Structural Engineering Commons^™

Voltage-Related Power Quality Issues And Impacts On Distribution Networks With Sensitive Loads - A Review, Godwin Elinazi Mnkeni, Jackson Justo, Aviti Thadei Mushi, Bakari M. M. Mwinyiwiwa

Tanzania Journal of Engineering and Technology (TJET)

Voltage disturbances are the most important power quality (PQ) complications that customers and power utilities face in this smart era. The growing adoption of sophisticated electronic equipment and integration of renewable energy sources (RES) into power grids has increased the susceptibility of power distribution networks (PDNs) to voltage sags, swells, interruptions, flicker, and voltage imbalance. These disturbances, mainly caused by upstream faults, switching operations, and RES integration, compromise voltage PQ and system reliability. Consequently, they accelerate equipment degradation, increase electronic waste (e-waste), raise reactive power demand and maintenance costs, increase power losses, and impose substantial economic losses on customers and …

Metrological Characterization Of Pavement Friction Measurements For High-Friction Surface Treatments: Si Traceability, Uncertainty Evaluation, And Adhesion–Hysteresis Separation Via Water–Soap Bpt Protocol, Alireza Roshan, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Laboratory friction measurements are central to material screening for High-Friction Surface Treatments (HFST), yet metrological aspects including a proposed metrological traceability framework or uncertainty, and reproducibility are consistently underreported. This study applies a metrology-aligned framework to British Pendulum Tester (BPT) measurements performed in three states: dry, wet (water), and water–soap to assess operational adhesion and hysteresis components, document traceability to the International System of Units (SI), and report GUM-style uncertainty with covariance for the adhesion difference. Measurements were obtained for calcined bauxite (CB) and rhyolite (Rhy) in HFST and Coarse gradations across seven polishing protocols (baseline; LAA-1000/2000; MDA-105/180; PSV-10 h/20 …

Optimization Of Bonding Behavior Of Crumb Rubber-Modified (Crm) Asphalt For Sustainable High-Friction Surface Treatment (Hfst) Applications, Abdallah Aboelela, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Binder bonding strength (BBS) is critical to aggregate retention and friction performance in high-friction surface treatment (HFST). Although epoxy resin is traditionally used, asphalt-based binders offer a sustainable alternative; however, their bonding behavior and influence on polishing performance remain insufficiently understood. This study investigated the evolution and optimization of BBS in crumb rubber-modified (CRM) asphalt for rhyolite-based HFSTs. BBS was measured under dry and wet-conditioned states for two CR contents (10% and 15%), two CR types (cryogenic and ambient), two interaction temperatures (170 and 200 °C), and interaction times from 10 to 240 min. HFST performance was assessed using the …

Flexural Performance Of Deficient Rc Beams Repaired With Gfrp Composite, Zena Aljazaeri, Hayder Alghazali, Zuhair Al-Jaberi, John J. Myers

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Fiber-reinforced polymer composite materials have been improved for use in repairing and strengthening existing infrastructure over the past few decades. This case study focuses on the effect of confinement with GFRP strips on the structural performance of out-of-service beams in bridge applications due to the impact of over-height vehicles or inadequate lap-spliced reinforcements. In this study, beams with inadequate lap splices in the tension zone were utilized to mimic the damaged area in out-of-service RC beams. The proposed repair technique is a glass fiber-reinforced polymer (GFRP) composite in the form of longitudinal sheets and U-wrapped strips. The experimental study determined …

Improving The Concrete Compressive And Flexural Strength With A Low Fraction Addition Of Carboxylated Nitro-Oxidized Cellulose Nanofibrils From Banana Rachis, Ngesa Ezekiel Mushi, Emmanuel Kagya

Tanzania Journal of Science

Conventionally, concrete strength depends on the bonding interface, especially in hydrated products such as calcium silicate hydrate (CSH). As a result, concrete is sensitive to tensile load. With its unique properties, a low fraction of carboxylated nitro-oxidized cellulose nanofibrils (NOCNF) from the banana rachis is employed to improve the mechanical performance of the concrete nanostructurally. Compressive and flexural strength using the NOCNF content at 0, 0.05, and 0.1 wt.%, cured for 7 and 28 days, were evaluated. Notably, the compressive strength increased by 16 % and the flexural strength by 13 % at 0.1 wt.% NOCNF compared to plain concrete …

