Engineering Commons^™

Automated Large-Scale Tornado Treefall Detection And Directional Analysis Using Machine Learning, Daniel G. Butt, Aaron L. Jaffe, Connell S. Miller, Gregory A. Kopp, David Sills

Civil and Environmental Engineering Publications

Abstract

In many regions of the world, tornadoes travel through forested areas with low population densities, making downed trees the only observable damage indicator. Current methods in the EF scale for analyzing tree damage may not reflect the true intensity of some tornadoes. However, new methods have been developed that use the number of trees downed or treefall directions from high-resolution aerial imagery to provide an estimate of maximum wind speed. Treefall Identification and Direction Analysis (TrIDA) maps are used to identify areas of treefall damage and treefall directions along the damage path. Currently, TrIDA maps are generated manually, but …

Numerical Study Of Flow Characteristics Around A 30° Yawed Circular Cylinder At R E = 10 4, Ran Wang, Shaohong Cheng, David S.K. Ting

Civil and Environmental Engineering Publications

Unstable motions of bridge stay cables have been observed on site and in wind tunnel tests when a cable is yawed at certain orientations to wind. To uncover the underlying mechanisms, flow around a circular cylinder at a yaw angle of 30° has been numerically analyzed in the current study using delayed detached eddy simulation (DDES) at R e = 10 4 . A comparison with the reference normal flow case indicates the presence of a more coherent span-wise flow structure when the cylinder is yawed at 30°. The application of proper orthogonal decomposition further reveals that at this orientation, …

Assessment Of Wind Speeds Along The Damage Path Of The Alonsa, Manitoba Ef4 Tornado On 3 August 2018, Sarah A. Stevenson, Connell S. Miller, David M.L. Sills, Gregory A. Kopp, Daniel M. Rhee, Franklin T. Lombardo

Civil and Environmental Engineering Publications

Given the impracticality of attempting to directly measure wind speeds in tornadoes, wind speed estimation typically relies on the assessment of damage to structures and vegetation using classifications described in the Enhanced Fujita (EF) Scale. The advent of technology enabling the collection of large amounts of data, including detailed ground, drone, and aerial imagery, has led to a growth in research on non-conventional approaches for estimating tornado wind speeds. Research methods focused on defining the tornadic wind field based on forensic analysis of damage observations have shown promise for improving tornado assessments in a quantitative manner. In this study, novel …

Direct Air Capture: Catalyzing A Carbon Negative Future, Tagg K. Lee

Civil and Environmental Engineering Publications

Direct Air Capture (DAC) technology has emerged as a promising means to address the escalating challenges of atmospheric carbon dioxide (CO₂) levels and mitigate climate change. This paper provides an elementary overview of DAC, encompassing its underlying principles, technological advancements, and associated challenges. Point Source Carbon Capture is compared against Direct Air Capture with a solid or liquid sorbent, and physisorbents/chemisorbents are outlined. The past decade has seen a steep rise in the usage of chemical sorbents in particular, which are explored alongside their regeneration processes. This review provides an introductory explanation for the mechanisms of common DAC …

Assessment Of Tornado Alerting Performance For Canada, David M.L. Sills, Lesley Elliott

Civil and Environmental Engineering Publications

The Northern Tornadoes Project (NTP) completed a first independent assessment of national tornado warning alerting (watches and warnings) in Canada covering the 2019–2021 period. The NTP undertook this study in the spirit of open data, understanding tornado warning issues unique to this country, and improving tornado warning performance. Utilizing the NTP tornado event database for verification, tornado alerts were reviewed for accuracy and timeliness. For the 250 tornadoes that occurred during the study period–and using a definition of what constitutes a warning ‘hit’ developed for the study–the standard 2 × 2 contingency table scores were Probability of Detection = 0.23, …

Fire-Resistance Testing Procedures For Construction Elements—A Review, Shashikant Chaturvedi, Ajitanshu Vedrtnam, Maged A. Youssef, Martin T. Palou, Gonzalo Barluenga, Kishor Kalauni

Civil and Environmental Engineering Publications

Fire accidents are a significant risk to human life and civil infrastructure. As a countermeasure, the regulatory bodies of different countries have established standards for evaluating the performance of construction elements during fire exposure. ISO 834 is the globally accepted fire-resistance testing standard. Other standards include ASTM E119, BS 476, IS 3809, JIS A 1304, AS 1503, EN 1363, and GB/T 9978, which are utilized by the US, Britain, India, Japan, Australia, Europe, and China, respectively. This article presents a summary and comparison of the fire-resistance testing standards. In reality, standard tests for isolated structural members may not efficiently portray …

