Structural Engineering Commons^™

Dynamics Of Flexible Freestanding Structures Under Ground Motion Excitation, Seyed Mohammadreza Farooghi Mehr

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Freestanding structures are characterized by being unattached at the base, exhibiting rigid or flexible motion under ground motion excitation with various potential responses including rocking (rotation at the base about corner points), pure sliding, slide-rocking, and overturning. While rigid freestanding structures have been extensively studied, the behavior of flexible freestanding structures—particularly the interaction between modes involving sliding—remains underexplored. Existing literature has focused on the deformation and rocking motions of flexible freestanding structures through both analytical and experimental approaches, which have shown indications of sliding at the base. These findings highlight the necessity of incorporating sliding motion into analytical models to …

Final Report - Qa/Qc Guidelines On Drone-Based Remote Sensing For Bridge Element Inspection, Genda Chen, Woubishet Z. Taffese, Ritesh Sharma, Zhenhua Shi

Project IM-4

Remote sensing of elevated infrastructure via robotic platforms has recently gained increasing interest in bridge inspection. Such automated bridge inspection can not only overcome accessibility and safety challenges but also improve objectivity and consistency of the measured data compared to current visual inspection practices. With the advent of advanced technologies, quality assurance (QA) and quality control (QC) for robot-based bridge inspection become imperative. This study aims (1) to understand actionable inspection activities and procedures in route planning, sensor preparation and measurement, ground truth selection, and statistical analysis; (2) to outline assessment matrices and best practices for drone-based images to achieve …

Enhancing Frp-Concrete Interface Bearing Capacity Prediction With Explainable Machine Learning: A Feature Engineering Approach And Shap Analysis, Yanping Zhu, Woubishet Zewdu Taffese, Genda Chen

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study introduces a novel approach to predict the shear bearing capacity of FRP-concrete interfaces using explainable machine learning. Eight algorithms are employed: three standalone models (Artificial Neural Network, Support Vector Regression, and Decision Tree) and five ensemble learning models (Bagging, Random Forest, Adaptive Boosting, Gradient Boosting, and Extreme Gradient Boosting). Four scenarios with varying input features, including engineered features inspired by mechanics-based bearing capacity equations, are examined. Notably, the inclusion of engineered features such as the stiffness of the FRP strip (Kf) significantly enhanced prediction accuracy and efficiency, although the width correction coefficient (bf/bc) did not yield significant benefits, …

Anti-Corrosion Performance Of Magnesium Potassium Phosphate Cement Coating On Steel Reinforcement: The Effect Of Boric Acid, Fan Zhang, Jihui Qin, Kangyi Cai, John J. Myers, Hongyan Ma

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

It has recently been found that magnesium potassium phosphate cement (MKPC) paste coating applied on the surface of steel reinforcement can effectively retard the onset of corrosion and suppress corrosion reactions. However, the fast-setting nature of MKPC—which is a merit in repair—can be problematic in a practical engineering process of coating the steel reinforcement with MKPC paste. To address this problem, boric acid (H₃BO₃) was added as a retarder in an MKPC formulation to prolong the setting time. This work investigated the impact of boric acid (at 5% by weight of MgO) on the anti-corrosion performance …

Development Of Multifunctional Wood Composites With Integrated Phase Change Materials For Enhanced Thermal Management, Self-Healing, And Sustainability., Emmanuel Igbokwe

LSU Master's Theses

Abstract

This study focused on incorporating self-healing, flame retardancy, and energy harvesting capabilities into the wood composite to contribute to more sustainable and energy-efficient building practices. Oriented strand board has been widely used as sheath for roofing or dry walls in residential buildings. Residential buildings account for a large portion of energy consumption. Therefore, an oriented strand board with energy harvesting capability is highly desired. Additionally, flame retardancy and damage self-healing and end-of-life recycling are also critical features for buildings.

In this study, we prepared a novel oriented strand board by constructing sandwich structures. The face sheets of the sandwich …

Semi-Annual Progress Report #15, Missouri University Of Science And Technology

Semi-Annual Progress Reports

No abstract provided.

