M.S. - Civil Engineering

Permanent URI for this collectionhttps://hdl.handle.net/10125/879

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Design, construction, and analysis of a modular structural model for shake tables
(University of Hawai'i at Manoa, 2025) Henry, Jason; Moon, Do Soo; Civil Engineering
Shake table testing remains a core method for advancing understanding of structural behavior under dynamic loading. While most tests involve either full-scale structures or simplified scale models, few address the need for compact, modular systems that allow targeted variation of individual components. This study responds to that gap by designing and evaluating a five-story, 2-by-1 bay structure with replaceable columns and adjustable floors. The model was developed to support studies involving structural parameter variations and numerical model validation. To assess its consistency across physical and virtual environments, three numerical models were developed and compared to experimental results. Modal periods were used to evaluate alignment, with a focus on the first five weak-axis modes as well as the primary torsional and strong-axis modes. The comparisons confirmed close agreement in the weak direction, demonstrating the model’s usefulness for future studies in dynamic analysis and structural model calibration.
Predicting equilibrium scour depth around circular bridge piers using hybrid machine learning models
(University of Hawai'i at Manoa, 2025) O'Connor, Christopher; Bateni, Sayed; Civil Engineering
Accurate prediction of scour depth is essential to bridge design in terms of safety, planning, and cost. Existing empirical methods for predicting scour depth are limited by their reliance on specific datasets and linear assumptions. As a result, these formulas fail to capture the complexities in real-world scour processes. Using a diverse dataset of 841 measurements sourced from 35 laboratory and field studies, this research applies hyperparameter tuning and hybrid machine learning models to predict equilibrium scour depth around circular bridge piers. Grid search (GS), grey wolf optimizer (GWO), and whale optimization algorithm (WOA) are leveraged to optimize support vector regression (SVR) hyperparameters. These optimization techniques are particularly effective in handling nonlinear data patterns typical of pier scour. By applying them in this study, improved model accuracy and adaptability to a complex scour process is achieved. Model performance is evaluated using RMSE, R², and MAE. WOA–SVR demonstrates the highest predictive accuracy, achieving RMSE = 0.03547 m, R² = 0.9267, and MAE = 0.02336 m. All three hyperparameter optimization techniques prove to significantly improve the SVR model in both training and testing phases. A 5-fold cross-validation analysis further confirms the stability and generalization capacity of the enhanced SVR models. Additionally, comparison with established methodologies validates the superior performance of the proposed models over well-known empirical equations.
DESIGNING AN INTEGRATED SOLUTION FOR THE ALA WAI WATERSHED: ANALYSIS OF PROPOSALS, GLOBAL FLOOD MITIGATION PROJECTS, AND WATER QUALITY IMPROVEMENT TECHNOLOGY
(University of Hawai'i at Manoa, 2024) Beebe, David; Singh, Amarjit; Civil Engineering
The Ala Wai Watershed in Honolulu, Hawaii, is situated in a densely populated region that faces unique challenges, including severe flood risks, steep topography, intense storm events, and an outdated single outlet canal system, constructed in the 1920s. The primary objective of this research was to develop an integrated solution that addresses flood mitigation, environmental restoration, and repairs to the existing, aging Ala Wai Canal.This research examines the existing problem, including a comprehensive evaluation of the major factors at play, such as flood risks, environmental concerns, outdated infrastructure, and cultural impacts. It also analyzes various existing proposals for flood mitigation within the Ala Wai Watershed with an understanding of all the major factors. The U.S. Army Corps of Engineers’ (USACE) Tentatively Selected Plan (TSP) for the Ala Wai Watershed Flood Mitigation Project is explored in detail, including the economic viability of the proposal. In addition, global flood mitigation projects such as the Delta Works in the Netherlands and the Glasgow Smart Canal in Scotland are reviewed to provide valuable insights into potential solutions for the Ala Wai Watershed. Furthermore, canal flood mitigation efforts in New Orleans and New Jersey are highlighted, offering insights into projects that demonstrated effective coordination among United States federal agencies, such as the USACE and the Federal Emergency Management Agency (FEMA), as well as other key stakeholders. Going beyond flood mitigation, environmental technologies utilized both locally and internationally were analyzed for their cost, effectiveness, and overall applicability for the Ala Wai Canal. Approaches varied widely, from surface-level systems aimed at removing trash and debris to advanced technologies designed to improve water quality using microorganisms. Following an in-depth review of the problem, proposed solutions, global flood relief projects, and water quality improvement initiatives, the author presents an integrated solution for the Ala Wai Watershed. This proposed solution addresses flood mitigation while also tackling broader environmental and infrastructural challenges, providing a long-term solution that utilizes modern engineering practices to retrofit the existing system. The proposed solution is an integrated strategy that incorporates best-fit systems and practices identified throughout this research. For flood control, the author proposes constructing floodwalls on the mauka side of the Ala Wai Canal to match the height of the existing makai walls, addressing flood risk disparities. Additionally, the proposal includes constructing a second canal outlet under Kapahulu Avenue to enhance water capacity and provide an alternative flow path, which will also facilitate incremental renovations of the existing canal infrastructure. Environmental improvements in the Author’s Integrated Proposal focus on enhancing water quality utilizing Genki Balls, invasive species removal and fencing, and the implementation of the Spinning Cogs system for debris management. The Author’s Integrated Proposal includes plans to upgrade the Ala Wai Canal’s structure with concrete flooring and walls. While the proposal’s estimated cost of $991 million is substantial, it offers significant benefits, including improved flood protection, enhanced water quality, and modernized infrastructure.
