Engineering Commons^™

Energy Dissipation Using Negative Stiffness Shells, Mohamed Elgawady, Yasser Darwish

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A negative stiffness shell has a convex first position, but can transition or snap to a concave second position under a force applied to the exterior surface of the shell in the convex first position. During the transition, the shell exhibits negative stiffness that permits a large amount of energy to be absorbed. The negative stiffness shell can withstand a high initial force threshold prior to transitioning. In the second, concave position the shell can still resist force. Moreover, it is possible for the shell to revert back to the first, convex position with minimal plastic deformation for subsequent use. …

Fiber Optic-Based Thermal Integrity Profiling Of Drilled Shaft: Inverse Modeling For Spiral Fiber Deployment Strategy, Wen Deng, Ruoyu Zhong, Haiying Ma

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The current state of practice to interpret the thermal integrity profiling (TIP) data of drilled shaft is the so-called effective radius method. It uses the concrete pouring log and average temperature to construct a relationship between temperature distribution and effective radius that can be used to reconstruct a drilled shaft model. While this effective radius method is computationally inexpensive and has good operationality, it is not good at predicting the dimensions and shape of shaft defects. Upgrading the sensor used in conventional TIP from thermocouples/thermal wires to fiber optic sensors, the spatial resolution of the measured temperature will be enhanced. …

Experimental And Numerical Studies Of Novel Thermal Energy Storage Materials For Applications In Concrete And Energy Storage Systems, Wenyu Liao

Doctoral Dissertations

In this work, several types of novel thermal energy storage (TES) materials and composites are explored, and a series of numerical simulation models and experimental protocols are developed to evaluate the potentials of these materials to be applied in concrete, pavement, and thermal energy storage systems.

The first two types of novel TES materials/composites are at the micro-scale, which use micro diatomite (DE) and cenosphere (Ceno) as carriers of phase change material (PCM), respectively. The third type of novel TES material is at the macro-scale, utilizing lightweight sand (LWS) and lightweight coarse aggregate as carriers to load PCM. The last …

Enhancing Mixed Traffic Flow Safety Via Connected And Autonomous Vehicle Trajectory Planning With A Reinforcement Learning Approach, Yanqiu Cheng, Chenxi Chen, Xianbiao Hu, Kuanmin Chen, Qing Tang, Yang Song

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The longitudinal trajectory planning of connected and autonomous vehicle (CAV) has been widely studied in the literature to reduce travel time or fuel consumptions. The safety impact of CAV trajectory planning to the mixed traffic flow with both CAV and human-driven vehicle (HDV), however, is not well understood yet. This study presents a reinforcement learning modeling approach, named Monte Carlo tree search-based autonomous vehicle safety algorithm, or MCTS-AVS, to optimize the safety of mixed traffic flow, on a one-lane roadway with signalized intersection control. Crash potential index (CPI) is defined to quantitively measure the safety performance of the mixed traffic …

Characterization Of Alaskan Modified Asphalt Binders And Mixtures, Jun Liu

Doctoral Dissertations

"Modified asphalt binders and mixtures have been used more in recent years in Alaska. However, there has not been systematic characterization and performance data development for these materials. This study intends to systematically characterize the Alaskan asphalt binders and mixtures and identify the performance benefits of these materials through laboratory tests and field sections monitoring. The research contains five sections: 1) a comprehensive characterization on the morphologies, chemical and rheological properties of modified asphalt binders and mechanical properties of asphalt mixtures with these modified asphalt binders. The lab testing results were further confirmed through field surveys of recent paving projects …

Reveal Wind Loading Of Tornadoes And Hurricanes On Civil Structures Towards Hazard-Resistant Design, Ryan Honerkamp

Doctoral Dissertations

"Extreme winds impacting civil structures lead to death and destruction in all regions of the world. Specifically, tornadoes and hurricanes impact communities with severe devastation. On average, 1200 tornadoes occur in the United States every year. Tornadoes occur predominantly in the Central and Southeastern United States, accounting for an annual $1 billion in economic losses, 1500 injuries, and 90 deaths. The Joplin, MO Tornado in 2011 killed 161 people, injured more than 1000, destroyed more than 8000 structures, and caused $2.8 billion of property loss. Hurricanes occur predominantly on the United States East coast regions and along the coast of …

Early Wildfire Detection By Air Quality Sensors On Unmanned Aerial Vehicles: Optimization And Feasibility, Doaa Rjoub

Masters Theses

“Millions of acres of forests are destroyed by wildfires every year, causing ecological, environmental, and economical losses. The recent wildfires in Australia and the Western U.S. smothered multiple states with more than fifty million acres charred by the blazes. The warmer and drier climate makes scientists expect increases in the severity and frequency of wildfires and the associated risks in the future. These inescapable crises highlight the urgent need for early detection and prevention of wildfires. This work proposed an energy management framework that integrated unmanned aerial vehicle (UAV) with air quality sensors for early wildfire detection and forest monitoring. …

Numerical Behavior Of Steel H-Plies Repaired Using Layered Concrete Jacket, Fareh Waleed Abudawaba