Ground To Roof Snow Load Ratio (Gr) Data Release, Brennan Bean, Cooper Nelson, Jesse Wheeler, Scout Jarman, Salam Adil Al-Rubaye, Marc Maguire

Browse all Datasets

This data release provides historical ground-to-roof snow load ratio (GR) datasets used for snow load research and model development. The release includes original referenced datasets, cleaned country specific datasets, and a master dataset that combines Canadian and United States datasets into a standardized format for research and engineering applications.

Expected Structural Damage, Residual Capacity, And Repairability Of Light-Frame Timber Houses, Mikayla Caruthers

Master's Theses

Earthquake damage in light-frame timber structures is commonly evaluated using peak inter-story drift. However, drift alone does not fully represent the remaining structural capacity of a building or its ability to be repaired following a seismic event. Although expected structural damage, residual capacity, and repairability have each been studied extensively, these concepts are often considered independently, leaving limited guidance that links them within a unified post-earthquake assessment methodology.

This thesis establishes an integrated framework that relates expected structural damage, residual capacity, and repairability for light-frame timber residential structures. Existing literature was synthesized to develop drift-based damage-state classifications, identify methods for …

Five-State Seismic Damage Classification Of Steel-Girder Bridges On Soft Soil Using Directional Intensity Measures And Multi-Parameter Damage Indices, Ibrahim Alomari, Woubishet Zewdu Taffese, Mohammad Hossein Afsharmovahed, Genda Chen

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Rapid yet accurate post-earthquake damage assessment of highway bridges is essential to ensure transportation network resilience. Traditional inspection, fragility analysis, and finite element modeling are time-consuming or inaccurate for real-time decision-making. This study compares ten machine-learning classifiers for the seismic damage states of highway steel-girder bridges that incorporate directional intensity measures to represent the variance of ground motions. Based on the nonlinear time-history analyses of two Missouri bridges, one Michigan bridge, and one Wisconsin bridge, multi-parameter structural damage indices were proposed and mapped to five damage states from none to collapse. Among ten supervised algorithms studied, the artificial neural network …

Probabilistic Modeling Of Hurricane Hazards And Structural Reliability Of Offshore Wind Turbines Under Climate Change, Susmita Bhowmik

All Dissertations

Hurricanes are among the most destructive natural hazards in the United States, especially along the Atlantic and Gulf coasts. Climate change is expected to affect hurricane activity by changing important environmental conditions. At the same time, offshore wind energy is expanding, creating a need to understand hurricane risks to offshore wind turbines.

This dissertation develops a stochastic hurricane simulation framework to estimate hurricane wind hazards for coastal and offshore regions along the U.S. East Coast and Gulf Coast. The framework generates synthetic hurricane tracks using updated storm-frequency data and is validated against historical records from HURDAT2, NOAA buoy wind observations, …

Effect Of Rheology Modification On Fiber Orientation And Dispersion In 3d-Printed Ultra-High-Performance Concrete, Haodao Li, Alfred Addai-Nimoh, Seongho Han, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The extrusion process in 3D concrete printing (3DCP) facilitates horizontal alignment of steel fibers along the printing direction, thus enhancing the load-bearing capacity of printed elements. However, such shear-induced fiber alignment is highly sensitive to rheological properties. This study investigates how variations in dynamic yield stress (τd) and plastic viscosity (μ), influence the extrudability, fiber orientation and dispersion, and anisotropic mechanical behavior of ultra-high-performance concrete (UHPC). Five viscosity-modifying agent (VMA) types were incorporated at two content levels to modify the rheology of printable UHPC. Results showed that moderate VMA additions improved printability, whereas excessive contents markedly increased τd and μ; …

