Engineering Commons^™

Effects Of City Growth On Tall Building Cladding Fatigue, Hang You

Electronic Thesis and Dissertation Repository

As city develops there will be changes in the aerodynamic characteristics due to varying building surrounding and topology. For example, the city growth around a tall building can cause an increase in wind load due to venturi or wake effects or decrease due to sheltering effects depending on the type of surrounding. The densification of cities will also increase the turbulence level due to wake effects. In the present study, the implication of these changes on the aerodynamic forces on cladding connections is investigated. With increased fluctuations in the wind loads, the cladding connections will also experience stress fluctuations, which …

Biodegradability Of Cellulose And Its Impact On Oxygen Transfer Efficiency And Biological Nutrients Removal, Ahmed Shawki Ahmed

Electronic Thesis and Dissertation Repository

Cellulose from toilet paper is a significant fraction of particulate organics, which is recoverable. For the first time, comprehensive mapping and tracking the fate of cellulose across various unit processes at full-scale in two water resource recovery facilities located in North America and Europe was undertaken. The influent cellulose content accounted for approximately one-third of the total suspended solids (TSS). More than 80% of the raw wastewater cellulose was captured in primary treatment. The high cellulose content of the primary sludge accounting for 17%-35% of the TSS facilitates cellulose recovery. Cellulose biodegradation efficiency varied between 70%-90% of the primary effluent, …

Geo-Structural Analysis Of Integral Abutment Bridges, Biyi Li

Electronic Thesis and Dissertation Repository

Integral abutment bridges are jointless bridges where bridge decks and girders are integrated with abutments. The longitudinal displacements and rotations of the bridge are partially accommodated by the soil-pile system wherein the soil surrounding the piles generates active and reactive lateral forces when the piles deflect due to the movement of the superstructure. Since the soil stress-strain responses are inherently nonlinear, the pile deflection and the soil stiffness are interdependent. Consequently, evaluating soil-pile interactions requires a detailed geo-structural analysis. There are two common approaches used to idealize the soil-pile interactions for laterally loaded piles: the p-y and continuum mechanics approaches …

Reliability-Based Calibration Of Design Wind Load, Snow Load And Companion Load Factors Considering Climate Change Effect, Qian Tang

Electronic Thesis and Dissertation Repository

Wind load and snow load are two of the environmental loads that need to be considered for structural design. This study compared the statistical characteristics of the annual maximum thunderstorm and non-thunderstorm winds based on the updated wind speed dataset and carried out the extreme value analysis for wind load by treating the synoptic and thunderstorm winds separately. The results indicated that for southern Ontario and the southern part of the Prairies, the extreme winds could be dominated by thunderstorm winds. The consideration of both thunderstorm winds and synoptic winds separately to recommend the reference wind velocity pressure for the …

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 …

Uncertainties In The Assessment Of Individual And Compound Flooding From River Discharge And Coastal Water Levels Under Climate Change, Shuyi Wang

Electronic Thesis and Dissertation Repository

It is widely recognized that climate change can impact the risks of flooding in many regions around the world especially the low-lying coastal areas. The concurrent occurrence of multiple flood drivers such as high river flows and coastal water levels can aggravate such impacts causing catastrophic damages. In this study, the individual and compounding effects of riverine and coastal flooding are investigated over Stephenville Crossing, a town located in the coastal-estuarine region of Newfoundland and Labrador (NL), Canada. The impacts of climate change on flood characteristics and the corresponding uncertainties associated with model inputs and structure, and emission scenarios are …

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 …

Effect Of The C-Source And Cod/N On Nitrite And Partial Nitrate Denitrification, Ahmed Fathy Elyas Badia

Electronic Thesis and Dissertation Repository

The main objectives of this study were: (i) to investigate dynamic specific denitrification rates (SDNR) from nitrite at various chemical oxygen demand (COD) / nitrogen (N) ratios using municipal wastewater (MWW) and acetate, and to study the kinetic parameters, (ii) to investigate the dynamic specific denitrification rates (SDNRs) from nitrite at various COD/N ratios in a system that uses methanol as a complementary carbon source, and studying the effect in case if nitrate replaced nitrite, and (iii) to investigate and compare between the nitrite shunt and N-PDN-anammox technologies through studying the dynamic specific denitrification rates (SDNRs) from nitrate and nitrite …

Chemically Enhanced Primary Treatment: Modelling And Resources Recovery, Wenjuan Mu

