• Numerical analysis of the stability of a column laterally restrained by a flexible brace

      Kulchitskaya, Natalia; Кульчицкая, Наталья Борисовна; Hulsey, Leroy; Yang, Liao; Metzger, Andrew; Shur, Yuri (2014-08)
      The paper analyses the behavior of a structure which includes a classically restrained steel column under an axial load and a single flexible brace attached at an arbitrary point along the column to restrict its lateral deformation. The column is assumed to have an initial imperfection limited according to the current code requirements. Focusing on lateral deformations only, the paper studies the maximum load the system can resist before failure, as well as a brace force arisen at this load. Due to the complexity of the problem when it is extended from the elastic region to the plastic domain, a numerical solution is utilized. In the current work, a student version of AbaqusTM provides results of finite-element analysis implemented for a variety of ASTM A992 steel W-Shaped columns. The results confirm that the failure load and brace force highly depend on brace location and its stiffness. It is also shown that the current code provision of a brace load is not always conservative for braces shifted from the center of the column.
    • Groundwater dynamics in degrading, discontinuous permafrost

      Barnes, Michelle L.; Barnes, David L.; Shur, Yuri L.; Schnabel, William E.; Leigh, Mary Beth (2014-12)
      In regions impacted by permafrost, discontinuities are areas of possible connection between the supra- and sub-permafrost portions of an aquifer. Permafrost discontinuities influence the transport of contaminants in an aquifer, necessitating delineation of these discontinuities and their influence on groundwater flow. Means of identifying the locations of permafrost discontinuities have previously been limited to geophysical methods and the evaluation of well logs. In this study we use groundwater elevation trends and environmental tracers (e.g., stable isotopes and temperature) to evaluate the dynamics in a sulfolane-contaminated aquifer located in a region of discontinuous permafrost in the Interior of Alaska. Using tracers to identify areas of discontinuities in the permafrost should help us locate thawed through-taliks and may also improve our understanding of the interaction between the supra- and sub-permafrost groundwater in discontinuous permafrost. With this approach we identified at least three discontinuities within the study area. The locations of these discontinuities coincide with transport of the contaminant found in this aquifer. The primary source of recharge for this aquifer is the Tanana River, a major tributary to the Yukon River. The source of water for the Tanana River is glacial melt in the summer and groundwater during the winter. Through the isotopic composition of the supra-permafrost groundwater we show the occurrence of additional recharge to the supra-permafrost groundwater from sub-permafrost groundwater and precipitation. Understanding these dynamics is paramount to characterizing the contaminant transport in permafrost impacted aquifers.
    • Performance of shallow anchor in ice-rich silt

      Lin, Chuang; 林闯; Zhang, Xiong; Shur, Yuri; Liu, Jenny; Connor, Billy (2014-12)
      Shallow anchor systems have been widely used for decades due to their time and cost efficiency. Yet when it comes to cold regions like Alaska, new challenges caused by the harsh environment need to be resolved before they are used extensively in cold regions. One challenge associated with anchor installation could be the potential thawing of warm permafrost due to the grout mortar hydration, which might undermine the capacity of the anchor. Another challenge is that due to low temperature the grout may cure slower or not cure at all, which will also result in a significant decrease in the ultimate strength of the anchor. Field tests were conducted to evaluate the performance of shallow anchors including duckbill anchors and grouted anchors with three types of different grouting materials, including Microsil Anchor Grout, Bentonite Clay and a newly-developed Antifreeze Grout Mortar. Constant-load creep test and pullout test were conducted to evaluate the performance of the anchors. Test results indicated that the anchors grouted with Antifreeze Grout Mortar caused the least permafrost disturbance and degradation, gained the largest tensile strength, exhibited the least creep displacement, and showed relatively large pullout capacity, and thus achieved the best performance among all types of shallow anchors.
    • The integrated hydrologic and societal impacts of a warming climate in Interior Alaska

