• 2-D bed sediment transport modeling of a reach on the Sagavanirktok River, Alaska

      Ladines, Isaac A.; Toniolo, Horacio; Barnes, David; Schnabel, Bill (2019-05)
      Conducting a 2-D sediment transport modeling study on the Sagavanirktok River has offered great insight to bed sediment movement. During the summer of 2017, sediment excavation of two parallel trenches began in the Sagavanirktok River, in an effort to raise the road elevation of the Dalton Highway to remediate against future floods. To predict the time in which the trenches refill with upstream sediment a 2-D numerical model was used. Three scenarios: (1) a normal cumulative volumetric flow, (2) a max discharge event, and (3) a max cumulative volumetric flow, were coupled with three sediment transport equations: Parker, Wilcock-Crowe and Meyer Peter and Müller for a total of 9 simulations. Results indicated that scenario (1) predicted the longest time to fill, ranging from 1-6 years followed by scenario (2), an even shorter time, and scenario (3) showing sustained high flows have the capability to nearly refill the trenches in one year. Because the nature of this research is predictive, limitations exist as a function of assumptions made and the numerical model. Therefore, caution should be taken in analyzing the results. However, it is important to note that this is the first time estimates have been calculated for an extraction site to be refilled on the Sagavanirktok River. Such a model could be transformed into a tool to project filling of future material sites. Ultimately, this could expedite the permitting process, eliminating the need to move to a new site by returning to a site that has been refilled from upstream sediment.
    • A Mechanical Evaluation Of Alaskan White Spruce

      Syta, Dean Edward; Curtis, Kevin; Gasbarro, Tony; Raad, Luffi (1993)
      This project serves to demonstrate the usefulness of Alaskan White Spruce as a construction material. This is done through the development of allowable strength values for design purposes. Such values allow engineers to design structures using Alaskan White Spruce, increasing the usefulness of the wood species.<p> The mechanical properties of Alaskan White Spruce are investigated. Summaries of the mechanical properties and of subsequently developed allowable structural design values are given. Included are discussions of the Alaskan White Spruce species, general wood behavior, mechanical testing of wood, statistical data analysis, and allowable property development. Results are compared against the work of other researchers. Appendices of test data are given.<p> Test results and subsequent data analysis indicate Alaskan White Spruce possesses strength similar to Douglas-Fir/Larch lumber and higher strength than Spruce/Pine/Fir type lumbers. This indicates that Alaskan White Spruce may have considerable worth as a construction material. <p>
    • Adsorption of Cu (II) and Cd (II) by chininous polymers

      Zhang, Hong (2006-12)
      Heavy metal contamination has emerged as a major health problem worldwide. Biosorption, using biological waste products as sorbents, may provide a cost effective treatment strategy. The current study investigated several types of biomass, generated from waste crab shells, as bio-sorbents to remove cadmium and copper in a batch reaction system. Isotherm studies suggested that uptake increased with increasing number of amine groups, i.e. increasing degree of deacetylation (DDA) as measured by hydrogen nuclear magnetic resonance (¹H-NMR) as well as Fourier Transform Infra-red (FTIR) spectroscopy. Potentiometric titration was shown not to be a valid method in measuring the DDA for medium DDA range. pH was proven to be a main factor affecting the adsorption because of the considerable competition of protons for the binding sites at low pH. Cu²+ had higher affinity than Cd²⁺ to the chitinous polymer. Metal adsorption was elevated by high ionic strength because of more adsorption sites becoming accessible as a result of significant expansion of the network under high ionic strength. Sulfate as salt, added in the solution, greatly stimulated the adsorption of metal ions by reducing the repulsion force between the charged surface and the metal cations.
    • Alaska Arctic coastal plain gravel pad hydrology: impacts to dismantlement removal and restoration operations ; a study on the human - hydrology relationship in Arctic environments