DEVELOPMENT OF A FRAGILITY ANALYSIS METHODOLOGY FOR COASTAL ROADWAYS: A CASE STUDY IN MAUI COUNTY
(University of Hawai'i at Manoa, 2024) Eyre, Kalen; Francis, Oceana P.; Civil Engineering
The vulnerability of coastal roadways within the Hawaiian Islands has become increasingly apparent over the last decade, with projections of sea level rise only set to worsen the effects of storm surge, waves and coastal erosion. Unfortunately, the development of fragility models, specific to Hawaii, for this type of infrastructure does not exist within the literature. Furthermore, the limited research that has been done in this area within the continental U.S. uses high-fidelity storm simulations. This approach hinders the replicability of the analysis, which leaves it at a disadvantage since theoretically the model becomes increasingly more robust through the repetitive application of its methodology for development on each new case study. For this purpose, this thesis proposes a methodology for fragility analysis that can be adopted for use on coastal roads within Maui County using open-source data allowing for an ease of replicability. The methodology is applied to a case study of South Kihei Road that experienced road failure in some sections during a Kona Low in December 2021. This application demonstrates the capabilities of the proposed methodology and led to the development of several fragility functions to understand the effects of certain morphological characteristics. Although a majority of the developed fragility functions demonstrated high precision and accuracy in classifying damage, the resulting models displayed contradictory behavior between predictor variables and probability of damage. This inconsistency highlighted the current limitations of the methodology, and areas where improvement could be made.
WIND-DRIVEN FIREBRAND DYNAMICS IN A NEAR-FOREST RESIDENTIAL AREA: A CASE STUDY OF MAUI WILDFIRE
(University of Hawai'i at Manoa, 2024) Sasaoka, Brenton Kaulana Tamotsu; Kim, Albert S.; Civil Engineering
The Lahaina wildfire disaster that occurred in early August 2023 resulted in a devastatingloss of life and history with an unprecedented rapid propagation rate. To better understand the rapid and unexpected movement of fires, the study aims to analyze the potential impact of winddriven movement of firebrand particles on fire spread. These firebrand particles can be primary or supplemental causes in the erratic and quick spread of fires throughout wild and urbanized areas through fire spotting. The present research focuses on the propagation of firebrand particles within urbanized areas of Lahaina during high wind events caused by Hurricane Dora. 3D building structures affected by the fire were reconstructed using the RHINO 8 software. The reconstruction incorporated public building outlines and heights found in ArcGIS Pro. The high wind conditions (from Hurricane Dora) are applied to a CFD model constructed using OpenFOAM software with six houses in Lahaina, Ka‘akepa Street. Assuming that each simulated firebrand particle was spherical and had a uniform combustion rate, the drag, gravitational, and random forces are included in a dynamics model programmed using MATLAB. The wind profiles calculated using OpenFOAM are inputted into the firebrand dynamics program to include realistic convective drag forces. The combination of the coupled Eulerian-Lagrangian simulations portrays the propagation of firebrands in the direction of the fast wind events observed on the day of the wildfire. The results show that these particles travel over non-flammable surfaces, such as roads and sidewalks, and land on flammable structures, such as downwind neighboring. The OpenFOAM simulations calculated wind magnitude data, which indicated that wind speed was lower along the streets and that the buildings were aligned with them after contact. Higher elevations had more significant wind speed magnitudes. The particles primarily propagated in the downwind wind direction. This propagation highlighted the impact of high wind conditions on the spread of firebrand particles. The results showed that fires could spread during these harsh conditions if flammable material existed downwind and wind conditions remained constant. These results demonstrate the ability of firebrands to travel quickly and spread fires during high wind events, which calls for changes to the materials used in constructing structures and the removal of highly flammable invasive grasses found in abundance in Lahaina. This change will help prevent future disasters from reoccurring. The research conducted can be used as an additional resource to avoid fire disasters further here in Hawai‘i.