Electronic Thesis and Dissertation Repository

The chemically enhanced primary treatment (CEPT) process is gaining momentum for carbon redirection, thereby lowering the downstream liquid train load and maximizing energy recovery from the primary sludge. CEPT technique enhances coagulation and flocculation, that enable faster settling of particulate and colloidal solids and dissolved ions such as phosphate to enhance removal efficiency. Comprehending the dynamic behaviour of CEPT clarifiers is critical to not only develop a reliable whole plant simulation but also fully understand the efficacy of the treatment plant performance. To achieve such purposes, a great amount of efforts has been contributed to the advancement of primary clarifier …

Performance Of A Drinking Water Treatment System For A Small Community In Rural Ghana, West Africa, Xiya Xu

Electronic Thesis and Dissertation Repository

In many African countries, the shortage of water resources is a common phenomenon. Providing safe and adequate water is an issue that must be considered by community leaders and municipal authorities. The present project investigated the performance of a small drinking water treatment system in a small community at Enyan Abaasa, Central Region, Ghana, through sampling and laboratory testing. The treatment system, which is fed by a deep borehole, consists sequentially of polypropylene (PP) yarn pre-filter, sand filter, layered activated carbon-softener resin filter, PP yarn micron filter, reverse osmosis (RO) membrane, PP yarn final filter and two ultraviolet (UV) disinfection …

Sustainable Smouldering For Waste-To-Energy: Scale, Heat Losses, And Energy Efficiency, Tarek L. Rashwan

Electronic Thesis and Dissertation Repository

Applied smouldering combustion is emerging as a highly energy efficient approach towards waste-to-energy. This thesis aims to better understand this potential by addressing a critical knowledge gap between laboratory scale smouldering research and large-scale applications. Altogether, new understanding in provided on the complex and dynamic interactions between the reaction zone (smouldering front) and the cooling zone (treated inert porous media) by integrating theory, experiments, analytical modelling, and global energy balance calculations. The experiments spanned a range of reactor sizes and smouldering conditions (from weak to robust) with dry (carbon) and wet (sludge) fuels mixed in sand. This work revealed that …

Machine Learning Prediction Of Mechanical And Durability Properties Of Recycled Aggregates Concrete, Itzel Rosalia Nunez Vargas

Electronic Thesis and Dissertation Repository

Whilst recycled aggregate (RA) can alleviate the environmental footprint of concrete production and the landfilling of colossal amounts of demolition waste, there need for robust predictive tools for its effects on mechanical and durability properties. In this thesis, state-of-the-art machine learning (ML) models were deployed to predict properties of recycled aggregate concrete (RAC). A systematic review was performed to analyze pertinent ML techniques previously applied in the concrete technology field. Accordingly, three different ML methods were selected to determine the compressive strength of RAC and perform mixture proportioning optimization. Furthermore, a gradient boosting regression tree was used to study the …

Assessment Of The Performance Of Field-Scale Bioretention Systems To Reduce Phosphorus Loads From Urban Stormwater, Jaeleah J. Goor

Electronic Thesis and Dissertation Repository

High nutrient loading can degrade surface water quality worldwide. Bioretention systems are low impact development stormwater management features designed to remove pollutants, including phosphorus (P), from urban stormwater runoff. In this study, two field-scale bioretention systems installed in London, Ontario, Canada were monitored to develop detailed understanding of P behaviour and the hydro-biogeochemical mechanisms that govern overall P retention. Net retention of total P and dissolved organic P, and net release of soluble reactive P (SRP) and total dissolved P were observed. Prolonged input of road de-icing salts (NaCl) in winter and early spring may result in high P release …

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 …

Hydrostatic Performance Of Reinforced Concrete Pipe For Infiltration, Lui Sammy Wong

Electronic Thesis and Dissertation Repository

Groundwater infiltration into underground sewer systems has long been a costly issue for municipalities. With reinforced concrete pipe (RCP) being a primary option for sewer systems, existing hydrostatic testing methods conducted by manufacturers to measure internal pipe pressure, as required by specifications, do not reflect in-situ external hydrostatic conditions. This thesis records the development of a novel testing method to evaluate the RCP joint performance for infiltration. The test is safe and easy to conduct by RCP producers at the factory. The test method mimics field conditions of possible RCP joint gap and joint offset. Over 100 tests were conducted, …

Ultimate And Serviceability Limit States Of Large Shallow Foundations Under Combined Loading, Pengpeng He

Electronic Thesis and Dissertation Repository

Estimation of the bearing capacity and deformations of large shallow foundations under combined loadings can be of great significance. Some geotechnical design guidelines recommend the failure load envelope method for ultimate limit state analysis. Since many investigations of this method focus primarily on undrained failure envelopes using unlimited-tension interfaces, zero-tension interfaces have not been well investigated. In addition, less work is available on drained failure envelopes. For serviceability limit states, the majority of approaches used are based on uncoupled, isotropic assumptions. Further work needs to be done on more appropriate elastic solutions for combined loadings.