      Miller, Ori; Barnes, David L.; Stuefer, Svetlana L.; Shur, Yuri (2019-08)
      To guard against thawing permafrost and associated thaw subsidence, the oil facilities in the Arctic are constructed on gravel pads placed on top of the existing arctic tundra, however the impacts of this infrastructure to the sensitive hydrology are not fully understood. Production in some of the older fields is on the decline; however oil exploration in the Arctic Coastal Plain is resulting in the discovery and development of new reserves. In the coming years, old sites will need to be decommissioned as production transitions to new sites. New facilities will also need to be designed and constructed. Oil companies in Alaska have historically conducted operations under leases issued through the Alaska Department of Natural Resources. The leases stipulate that once resource extraction operations are completed, the facilities must be decommissioned and the sites restored, however they are often vague in their requirements and are variable in their specifics from lease to lease. As the oil companies transition to the new sites, decisions must be made regarding what should be done with vacated gravel pads. The construction of gravel pads essentially destroys underlying arctic tundra. In undisturbed areas in the Arctic, the tundra itself creates an insulating layer that limits the seasonal thaw depth to around 0.5 m. Removal of this layer causes thaw depths to greatly increase impacting the stability of the ground and the hydrology of the surrounding area. Because of this impact, other possible restoration techniques are being considered, such as vegetating and leaving the pads in place. Water movement is one of the major driving factors in the arctic contributing to permafrost degradation. Groundwater carries with it heat, which is transferred to the soil as the groundwater moves. Therefore, hydrology plays a major role in the stability of the arctic environment. This is especially relevant in areas where gravel pads exist. Gravel pads are anthropogenic structures that have significant water storage potential. Because of the unique conditions in the Arctic, pore-water flow through these gravel pads is not yet well understood. The purpose of this study is to develop a more complete scientific understanding of the driving forces behind pad pore-water movement. This study expands on fieldwork from a prior hydrological field study conducted by others. The prior study is expanded through this work by developing an associated groundwater model to the gravel pad from the field study to examine the flow through it and the controlling factors for this flow. The study site used for this project is located in Prudhoe Bay and is the pad constructed for the very first production well in Prudhoe Bay in 1968. This study demonstrates that it is the topography of the silt layer beneath the gravel pads that is the most significant factor controlling pad pore-water movement. The results from the modeling study will assist engineers and environmental scientists in better understanding the groundwater flow. This understanding will aid in the decommissioning and restoration process and help inform decision making in regards to the future of the existing pads. The results may also be used to inform the development of new infrastructure such that any new pads which are built may be constructed with their relationship to the local hydrology more in mind.
    • Altering the thermal regime of soils below heated buildings in the continuous and discontinuous permafrost zones of Alaska

      Perreault, Paul Vincent; Shur, Yuri; Hulsey, J. Leroy; Barnes, David; Ahn, Il Sang (2016-05)
      This research investigates the impacts of thermal insulation on the thermal regime of soils below heated buildings in seasonally and perennially frozen soils. The research provides practical answers (A) for designing frost‐protected shallow foundations in unfrozen soils of the discontinuous permafrost zone in Alaska and (B) shows that applying seasonal thermal insulation can reduce the risk of permafrost thawing under buildings with open crawl spaces, even in warming climatic conditions. At seasonal frost sites, this research extends frost‐protected shallow foundation applications by providing design suggestions that account for colder Interior Alaska’s air freezing indices down to 4 400 °C∙d (8,000 °F∙d). This research includes field studies at six Fairbanks sites, mathematical analyses, and finite element modeling. An appendix includes frost‐protected shallow foundation design recommendations. Pivotal findings include the discovery of more pronounced impacts from horizontal frost heaving forces than are likely in warmer climates. At permafrost sites, this research investigates the application of manufactured thermal insulation to buildings with open crawl spaces as a method to preserve soils in the frozen state. This research reports the findings from using insulation to reduce permafrost temperature, and increase the bearing capacity of permafrost soils. Findings include the differing thermal results of applying insulation on the ground surface in an open crawl space either permanently (i.e., left in place), or seasonally (i.e., applied in warm months and removed in cold months). Research includes fieldwork in Fairbanks, and finite element analyses for Fairbanks, Kotzebue, and Barrow. Pivotal findings show that seasonal thermal insulation effectively cools the permafrost. By contrast, Fairbanks, Kotzebue, and Barrow investigations show that permanently applied thermal insulation decreases the active layer, while also increasing (not decreasing) the permafrost temperature. Using seasonal thermal insulation, in a controlled manner, satisfactorily alters the thermal regime of soils below heated buildings and provides additional foundation alternatives for arctic buildings.
    • Application of wicking fabric to reduce damage in Alaskan pavements