Masters Theses

“This study developed finite element models (FEMs), using LS-Dyna software, to investigate the repair of corroded steel H-piles using concrete jacket. The concrete modeled as a layered material simulating 3D printed concrete. 3DPC is a new technology that can be used to repair or build structures without formwork by depositing concrete mixture layer by layer. For the 3DPC, this study investigated the feasibility of using alkali-activated concrete (AAC) synthesized using class C fly ash as the main binder. The fresh properties, extrudability, and buildability of the proposed concrete were investigated through open time and deformation tests, respectively. Hardened properties were …

Effect Of Spike Anchors On The Bond Behavior Of Steel Reinforced Polymer Composite Externally Bonded To A Concrete Substrate, Keenan Lorence Mcburney

Masters Theses

Steel reinforced polymer (SRP) composites are a strengthening material that consist of continuous high-strength steel cords embedded in a polymeric matrix. SRP has demonstrated a high potential for providing additional flexural and shear strength in existing concrete structures when bonded to the concrete surface. However, premature debonding from the concrete substrate at low load levels is a major shortcoming of SRP composites. It has been demonstrated in previous studies that anchors can limit the effect of debonding in fiber reinforced polymer (FRP) composites by increasing the load capacity and ductility of the composite-concrete interface.

This study aims to investigate the …

Fiber Reinforced Polymer Bar Investigation: Long-Term In-Situ Durability And Bond Strength Assessment In Conventional And Sustainable Concrete, Ali Fadhil Al-Khafaji

Doctoral Dissertations

"Corrosion of steel reinforcement and carbon dioxide emissions are two major global problems. Different methods, techniques, and materials have been implemented to mitigate these problems. Glass fiber-reinforced polymer (GFRP) bar presents itself as a solid alternative to replace conventional steel reinforcement owing to its fantastic features in resisting corrosion. Its demand is progressively increasing. Cement-based concrete, on the other hand, is not eco-friendly due to the excessive amount of carbon dioxide (CO₂) emissions yielded from its cement production. One of the alternatives used to mitigate the use of cement in concrete is fly ash. Fly ash is considered …

Innovative Modeling And Management Of Infrastructure Systems, Engineering And Construction Operations, And Offsite Construction Technology Using Computational Data Analytics, Rayan Hassane Assaad

Doctoral Dissertations

“The construction industry has been facing considerable challenges due to the inadequacy of the traditional methods in executing, managing, and modeling infrastructure and construction projects. While many techniques have been developed to improve the decision-making process in the industry, there is no evidence of sufficient and continuous improvements in the industry’s adoption and implementation of innovative techniques such as new management approaches, modern modeling methods, and emerging computational data analytics. To this end, the goal of this research is to address some of the recent challenges faced in the industry with a focus on infrastructure asset management, construction engineering and …

Studies On Tornado-Structure Interactions And Guidance On Design Tornadic Wind Loading, Zhi Li

Doctoral Dissertations

“Tornadoes are violent natural hazards that could caused significant property loss and fatalities. Statistical data indicates that most fatalities during tornado incidents were caused by the building failure under tornadoes. For example, in the 2011 Joplin Tornado, 161 people were killed, and 84 percent of the fatalities were related to the failure of buildings. In addition, most of the significant, tornado-induced property loss and fatalities are relevant to the tornadoes passing through the densely populated regions. Besides buildings, bridges were also severely damaged or destroyed by tornadoes in the United States. To reduce the tornado-induced loss, it is imperative to …

Collaborative Planning In The Construction Industry: A Holistic Framework For Assessing Collaborative Planning Practices And Predicting Project Performance, Amr Elsayegh

Doctoral Dissertations

"The fragmentation of the construction industry prompted developing novel methods such as collaborative planning, lean construction, advancements in technology, integrated project delivery, and relational contracting. Current research focused on specific facets of collaborative planning without presenting a comprehensive analysis of its factors. As such, the goal of this research is to develop a holistic framework that studies and evaluates collaborative planning practices in construction projects. This research offers significant addition to the body of knowledge through various theoretical and practical contributions. In relation to that, this research developed a comprehensive framework by (1) identifying a comprehensive list of factors influencing …

Use Of Portable Seismic Property Analyzer And Ground Penetrating Radar To Assess Bridge Decks, Samie Ramadan A Hamad

Doctoral Dissertations

The Montauk Bridge deck was assessed based on the portable seismic property analyzer and ground penetrating radar data. Based on the analysis of the portable seismic property analyzer data, it was determined that over 65% of bridge conditions were rated serious to poor condition with an average compressive strength of less than 2500 psi; less than 35% of bridge deck conditions were rated fair to good with an average compressive strength over 2500 psi. Based on ground penetrating radar data, it was determined that 72% of the bridge deck was in serious to poor condition, and only 28% of the …

Hydromechanical Stress And Internal Erosion Under Earthen Structures, Kerry Allen Magner

Doctoral Dissertations

"Dam failures by seepage and internal erosion have reportedly been attributed to up to 40% of all dam failures in the United States. Backwards piping erosion either through the embankment or foundation soils has been reported to be the major contributing method to seepage and internal erosion dam failures. This proposed research is motivated by the lack of understanding of the complex stress regimes associated with internal erosion in cohesionless soils under earthen structures. The overall goal of this research is to provide a fundamental understanding of internal erosion and the hydromechanical stress conditions necessary for the initiation and continuation …