2017-2024 Emerging Technologies And Milestone Achievements Toward Automated Bridge Inspection And Maintenance, Genda Chen

INSPIRE Archived Webinars

Main hardware and software systems developed in the INSPIRE University Transportation Center from 2017 to 2024 will be presented. Their characteristic parameters, operation procedures, performance metrics, advantages over the state of practice, and application limitations will be summarized. These systems include, but not limited to,

 Flying and climbing robots for high-quality data collection from remote sensing and nondestructive testing,

 Explainable artificial intelligence and machine learning for element segmentation and defect classification,

 3D reconstruction and digital twins for virtual inspection,

 Framework for the probability of detection for various defects and damage from in-situ sensors,

 Defect detection, …

Urbanization And Urban Sprawl In The Post-Colonial Era Douala City, Cameroon, Sylvia Munisi

Tanzania Journal of Engineering and Technology (TJET)

The history of the port city of Douala spans pre-colonial period, colonial period of the Germans and French occupation, the post-colonial era and the contemporary situation with continuous occupancy of the coastal environment. This article looks at the relationship between the history of the city of Douala to the resulting urban situation focusing on governance structure as well as rapid urbanization. The findings show that governance structure allowing for a duality of modern political system and traditional cultural system of kingships and chiefdoms has an effect to the resulting urban sprawl. Moreover, rapid urbanization under this condition has an overall …

The Use Of Locally Available Materials Towards Urban Planning For Sustainable Construction: The Case Of Gondar-Ethiopia, Kidist Dereje

Tanzania Journal of Engineering and Technology (TJET)

The city of Gondar in northern Ethiopia has a rich history that is connected to urban planning and construction. From the era of the Fasiledes that built masonry castles, Italian colonialism that zoned the city on racial boundaries and the post-colonial planning that wanted a more global standard, Gondar has been subjected to different planning and construction methods. This evolution however, has brought about challenges related to the sustainability of the construction industry and the communities within the city. This paper analyses the relationship between urban planning and use of local construction materials to attain sustainable development of the city. …

Transport Mobility Analysis For Informal Settlements In Dar Es Salaam, Tanzania, Fatma Kassim Mohamed

Tanzania Journal of Engineering and Technology (TJET)

Dar es Salaam is one of the world’s fastest growing cities and is expected to be the third largest by 2100 with a population of 76 million. Dar es Salaam city is made of multiple neighbourhoods that are very diverse in terms of socio-economic status, gender, age and prevalent activities. One of the biggest challenges facing the city of Dar es Salaam is urban sprawl due to informal settlements that in turn leads to very long travel time and hinders equal mobility and accessibility of labour and goods. This study found that the current mobility vision for Dar es Salaam …

Relationship Between Historic Evolution, Urbanization And Mobility In Ibadan, Nigeria, Aisha Adams

Tanzania Journal of Engineering and Technology (TJET)

Ibadan is said to be the biggest indigenous city in Nigeria with a population of about 4.04 million, making it the third largest city in the country after Lagos and Kano. Since its founding in 1829, Ibadan has experienced urban evolution that is mostly unguided. With its high fertility rate, population growth and rural-to-urban migration, Ibadan has experienced significant urban sprawl that has resulted in challenges in urban mobility especially to the lower-income earners. This study looks at the relationship between urban planning, urbanization and mobility in the city of Ibadan. The study found that lack of integrated land use …

Investigating The Relationship Between History, Urbanization And Wealth Gap In Johannesburg, South Africa, Abdallah F. Kaamah

Tanzania Journal of Engineering and Technology (TJET)

The city of Johannesburg is the largest city in South Africa and named as one of the economic drivers of the country. However, the city has the widest wealth gap in the country. This article examines the relationship between historical occurrences, urbanization, and the resulted wealth disparity in Johannesburg and look at the mitigation measures. The findings point to the wealth disparity in the city as a multifaceted problem influenced by historical, urbanization, and political variables. Comprehensive and multifaceted policy initiatives are required to address the structural causes of inequality and the urgent needs of vulnerable populations to close the …

The Influence Of Planning And Architectural Styles On The Sustainability Of The City Of Kumasi, Ghana, Elom Ayeke

Tanzania Journal of Engineering and Technology (TJET)

The city of Kumasi that was once dubbed the ‘Garden City of West Africa’ was founded in the late 17th century and served as the seat of government for the medieval Greater Asante Union. It later served as a commercial hub for the British Colony after undergoing massive transformation in the first two decades of the 19th century. Post-independence, the city went through various urban planning projects that mostly targeted social development. The architecture of Kumasi has also been changing through different periods of its history. This article examines the relationship between the evolution of the city of Kumasi through …

Investigating The Influence Of Confinement Stress And Concrete Type On The Performance Of Precast Segmental Dry Shear-Keyed Joints, Khaled Ramzy, Mahmoud Ahmed Abdel Aziz Mohammed

Journal of Engineering Research

This investigative research delves into the correlation between dry joint ultimate load and varied applied confinement stress levels – low at 2 MPa, moderate at 4 MPa, and high at 6 MPa – within structural joints. The focus is on diverse configurations of shear key quantities (single, dual, and triple shear keys) within these joints. Additionally, an examination was conducted on the influence of concrete types –Normal Strength Concrete (NSC) rated at 30 MPa, High Strength Concrete (HSC) at 60 MPa, and Ultra-High Strength Concrete (UHSC) at 120 MPa – alongside the aforementioned confinement stress levels on load capacity. The …

Influence Of Concrete Jacketing On The Performance Of Steel Columns Under Blast Induced Progressive Collapse, Hanan Eltobgy Prof., Mohamed Saeed Refaey Dr., Mohamed Ahmed Aboshok Dr., Ahmed Emadel-Din Abdel-Aal Eng.

