power over the last few decades, the capability of computational fluid dynamics (CFD) to simulate turbulent flows of practical interest has progressed rapidly. In the past, a notable research effort has been dedicated to applying CFD for modeling wind loads on structures, particularly for tall buildings. However, the current state of CFD for wind load evaluation of tall buildings using Large-Eddy Simulation (LES) has several critical challenges, including the treatment of atmospheric boundary layer (ABL) flow conditions, turbulence modeling of separated flows around buildings, and simulation of wind-structure interaction for dynamically sensitive buildings. …

An Explicit Model For Simplified Flutter Analysis Of Long-Span Bridges, Tibebu Hunegn Birhane

Electronic Thesis and Dissertation Repository

The collapse of the First Tacoma Bridge in 1940 at a wind speed of about 18m/s triggered the need to recognize aerodynamic stability as a design constraint for long-span bridges. The advancement in understanding and modeling of dynamic wind effects has played a significant role in the realization of long-span bridges with a clear span of up to 2 km. However, the need to span longer, the risk of windstorms exceeding the strongest recorded in the past, and consequently, the quest for optimized design solutions continue to evolve.

A rigorous nature of aerodynamic stability analysis techniques poses a challenge to …

Performance And Ultimate Limit State Of Large-Span Soil-Steel Structures, Kareem Embaby

Electronic Thesis and Dissertation Repository

This thesis investigates the structural behavior and soil-structure interaction mechanism of large-span soil-steel structures utilizing steel plates with the deepest corrugation profile, 500 mm X 237 mm. The world’s largest-span soil-steel bridge, with a span of 32.40 m, was constructed using 12 mm thick steel plates with the deepest corrugation profile and was instrumented extensively to monitor the displacements and straining actions of the steel structure. Lateral reinforcement steel mesh was attached to the steel structure and the ends of the structure were strengthened by circumferential reinforced concrete collars. Three-dimensional (3D) nonlinear finite element (FE) model was conducted and validated …

Hydration Kinetics, Microstructure, And Mechanical Strength Development Of Cement-Based Composites Incorporating Phase Change Materials, Afshin Marani

Electronic Thesis and Dissertation Repository

The research conducted in this thesis investigates the effects of phase change materials (PCMs) on the hydration kinetics and strength development of cement-based composites using extensive experimental and numerical analyses. Purposefully, the effect of microencapsulated PCMs (MPCMs) on the strength development of cement-based mortars and concretes was evaluated using powerful machine learning models trained with the largest available experimental data. Furthermore, a novel ternary machine learning approach was proposed to optimize the mixture design of mortars and concretes based on the thermos-physical properties of the MPCMs. The results obtained from machine learning simulations suggest the assessment of the effects of …

Effect Of Structural Nonlinearities On Flutter Of Cable-Supported Bridges, Sébastien Maheux

Electronic Thesis and Dissertation Repository

It is well known that cable-supported bridges, like suspension bridges and cable-stayed bridges, are structures that are highly sensitive to wind. This is why there has been an important research effort over the past decades on aeroelastic instability phenomena in bridges like flutter. This has allowed the safe design of long-span bridges with respect to wind effects. Nonetheless, the analysis methods that have become the norm in the field of bridge engineering, such as flutter analysis and wind tunnel tests, rely on some simplifications to facilitate analysis. For example, they assume a linear structural behavior of the bridge structure. Therefore, …

Behaviour Of Transmission Line Conductors Under Tornadoes, Dingyu Yao

Electronic Thesis and Dissertation Repository

Transmission line (TL) structure failures caused by tornadoes have been observed in multiple countries around the globe. The objective of this study is to develop an accurate load case that can simulate the critical tornado forces transmitted from the TL conductors to the towers. In order to achieve the goal, three different tornado wind fields, which were previously developed using computational fluid dynamic simulations, are considered. The tornado wind field provides the most critical forces on the TL conductors is determined and considered to obtain the critical load cases. Using the critical wind field, parametric studies are conducted to identify …

Behavior Of Wind Turbine Towers And Blades Under Tornado Wind Fields, Mohamed Abugazia