      Presler, Wendy A.; Zhang, Xiong; Liu, Juanyu; Shur, Yuri; Connor, Billy (2016-05)
      Beaver Slide is located near kilometer 177.8 (mile 110.5) on the Dalton Highway. The road is sloped downhill when heading north. The road gradient is approximately 11%, and the road prism is on a side hill. Each year, soft spots usually appear in the pavement structure in late April and remain all summer. These soft spots have been called “frost boils”. The “frost boils” have resulted in extremely unsafe driving conditions and frequent accident occurrences. Conventional repair methods have not worked. A newly developed geosynthetic wicking fabric was installed in the road structure in August 2010. The fabric has a high specific surface area (consequently high wettability and high capillary action) and high directional permittivity. Test results over the initial two year period proved the effectiveness of the wicking fabric to mitigate “frost boils” and the subsequent road softening issue. Data collected during the past four years were analyzed to evaluate the long-term performance of the wicking fabric. A scanning electron microscope (SEM) was used to explore the interaction between the wicking fabric and in situ soils, and to determine the condition of the fabric five years after installation.
    • Assessing the fate of crude oil in Arctic coastline sediments: effect of exposure time and sediment structure

      Iverson, Anna Christine; Schiewer, Silke; Perkins, Robert; Barnes, David (2015-08)
      The research presented in this thesis will allow for a better understanding of how crude oil interacts with the shoreline. Offshore oil production along Alaska's arctic coast is expected to increase in coming years. While this is likely to create large economic benefits for the state, crude oil spills may occur. An oil spill may reach the shoreline, where it could create adverse short and long-term ecological effects. Mass transfer processes, affected by sediment characteristics, play an important role in determining the fate of crude oil along shorelines. Crude oil viscosity and diffusion are strongly temperature dependent. Nutrients, commonly added to stimulate bioremediation, may be washed out with waves and tides. It is therefore necessary to study how factors such as the beach matrix, nutrient addition and temperature affect hydrocarbon distribution. Laboratory experiments were implemented to help better understand how the soil composition and tidal action will affect the oil's movement through the shoreline sediments. Experiments were conducted for two different sediment types (sandy-gravel versus pebble) obtained from Barrow, AK and two different temperatures (20° and 3° Celsius). A microcosm study using a PVC pipe set-up was used to simulate the transport of oil through the sediment profile. Data obtained from this study show that the amount of pooling and its location was dependent on sediment structure. In sandy gravel sediment, Total petroleum hydrocarbons (TPH) persisted 6 inches below the surface, indicating pooling does occur. In pebble sediment, TPH persisted at the top and bottom of the column, but only for the first few days, indicating the pooling would not be a long term problem. Both sediments had higher CO₂ production at higher temperatures, with the highest respiration, i.e. more biodegradation, found in sandy-gravel. While CO₂ releases were slightly higher in sediments with the addition of fertilizer, overall the application of fertilizer did not have a significant impact on the fate of crude oil in shoreline sediments.
    • Assessing the potential of Salix alaxensis for the rhizoremediation of diesel contaminated soil

