Engineering Commons^™

The Influence Of Frontal And Axial Plane Deformities On Contact Mechanics During Squatting: A Finite Element Study, Yidan Xu

Electronic Thesis and Dissertation Repository

Knee Osteoarthritis (KOA) is a degenerative joint disease and a leading cause of disability worldwide. Lower limb malalignment was a risky factor leading to KOA, altering the load distributions. This study aimed to study the influence of knee deformities on knee contact mechanics and knee kinematics during squatting. A full-leg squat FE model was developed based on general open-source models and validated with in vivo studies to investigate the outputs under frontal malalignment (valgus 8° to varus 8°) and axial malalignment (miserable malalignment 30°). As a result, Varus-aligned and miserable aligned models increased medial tibiofemoral force and lateral patellar contact …

Behaviour Of Transmission Lines Subjected To Tornadoes Through Aeroelastic Testing And Numerical Modeling, Nima Ezami

Electronic Thesis and Dissertation Repository

Tornadoes, as a form of high intensity wind (HIW) events, represent major threats to transmission line systems in many regions around the globe. Transmission line systems are among the most vulnerable structures to tornadoes due to their expansion over hundreds of kilometers and, therefore, increased exposure to such localized wind events. A comprehensive research project has been developed over the past two decades at Western University to study this problem. The research conducted in this thesis provides a significant development to the advancement of knowledge in this area through achieving three main objectives. The first objective is to assess and …

Performance Of Single And Groups Of Hollow Bar Micropiles In Sand, Maged Abdlrahem

Electronic Thesis and Dissertation Repository

Micropiles offer an efficient load transfer mechanism, which facilitates carrying considerable load in compression and tension. Recently, hollow bar micropiles (HBMP) have gained wide acceptance due to their fast installation and small installation equipment, which allows installation in sites with limited access. The HBMP is commonly constructed using a drill bit/ hollow bar diameter ratio (D_b/D_h) of around 2, and they are typically designed assuming type B micropiles as classified by the Federal Highway Administration (FHWA). However, increasing the drill bit diameter should increase the micropile diameter and hence may enhance its performance and increase its …

Thermo-Hydro-Mechanical Analysis Of Evaporation From Unsaturated Soils, Seyed Morteza Mousavi

Electronic Thesis and Dissertation Repository

ABSTRACT

Estimating evaporation from unsaturated soil is important for many applications including agriculture, climate, hydrology, water resources, saturated and unsaturated groundwater flow, slope stability, and soil covers. As an example, the long term performance of soil covers, which are widely used in mining and landfill applications to protect the environment, strongly depends on evaporation from their surfaces.

Evaporation depends on both moisture flow within an unsaturated soil mass, which is generally coupled with heat flow, and void ratio and hydraulic and air conductivities, which are in turn affected by stress and strain and resulting soil settlement. This makes thermo-hydro-mechanical (THM) …

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 installing …

Time-Dependent Behaviour Of Micro-Tunneling Construction In Queenston Shale, Hayder Mohammed Salim Al-Maamori

Electronic Thesis and Dissertation Repository

The Queenston shale among other shales from southern Ontario exhibits time-dependent deformation behaviour. This behaviour is manifested in the form of volume increase which can cause damages to the hosted underground structures. The time-dependent deformation of rocks can cause cracks in the springline of tunnels, wall inward movement, roof spalling and floor heave, which requires costly remedial measures. The expansion of the existing infrastructures in southern Ontario requires construction techniques, such as micro-tunneling to build new tunnels and pipelines under the existing structures with minimal impact to these structures and to the environment. However, adopting this technique in swelling rocks, …

Analysis And Design Procedure For Liquid-Filled Conical Tanks Under Seismic Loading, Ahmed Musa

Electronic Thesis and Dissertation Repository

Steel conical tanks are widely used for liquid storage in North America and elsewhere. A number of those tanks collapsed in the last decades as a result of instability of the steel shells. Despite being widely used, no specific design procedure is available for conical tanks under dynamic conditions. The research conducted in the current thesis presents a simplified approach for the design of steel conical tanks when subjected to ground excitations in the form of horizontal and vertical excitations.

First, the capacity of steel conical tanks to avoid yielding and buckling of the tank vessel under hydrodynamic pressure resulting …

Behaviour Of Reinforced Concrete And Composite Conical Tanks Under Hydrostatic And Seismic Loadings, Ahmed Elansary

Electronic Thesis and Dissertation Repository

Conical liquid storage tanks are widely used to store different liquids and to provide water supply at cities and municipalities. However, no comprehensive guidelines currently exist in the codes of practice for the structural analysis and design of such tanks. The walls of a conical tank can be made of steel, reinforced concrete, or a combination of the two materials in a composite type of construction in which steel and concrete walls are connected using steel studs. The research conducted in this thesis provides a comprehensive understanding of the structural behaviour of reinforced concrete and composite conical tanks under hydrostatic …

Monotonic And Cyclic Performance Of Spun-Cast Ductile Iron Helical Tapered Piles, Ahmed Fahmy

Electronic Thesis and Dissertation Repository

The performance of a novel piling system is investigated, which involves a spun-cast ductile iron (SCDI) tapered shaft fitted with a lower helical plate. It combines the efficiency of the tapered section, the competitive cost, effectiveness and durability of spun cast ductile iron with a rough surface and the construction advantages of helical piles. The system is installed using a fast, low vibration and reduced noise process. Seven instrumented piles including five SCDI tapered and two steel straight pipes were installed in sand using mechanical torque. The piles were subjected to cyclic and monotonic compression, uplift and lateral load tests. …

Numerical And Experimental Studies Of Transmission Lines Subjected To Tornadoes, Ahmed Hamada

Electronic Thesis and Dissertation Repository

The majority of worldwide weather-related transmission line failures have been attributed to High Intensity Wind (HIW) events in the form of tornadoes and downbursts. The research conducted in the current thesis presents a significant development in the understanding of the structural behaviour of transmission line systems under tornado loading. A comprehensive in-house numerical model that combines the data of computational fluid dynamic (CFD) simulations of tornado wind fields with three dimensional nonlinear structural analysis modelling is developed. A three dimensional four-nodded cable element is first formulated to simulate the nonlinear large deformation behaviour of the conductors. The support provided to …

Experimental And Numerical Development Of Anchor-Jointed Precast Structural Wall System And Optimum Design Of Prestressed Slabs, Mohamed El Semelawy

Electronic Thesis and Dissertation Repository

Precast concrete shear walls are used to resist lateral loads in low- to medium-rise buildings. An innovative joining technique is proposed to accelerate construction process and to reduce concrete damage possibility and capital loss during an earthquake event. Panels are jointed using steel anchor bolts, therefore, the system is designated "anchor-jointed precast structural wall system". In this system, anchors are utilized as a structural fuse. Damaged anchors are easily replaced after an earthquake, thus minimizing repair costs and serviceability disruptions. In the first part of this thesis, conceptual development of the system is carried out. A research program of combined …