Electronic Thesis and Dissertation Repository

The installation rate of wind turbines around the world is increasing significantly. Therefore, wind turbine farms are constructed in plentiful wind resources areas that put a considerable number of wind turbine towers under severe wind conditions. As a result, failures due to unexpected wind loads on either the blades or the tower are increasing. In addition, wind turbines are designed to resist synoptic wind loads as per the current guidelines, which do not consider high-intensity wind (HIW) events such as tornadoes. The built-in-house numerical code “HIW-WT” has been developed in this study to model wind turbines under three-dimensional wind fields …

Effects Of The Soil Spatial Variability On Pipelines, Jose Luis Espinosa Mendez

Electronic Thesis and Dissertation Repository

Pipelines are the safest and most efficient way to transport large volumes of oil and gas from extraction fields, to refineries, industry and home consumption. Extensively used to transport fluids over long distances, pipelines may pass through terrain features exposed to geohazards. The performance of buried pipelines in areas subjected to ground displacements constitute a criterion for design, assessment and management of gas pipelines, to ensure public, environment and property safety in a cost-effective manner. Modern surveying and sampling techniques allow for better geotechnical characterization of ground movements and the variability of the soil properties with confidence. The statistical data …

Experimental Simulation Of Tornado-Like Vortices And Their Impact On High-Rise Buildings, Arash Ashrafi

Electronic Thesis and Dissertation Repository

One of the most crucial research areas in wind engineering is tornadoes due to the widespread damages to infrastructure and the environment in North America and other parts of the world. The proper scaling of tornadoes in experimental facilities, generating tornado-like vortices (TLVs) is, therefore, an essential part of evaluating tornado-indued damages on engineered buildings. The capability of producing TLVs of length scales in the range between 1:300 and 1:150 inside the Wind Engineering, Energy and Environment (WindEEE) Dome at Western University has already been demonstrated using only one mode of the full potential of this simulator. A new mode …

Structural Performance Of Glass Façades Exposed To Fire, Mohamed Badr

Electronic Thesis and Dissertation Repository

Glass façades are commonly used in the modern construction industry. The thesis starts by providing a general background about glass façades, their design criteria, and related previous research studies. The common concern among the previous studies was the inadequate performance of glass façades during fire incidents, which accelerates the spread and severity of the fire. This concern is magnified by the recent worldwide increase in wildfires. Thus, it is critical for engineers to be able to assess the structural performance of glass façades at elevated temperatures. The thesis addresses this need by presenting a simplified technique to model single skin …

Implication Of City Growth On Wind-Induced Loads For Cladding And Structural Design, Hadil M. Abdallah

Electronic Thesis and Dissertation Repository

As cities grow, the urban topology changes in density resulting in continuous variations in wind flow. The interaction of flow with this changing surrounding environment drives the aerodynamics to become more complex and varying, subjecting the building to significant changes in wind-induced-loads both on structural and non-structural elements. In this study, a series of boundary layer wind tunnel tests are conducted to investigate the impact of city growth on cladding and structural loading by using a typical tall building adopted from the Commonwealth Advisory Aeronautical Council (CAARC) building model. The city growth is represented by five different generic surrounding configurations, …

Machine Learning Prediction Of Structural Response For Reinforced Concrete Members Under Blast Loading, Monjee Almustafa

Electronic Thesis and Dissertation Repository

With increasing accidental and intentional explosions and blast events inflicting life loss and economic damage to civil infrastructure, greater attention is given to the analysis and design of blast-resistant structures. Accordingly, this thesis introduces state-of-the-art machine learning models dedicated to predicting the structural behavior of various reinforced concrete (RC) members under blast loading, including slabs, columns, and beams. Moreover, extended prediction models were developed for RC members that employ fiber-reinforced polymer (FRP) retrofitting and steel fiber-reinforced concrete as blast mitigation strategies. For each model, extensive validation was conducted through statistical performance measures and comparisons to existing prediction methods. Additionally, feature …

Burst Capacity Evaluation Of Corroded Pipelines Under Internal Pressure And Internal Pressure Combined With Longitudinal Compression, Shulong Zhang

Electronic Thesis and Dissertation Repository

Central to the design and integrity assessment of oil and gas transmission pipelines is to accurately evaluate their pressure containment capacities, i.e. burst capacities. Corrosion defects threaten the structural integrity of pipelines as they cause thinning of the pipe wall and therefore reduce the burst capacity. Corroded in-service pipelines may be subjected to longitudinal compression resulting from, for example, ground movement or formation of free spans, in addition to internal pressures. The main objective of the research reported in this thesis is to facilitate Fitness-For-Service (FFS) assessment of corroded pipelines.