      Jones, Charles E.; Kielland, Knut; Hinzman, Larry; Kane, Douglas; Prakash, Anupma; Schneider, William (2014-12)
      In this dissertation, interdisciplinary research methods were used to examine how changes in hydrology associated with climate affect Alaskans. Partnerships were established with residents of Fairbanks and Tanana to develop scientific investigations relevant to rural Alaskans. In chapter 2, local knowledge was incorporated into scientific models to identify a socialecological threshold used to model potential driftwood harvest from the Yukon River. Anecdotal evidence and subsistence calendar records were combined with scientific data to model the harvest rates of driftwood. Modeling results estimate that between 1980 and 2010 hydrologic factors alone were responsible for a 29% decrease in the annual wood harvest, which approximately balanced a 23% reduction in wood demand due to a decline in number of households. The community's installation of wood-fired boilers in 2007 created a threshold increase (76%) in wood demand that is not met by driftwood harvest. Modeling of climatic scenarios illustrates that increased hydrologic variability decreases driftwood harvest and increases the financial or temporal costs for subsistence users. In chapter 3, increased groundwater flow related to permafrost degradation was hypothesized to be affect river ice thickness in sloughs of the Tanana River. A physically-based, numerical model was developed to examine the importance of permafrost degradation in explaining unfrozen river conditions in the winter. Results indicated that ice melt is amplified by increasing groundwater upwelling rates, groundwater temperatures, and snowfall. Modeling results also suggest that permafrost degradation could be a valid explanation of the phenomenon, but does not address the potential drivers (e.g. warming climate, forest fire, etc.) of the permafrost warming. In chapter 4, remote sensing techniques were hypothesized to be useful for mapping dangerous ice conditions on the Tanana River in interior Alaska. Unsupervised classification of high-resolution satellite imagery was used to identify and map open water and degraded ice conditions on the Tanana River. Ninety-five percent of the total river channel surface was classified as "safe" for river travel, while 4% of the channel was mapped as having degraded ice and 0.6% of the channel was classified as open water (overall accuracy of 73%). This research demonstrates that the classification of high-resolution satellite images can be useful for mapping hazardous ice for recreational, transportation, or industrial applications in northern climates. These results are applicable to communities throughout the North. For people that rely upon subsistence activities, increased variability in climate cycles can have substantial financial, cultural, recreational, or even mortal consequences. This research demonstrates how collaborations between scientists and local stakeholders can create tools that help to assess the impacts of increased environmental variability (such as flooding) or to detect or predict unsafe conditions (such as thin or unpredictable ice cover). Based upon this research, I conclude that regional-scale adaptations and technological advances (such as modeling and remote sensing tools) may help to alleviate the effects of environmental variability associated by climate.
    • Research in advanced nuclear development and planning

      Kuca, Michael; Perkins, Robert A.; Schnabel, William E.; Barnes, David L. (2014-12)
      This project began as an examination of small and mini nuclear power plants as an emergent energy technology capable of sustained base-load power generation in northern climates. Literature review immediately demonstrated Alaska should remain current on small and mini nuclear power plants because commercial vendors are promoting their products to state leaders as certain solutions. Is Alaska prepared to receive, operate, and decommission advanced nuclear technology as an alternative to traditional hydrocarbon power plants? The graduate committee encouraged me to facilitate discussions with Alaska Center for Energy and Power (ACEP) leadership in reference to their 2010 study on small modular reactors. Gwen Holdman, Brent Sheets, and George Roe offered great encouragement for this project and allowed me to participated in nuclear related meetings with affiliates. In fall 2013, ACEP was hosting Idaho National Laboratory guests to discuss areas of common research interest. I was invited to prepare a short presentation of this project to Dr. Steven Aumeier, Director of Center for Advanced Energy Studies and Michael Hagood, Director of Program Development. ACEP and INL later determined a mobile mini reactor design for remote terrestrial deployment represents common research interests, and INL funded three UAF student fellowships at the Center for Space Nuclear Research (CSNR) Dr. Stephen Howe, Director of CSNR, allocated a team of six graduate fellows to explore terrestrial applications of a tungsten fuel matrix currently under design for nuclear thermal propulsion. UAF students selected for CSNR fellowship included Haley McIntyre, Alana Vilagi, and me. The team designed a Passively Operating Lead Arctic Reactor (POLAR), presented the POLAR design to INL staff and industry leaders and a subsequent poster was provided for the INE conference for Alaska Energy Leaders in October 2014. In addition to exceptional engineering experience, I was able to advance the graduate project in areas of technology, policy, economics, and energy infrastructure requirements needed to accept advanced nuclear technology. Concurrently, under a memorandum of agreement between the University of Alaska and Alaska Command ALCOM, I was able to advance the project to consider military applications of small modular reactors with ALCOM Energy Steering Group. It was in this context where I evaluated military installation energy usage in interior Alaska as compared to production of integral pressurized water reactors likely to emerge first in the commercial sector, and the ability of Alaska military to adopt this technology. As a side project, select courses of action were prepared and briefed to the commanding general of ALCOM should the nuclear option become attractive to the military. What began as an independent examination of small and mini nuclear power plants to satisfy a three-credit project requirement became an incredible collaboration among civilian, state, university, military, and industrial shareholders of the Alaska energy sector. Specific recognition for this report belongs to Haley McIntyre for her contribution to policy frameworks and as editor for this report, and Alana Vilagi for her contribution to process heat applications. The graduate committee along with ACEP leadership, INL-CSNR, and ALCOM should all be recognized as facilitators in this review of nuclear power in Alaska. The following report is presented in six chapters. The first two chapters attempt to introduce the reader to the current state of commercial nuclear energy in the nation as a pretext to developing the advanced reactor designs. Modifications to the existing framework are provided and the total cost of nuclear in Alaska is considered as opportunities and barriers to deployment are evaluated. As a conclusion, scenarios are developed to explain how this technology may contribute to our energy sector in the future. This project was unfunded, and its findings are intended to present a neutral examination of emergent nuclear design in the Alaska energy sector.
    • Analysis of steel-reinforced concrete-filled steel tube columns (CFT) under axial compression and moment

