Engineering Commons^™

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 …

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 …

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 …

Lateral Load Analysis Of Multi-Storey Light-Frame Wood Buildings Through Detailed And Simplified Numerical Approaches, Chu Peng

Electronic Thesis and Dissertation Repository

Increasing global demand for a sustainable society is driving the development of multi-storey light-frame wood structures (LFWSs). A high-resolution finite element modelling (FEM) procedure for three-dimensional multi-storey LFWS buildings is developed. This tremendous effort is carried out to have a benchmark model that can be used for the validation of simpler models and for the assessment of the structural performance considering system effects. High-resolution FEM of all components of a building is not practical. A simplified FEM procedure is developed based on equal work principle. Verification of the accuracy of the high-resolution model is undertaken by comparing the natural frequencies …

Progressive Failure Of Transmission Line Towers Under Different Tornado Wind Fields, Wesam Abdelhamid Mohamed

Electronic Thesis and Dissertation Repository

High-intensity wind events (downbursts and tornadoes) cause the majority of weather-related transmission line (TL) failures, which detrimentally affect society. This study investigates the progressive failures of single TL towers and TL systems under different F2 tornadoes. Different tornado wind fields are incorporated in a fluid-structure software developed at Western University. Progressive failure analysis is then conducted for four towers under the most critical tornado configurations identified from extensive parametric studies. Moreover, the cost associated with designing TLs to sustain F2 tornadoes is investigated by strengthening the TL towers. Finally, the progressive failure within self-supported TL systems under different tornadoes, and …

System Reliability Analysis Of Defected Pile Group Foundations, Abdalla E. Adlan Alhashmi

Electronic Thesis and Dissertation Repository

Deep foundations design suffers some degrees of uncertainties. This thesis studies the behavior of defected pile group foundations installed in sand and calibrates the resistance factor of pile group foundation, utilizing a rational based system reliability analysis. This was achieved by conducting a comprehensive numerical parametric investigation using the computer program ABAQUS/Standard. The result of the parametric study showed that the presence of a defected pile in a pile group foundation causes lateral deflection of the pile cap and hence induces bending moment at the adjacent piles which affects the load distribution mechanism of the system. It was also found …

Seismic Performance Of Superelastic Shape Memory Alloy Reinforced Concrete Shear Wall Systems, Emad A. Abraik

Electronic Thesis and Dissertation Repository

A major sustainability issue for reinforced concrete (RC) structures is the residual deformations caused by the yielding of the steel bars during extreme seismic events. Numerous efforts have been made to develop self-centering structures, which minimize these deformations and the associated seismic damage. Superelastic shape memory alloys (SE-SMA) can be utilized in concrete elements to achieve such behaviour. This thesis focuses on the use of SE-SMA bars in RC walls.

First, the thesis starts by conducting a fragility analysis to assess the seismic performance and vulnerability of ten and twenty-story SE-SMA RC walls. SE-SMA bars are used within the plastic …