ABOVE VERSUS BELOW-GROUND POWER LINES: A MULTI-SCENARIO AND GEOGRAPHICAL PERSPECTIVE
(University of Hawai'i at Manoa, 2024) Corizzi, Kevin; Singh, Vir A.; Civil Engineering
The choice between above-ground and below-ground power lines is critical in designing and deploying electrical infrastructure, with implications for reliability, safety, and environmental impact. This research paper comprehensively analyzes the differences between above-ground and below-ground power lines, highlighting their pros and cons across multiple scenarios and geographical locations. This study examines the factors influencing the choice of powerline installation, including cost considerations, reliability, maintenance requirements, environmental impact, and resilience in natural disasters. By conducting an extensive literature review and utilizing case studies from diverse geographical locations, we provide a holistic understanding of the trade-offs associated with each installation method. Our findings reveal that above-ground power lines offer cost advantages in initial deployment but are susceptible to weather-related disruptions, pose fire hazards, and have aesthetic and environmental concerns. Conversely, below-ground power lines are more resilient to weather events, have a lower environmental impact, and are aesthetically pleasing. Still, they involve higher installation costs and longer repair times in case of faults. Furthermore, our research assesses the suitability of each installation method in different scenarios, such as urban, suburban, and rural areas. It considers geographical factors such as climate, population density, and geological conditions. We demonstrate that the optimal choice between above-ground and below-ground power lines varies significantly based on these factors. By shedding light on the nuanced advantages and disadvantages of above-ground and below-ground power lines, this research paper aims to provide valuable insights for policymakers, utility companies, and engineers involved in the planning and development of electrical infrastructure. The findings presented herein can provide informed decisions prioritizing safety, reliability, and sustainability in diverse geographical contexts, ultimately contributing to enhancing our electrical power distribution systems.
Investigating the Effect of Road Characteristics on Pedestrian and Bike Crash Frequency
(University of Hawai'i at Manoa, 2024) Azimi, Shiva; Chen, Roger RC; Civil Engineering
The World Health Organization's 2023 report highlights a critical global concern, revealing that vulnerable road users, including pedestrians and cyclists, account for over half of all road traffic fatalities. This alarming statistic underscores the imperative need for enhanced pedestrian and bicycle safety. Road alignment emerges as a pivotal factor influencing the frequency of crashes involving these groups. This thesis examines the relationship between road alignments and features and incidents involving pedestrians and bikes in Oahu, Hawaii, from 2015 to 2022. Structured into two primary sections, the study first develops a methodology for road segmentation based on road alignments, leveraging GPS data and. Subsequently, it employs both Negative Binomial regression and Zero-Inflated Negative Binomial regression analyses to explore the association between segment-level horizontal and vertical road alignments, alongside other road features, and the frequency of crashes involving pedestrians and cyclists. This approach aims to shed light on how specific road configurations contribute to the road safety challenges faced by vulnerable user groups. Key findings indicate that both extremely sharp curves and straight segments elevate crash risks due to navigation difficulty and decreased vigilance respectively. While steeper grades initially decrease crashes, further increases in steepness can escalate crash frequency due to heightened navigational challenges, potentially overriding the cautionary effect observed with moderate steepness. These findings highlight the complex interplay between road geometry and crash incidents. Moreover, higher traffic volumes and more lane numbers emphasizes the heightened risk to pedestrians and bicyclists on roads probably due to increased interactions and challenges of crossing and maneuvering through multi-lane roads. Road segments with higher speed limits tend to have a lower incidence of crashes, likely due to inherent safety features designed for higher speeds and lower speeds in areas frequented by pedestrians and bicyclists. The findings of this study can aid planners and policymakers in enhancing pedestrian and cyclist safety measures.
Predicting Short-term Demand and Exploring Influencing Factors in Bike Sharing Systems
(University of Hawai'i at Manoa, 2024) Azizzadeh, Ahmadreza; Chen, Roger RC; Civil Engineering
Bike share systems worldwide are increasingly recognized for their environmental benefits and potential role in promoting active transportation. These systems are particularly valued for addressing the first and last mile problem by providing access to public transport services and facilitating multimodal travel. This study explores the impact of subway and bus operations on the usage of New York City's Citi Bike system. Utilizing a Random Effects Spatial Autoregressive (RE-SAR) model on the counts of bikes rented and returned at each station, to account for spatial and temporal dynamics between bike station usage and public transportation is investigated, with a particular focus on subway and bus operations. The estimation results indicate a positive correlation between both subway and bus arrivals and the usage of the bike share system, with subway access exerting a more significant impact. Furthermore, the study employs a Graph Attention Network (GAT) model, enriched with key factors identified through the RE-SAR model, to forecast short-term usage for bike shares at individual stations. This research underscores the influence of public transit on bike share systems, demonstrating how the environment surrounding the stations and temporal variables affect usage. Additionally, integrating the GAT model into public transit and bike share program applications could significantly enhance user experiences by addressing common issues such as empty or full bike stations, thereby promoting the adoption of this sustainable mode of transportation.