      Starsman, Jessica; Leigh, Mary Beth; Schiewer, Silke; Schnabel, William (2016-08)
      Alaska has over 280 remote communities that rely on diesel as their main source of heat; as a result, there have been multiple diesel spills across the state. Research has shown that plants are able to assist in the degradation of diesel through rhizoremediation, relying on the interaction between microorganisms, plant roots, and other components of the soil environment. Greater attention is now being given to the potential role of secondary plant compounds released during fine root turnover and the stimulatory effects they may have on the rhizoremediation process. For this study the native plant species, Salix alaxensis (felt leaf willow) was chosen. Fine root turnover in the sub-Arctic was mimicked through a microcosm study performed with sub-Arctic soil contaminated with weathered and fresh diesel, incubated at 4 °C and 20 °C. The effect of adding crushed willow roots was compared against addition of pure salicylic acid, a secondary plant compound found in the salicaceae family, and/or addition of fertilizer. Results showed that the addition of crushed fine willow roots with or without fertilizer increased diesel loss. Overall, greater loss and higher respiration occurred at 20 °C. The addition of salicylic acid with or without fertilizer increased soil toxicity. Toxicity may have been the result of observed phenol production and/or fungal growth. Findings show promise for the use of Salix alaxensis for the rhizoremediation of diesel contaminated soils in the sub-Arctic.
    • Assessment of contaminant concentrations and transport pathways in rural Alaska communities' solid waste and wastewater sites

      Mutter, Edda Andrea; Schnabel, William; Barnes, David; Duddleston, Khrys; Duffy, Lawrence; Hagedorn, Birgit (2014-05)
      Waste management practices currently employed in many rural Alaska communities are potentially contributing to human and environmental health impacts, and this problem may be exacerbated with the anticipated warming climate. For rural communities, factors that contribute to insufficient waste management practices include climate and environmental conditions, limitation of federal and state capital funding for construction, and the continuing financial burden associated with providing adequate operations and maintenance. As a response, federal regulatory exemptions are granted for construction and design of solid waste sites and limited state regulations are in place for wastewater discharge criteria. Due to the absence of proper site assessment and monitoring, very little is known about the fate and transport of point source pollutants arising from these wastewater and solid waste sites. Moreover, these fate and transport processes may be susceptible to changes resulting from human activity or a warming climate. Thus, this knowledge gap associated with waste-related pollutants in rural Alaska could obscure potential threats to human and environmental health by concealing impacts to freshwater systems. This research was intended to achieve a better understanding of rural Alaska waste leachate compositions by evaluating contaminant prevalence and diversity, quantifying contaminant concentration levels, and evaluating their potential migration into nearby freshwater systems. Over the course of three years, waste sites at five rural Alaska communities were sampled and tested for heavy metals, organic constituents, and microbial indicator organisms. The purpose of the analysis was to evaluate the impact of waste sites on soil, surface, and subsurface waters in the vicinity of the sites. The resulting findings are assembled into three chapters describing 1) the assessment of heavy metal leachate in rural Alaska solid waste sites, 2) the identification of new emerging organic pollutants in rural Alaska waste sites, and 3) the partitioning and transport behavior of pathogen indicator organisms in cold regions. The research outcome of E.coli and Enterococcus sp. were observed in waste impacted water and soil samples, heavy metal migration into nearby freshwaters, and pharmaceuticals, phthalates, and benzotriazole in waste impacted water samples. The research findings highlight the need to apply state regulations to remove potentially hazardous components from rural Alaska wastewater and municipal solid waste streams. Additionally, there is a need to establish effective solid waste and wastewater leachate monitoring and assessment strategies for active and closed rural Alaska waste sites.
    • An assessment of suspended sediment transport in Arctic Alaskan rivers

      Lamb, Erica K.; Toniolo, Horacio; Schnabel, William; Kane, Douglas (2013-05)
      Provided here is an initial assessment of suspended sediment transport in several rivers on the North Slope of Alaska. This study was divided into two parts: the Umiat project, which involved the Chandler, Anaktuvuk and Itkillik Rivers, and the NPR-A study, which considered Prince, Seabee and Fish Creeks, as well as a brief look at the lkpikpuk River, Otuk Creek, Judy Creek and the Ublutuoch River. Methods used included depth-integrated suspended sediment samples, grab samples, automatic pump-style samplers, discharge measurements, bed sediment grain size analysis and the inclusion of a variety of meteorological measurements from other projects. With slightly less than two years of data collection from May 2011 to September 2012, an initial analysis was completed. Suspended sediment rating curves developed for the Anaktuvuk and Chandler Rivers over the two-year study period revealed a strong correlation between suspended sediment concentration (SSC) and discharge. The most data was collected for the Anaktuvuk and Chandler Rivers; on these rivers, suspended sediment discharge was also analyzed, showing that over 90% of suspended sediment transport occurred during the spring melt period in 2011. Spring melt was not measured in 2012, so analysis was only completed for 2011.
    • Attenuation of the herbicide glyphosate along railroad corridors in Alaska