Seismic Performance Of Ductile Corrosion-Free Reinforced Concrete Frames, Mohamed Meshaly, Maged A. Youssef, Ahmed Elansary

Civil and Environmental Engineering Publications

Corrosion of steel bars is the main cause of the deterioration of reinforced concrete (RC) structures. To avoid this problem, steel rebars can be replaced with glass-fiber-reinforced-polymer (GFRP). However, the brittle behaviour of GFRP RC elements has limited their use in many applications. The use of shape memory alloy (SMA) and/or stainless steel (SS) rebars can solve this problem, because of their ductile behaviour and corrosion resistance. However, their high price is a major obstacle. To address issues of ductility, corrosion, and cost, this paper examines the hybrid use of GFRP, SS, and SMA in RC frames. The use of …

Structural Performance Of Single-Skin Glass Façade Systems Exposed To Fire, Mohamed Badr, Maged A. Youssef, Salah El-Din F. El-Fitiany, Ajitanshu Vedrtnam

Civil and Environmental Engineering Publications

Purpose

Understanding the structural performance of external glass curtain walls (façades) during fire exposure is critical for the safety of the occupants, as their failure can lead to fire spread throughout the entire building. This concern is magnified by the recent increase in fire incidents and wildfires. This paper presents the first simplified technique to model single skin façades during fire exposure, and, then utilizes it to examine the structural behaviour of vertical, inclined, and oversized façade panels.

Design/methodology/approach

The proposed technique is based on conducting simplified heat transfer calculations, and, then utilizing a widely used structural analysis software to …

Residual Axial Behavior Of Restrained Reinforced Concrete Columns Damaged By A Standard Fire, M. Monir M. Ajan Alhadid, Maged A. Youssef

Civil and Environmental Engineering Publications

A simplified procedure to predict the residual axial capacity and stiffness of both rectangular and circular reinforced concrete (RC) columns after exposure to a standard fire provides the means to replace the current descriptive methods. The availability of such a procedure during the design phase provides engineers with the flexibility to come up with better designs that ensure safety. In this paper, finite difference heat transfer and sectional analysis models are combined to determine the axial behavior of RC columns with various end-restraint conditions at different standard fire durations. The influence of cooling phase on temperature distribution and residual mechanical …

Influence Of Natural Fire Development On Concrete Compressive Strength, Robert T. Kuehnen, Maged A. Youssef, Salah El-Din F. El-Fitiany

Civil and Environmental Engineering Publications

With increasing acceptance of performance-based design principles in the field of fire safety, it is imperative to accurately define the behaviour of materials during fire exposure. Real-world fire events, otherwise referred to as natural fires, are defined by four characteristics: heating rate, maximum temperature, exposure duration, and cooling rate. Each of these four characteristics influences concrete’s behaviour in a different manner. In this paper, the available experimental work for concrete, tested at elevated temperatures, is examined to identify the influence of the four natural fire characteristics on concrete compressive strength. This review focuses on normal strength concrete tests only, omitting …

Are Significant Tornadoes Occurring Later In The Year In Southern Ontario?, D. M.L. Sills, C. S. Durfy, C. P.E. De Souza

Civil and Environmental Engineering Publications

Using a long-term data set (1875–2019), we investigate whether the month having peak tornado frequency changes over time in southern Ontario, Canada. Using only F/EF2+ tornadoes and 10-year rolling periods having modes at 5-year intervals, we find a statistically significant (99% confidence interval) moderate positive trend. However, we identify no statistically significant trend (positive or negative) using the same methods with tornado data from neighboring US states Michigan and New York. Though we do not investigate causes here, the study is the first to identify a robust long-term trend in the frequency of significant tornadoes for any region of Canada. …

Seismic Performance Of Hybrid Corrosion-Free Self-Centering Concrete Shear Walls, Emad A. Abraik, Maged A. Youssef, Salah El-Din F. El-Fitiany

Civil and Environmental Engineering Publications

Reinforced concrete (RC) walls are extensively used in high-rise buildings to resist lateral loads, while ensuring an adequate level of ductility. Durability problems, including corrosion of conventional steel reinforcements, necessitate exploring alternative types of reinforcement. The use of glass fiber reinforced polymer (FRP) bars is a potential solution. However, these bars cannot be used in seismic applications because of their brittleness and inability to dissipate seismic energy. Superelastic shape memory alloy (SMA) is a corrosion-free material with high ductility and unique self-centering ability. Its high cost is a major barrier to use in construction projects. The clear advantage of utilizing …