The Impact of Nutrient Loading on the Survival Dynamics of Staphylococcus aureus in Beach Sand
(University of Hawai'i at Manoa, 2024) Hugger, Joslyn; Kirs, Marek; Civil Engineering
Community-acquired Staphylococci infections are becoming more prevalent where human activity at recreational beaches constitutes a large component of the source of Staphylococcus aureus. Monitoring the dynamics of microbial survival in beach sand is important for the protection of human health, and while previous studies have shown the health risks associated with S. aureus and MRSA infections, there is limited understanding of the ecology of this species. This study aims to assess the impact of nutrient loads on the survival dynamics of S. aureus in beach sand in order to gain insight on the ecology of microbial pathogens with respect to changing environmental conditions and their potential impact on water quality. This work identifies the impact of sand types, S. aureus strains, and nutrient levels on S. aureus survival dynamics using microcosm experiments to replicate natural beach conditions. Sand sample eluates obtained from recreational beaches on Oahu, Hawaii were assayed for the cultivation and isolation of a native S. aureus strain. S. aureus was found to have higher viability in locally collected Waikiki sand in comparison to commercially bought coral sand. In the absence of competing bacteria, analysis of variance (ANOVA) testing indicated that additional nutrient loads were found to have no statistically significant impact on the growth dynamics of S. aureus in beach sand. The native S. aureus strain was found to have higher initial growth rates in beach sand, but entered the death phase faster than the laboratory S. aureus strain. These results suggest that the micronutrients present within the Waikiki sand were sufficient to support the S. aureus population and that specific growth rate is independent of nutrient concentration at high concentrations. The starvation-survival mechanisms for S. aureus outside of its main ecological niche requires further research to understand not only what limits S. aureus growth in natural environments, but also how S. aureus alters its metabolism in response to the availability of nutrients.
Developing a Novel Testing Configuration for Assessment of Fatigue Resistance in Asphalt Concrete Mixtures
(University of Hawai'i at Manoa, 2024) Sickels Jr, Arthur Joseph; Archilla, Adrian Ricardo AR; Civil Engineering
Laboratory testing of asphalt concrete (AC) mixtures is a critical element of transportation engineering that facilitates performance-based design. Over time, numerous tests have been developed to evaluate AC mixture performance to withstand different distress types. This study offers an initial evaluation of a novel test configuration to evaluate the mixture cracking performance with the following key features: ease of preparation, potential use of field cores, possible implementation in quality control, potential use of both monotonic and cyclic loading, simulation of layer bending and an elastic sublayer support. The proposed testing configuration utilizes common 150-mm diameter samples lying flat on a cylindrical support with or without a supporting aluminum plate with loading applied to the uncut compacted surface or a cut face. In this configuration, the AC sample is subject to bending with maximum strains at the bottom of the sample beneath the load mirroring the state of stresses which are related to bottom-up fatigue cracking seen in AC pavement structures.The results of this study yielded a finite element model of the state of stresses present in the proposed testing configuration along with laboratory validation and troubleshooting of the test configuration geometry and procedure. Based on the experimental validations and several trials performed with various configurations, an optimized setup of a 30-mm thick sample supported with a 3-mm beveled aluminum pipe and a rubber load applicator was developed in combination with a quick and relatively simple procedure to be used in a monotonic loading mode for correlation to fatigue cracking performance.
Characterizing Flows in Ahupua'a, a Native Hawai'ian Water Management System: Theory and Simulation Studies
(University of Hawai'i at Manoa, 2023) Acorda, Isaiah Kawena; Kim, Albert S.; Civil Engineering
The concepts of specific energy and momentum have been fundamental to understanding hydraulicengineering for more than a century in modern times. The importance of water in Native Hawaiian culture was exposed through religion, language, and land. Such examples include the ahupua‘a system, where water was the primary indicator of dividing land and other resources. To have an in-depth understanding of ancient Native Hawaiian agricultural practices, computational fluid dynamics simulations will be performed for the Native Hawaiian ahupua‘a agricultural systems to connect hydraulic engineering and Native Hawaiian traditional practices with scientific visualization of flow patterns. Specifically, irrigation systems on ahupua‘a, such as that on Limahula Garden & Preserve on Kaua‘i, will be modeled through an OpenFOAM package for CFD simulations that will mimic flow within the ahupua‘a as slow overflows in a series of weirs. The model displays water flowing through three terraces in order to observe streamlines and overall flow. For the first part of the thesis, I will review the literature on the historical and cultural aspects of Ahupua’a, and perform CFD simulations for a better understanding of lo‘i kalo flow patterns, modeled as overflow in weirs in series. My final results will include mathematical, computational, and cultural aspects of ahupua‘a flows. For the second topic of this research, the specific energy and specific momentum will be mathematically re-investigated for quasi-rectangular channels with irregular bottoms. For open channel flow passing through wide rectangular channels, specific energy and momentum are used to find subcritical and supercritical water depths for various hydraulics applications, such as, but not limited to, sluice gates and hydraulic jumps. Historically, sequent or alternate depths and Froude number analyses were utilized to find solutions for flow depths using symbolic software. This thesis will include detailed mathematical derivations leading to the analytic solutions in the literature and will discuss the similarity and reciprocal relationship between the fundamental specific energy and momentum equations. These similarities of derivations can be extended to quasi-rectangular channels where the specific energy and specific momentum can be easily calculated. The main part of the mathematical work will inspect the depreciated cubic equations of specific energy and specific momentum and apply these equations for cases of quasi-rectnagular channels with a few examples. This thesis will include analyses of specific momentum and energy and physical analyses of the mathematical solutions in accordance with previous studies available in the literature.