Journal of Engineering Research

This study investigates the influence of concrete jacketing on the performance of steel columns subjected to blast loading, which can lead to progressive collapse. Using Finite Element Method (FEM) simulations, the research evaluates concrete-encased steel columns with different concrete cover thicknesses to measure their resistance to lateral displacements induced by blasts. Findings reveal that increasing the thickness of the concrete cover markedly improves the column's ability to withstand such loads. The study also highlights that steel has better energy dissipation properties than concrete. It examines how the combined challenges of progressive collapse and blast loading influence the overall structural response …

Experimental Investigation Of Light-Weight Concrete-Filled Stainless Steel Tube Composite Long Columns, Nadia Fath Alla, Kamel Kandeel, Mahmoud El-Nagar

Journal of Engineering Research

The main target of this study is to investigate the behavior and performance of long composite circular stainless steel columns filled with light-weight concrete. An experimental study was carried out on four specimens, two of them are long composite circular stainless steel columns with length 1400 mm, diameter 100 mm and thickness of stainless steel tube 2 mm filled with light-weight and normal concrete with strengths 12 and 26 mpa respectively, which denoted by C1400/12 and C1400/26. The other two specimens are short composite circular stainless steel columns with length 500 mm, diameter 100 mm and thickness of stainless steel …

Seismic Resilience Of Timber Homes, Melia R. Costa

College of Engineering Summer Undergraduate Research Program

The vast majority of residential buildings in California are wood-frame structures. A home is typically a very large investment for families, and damage to the home can be detrimental to a family’s economic success. Thus, reducing the economic impacts of an earthquake on residential timber housing is crucial. A full scale, two-story section of a residential timber house is in construction in the Parson’s Geotechnical and Earthquake Engineering Laboratory on the Cal Poly campus in San Luis Obispo, California. Once built it will be put through earthquake simulation tests on a shake table with various magnitudes of seismic activity. Next, …

Durability Assessment And Service Life Prediction Of Concrete In Extreme Aggressive Environment, Mohamed Ismail

Doctoral Dissertations and Master's Theses

The objective of this research is to enhance the durability of newly constructed structural elements by assessing the performance of various concrete mixes for chloride resistance. The study focuses on establishing and developing correlations between chloride diffusion rates and concrete resistivity. By identifying these correlations and based on the target service life, the research aims to set appropriate thresholds for Surface Resistivity (SR) and Bulk Resistivity (BR) tests, which will be used to qualify concrete mixes used in in extremely aggressive chloride environments. To achieve these objectives, the research uses a systematic approach that combines experimental testing with analytical modeling. …

Final Report - Mixed Reality For Beyond Visual Line-Of-Sight Bridge Inspection Using Robot-Assisted Nondestructive Evaluation, Genda Chen, Joel Runji

Project IM-5

To improve data consistency, work efficiency, inspector safety, and cost effectiveness during routine inspections, drones have been increasingly used in recent years to support imaging and scanning over the surface of various elements in a bridge for surface condition assessment. Most drones are operated manually within a visual line of sight and unable to inspect river-crossing bridges completely since not all elements can be viewed by a drone operator using a binocular. Even for autonomous drones with collision-avoidance features, physical interaction with a bridge for nondestructive evaluation (NDE) is currently impossible in practice. An alternative solution with robot-assisted remote nondestructive …

Final Report - Probability Of Detection In Corrosion Monitoring With Fe-C Coated Lpfg Sensors, Genda Chen, Ying Zhou, Pengfei Ma

Project SN-8

This project aimed to develop and evaluate two statistical methods for determining the probability of detection (POD) in corrosion monitoring using Fe–C coated long-period fiber grating (LPFG) sensors. These methods, referred to as the Size-of-Damage-at-Detection (SODAD) method and the Random Parameter Model (RPM), addressed limitations in traditional POD models by considering the time dependency inherent in sensor data. The goal was to assess steel mass loss at 90% detection probability and establish the largest undetectable mass loss threshold at a 95% lower confidence bound. Both methods were assessed for computational efficiency, sensitivity to distribution assumptions, and robustness under varying model …