Impact Of Climate Change On Extreme Windstorms And Implications For Structural Design In The United States, Teng Wu, Reda Snaiki, Frank Lombardo, Sihan Li, Michele Barbato, Guirong Yan, Robert J. Trapp

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Climate change impacts various extreme windstorms associated with specific meteorological phenomena in different ways. Because various windstorms contribute to the design wind speeds, this study systematically reviewed the state-of-the-art understanding of climate change effects on wind events that collectively contribute to structural wind design in North America, particularly the US, including extratropical cyclones (as well as nor'easters), tropical cyclones, thunderstorms, and tornadoes. For each windstorm type, the general evidence of climate change impacts on storm activities (e.g., occurrence frequency and intensity) are summarized, followed by the introduction of existing simulation frameworks for yearly (or subyearly) maximum storm winds under changing …

Wind Effects Induced By Multivortex Tornadoes On A Low-Rise Building, Yi Zhao, Guirong Yan, Tetsuya Takemi, John Van De Lindt

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Multivortex tornadoes contain two or more subvortices that orbit within a parent vortex and can generate highly intermittent and localized near-ground wind fields. This study investigates how tornado flow structure affects wind effects on a low-rise building using large-eddy simulations. One single-vortex tornado and three multivortex tornadoes with different subvortex configurations are examined by systematically varying swirl ratio. Tornado translation is modeled using a relative-motion framework in which the building traverses the vortex field. Aerodynamic force and moment coefficients are evaluated along the traversing path. Additional stationary simulations are conducted to examine repeated load amplification associated with subvortex passages. Compared …

Experimental Studies Of Compressive Strength Of Sustainable Concrete With Partial Cement Substitution Using Palm Oil Boiler Ash, Daral Suraedi, Jessica Sjah, Nuraziz Handika, Saffanah Fasya Aulia, Karmenita Olivia Edwardo

CSID Journal of Infrastructure Development

This study investigates the mechanical performance of sustainable concrete incorporating Palm Oil Boiler Ash (POBA) as a partial cement replacement. As the construction sector seeks to reduce CO₂ emissions and manage agro-industrial waste, POBA emerges as a promising supplementary cementitious material due to its pozzolanic potential and abundance in palm oil–producing regions such as Indonesia.Concrete specimens were prepared with POBA substitution levels ranging from approximately 10% to 30% by weight of cement, in combination with nanosilica and a polycarboxylate ether (PCE) superplasticizer to enhance performance. The mix design was developed in accordance with ACI 211 guidelines to maintain comparable workability …

A Machine-Learning-Based Systematic Framework For Modeling Compression And Recompression Indices For Florida Soils, Michael Morales

Doctoral Dissertations and Master's Theses

This thesis develops a machine-learning framework for estimating the compression index and the recompression index of Florida soils from routinely measured index properties, and reports two studies that build it. Consolidation settlement design requires both indices, and both are obtained from the incremental-loading oedometer test, which occupies a specimen for one to two weeks; the index tests that accompany it are complete within hours. Empirical correlations have filled that interval since the 1950s, but their coefficients are calibrated on specific soil populations and transfer poorly between regions. The first study analyzes 376 consolidation tests compiled for the Florida Department of …

How Does Competitive Adsorption Between Vma And Pce Influence Yield Stress Of Cement Paste? A Novel Insight From Interparticle Forces And Percolation Threshold, Huamin Sun, Le Teng, Xiaohan Yu, Xin Shu, Zhangli Hu, Jiaping Liu, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Viscosity modifying admixture (VMA) and polycarboxylate superplasticizer (PCE) are often combined to optimize rheological properties of cement-based materials. However, the competitive adsorption of these complex admixtures can greatly influence rheological properties. Many studies have investigated the variation of yield stress due to competitive adsorption between VMA and PCE; but the mechanisms are not fully understood. This study aims to shed a new light on this question in cement paste systems prepared with low water-to-binder ratios of 0.16–0.30. The competitive adsorption of VMA and PCE was quantitatively assessed using the Total Organic Carbon and Ultraviolet-Visible Spectroscopy measurements. The effect of competitive …