APPLICATION OF SMALL BASELINE SUBSET (SBAS) TIME-SERIES ANALYSIS FOR LANDSLIDE DETECTION IN HAWAIʻI
(University of Hawai'i at Manoa, 2022) Hendrix, Ryan N.; Hendrix, Ryan N.; Civil Engineering
The occurrence of landslides or rockfalls onto public roadways can result in a wide variety of issues for commuters and government agencies affiliated with the roadway systems. Under the best circumstances, landslide or rockfall debris on a roadway will cause commuter delays and result in minimal costs associated with remedial efforts. Under worst case circumstances, these occurrences can result in property and roadway infrastructure damage, injury, and even loss of life. The Hawaiʻi Department of Transportation (HDOT) is proactively attempting to identify areas near public roadways that may pose potential concern for landslide or rockfall activity. As part of these efforts, they have requested research be conducted involving the use of satellite synthetic aperture radar (SAR) imagery to conduct interferometry (InSAR) for two locations: Hawaiʻi Route 19 between mileposts 10 and 30; and Hawaiʻi Route 360 between mileposts 0 and 35. The Small Baseline Subset (SBAS) InSAR approach was determined to be the best method for the areas of HDOT interest. An extensive search of SAR imagery for the Hawaiian Islands proved that only limited datasets are publicly available for the areas of interest. To provide a proof of concept for implementation of SBAS analysis in the Hawaiian Islands, a case study of the Waiʻōmaʻo landslide located in Pālolo Valley on the Island of Oʻahu was conducted to compare available inclinometer data with SBAS datasets. Two-dimensional decomposition was implemented for opposite orbits of descending and ascending Sentinel-1 datasets. Decomposition was conducted to compare and review with in situ Waiʻōmaʻo landslide inclinometer data. Overall, the case study results show that when both ascending and descending datasets are used to derive displacements that are resolved in the direction of movement, InSAR analysis can effectively capture inclinometer trends in areas experiencing relatively small displacements over time (< 30 mm/year) but the accuracy diminished in fast moving slides (≥ 270 mm/year). Following the case study, the SBAS method was then applied to the Hawaiʻi Island and Maui study areas. Application of the InSAR technique was limited by the following: SAR data availability; geographic positioning and radar shadowing; and amount of vegetation in the research areas. The Hawaiʻi Island study area displacements were decomposed in a direction perpendicular to the slope contours to estimate the true displacements. Review of two-dimensional decomposition results was conducted for the potential of landslides and rockfalls in Hawaiʻi Island. Of the areas, minimal displacements were measured. Obtaining SBAS descending and ascending opposite orbits for Maui proved unsuccessful due to radar shadowing caused by Haleakalā shield volcano. SBAS processing was only successful for the descending orbit for Maui.
LEACHING BEHAVIOR OF SELECTED METALS IN ALKALI-ACTIVATED CONCERETE MADE WITH INDUSTRIAL WASTE
(University of Hawai'i at Manoa, 2023) Hargraves, Jonathan S.; Shen, Lin; Civil Engineering
The use of alkali-activated materials to immobilize heavy metals in precursors represents a promising avenue in environmental remediation and waste management. Alkali-activated materials, with their unique properties and ability to form stable matrices, offer a potential solution to mitigate the environmental impact of heavy metal contamination.Over the course of industrial development, several materials once widely used for their advantageous properties were later found to pose significant risks to human health and safety. Two notable examples are asbestos and per- and polyfluoroalkyl substance, both of which became prevalent in various industries before their detrimental health effects were fully understood. In this vein, the ability of alkali-activated materials utilizing H-Power Municipal Solid Waste Incineration Ash, AES fly ash, and red mud to immobilize heavy metals present in precursor materials should be thoroughly understood before they can be adopted into industrial use. This study furthers the research of Reza Mirmoghtadaei and Lin Shen by subjecting three samples of alkali-activated materials, and the granular materials used as precursors in the mix design of the aforementioned monolithic alkali-activated samples, to EPA Test Method 1315 leaching tests to evaluate the leaching behavior of each mix and the constituent granular precursor material. Significant reductions in leached metal concentrations were found when comparing compacted granular precursor materials to their alkali-activated counterpart.
