Engineering Commons^™

Design Of Stick-Framed Wood Roofs Under Extreme Wind Loads, Caspar Bain

Electronic Thesis and Dissertation Repository

Light-frame wood construction comprises nearly 90% of the housing industry in
Canada and the United States. The roofs of these houses can be constructed either
entirely on site or using prefabricated trusses. Assembling the roof structure on site,
otherwise known as stick-framing, is a framing technique with current code guidelines
that are based on past practice and limited consideration of wind loads. This makes
these roof structures susceptible to failure in high-speed wind events, such as tornadoes. Around 90% of all tornadoes in Canada fall in or below the EF-2 category,
making it a possible target for design of wood-frame …

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 …

Modelling And Simulation Of Nonstationary Non-Gaussian Wind Speed And Wind Pressure Coefficients, Minyu Xiao

Electronic Thesis and Dissertation Repository

The time series of the wind speed from hurricane and downburst events can exhibit nonstationary non-Gaussian characteristics. Moreover, the time series of the wind pressure for a stationary wind may not be Gaussian. This thesis is focused on analyzing, characterizing, and simulating nonstationary/stationary Gaussian/non-Gaussian of wind speed and wind pressure coefficients by using time-frequency transform techniques such as the S-transform (ST) and discrete orthonormal S-transform (DOST). It is shown that by removing the mean of downburst winds, the multivariate nonstationary downburst wind speed processes can be efficiently decomposed and simulated by applying ST and DOST. It was also found that …

Flexural Behaviour Of Concrete Beams With High Strength Reinforcement, Sohaib Akbar

Electronic Thesis and Dissertation Repository

Using High Strength Reinforcement (HSR) in concrete construction allows steel volumes to be reduced, and economies to be realized. CSA Standard A23.3:19 “Design of Concrete Structures” limits the maximum yield strength for design to 500 MPa. This thesis investigates the flexural behavior of concrete beams reinforced with HSR to assess whether current code provisions are appropriate. Curvature ductility ratios are calculated for cross-sections with varying concrete compressive strengths, and reinforcement types and quantities. The effects of utilizing HSR on extreme fibre concrete compressive strains at Ultimate Limit State (ULS), moment redistribution at ULS, and deflections at Serviceability Limit States, are …

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 …

Performance Of Fouled Railroad Superstructure Subjected To Traversing Heavy Haul Trains, Majid Kh Touqan

Electronic Thesis and Dissertation Repository

Railway transportation offers capacity, efficiency, and safety to serve the needs of modern societies for moving freight and people. Therefore, the sustainability and safety of railroad infrastructure are of paramount importance for securing transportation needs. Freight train passby loads increase the surface deformation of railroad substructure due to cumulative plastic strains, which lead to surface deviation of the railroad tracks. Correspondingly, railroad maintenance is necessary to sustain track geometry alignment and to prevent deterioration of the sub-structure over time, which can increase operating costs significantly. Therefore, this thesis evaluates the performance of fouled railroad superstructure through laboratory testing of fouled …

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, …

Analysis Of Standing Seam Metal Roofs Subjected To Extreme Wind Loads, Yuchao Xia

Electronic Thesis and Dissertation Repository

Standing seam metal roof (SSMR) systems are widely used in low-rise buildings. This study aims to understand the behavior of SSMR systems, especially the failure mechanisms, under severe wind loads. Full-scale experiments conducted at Insurance Research Lab for Better Homes make it possible to examine the performance of SSMR systems with realistic dimensions and boundary conditions. The induced loads on the clips could be measured directly. The results show that there is a linear relationship between the wind pressure and clip reaction under low wind pressure (less than 500 Pa). It is found that load sharing among clips changes at …

Physical Investigation Of Downburst Winds And Applicability To Full Scale Events, Federico Canepa

Electronic Thesis and Dissertation Repository

Thunderstorm winds, i.e. downbursts, are cold descending currents originating from cumulonimbus clouds which, upon the impingement on the ground, spread radially with high intensities. The downdraft phase of the storm and the subsequent radial outflow that is formed can cause major issues for aviation and immense damages to ground-mounted structures. Thunderstorm winds present characteristics completely different from the stationary Gaussian synoptic winds, which largely affect the mid-latitude areas of the globe in the form of extra-tropical cyclones. Downbursts are very localized winds in both space and time. It follows that their statistical investigation, by means of classical full scale anemometric …

Erosion Control Of Steep Open Channels Using Articulated Concrete Blocks, Mohammadomid Marandi

Electronic Thesis and Dissertation Repository

Overtopping flow can undermine the stability of hydraulic structures including embankments and spillways through the shear stress and the subsequent soil erosion. Increased flow velocity can cause scour, which can result in the failure of dams, bridges, and overall open channel hydraulic structures. Sediment transport is another crucial issue in open channels that can cause severe socioeconomic and environmental consequences. Two general approaches are commonly considered for scour prevention. The first approach involves flow modifications to minimize the corresponding effects on the structures. The second approach is associated with bed armoring and placing physical barriers on the natural bedding such …