General VHMT failure envelopes for …

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 …

Tornado Occurrence Modelling And Equivalent Tornado Design Wind Profile For Canada, Qian Huang

Electronic Thesis and Dissertation Repository

The tornadoes can be devastating to structures and infrastructure systems. They can cause fatalities and economic losses. In this thesis, the tornado hazard for Canada is systematically assessed. The use of three spatial point processes (i.e., Poisson, zero-inflated Poisson, and negative binomial models) are first investigated in a hierarchical structure to predict the tornado occurrence rate by considering the annual cloud-to-ground lightning flash density and annual thunderstorm days as covariates. An existing historical tornado catalogue with reported tornado events up to 2009 is considered and the population bias effect in estimating the tornado occurrence rate is included. Both the Bayesian …

Evaluation And Bias Correction Of Remotely Sensed Precipitation Products Across Canada, Saber Moazamigoodarzi

Electronic Thesis and Dissertation Repository

Reliable estimation of precipitation, as the most important variable in hydrological modelling, is crucial for water resources management. Rain gauges that provide precipitation measurements at point scale have inherent limitations and difficulties in remote regions and complex terrains due to accessibility, gauge undercatch, among others. Alternatively, satellite and radar precipitation data can estimate precipitation at high spatial and temporal resolution by utilizing several types of space and ground-borne sensors. However, due to the indirect estimates of precipitation by remotely sensed products, their measurements are subject to systematic biases and are required to be evaluated and bias adjusted before using at …

Biological Nutrient Removal: Minimizing Carbon And Oxygen Requirements, Masuduz Zaman

Electronic Thesis and Dissertation Repository

With increasing focus on the carbon footprint of wastewater treatment and rapidly emerging paradigm shift towards resource recovery, energy consumption minimization and utilization of readily available organics for biological nutrient removal in municipal wastewater treatment plants is eliciting significant interest. The objective of this PhD work is to investigate non-traditional approach to minimize carbon and energy demand for biological nutrient removal

The feasibility of using thermal alkaline treated municipal wastewater biosolids as an alternative carbon source for biological phosphorus removal was investigated. Two sequencing batch reactors (SBRs) were operated with synthetic volatile fatty acids (acetic acid and propionic acid) and …

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 …

Effects Of Corner Radii On Wind Tunnel Testing Of Low-Rise Buildings, Kytin Kwan

Electronic Thesis and Dissertation Repository

Wind effects on buildings are commonly studied by testing 3D printed building models in a wind tunnel. A challenge with 3D printing is that the edges of these models may not be perfectly sharp, but rounded with a radius of curvature, R. It is well known that when edges are significantly rounded, the aerodynamics of the building can be altered (Robertson, 1991; Mahmood 2011), leading to inaccurate predictions of full-scale surface pressures and wind loads. However, there is presently no guidance on model edge radii prescribed in wind tunnel testing standards such as ASCE 49-12. The objective of the present …

Internal Pressure Modelling For Low-Rise Buildings In Tornadic Winds, Aaron L. Jaffe

Electronic Thesis and Dissertation Repository

Internal pressures play a large role in the failure of wood-frame houses as the loss of the entire roof section becomes much more likely once the envelope of the building has been breached. Many studies have used internal pressure modelling to simulate internal pressures in structures from atmospheric boundary layer (ABL) winds, however, relatively little work has been done on this subject using tornadic winds. The objective of this study is to explore internal pressure modelling issues for tornadoes. The first part of the study uses a computational internal pressure model to simulate tornadic internal pressures of a low-rise structure; …

Identification Of Aerodynamic Damping For Flexible Structures Using Wind-Induced Response, Shea Laventure

Electronic Thesis and Dissertation Repository

Damping estimation is a critical task to perform during the design of slender structures, or for existing structures. This is to ensure the response of the structure is within allowable limits and to determine if additional damping is necessary from auxiliary devices. If a slender structure is experiencing wind loading, a phenomenon known as aerodynamic damping arises, which has the potential to reduce the damping of the structure. The most efficient method to estimate aerodynamic damping is to use a system identification technique, which requires only the input forces and output response of the structure. This thesis describes how to …