Surface Pressure Measurements In Translating Tornado-Like Vortices, Aya Kassab, Chowdhury Jubaye, Arash Ashraf, Horia Hangan

Civil and Environmental Engineering Publications

High spatial and temporal surface pressure measurements were carried out in the state-of-the-art tornado simulator, the Wind Engineering, Energy and Environment (WindEEE) Dome, to explore the characteristics of stationary and translating tornado-like vortices (TLV) for a wide range of swirl ratios (𝑆=0.21 to 1.03). The translational speed of the TLV and the surface roughness were varied to examine their effects on tornado ground pressures, wandering, and vortex structure. It was found that wandering is more pronounced at low swirl ratios and has a substantial effect on the peak pressure magnitude for stationary TLV (error percentage ≤ 35%). A new method …

Effect Of Non-Uniform Temperature Exposure On The Out-Of-Plane Bending Performance Of Ordinary Laminated Glass Panels, Maged A. Youssef, Ajitanshu Vedrtnam, Chiara Bedon, Shashikant Chaturvedia

Civil and Environmental Engineering Publications

Among the open design issues for structural laminated glass (LG) elements, their mechanical performance during fire exposure stands as a safety concern. This issue is the focus of this paper. An experimental investigation is conducted to evaluate the effect of non-uniform thermal gradients on the out-of-plane bending capacity of standard LG specimens. The pre-fracture, cracking, and post-fracture performances of LG panels were examined using a three-point bending setup. The bending tests were carried out on un-heated LG samples and heated samples, which were either hot or cooled down. The reliability of available analytical and numerical methods to predict the out-of-plane …

Ductility And Overstrength Of Shape-Memory-Alloy Reinforced-Concrete Shear Walls, Emad A. Abraik, Maged A. Youssef

Civil and Environmental Engineering Publications

The unique properties of superelastic shape-memory-alloy (SMA) bars have motivated researchers to investigate their use as reinforcing bars for concrete elements. They were found to decrease seismic residual deformations, while increasing seismic inelastic deformations. This characteristic deformation behaviour requires an assessment of the seismic design parameters of SMA reinforced concrete walls. This paper addresses this requirement by evaluating their ductility and overstrength factors. A total of 972 walls were analyzed under a quasi-static lateral load. Suitable values for the overstrength and ductility factors were estimated for two proposed locations of SMA bars. FEMA P695 was then utilized to evaluate the …

Simplified Structural Analysis Of Framed Ordinary Non-Tempered Glass Panels During Fire Exposure, Amer Sabsabi, Maged A. Youssef, Salah El-Din F. El-Fitiany, Ajitanshu Vedrtnam

Civil and Environmental Engineering Publications

Ordinary non-tempered glass is one of the most widely used materials in the construction industry. Knowing its fire resistance is essential to ensure the safety of emergency personnel as its failure increases the oxygen supply and causes a rapid spread of the fire (flashover phenomenon). Existing approaches for evaluating the structural fire safety of glass façades require expensive experimental tests and/or extensive knowledge of Finite Element modeling. This paper provides a simplified, rational, and reliable approach to assess the structural capacity of ordinary glass panels during fire exposure. A simplified method is developed to predict the temperature difference between …

Seismic Performance Of Rc Beam-Column Edge Joints Reinforced With Austenite Stainless Steel, C Xu, Moncef L. Nehdi, Maged A. Youssef, L. V. Zhang

Civil and Environmental Engineering Publications

Using stainless steel (SS) reinforcement can mitigate colossal corrosion damage inflicted to reinforced concrete (RC) structures worldwide. However, there is still dearth of studies on the seismic behavior of SS-RC structures. Hence, quasi-static tests were carried out in this study to explore the seismic performance of three RC frame edge joint specimens reinforced with SS having strength grade of 500 and one control RC specimen made with grade 400 normal steel. RC edge frame joints reinforced with ordinary steel and SS exhibited similar bending-shear failure patterns at the beam root. The load bearing capacity of the SS-RC edge fame joint …

Bridge Damage Identification Using Deep Learning-Based Convolutional Neural Networks (Cnns), Sandeep Sony

Civil and Environmental Engineering Publications

In this paper, a novel method is proposed based on a windowed-one-dimensional convolutional neural network for multiclass damage detection using acceleration responses. The data is pre-processed and augmented by extracting samples of windows of the original acceleration time series. 1D CNN is developed to classify the signals in multiple classes. The damage is detected if the predicted classification is one of the indicated damage levels. The damage is quantified using the predicted class probabilities. Various signals from the accelerometers are provided as input to the 1D CNN model, and the resulting class probabilities are used to identify the location of …