      Li, Fei (2015)
      This study presents an investigation into the behavior of steel-reinforced concrete filled steel tubular columns (CFT) using the finite element software ABAQUS. The steel tube provides lateral confinement to the concrete core which results in an increased concrete compressive strength and deformation capacity. The concrete infill, in return, prevents the inward local buckling within steel tubes. The axial load bearing capacity of CFT is thus higher than the summation of axial load-bearing capacities of the concrete core and the hollow steel tube. The axial force P and moment M interaction diagram is generated.
    • Wind energy: is there an economy of scale in Alaska?

      Ellanna, Dayne; Lewellyn, Levi; Hulsey, J. Leroy; Perkins, Robert; Whitaker, Keith (2015)
      The purpose of this project is to show the cost relationship per kilowatt hour (kWh) between small scale (< 25kWh), medium scale (> 25 kWh and < 100 kWh), and large scale (> 100kWh) wind turbines. Our analysis will compare the cost per kWh and identify the economy of scale between our custom small scale models to commercial models. The commercial models used for this project were installed by Golden Valley Electric Association (GVEA) at their Healy, Alaska wind farm. We requested their wind data, capital investment breakdown, and their operations and maintenance costs. This data will be compared to the costs and wind data associated with our custom built wind turbine. Wind energy is dependent on one major variable, the wind. Regardless of the wind turbine size, wind speed, frequency, and duration will affect the efficiency of every wind turbine. Commercial wind farms are new to Alaska. The first major wind power project in Alaska was in 1997 in Kotzebue. This wind farm, of 17 wind turbines, represents the first megawatt of wind power in Alaska. Installation and maintenance of these systems is more expensive in Alaska due to the states' remoteness. Small scale systems used in this study are custom built because small scale commercial systems are not "hardy" enough to withstand Alaska's harsh weather systems. Both medium and large scale systems, for this study, are commercially constructed systems that have been designed to withstand these harsh conditions.
    • Evaluate unsaturated soil behavior using constant water content triaxial tests