Indicators For Coral Health For The Coastal Road Erosion Susceptibility Index (CRESI) On Oahu, Hawaii, USA
(University of Hawaii at Manoa, 2022) Hunter, Nykell; Francis, Oceana P.; Civil Engineering
Natural coastal protection possesses the capability of dissipating large amounts of incoming wave energy, protecting the coastline, while providing more adaptability into the ecosystem than hard-engineering coastal protection. Healthy nearshore coastal waters provide an environment more conducive for coral reef growth and prosperity, resulting in a higher degree of wave attenuation and adaptability as reefs build and grow. The health of the fringing reefs surrounding the Hawaiian Islands are of significant importance to the protection of coastal infrastructure and communities. To assess coral health, a coral health matrix is developed using seven variables, watershed percent conservation area, rainfall amount, coral coverage, total effluent, sedimentation, depth, and significant wave height, to quantitatively and qualitatively assess the condition and vulnerability of the coral and coral reef environment. The matrix is implemented at two case study locations, located in Waimanalo and Punaluu, Oahu, HI, respectively. Milepost (MP) 24+0.48, receiving a final vulnerability score of 3.71, is deemed as having a coral that is more vulnerable than MP 5+0.93, receiving a vulnerability ranking of 2.86 primarily due to the significantly higher rainfall and sedimentation occurring at this location. Additionally, MP 24+0.48 possesses a lower significant wave height and depth, resulting in less ocean circulation and coral reefs that are more exposed to potential threats. This coral vulnerability matrix may be adopted into the Coastal Road Susceptibility Index (CRESI) in the future.
Evaluation of Sandsavers for Wailua Beach, Kauaʻi using the Coastal Modeling System
(University of Hawaii at Manoa, 2022) Hataishi, Mallory; Francis, Oceana P.; Civil Engineering
Hawaiʻi spends millions, each year, on beach nourishment projects due to coastal erosion. With little beach width in many areas, the encroaching sea is often directly upon aligning shoreline structures. Wailua Beach, Kauaʻi, Hawaiʻi experiences the impacts of coastal erosion and has been chosen to be the first beach in Hawaiʻi to have the Sandsavers structures installed to help build back the beach and prevent further erosion. The Sandsaver is a trapezoidal structure with conical holes, with the larger holes facing the ocean and the smaller holes facing the shore. The goal of the Sandsaver is to have sediment flow through the holes and settle on both sides to build back the beach. Two separate arcs, where the Sandsavers will be “tied” together, are planned for installation at Wailua Beach in the near future. The performance of the Sandsavers is analyzed during two periods, a non-storm and storm event. Hurricane Iniki was the largest storm event to hit the island on September 11, 1992, therefore, the modeling period for the storm event is set for September 8, 1992 at 0:00 to September 14, 1992 at 23:00 (7 days). The non-storm event is also the same month/day/time but a year prior, 1991, to understand normal conditions during that time of year. The Surface-water Modeling (SMS) is used with the Coastal Modeling System (CMS) to perform the simulation. The model is set up for 1991 and 1992 conditions using a 2013 - present Digital Elevation Model (DEM). Each study period is modeled with and without the structures to determine if there are changes in the results when the structures are used. CMS is used to simulate water elevation, waves, current velocity, morphology change, and total sediment transport. Observation points are placed on the seaward and landward sides of each arc to determine if the Sandsavers dampen wave energy. Sediment budget areas are analyzed landward and seaward of the structures to determine if the Sandsavers are accreting or eroding the beach. Based on the analysis, the Sandsavers show an increase in sediment on their landward sides and a decrease in wave height when the structures are installed. The Sandsavers are a new solution to coastal erosion.