The first study investigates the conservatism associated with the rectangular …

Towards Multiclass Damage Detection And Localization Using Limited Vibration Measurements, Sandeep Sony

Electronic Thesis and Dissertation Repository

Traditional vibration-based damage detection methods provide structural health information based on their measured data (i.e., acceleration and displacement response). Over the last few decades, various model-based and time-frequency methods have shown great promises for damage identification and localization. However, the existing methods are unable to perform satisfactorily in many situations, including the presence of limited sensor measurements and training data, detection of minor and progressive damage, and identification of multiclass damage, creating constraints to make them free of user-intervention and implemented using the modern sensors. The main objective of this thesis is to develop algorithms capable of damage identification and …

Finite Element Analyses And Random Field Modeling Of Naturally Corroded Underground Energy Pipelines, Ji Bao

Electronic Thesis and Dissertation Repository

Metal-loss corrosion is one of the major threats to the integrity of oil and natural gas pipelines. The Fitness-For-Service (FFS) assessment is commonly carried out to demonstrate the integrity of the corroded pipelines. The naturally occurring corrosions on the external surfaces are irregularly shaped three-dimensional features. Due to the geometric complexity of the natural corrosion features, the research of FFS assessment in the previous studies always employed the pipe segments containing artificially induced corrosion features. However, since artificial features are in general regular-shaped, e.g. cubic or semi-ellipsoidal, they do not capture geometric characteristics of naturally occurring corrosions. The thesis develops …

Machine Learning Prediction Of Shear Capacity Of Steel Fiber Reinforced Concrete, Wassim Ben Chaabene

Electronic Thesis and Dissertation Repository

The use of steel fibers for concrete reinforcement has been growing in recent years owing to the improved shear strength and post-cracking toughness imparted by fiber inclusion. Yet, there is still lack of design provisions for steel fiber-reinforced concrete (SFRC) in building codes. This is mainly due to the complex shear transfer mechanism in SFRC. Existing empirical equations for SFRC shear strength have been developed with relatively limited data examples, making their accuracy restricted to specific ranges. To overcome this drawback, the present study suggests novel machine learning models based on artificial neural network (ANN) and genetic programming (GP) to …

Joint Wind And Ice Effects On Transmission Lines In Mountainous Terrain, Daniel Davalos Arriaga

Electronic Thesis and Dissertation Repository

Atmospheric icing on mountainous terrain can produce catastrophic damages to transmission lines when incoming particles impinge and accrete on the cable surface of the system. The first challenge in wind-ice loading is determining joint statistics of wind and ice accretion on transmission lines. This study analyzes the weather characteristics for a specific site of study using 15 years of historical data to use as inputs for ice accretion modeling. The joint wind and ice hazard is characterized by simulating 500 years of icing events from the fitted probability distributions of ice accretion and wind on ice velocities. The second challenge …

Biomechanics Of Trees Under Extreme Wind Loading Events, Mojtaba Dargahi

Electronic Thesis and Dissertation Repository

For urban planners, arborists and foresters, understanding tree stability under self-weight and applied loads from wind and snow is important when developing management strategies to reduce the risk of damage from these abiotic agents. Current predictive approaches are generally empirical and based on a posteriori surveys of failures. A more rigorous engineering approach to understanding response phenomenon in trees subjected to extreme winds has been attempted herein. The size of trees and their architecture (shape and structure) greatly influence their mechanical stability under dynamic loading. Considering trees as porous media, wind loads on them are affected by their resistance to …

Structural Performance Of Ordinary And Laminated Glass During Fire Exposure, Amer Sabsabi

Electronic Thesis and Dissertation Repository

Façade and glazing elements constitute the skin of buildings. They are the interface between the inside and outside environment. Glass has low fire resistance and can quickly break during fire events. This creates new vents, which increase the oxygen supply and promote the flashover phenomenon. Existing methods for evaluating the structural fire safety of glass require expensive experimental tests or extensive knowledge of finite element (FE) modeling. This research provides simplified, rational, and reliable methods to assess the behavior of ordinary and laminated glass panels during fire exposure. The proposed methods provide the means to determine the glass temperature and …

Material Evaluation And Structural Monitoring Of Early-Age Masonry Structures, Kyle Dunphy