      Li, Lin; 李林; Zhang, Xiong; Hulsey, J. Leroy; Shur, Yuri; Lytton, Robert; Chen, Gang (2015-05)
      The triaxial test has been extensively used to evaluate both saturated and unsaturated soil behaviors. The conventional triaxial test apparatus for saturated soils cannot be used to test unsaturated soils due to difficulties in soil volume and suction measurement. In 1961, a suction-controlled triaxial test apparatus was developed to investigate behavior of unsaturated soils. Since this development, the suction-controlled test has been widely used for unsaturated soil characterization. Most important concepts concerning unsaturated soil mechanics were developed based upon results from suction-controlled tests. However, the suction-controlled triaxial test on unsaturated soils, which is a drained test, is usually laborious, time-consuming, and costly, and may not be justifiable for routine engineering projects. The constant water content (undrained) test has been widely used to investigate saturated soil behaviors. However, for unsaturated soils, due to difficulties in direct, rapid, and reliable suction measurement, the constant water content test was rarely used for unsaturated soil behavior evaluation. In addition, accurate volume change measurement of unsaturated soils was a great challenge for researchers. Recently, the Modified State Surface Approach (MSSA) has been developed to calibrate unsaturated soil behaviors. According to MSSA, both results from suction-controlled and constant water content triaxial tests can be used for constitutive behavior calibration on unsaturated soils. In this study, a new triaxial test system was developed to investigate unsaturated soil behaviors through constant water content triaxial tests. To measure soil suction variation during testing, a new type of high-suction tensiometer was developed based on a commercial miniature pressure transducer. A 15 bar air-entry ceramic disc was used as the filter of the high-suction tensiometer. After saturation and calibration, this new type of high-suction tensiometer could be utilized for matric suction measurement on unsaturated soils with a maximum measurable suction up to 1100 kPa determined via a free evaporation test. To measure the volume change of unsaturated soils during triaxial testing, a photogrammetry-based method was developed by integrating photogrammetry, optical-ray tracing, and least-square estimation techniques. Through two validation tests on a stainless steel cylinder and a saturated sand specimen, the average point and total volume change measurement accuracy were determined to be approximately 0.065 mm and 0.05%, respectively. With this method, the conventional triaxial test apparatus for saturated soils can be used for triaxial testing on unsaturated soils without any modification. In addition to total volume change measurement, the newly developed photogrammetry-based method can also be used to investigate the deformation characteristics of soils during triaxial testing such as full-field deformation, volumetric strain non-uniformity, full-field strain distribution, and shear band evolution process. To evaluate the performance of the new triaxial testing system, a series of constant water content triaxial tests were carried out on unsaturated soils. New methods were proposed to characterize shear strength of the tested unsaturated soils. Also, an example was given to calibrate the constitutive behavior of an unsaturated soil based on results from the constant water content triaxial tests. Analysis results indicated that the proposed triaxial testing system is a cost effective and time efficient alternative to the suction-controlled triaxial testing system. In geotechnical and highway engineering, many projects involve unsaturated soils at shallow depths with low confining stresses (less than 100 kPa). To investigate the behavior of unsaturated soils at low confining stresses, the new triaxial testing system was simplified to a modified unconfined compression testing system. In this simplified system, negative air pressure (i.e., vacuum pressure) was used to provide the low confining stress for the triaxial tests. The high-suction tensiometers were used to monitor soil matrix suction variation during testing. A photogrammetric method was utilized for deformation measurements of unsaturated soils during triaxial testing. A series of undrained triaxial tests was also carried out to demonstrate the use of the modified unconfined compression testing system for unsaturated soil behavior evaluation under different confining stresses.
    • Determination of lateral inflows in the Kuparuk River watershed, a study in the Alaskan Arctic

      Overbeck, Levi D.; Kane, Douglas; Stuefer, Svetlana; Toniolo, Horacio (2015-05)
      The objectives of this research were to investigate the relationships between lateral inflows and watershed characteristics within the Kuparuk watershed of Arctic Alaska, as well as to quantify the lateral inflows to be used as an input for calibrating and running a process-based instream water temperature model. Determination of lateral inflows was accomplished by constructing hydrographs at multiple locations along Imnavait Creek and the Kuparuk River using stage and discharge field measurements. The hydrographs were then routed between gauging stations downstream (starting upstream) using the Muskingum routing method; and finally subtracting the routed hydrograph from the downstream measured hydrograph to calculate any additional water that had entered the reach between gauging stations. Results showed, as a general trend, that reaches within the northern foothills of the Brooks Range experienced larger lateral inflow contributions per square kilometer and had larger runoff ratios than subsequent reaches to the north where the terrain flattens out and transitions into the coastal plain. Two reaches within the watershed contradicted the general trend. The low-gradient reach nearest to the Arctic Ocean experienced larger lateral inflows throughout the summer that were unaffected by rainfall precipitation events; this is believed to be caused by snowmelt water initially stored in the low gradient terrain and slowly released into the drainage network during summer months. This area is rich with wetlands, ponds, and lakes and snow-damming during break up is prevalent. The other reach was located upstream of the Kuparuk aufeis field and was observed to lose water during the summer of 2013, supporting a hypothesis that the aufeis formation in this area is fed throughout the winter by a large talik upstream.
    • Using the USDA wind erosion equation for comparative modeling of natural and anthropogenic sources of particulates measured at the Fort Greely PM₁₀ monitoring station, Alaska, a case study