Measurement and Application of Household Activity Spaces: A Comparison of Representations
(University of Hawaii at Manoa, 2022) Tallman, Cody; Chen, Roger; Civil Engineering
The ability to measure and forecast the spatial dimensions of travel behavior has emerged as an important part of transportation planning analysis over the past few decades. The main goal of most transportation departments and public transit agencies is to provide equitable accessibility to activities of varying needs, such as employment, food consumption, and medical services. This involves identifying disadvantages in terms of the spatial reach of daily household activities, requiring policymakers to consider not only transportation attributes but also spatial behaviors in activity location. An activity space is a measure that represents the space frequently visited by a decision maker, either an individual or entire household, over time. This builds on the assumption that humans are territorial and repeatedly use a small subset of possible activity locations. This thesis investigates three possible measures for activity spaces found in literature, including the (a) confidence ellipse, (b) kernel density estimation, and (c) minimum spanning tree network. These measures are applied to a sample of one-day travel behavior from the 2012 Oʻahu Household Travel Survey. The relationship between the estimated measures and various household characteristics, such as sociodemographic information and travel transportation resources, are examined. In addition, this thesis highlights the strengths and weaknesses associated with each measure. In summary, the confidence ellipse, kernel density estimation, and minimum spanning tree network perform similarly in assessing household activity spaces, but with subtle differences. The results indicate that households located within North Shore, Wai‘anae, and Makakilo have the largest activity spaces across all measures, while households located within Downtown, Mo‘ili‘ili/Ala Moana, and Waikīkī have the smallest. Generally, household activity spaces increase in magnitude with greater distance from the Primary Urban Center. This suggests that households located throughout the island must travel longer durations and distances to access opportunities and resources. In addition, it was found that an increase in the number of persons and students per household, results in decreased activity spaces. Furthermore, households with a higher annual income tend to have more dispersed activity locations than those with a lower income.
Using Soil Erodibility Factor and Saturated Hydraulic Conductivity to Assess Coast and Beach Geomorphology for the Coastal Road Erosion Susceptibility Index (CRESI) on Oahu, Hawaii, USA
(University of Hawaii at Manoa, 2022) Takahashi, Chandelle; Francis, Oceana P.; Civil Engineering
Soils play an important role in the coast and beach regions’ susceptibility to erosion. Many of Hawaii’s state roads were aligned along the coasts and are currently experiencing erosion. The Coastal Road Erosion Susceptibility Index (CRESI) was developed as a tool to assist road agencies in identifying and ranking specific road locations that are susceptible to erosion. Two of the eleven parameters in CRESI are coast geomorphology and beach geomorphology, which are defined qualitatively in the current index. Typically, the coast is composed of volcanic geology and the beach is composed of non-cohesive soils such as sand. Therefore, this study aimed to relate erodibility to the materials found in the CRESI coast and beach regions and introduce more quantitative criteria to the two parameters. Although all of the coast and beach soil samples in this study can be broadly classified as sand according to USDA and as sand with fractions of silt and clay according to USCS, each sample had different compositions where its associated properties were considered when relating it to the soil’s erodibility. For the coast geomorphology parameter, physico-chemical parameters of soil texture, structural class, permeability class, and organic matter were used to calculate the soil erodibility factor, K, for a representative coast soil sample. The K-factor was calculated using an altered nomograph equation derived from various rainfall simulations. A series of 1 hour and two 0.5 hour rainfall simulations with an intensity of 6.35 cm/hr and combinations of thirteen 6.35 cm rains on moderately dry soil, four 3.18 cm rains on wet soil, and three 6.35 cm rains on wet soil were performed. A higher K-factor indicated that the soil was more susceptible to erosion while a lower K-factor indicated that the soil was less susceptible. The K-factors obtained in this study were used to create a proposed improved criteria for the CRESI coast geomorphology parameter. The results of this study also found that a coast soil sample’s erodibility is highly dependent on the silt and rock fragment fractions. Silt particles are easily detached due to its lower particle mass and lack of cohesive properties, while rock fragment fractions, such as vegetation or coarse aggregates, provide a protective layer to the soil’s surface. Organic matter, clay particles, and coarse sand particles also help to reduce the soil’s erodibility. For the beach geomorphology parameter, the physical property of effective diameter was used to calculate a representative beach soil sample’s saturated hydraulic conductivity, ksat. A higher ksat-value indicated that the soil was less susceptible to erosion while a lower ksat-factor indicated that the soil was more susceptible to erosion. The ksat-factors obtained in this study were used to create a proposed improved criteria for the CRESI beach geomorphology parameter that only considered saturated hydraulic conductivity. For beach soil samples, a greater erosion susceptibility was attributed to larger grain sizes, which created a matrix with larger voids between the particles. The larger voids enhanced the sand’s infiltration capacity and ability to absorb and dissipate the water flow’s energy. With smaller grain sizes, the pore water pressure needed to detach the sand particle is more easily reached, increasing the sand’s erosion susceptibility.