      Ballou, Nellie B. (2011-05)
      Following the application of glyphosate in the formulation of AquaMaster® at two contrasting sub-arctic zones along the railroad corridor in Alaska, attenuation of the herbicide glyphosate was investigated. Study sites were established in continental and coastal zones. Glyphosate soil attenuation was similar to temperate regions during the growing season but exhibited an extended persistence during the winter months. Although glyphosate microbial degradation likely slowed during winter, both sites showed evidence of slight glyphosate degradation during the winter months. The coastal site attenuated more rapidly than the continental site which is presumably due to increased rainfall relative to the continental site. Glyphosate attenuation at the coastal site was likely driven by dispersion while microbial degradation was responsible for the attenuation of glyphosate at the continental site. Movement to subsurface soils (10-25 cm) at low concentrations was observed at both sites with slightly more transport at the coastal site than the continental site. Glyphosate transport to groundwater along railroad corridors was not conclusive. Vegetation cover reduction was reduced at the continental site but could not be determined at the coastal site.
    • Behavior Of Granular Materials Under Cyclic And Repeated Loading

      Minassian, George H.; Raad, Lutfi (2003)
      Granular layers are essential contributors to the structural integrity of the pavement system, their premature deformation radically decrease support of the asphalt concrete surface layer, thus leading to the early deterioration of the overall pavement structure. This research was conducted to better understand the behavior of granular materials when subjected to the complex nature of traffic loading. Long-term triaxial tests were conducted on typical Alaskan base course material using both repeated as well as cyclic loading to also account for the shear reversal effects induced by wheel load. Results show that the shear reversal component of the traffic loads, which have been ignored so far, induces considerable damage to the granular layers. Models were presented to predict the different soil moduli while also accounting the effect of strain hardening or densification due to the repetitive nature of the loads applied. Moreover, a simple yet powerful model was presented to predict accumulated permanent strains as function of the stress state, number of load repetitions and the strength level applied. The results obtained in this study also show a clear indication of the existence of given stress level limit beyond which incremental collapse of the system takes place. Furthermore, regions of instability of granular layers subjected to dynamic loading have been defined using a simple response parameter and monotonic shear strength of the soil. An effort was made to explain the instability zones identified in this research by the shakedown theory.* *This dissertation is a compound document (contains both a paper copy and a CD as part of the dissertation). The CD requires the following system requirements: Microsoft Office.
    • Biodegradation Of Petroleum And Alternative Fuel Hydrocarbons In Moderate To Cold Climate