Transforming Dredged Sediment Into Reactive Clay: Critical Review Of Calcination, Reactivity, And Sustainable Valorization As Supplementary Cementitious Material, Seongho Han, Sanghwon Wi, Koochul Ji, Keun Hyeok Yang, Farshad Rajabipour, Kamal H. Khayat, Jinyoung Yoon

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Dredged sediment (DS) is generated worldwide in large volumes through routine port and waterway maintenance, yet its disposal presents environmental and economic challenges. Recently, calcined dredged sediment (CDS) has emerged as a supplementary cementitious material (SCM), offering a viable alternative to traditional SCMs, such as fly ash and slag cement. This review synthesizes current knowledge on the physical, chemical, and mineralogical characteristics of raw DS and pretreatment strategies aimed at dewatering, organic matter removal, and contaminant stabilization. The effects of calcination on the production of reactive amorphous aluminosilicates are also discussed. Emphasis is placed on physicochemical changes revealed by experimental …

Low-Carbon Concrete For Sustainable Construction: A Comprehensive Review Of Performance Characteristics, Implementation Challenges, And Decarbonization Pathways, Fazel Azarhomayun, Jingjie Wei, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Reducing the carbon footprint of concrete has become a central objective in sustainable construction. Low-carbon concrete (LCC), developed primarily through clinker reduction, supplementary cementitious materials, and alternative binder strategies, offers a promising route for lowering embodied emissions while maintaining the performance requirements of structural concrete. This comprehensive review consolidates the current state of knowledge on LCC, identifies critical research and implementation gaps, and examines its material composition, mixture-design methodologies, performance characteristics, structural applications, implementation challenges, and decarbonization pathways. Single-SCM systems have been reported at clinker-replacement levels approaching 50%, although durability at these replacement levels, particularly carbonation resistance, remains system- and …

Strategies For Extending The Service Life Of Prestressed Concrete I-Shaped Beams, Sanjoy Kumar Bhowmik

Dissertations

Prestressed concrete (PSC) I-shaped beams are widely used in bridge construction because of their structural efficiency and durability. The service life of these beams is reduced and the maintenance frequency is increased due to the distress during fabrication and subsequent deterioration. Although several mitigation strategies have been proposed and implemented, beam end cracking during fabrication remains a major concern. The causes and mitigation strategies for beam end cracking have been studied for decades, but there have been no comprehensive studies utilizing beam end strains during fabrication and lifting at prefabrication plants under normal operational conditions. Moreover, existing maintenance and repair …

A Workflow For Automating Geospatial And Data Visualizations For Post-Earthquake Building Damage Data, Alejandra Bravo

Architectural Engineering: Graduate Reports

After major seismic events, reconnaissance efforts of various types are made to gather data. Coarse data can be collected with satellite imagery, mid-scale data can be recorded by capturing thousands of images, and granular data is typically documented manually by humans. Post-earthquake reconnaissance teams can be deployed by universities, research organizations, professional associations, and private firms. Academics, engineers, and students with varying degrees of expertise are tasked with collecting building metadata and damage data, typically in a short period of time. This data can be of various types including numerical (i.e. number of stories, height, etc.), categorical (i.e. damage level, …

Characterization Of The Thermally Driven Red Hue Effect In Coated And Uncoated Concrete Systems: Implications For Post-Fire Assessment In Wildland Urban Interface Communities, Juan C. Palominos Jr

Master's Theses

The increasing frequency and intensity of Wildland-Urban Interface (WUI) wildfires, such as the destructive 2025 Pacific Palisades Fire that destroyed over 6,000 structures, have underscored the urgent need for rapid post-fire safety assessment methodologies. This study sought to quantitatively characterize the Thermally Driven Red Hue Effect (TRHE), a unique, irreversible color shift observed in architectural coatings and concrete substrates, to determine its reliability as a permanent visual record of thermal exposure. Concrete substrates were formulated with three distinct coarse aggregates: gold granite (14.7% Fe), red cinder (22.4% Fe), and green rock (33.6% Fe) and coated with a 20 PVC waterborne …