Assessment Of Stakeholder Perceptions Of Ocean Hazard Risk For Coastal Infrastructure/roadways, Maui County, Hawai‘i
(University of Hawaii at Manoa, 2022) Han, Rachael; Francis, Oceana P.; Civil Engineering
Coastal roads in Maui County are at-risk of sea level rise and related coastal hazards. These coastal roads are often the only way people can travel, so the inundation and deterioration of coastal roads increases communities’ vulnerability in emergency situations and negatively impacts local economies and the everyday life of residents. Recognizing the urgency of this issue, Maui County and HDOT asked the University of Hawaii Department of Civil and Environmental Engineering (UH CEE), Coastal Hydraulics Engineering Resilience (CHER) lab at University of Hawai‘i at Mānoa for assistance on creating a plan to adapt coastal county roads for future coastal hazard scenarios, which is necessary for federal funding. To inform this project’s engineering design, a stakeholder assessment is required to ensure the most sustainable and culturally-sensitive development option is recommended. The assessment also helps Maui and the State of Hawaii Department of Transportation (HDOT) identify stakeholder needs. In addition to semi-structured interviews with all levels of stakeholders, a questionnaire ranking all possible coastal adaptation options was given. This project is focused on the islands of Maui and Molokai. Lāna‘i is not included, as the island does not have any coastal county roads. A total of 112 subjects were interviewed and 102 stakeholders responded to the survey. Given the large dataset created from this assessment, we describe and analyze an example of each figure/table created using the Native Hawaiian (41 subjects in the oral interview, 13 respondents to the survey) and West Maui (35 respondents to the survey) stakeholder groups. Results of the stakeholder assessment contain 1) stakeholder preferences of coastal road adaptation options, 2) areas and roads of stakeholder concern, 3) stakeholder desires surrounding coastal issues, 4) tools and information needed for stakeholders to prepare for coastal disasters and road disruptions, 5) identified barriers and limitations to adaptation, 6) information on current and upcoming stakeholder and government actions to increase resilience, and 7) information on government-resident experiences. The application of the results is shown through a case study where data is used to identify an issue and make recommendations to improve organizational efficiency within Maui County for infrastructure coordination. Our initial findings show the County of Maui Public Works is aware of the areas and roads stakeholders are concerned about, and the Native Hawaiian stakeholder group prefers nature-based solutions over engineered ones, no matter the financial cost. Future work includes publication of the dataset for public use, further analysis of the data, and inclusion of stakeholder opinions as a parameter in CRESI. By incorporating community perspectives and providing an outlet for resident voices, the CHER lab’s adaptation recommendations aim to gain community support and receptiveness, which is critical to an infrastructure project’s success.
Collapse Potential Of The Soils At Kualakai Parkway
(University of Hawaii at Manoa, 2022) Lum, Charmaine; Ooi, Phillip S. K.; Civil Engineering
The concrete pavements at Kualakai Parkway have been experiencing differential lateral and horizontal movements. One of the many possibilities to explain this is the fact that the foundation soils are collapsible soils. A boring was drilled to collect soil samples in the median and a variety of tests were conducted to determine its collapse potential. Index tests of the fine-grained soils were used to characterize the soil properties such as moisture content, Atterberg limits, Unified Soil Classification System group names and symbols, and specific gravity. Mineralogically, the soil elements present were identified using scanning electron microscopy (SEM) with both energy dispersive spectroscopy (EDS) and wave dispersive spectroscopy (WDS) analyses and crystalline phases of the soil were identified using X-ray Diffraction (XRD). Mechanical properties were then characterized using the double oedometer procedure.
Sustainable Waste Management for Hawaii’s Correctional Facilities: Barriers to Implementation
(University of Hawaii at Manoa, 2022) Yadao, Kanoelani; Babcock, Roger; Civil Engineering
As correctional facilities seek to address overcrowding, increased expenses, and a 50% national recidivism rate, many facilities are looking towards creative measures in sustainability programs such as waste management (Benecchi, 2021). In order to implement successful waste management programs, the barriers to implementation must first be addressed. These barriers were discovered through a waste audit conducted on 8 of Hawaii’s correctional facilities due to the lack of national correctional facility data on waste composition and operations. The correctional facilities under this study include: Hawaii Community Correctional Center (HCCC), Kulani Correctional Facility (KCF), Kauai Community Correctional Center (KCCC), Maui Community Correctional Center (MCCC), Oahu Community Correctional Center (OCCC), Halawa Correctional Facility (HCF), Waiawa Correctional Facility (WCF), and Women’s Community Correctional Center (WCCC). The completion of the waste audit provided data for the overall waste operations, waste composition make-up for each site, potential areas to implement waste management programs and barriers to implementation of the waste management programs. Through the study and waste audit, the following barriers to implementation of a more sustainable waste management program were found: the need to determine site specific waste composition make-up to act as a benchmark or standard for each site, cost of equipment or budget constraints, understaffing of adult correctional officers (ACO), and ease of implementation. The data gathered from the waste audit, environmental assessment previously completed for each site, as well as research on successful programs with waste management programs implemented provided methods to potentially eliminate or mitigate the barriers to implementation. These include leadership support, policy changes, scorecard matric, training and education, and cost savings and revenue. The greatest limitation to this study is the COVID-19 Pandemic that caused an increase in certain wastes produced as well as an inaccurate depiction of inmate populations as many inmates were released prematurely to deal with the overcrowding and rapid spread of the disease.

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