      Horel, Agota Anna (2009)
      Microbial degradation of hydrocarbon fuels contaminating soil in the Arctic and subarctic environment is a relatively slow process. Nevertheless, due to transportation and logistical limitations in rural Alaska, biodegradation might be the best and cheapest contaminant removal option. The aim of this thesis was to investigate the environmental effects on biodegradation by naturally occurring microorganisms for some innovative hydrocarbon fuels and to determine the overall fate of hydrocarbons in soil, including degradation by fungi and bacteria, volatilization, and transport in the soil. Three major types of fuels were investigated in small scale microcosms and larger soil columns: conventional diesel as a control substance, synthetic diesel (arctic grade Syntroleum) and different types of fish oil based biodiesel. The environmental conditions investigated included different soil types (sand and gravel), different temperatures (constant 6�C, 20�C, and fluctuating between 6 and 20�C), moisture levels (from 2% to 12% GWC), fuel concentrations (from 500 to 20,000 mg fuel/kg soil) and nutrient dosages (0 or 300 mg N/kg soil). Microbial response times and growth phases were also investigated for different inoculum types. Conditions of 20�C, 300 mg N/kg soil, sand, ?4000 mg of fuel/kg soil and ?4% GWC were favorable for bioremediation, with a short lag phase lasting from one day to less than a week, and pronounced peaks of daily CO 2 production between week 2 and 3. At suboptimal conditions, all phases were extended and slow, however at low temperatures steady metabolization continued over a longer time. The relative importance of fungal and bacterial remediation varied between fuel types. Diesel fuel degradation was mainly due to bacterial activities while fish biodiesel degradation occurred largely by mycoremediation. For Syntroleum both bacterial and fungal remediation played key roles. Volatilization contributed up to 13% to overall contaminant removal. In soil columns, degradation was slower than in microcosms, due to an uneven concentration profile of contaminants, nutrients and oxygen with depth. In general, biodegradation showed promising results for soil remediation and the alternate fuel types were more biodegradable compared with conventional diesel fuel.
    • Biosorption of heavy metals by citrus fruit waste materials

      Patil, Santosh Bramhadev (2004-12)
      Conventionally used processes for removing heavy metals from wastewater are usually either expensive, such as ion exchange, or inefficient, such as precipitation. An innovative technique that is both efficient and economical is biosorption, in which living and dead biomass can act as biosorbents through physical-chemical processes like ion exchange and micro-precipitation. Pectin, a structural polysaccharide present in plant cell walls, is similar to alginate, a molecule that is often responsible for the high metal uptake by algae. Based on the structural similarity between alginate and pectin, it was expected that pectin rich bio-wastes may be as good a biosorbent material as brown algae. A comparison between different pectin-rich materials showed high stability and metal binding capacity of citrus peels. Sorption isotherms for citrus peels showed higher metal uptake capacity at pH 5 compared to pH 3. Kinetic studies revealed the time required to reach equilibrium for lemon fruit waste (0.177 mm) was 20 min while for larger particles the time increased to 30 min-60 min. For lemon fruit waste, the content and pKa values of acidic groups were determined by using a pKa spectrum technique. Isotherm modeling was carried out by using Langmuir isotherms and pH sensitive modeling.
    • Biosorption of lead by citrus pectin and peels in aqueous solution

      Balaria, Ankit (2006-05)
      Biosorption of heavy metal ions by different pectin rich materials such as waste citrus peels is emerging as a promising technique for metallic contaminant removal. While binding rate and capacity of citrus peels were previously investigated, there is a lack of mechanistic information about Pb-citrus pectin/peels interaction mechanisms. Present research focused on evaluating this binding mechanism by corroborating macroscopic studies with spectroscopic techniques. Citrus pectins of two different methoxylation degrees and orange peels were characterized using potentiometric titrations and Fourier transform infrared (FTIR) spectroscopy. Binding mechanisms were evaluated using molecular scale FTIR analyses. The effects of particle size, pH, co-ion presence, and background electrolyte concentrations were also investigated for biosorption of Pb by orange peels. Both citrus pectin and orange peels reached their sorption equilibrium within 45 minutes. The maximum uptake capacity for orange peels was found to be 2.32 mmol/g. Citrus peels have very similar FTIR spectra to citrus pectin, suggesting that they have similar functional groups and pectin can be used as a model for citrus peels. Furthermore, carboxylic acid groups were found to be responsible for binding of Pb by citrus pectin and orange peels.
    • Characterization and implementation of stress dependent resilient modulus of asphalt treated base for flexible pavement design