The Northern Tornadoes Project - Uncovering Canada’S True Tornado Climatology, David Sills, Gregory A. Kopp, Aaron Jaffe, Elizabeth Sutherland, Connell Miller, Joanne Kunkel, Emilio Hong, Sarah Stevenson, William Wang

Civil and Environmental Engineering Publications

Canada is a vast country with most of its population located along its southern border. Large areas are sparsely populated and/or heavily forested, and severe weather reports are rare when thunderstorms occur there. Thus, it has been difficult to accurately assess the true tornado climatology and risk. It is also important to establish a reliable baseline for tornado-related climate change studies.

The Northern Tornadoes Project (NTP), led by Western University, is an ambitious multidisciplinary initiative aimed at detecting and documenting every tornado that occurs across Canada. A team of meteorologists and wind engineers collects research-quality data during each damage investigation, …

Numerical Study Of Roundness Effect On Flow Around A Circular Cylinder, Ran Wang, Shaohong Cheng, David S.K. Ting

Civil and Environmental Engineering Publications

Imperfectly round bridge stay cable cross section is speculated to be a key factor for wind-induced large-amplitude cable vibrations observed on site. A delayed detached eddy simulation implemented in Open source Field Operation and Manipulation is used to investigate the flow structure around and in the near-wake of an imperfectly round circular cylinder and the corresponding aerodynamic forces at a Reynolds number of 104 and an attack angle of 0° or 45°. With the increase in roundness imperfection, both monotonic and non-monotonic changes of the mean surface pressure and the wake velocity are found when the cylinder is normal to …

Performance-Based Design Of Rc Beams Using An Equivalent Standard Fire, Robert T. Kuehnen, Maged Youssef, Salah El-Din F. El-Fitiany

Civil and Environmental Engineering Publications

The design of buildings for fire events is essential to ensure occupant safety. Supplementary to simple prescriptive methods, performance-based fire design can be applied to achieve a greater level of safety and flexibility in design. To make performance-based fire design more accessible, a time equivalent method can be used to approximate a given natural fire event using a single standard fire with a specific duration. Doing so, allows for natural fire events to be linked to the wealth of existing data from the standard fire scenario.

In this paper, the use of an existing time equivalent method is reviewed and …

Experimental And Numerical Structural Assessment Of Transparent And Tinted Glass During Fire Exposure, A Vedrtnam, C Bedon, Maged A. Youssef, M Wamiq, Amer Sabsabi, S Chaturvedi

Civil and Environmental Engineering Publications

Transparency, illumination, aesthetic and energy requirements have considerably increased the use of glass in modern high-rise buildings. During fire exposure, fracture and shattering of windows and facades accelerate the spread and severity of fire, which increases the risk for the occupants and the amount of structural damage. This paper aims at analyzing the effect of non-uniform thermal gradients on the flexural capacity of ordinary glass panels. Both transparent and tinted glass panels are considered to account for widely-used glass compositions. The bending response of fire-damaged glass panels is experimentally explored considering different durations of thermal exposure. The thermal breakage due …

Seismic Performance Of Modular Steel-Braced Frames Utilizing Superelastic Shape Memory Alloy Bolts In The Vertical Module Connections, Papia Sultana, Maged A. Youssef

Civil and Environmental Engineering Publications

In modular construction, individual modules are constructed at a controlled industrial environment before being transported to site. They are then connected horizontally and vertically to form a structure. The vertical connections can be achieved by welding or bolting the columns of stacked modules. This study investigates the seismic performance of modular steel-braced frames (MSBFs) connected vertically using superelastic shape memory alloy (SMA) bolts. The study also identifies the required locations of SMA connections, in a typical MSBF, to optimize its seismic performance in terms of maximum inter-story drift (MID), maximum residual inter-story residual drift (MRID), and damage scheme.