Electronic Thesis and Dissertation Repository

During the initial construction period, “early-age” masonry walls are susceptible to lateral loads induced by wind or earthquake, which may result in damages or catastrophic failures. To mitigate such consequences at construction sites, temporary bracings are adopted to provide lateral support to masonry walls until they are matured enough to serve as the inherent lateral system of the structure. However, current temporary bracing guidelines provide oversimplified design due to the lack of available information on the material properties of early-age masonry. Moreover, there are no existing techniques for monitoring masonry walls to detect cracks due to construction activities. …

Seismic Hazard Assessment For Mainland China Based On Spatially Smoothed Seismicity And Projected Sets Of Ground Motion Models, Chao Feng

Electronic Thesis and Dissertation Repository

The latest version of the Chinese seismic hazard map (CSHM) (i.e., fifth-generation CSHM) was developed based on the delineated seismic source model, which is defined based on geological and seismological information but also with some subjectivities. The results of the CSHM were presented in terms of peak ground acceleration (PGA) and peak ground velocity. No maps for spectral acceleration (SA) are given. This is partly due to the ground motion models (GMMs) to predict SA for mainland China are unavailable. The unavailability of the GMMs for SA results in the lack of uniform hazard spectra (UHS) that is important for …

Classification, Localization, And Quantification Of Structural Damage In Concrete Structures Using Convolutional Neural Networks, Majdi Flah

Electronic Thesis and Dissertation Repository

Applications of Machine Learning (ML) algorithms in Structural Health Monitoring (SHM) have recently become of great interest owing to their superior ability to detect damage in engineering structures. ML algorithms used in this domain are classified into two major subfields: vibration-based and image-based SHM. Traditional condition survey techniques based on visual inspection have been the most widely used for monitoring concrete structures in service. Inspectors visually evaluate defects based on experience and engineering judgment. However, this process is subjective, time-consuming, and hampered by difficult access to numerous parts of complex structures. Accordingly, the present study proposes a nearly automated inspection …

New Model And Simulation Algorithm Of Nonstationary Non-Gaussian Ground Motions Based On S-Transform, Xizhong Cui

Electronic Thesis and Dissertation Repository

The seismic ground motions are nonstationary stochastic processes and vary from site to site. The time histories of synthetic ground motions are used for nonlinear inelastic structural dynamic analysis since the historical records are limit or unavailable for a particular scenario seismic event. This is especially the case for structures with multiple supports. The characteristics of the nonstationary stochastic ground motions depend on the earthquake magnitude, fault mechanism, source-to-site distance, and local site conditions. The characteristics could be represented by time-frequency (dependent) power spectral density (TFPSD) and coherence functions. The assessment of such power spectral density and coherence functions are …

Experimental And Numerical Study On Three-Edge Bearing Test For Reinforced Concrete Pipe, Abdul-Aziz Younis

Electronic Thesis and Dissertation Repository

Reinforced Concrete Pipe (RCP) is widely used in storm and wastewater management owing to its resiliency and reliability. The century old Three-Edge Bearing Test (TEBT) is currently used to classify RCP strength. The test relies on the skill and experience of the operator for capturing the occurrence of a 0.3-mm-wide crack using a leaf-gauge, which induces subjectivity and error. Studies have also indicated the TEBT crack bears little structural significance.

This thesis aims at improving the TEBT by replacing the arbitrary crack-width with rational capacity-driven criteria. A wide range of full-scale RCP were instrumented and subjected to the modified TEBT …

Experimental And Numerical Study Of Precast Concrete Pipe With Single Elliptical Steel Cage Reinforcement, Abdullah Samir Ramadan

Electronic Thesis and Dissertation Repository

Reinforced concrete pipe (RCP) with single elliptical (SE) reinforcement offers cost savings and is permitted by Canadian and American standards. Yet, its use has not yet gained momentum primarily due to limited knowledge of its structural performance. This study explores the structural behaviour of full-scale 1050 mm and 1200 mm diameter RCP reinforced with SE cold drawn steel wire cage under the Three-Edge Bearing Test. Results indicate that RCP with SE reinforcement designed per current standards did not meet the specified 0.3-mm crack and ultimate load capacity. Hence, pertinent provisions in CSA A257.2 and ASTM C76 for RCP need to …