      Li, Peng; 鹏 李; Liu, Juanyu; Connor, William; Zhang, Xiang; Shur, Yuri; Saboundjian, Stephan (2013-08)
      Asphalt treated base (ATB) is the most commonly used type of stabilized material in pavements because of material availability and relatively low cost in Alaska. The treatment enhances the material's properties to overcome deficiencies in some marginal materials. Resilient modulus (MR) of these materials is an essential pavement design input. Currently, in the Alaska Flexible Pavement Design (AKFPD) Manual, MRS of ATBs were back calculated using testing results of falling weight deflectometer (FWD). There is a need for an accurate laboratory characterization of these materials. In this study, the MRS of hot asphalt treated base (HATB), emulsifed asphalt treated base (EATB), foamed asphalt treated base (FATB), and a mixture of reclaimed asphalt pavement (RAP) and D-1 aggregate at a 50: 50 ratio (RAP 50:50) were measured using repeated triaxial tests. D-1 granular materials used for base course construction were collected from three regions in Alaska. HATB specimens were compacted using Superpave gyratory compactor and three binder contents were used: 2.5%, 3.5% and 4.5%. EATB and FATB specimens were compacted according to ASTM D1557 and three residual binder contents were used: 1.5%, 2.5% and 3.5%. RAP 50:50 was also compacted according to ASTM D1557 and no additional additives were added. MR was measured at three temperatures (i.e. -10°C, 0°C, 20°C for HATB, EATB and FATB; -10°C, -2°C, 20°C for RAP 50:50). The stress-dependent property of MR was successfully characterized by the modified universal soil model, in which the MR was expressed as a function of bulk stress (θ) and octahedral shear stress (τoct). Generally, MR increased with an increase of θ and decreased with an increase of τoct. Stress-dependent patterns of each type of ATB were analyzed and discussed. Predictive equations for MR were developed for all types of ATBs investigated in this study. The equations were based on the modified universal soil model. The material properties (i.e. binder content and percentage fracture surface), temperature and the interactions among them were incorporated into equations. The developed predictive equations had very high coefficient of determination (R²). The R² s of equations HATB_10, EATB_10, FATB_10 and RAP_9, in which the influencing factors and second order interactions among factors were included, were all greater than 99%. These equations can be also used to estimate nonlinear elastic constants of ATBs in the modified universal soil model (i.e. k₁, k₂ and k₃). The stress dependent property of MR was incorporated into pavement structural analysis using the finite element method (FEM) program Abaqus through user defined material that was programmed in the user subroutine. Comparisons were made between pavement responses obtained from nonlinear FEM and traditional linear elastic layered system. The representative MR of ATBs were determined and recommended based on the equivalent critical pavement response of the typical Alaska flexible pavement structure. Predictive equations were developed to estimate the critical pavement responses. The equations were developed through regression analyses using a database generated from 16,848 nonlinear pavement FEM analyses, which covered a variety of pavement structure combinations. These nonlinear pavement analyses were implemented through the function of a parametric study provided in Abaqus FEM package. In total 9 independent variables were included, which were the thickness of the surface course, base course, and subbase, moduli of HMA, subbase and subgrade, and nonlinear elastic constants of ATB (i.e. k₁ k₂ k₃) in the MR model. The interactions among these variables were also included. The R²s of predictive equations were at least 0.9725. The predictive equations can be used for routine pavement analysis and design purposes.
    • Characterizing the berthing load demand at Alaska Department of Transportation and Public Facilities Ferry Landings

      Hutchinson, Jonathan; Metzger, Andrew; Hulsey, Leroy; Dong, YongTao (2011-08)
      This report provides design guidelines and recommendations for side-berthing loads on ferry landing structures. Berthing loads on ferry berthing structures are not well understood due to a lack of information and research for ferry class vessels. The load criteria for the design of ferry berthing structures are thus often based on a number of assumptions, often leading to uneconomical or unreliable structures. The Alaska Department of Transportation (AKDOT&PF) recognizes the need for an improved information base on berthing loads from ferry class vessels, for the design and operation of future facilities within the Alaska Marine Highway System (AMHS). This study involves a one year empirical investigation into side-berthing loads at the Auke Bay ferry landing located in Juneau, Alaska. Measurements of fender displacement, approach velocity, and pile strain were used to determine berthing loads from scheduled berthings from four different vessels. Measured parameters were analyzed statistically, and used to establish distributions and design recommendations for berthing energy, force, velocity, and berthing coefficient based on reliability theory. This study provides an assessment of load criteria currently used by the AK DOT&PF Marine Department, as well as design load recommendations for both service and ultimate side-berthing loads from ferry class vessels.
    • Characterizing the berthing load environment of the Seattle ferry teminal, Bremerton slip