Performance-Based Design Of Rc Columns Using An Equivalent Standard Fire, Robert T. Kuehnen, Maged A. Youssef, Salah El-Din F. El-Fitiany

Civil and Environmental Engineering Publications

The extreme variability of natural compartment fires poses a significant challenge in the process of performance-based fire design. To reduce this variability, the severity of a natural fire can be related to that of a standard fire, known as a time equivalent (te). In this paper, the applicability of a time equivalent, previously derived based on the average internal temperature profile (AITP) that develops within reinforced concrete (RC) beams exposed to fire from three sides, is examined for RC columns exposed to fire from four sides. A parametric study is presented to examine the suitability of the …

Equivalent Standard Fire Duration To Evaluate Internal Temperatures In Natural Fire Exposed Rc Beams, Robert T. Kuehnen, Maged A. Youssef

Civil and Environmental Engineering Publications

With the recent shift towards performance-based fire design, practical methods to account for natural fire loading when designing concrete structures are needed. Available design methods and analysis approaches are based on standard fire curves. To apply these methods, a natural fire event can be converted to a standard fire with a specific duration (time equivalent). However, existing time equivalents often ignore the influence of internal temperature gradients on the section behaviour, which is unacceptable for concrete structures.

This paper introduces a time equivalent method suitable for reinforced concrete (RC) beams exposed to natural fire. The method is based on the …

Effect Of Yaw Angle On Flow Structure And Cross-Flow Force Around A Circular Cylinder, Ran Wang, Shaohong Cheng, David S.K. Ting

Civil and Environmental Engineering Publications

Flow around an inclined circular cylinder at yaw angles of α = 0°, 30°, 45°, and 60° has been numerically studied using the delayed detached eddy simulation at a Reynolds number of 1.4 × 104. Periodic boundary conditions are utilized to minimize the end effect. The focus is to explore the effect of yaw angle on the flow structure and the spatial distribution of the cross-flow forces. For the normal flow case, the modulation of the span-wise averaged lift force coefficient is found to be related to the unstable shear layer. For the inclined cases, contours of the sectional lift …

Ductile Corrosion-Free Self-Centering Concrete Elements, Maged Youssef, Mohamed E. Meshaly, Ahmed Elansary

Civil and Environmental Engineering Publications

Corrosion is a major factor in the deterioration of reinforced concrete (RC) structures. To mitigate this problem, steel bars can be replaced with glass-fiber-reinforced-polymer (GFRP) bars. However, the lack of ductility of GFRP-RC elements has prevented their use in many structural applications, especially in seismic areas. Superelastic shape memory alloy (SMA) bars have been proposed to be used in seismic areas because of their self-centering characteristics. Also, they have the added advantage of being corrosion resistant. This paper examines the combined use of SMA and GFRP bars to achieve ductile self-centering and corrosion-free elements. The first challenge for such a …

Flexural Behaviour Of Superelastic Shape Memory Alloy Reinforced Concrete Beams During Loading And Unloading Stages, Yamen Ibrahim Elbahy, Maged Youssef

Civil and Environmental Engineering Publications

Trend of using smart structures, which can adjust when exposed to severe unexpected loading, is increasing. One of the methods to achieve such structures relies on smart materials. For example, replacing conventional steel reinforcing bars in Reinforced Concrete (RC) structures with superelastic Shape Memory Alloy (SMA) bars significantly reduces the residual deformations caused by post-yielding behaviour. This paper provides in-depth understanding of the flexural behaviour of SMA RC beams. A sectional analysis method, which predicts the flexural behaviour of SMA RC beams during both loading and unloading stages, is adopted and validated using available experimental data. An extensive parametric study …

Seismic Performance Of Reinforced Concrete Frames Retrofitted Using External Superelastic Shape Memory Alloy Bars, Yamen Ibrahim Elbahy, Maged A. Youssef, Mohamed E. Meshaly

Civil and Environmental Engineering Publications

Pre-1970s designed and built reinforced concrete frame structures are considered unsafe when subjected to seismic loads. Insufficient anchorage of the beam reinforcement in the beam-column joints of these structures is considered a main deficiency. Newly built frame structures are seismically designed for safety, where high inelastic deformations can occur under moderate to strong earthquakes. Minimizing these inelastic deformations makes the structure repairable. One way to minimize these residual deformations is by using smart materials such as superelastic shape memory alloys (SMAs). In this paper, the seismic performance of RC frames retrofitted using external superelastic SMA bars is investigated and compared …

Simulating The Role Of Axial Flow In Stay Cable Vibrations Via A Perforated Wake Splitter Plate, Ran Wang, Shaohong Cheng, David Ting

Civil and Environmental Engineering Publications

The inclined and/or yawed orientation of bridge stay cables results in the formation of secondary axial flow on the leeward side of cable surface, which is believed to be one of the contributing factors exciting some unique wind induced cable vibration phenomena. To clarify the role of axial flow in triggering aerodynamic instability of stay cables, a numerical study has been conducted to indirectly examine the axial flow effect via a perforated splitter plate placed along the central line of a circular cylinder wake. By manipulating the perforation ratio of the perforated plate at four different levels, the variation of …