      Kwiatkowski, Jason E. (2012-12)
      This manuscript characterizes and presents design recommendations for berthing demands on ferry landing structures. There is a lack of research focused on the berthing load demand imparted by ferry class vessels, therefore the load criteria used for design is often based on a number of assumptions. This study involved a one-year field study of the structural load environment of wingwalls at the Bremerton Slip of the Seattle Ferry Terminal, located in Elliott Bay adjacent to Seattle, Washington. Measurements of marine fender displacement, vessel approach distance with respect to time, and. pile strain were used to determine berthing demands. Berthing event parameters were characterized using the Python programming language, compiled, and analyzed statistically. Probability theory was used to provide design value recommendations for berthing energy, force, approach velocity, berthing factor, and berthing coefficient. This study presents a number of engineering design aids intended to quantify the berthing load environment of wingwalls in the Washington State Ferry System.
    • Climatic and physiographic drivers of peak flows in watersheds in the North Slope of Alaska

      Hinzman, Alexa Marion Hassebroek; Stuefer, Svetlana; Arp, Christopher; Barnes, David (2017-08)
      The failure to accurately predict peak discharge can cause large errors in risk analysis that may lead to damage to structures and in some cases, death. Creating linear regression (LR) equations that accurately predict peak discharges without historic data provides a method to estimate flood peaks in ungauged watersheds on the North Slope of Alaska. This thesis looks at the independent variables that drive, or are significant in predicting snowmelt peak discharge in the North Slope watersheds. The LR equations created use independent variables from meteorological data and physiographic data collected from four watersheds, Putuligayuk River, Upper Kuparuk River, Imnavait Creek and Roche Moutonnée Creek. Meteorological data include snow water equivalent (SWE), total precipitation, rainfall, storage, length of melt. Physiographic data summarize watershed area (2.2 km2 to 471 km2) and slope (0.15:100 to 2.7:100). This thesis compared various Flood Frequency Analysis techniques, starting with Bulletin 17B, multiple USGS regional methods and finally created LR equations for each watershed as well as all four watersheds combined. Five LR equations were created, three of the LR equations found SWE to be a significant predictor of peak flows. The first equation to estimate peak flows for all watersheds used only area and had a high R2 value of 0.72. The second equation for all watersheds included area and a meteorological independent variable, SWE. While the evidence presented here is quite promising that meteorological and physiographic data can be useful in estimating peak flows in ungauged Arctic watersheds, the limitations of using only four watersheds to determine the equations call for further testing and verification. More validation studies will be needed to demonstrate that viable equations may be applied to all watersheds on the North Slope of Alaska.
    • A comparison of northern research basins and their landscape characteristics

      Kitover, Danielle C. (2005-05)
      In 2004, a Northern Research Basins (NRB) workshop was coordinated to synthesize water balance research of experimental watersheds. This study examined 10 of those basins more closely. Their landscape features were of special interest as past research has attributed one or more of these characteristics to watershed hydrology. However, the key question posed by this study was how such landscape features influence the water balance of northern basins. Water balance characteristics of a basin may be quantified using the runoff ratio (Q/P) and the ET ratio (ET/P). This study linked those parameters to landscape attributes using both conceptual methods and statistical analysis. The hypothesis was that landscape characteristics of the research basins examined in this study will exhibit identifiable trends in the annual water balance of those research basins. Landscape features are divided into two modes. The first was qualitative characteristics considering permafrost extent, major vegetation type, and soil texture. The second was quantitative characteristics, inferred from a series of terrain indices extracted from DEMs. This research demonstrated that although most features included in this study play some role in the hydrology of northern basins, some were more prominent than others. Overall, the water balance of northern basins is effected by the components of latitude, climate, and topography.