      Becker, Steven R.; Perkins, Robert; Barnon, David; Whitaker, Keith; Aggarwal, Srijan (2015-05)
      In April of 2010, the Alaska Department of Environmental Conservation (ADEC) opened a compliance case against the U.S. Army Garrison Fort Greely, Alaska (FGA), for then repeated failure to comply with a permit condition requiring the collection of one year of Prevention of Significant Deterioration (PSD)-quality data on ambient levels of particulate matter less than 10 microns in effective aerodynamic diameter (PM₁₀). During the monitoring period of 2012-2013, background levels of PM₁₀ were more than 80% the Alaska Ambient Air Quality Standards (AAAQS) for a total of seven days in the winter of 2012-2013. On March 17, 2014, ADEC requested that FGA provide substantive documentation that PM₁₀ exceedances observed during the monitoring period were of natural provenance and not from anthropogenic sources. In response to this request, the author used Geographic Information System (GIS) technology to analyze basic meteorological data and outputs from the USDA Wind Erosion Equation (WEQ) to generate a simple back-trajectory model for determining the sources and relative contributions to PM₁₀ experienced at a given receptor. Using this model, the author was able to show that the vast majority of PM₁₀ at Fort Greely was natural rather than anthropogenic in nature. The ADEC Division of Air Quality determined that results of this study constituted substantive documentation that PM₁₀ exceedances observed during the monitoring period were of natural provenance and not from anthropogenic sources, and issued a compliance case closure letter on June 20, 2014. In addition to the direct results of the study, the project also serves to demonstrate a low-complexity model that can be used to assess the relative contribution of anthropogenic and natural sources of PM₁₀ at a given receptor. Additionally, it can be used in complex situations as a screening tool to focus data collection efforts on significant sources of PM₁₀ and facilitate the prioritization of PM₁₀ sources for more precise quantitative dispersion or receptor models when precise quantitative data are required.
    • Crude oil bioremediation in Arctic seashore sediments

      Sharma, Priyamvada; Schiewer, Silke; Trainor, Thomas; Schnabel, William (2015-08)
      Oil is an important energy source but also an environment pollutant. Crude oil spills along Arctic shorelines might occur due to the expected increase in offshore oil production. To reduce adverse effects on the environment in the case of a spill, it is important to develop approaches to remove spilled oil. Bioremediation with addition of nutrients has shown promising results in enhancing oil degradation rates. This research focuses on determining the effect of different environmental conditions on the rate of crude oil biodegradation in laboratory experiments, as a proxy for oil spills at Arctic seashores. Laboratory microcosms were set up containing beach sediments collected from Barrow, spiked with North Slope Crude. These microcosms were incubated at varying temperatures (3°C vs. 20°C), salinities (30 vs. 35 g/L) and crude oil concentrations (1 vs. 5 mL/kg), all with a standard concentration of nutrients. Measurements of respiration rates (breakdown of hydrocarbons to CO₂), hydrocarbons remaining in the sediment (GC/FID), and hydrocarbons volatilized and sorbed to activated carbon (GC/MS) were performed. In all microcosms, higher respiration rates by naturally occurring microorganisms were observed at 20ºC compared to 3°C. Surprisingly, volatile organic compounds (VOC) release was similar at both temperatures, for different crude oil concentration and salinities. High total petroleum hydrocarbon (TPH) levels remained at 3°C for microcosms with high initial crude oil concentration. Regardless of temperature, increased salinity had a positive impact on the rate of crude oil removal, i.e. high CO₂ release, high VOC production and low amount of TPH in sediments. At higher crude oil dosages, a larger amount of volatiles was released, however CO₂ production did not significantly increase with the contaminant concentration. The results of this study will assist decision-makers in choosing effective spill response strategies for future crude oil spills in Arctic shorelines.
    • 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.
    • Precipitation in the Alaska central Arctic

      Homan, Joel W.; Kane, Douglas; Hinzman, Larry; Sturm, Matthew; Toniolo, Horacio (2015-12)
      Environmental change currently stimulates much of the interest in high-latitude hydrologic studies, as northern areas are expected to be strongly impacted by warming. This thesis consists of a comprehensive assessment of solid and liquid precipitation throughout the Alaska Central Arctic. The founding hypothesis are: (1) the spatial distribution of snow and warm season precipitation are linearly related to elevation, (2) annual precipitation inputs are dominated by warm season precipitation when potential moisture sources are ice free, and (3) moisture responsible for snow-producing storms is primarily advected through atmospheric circulation. To verify the validity of the hypothesis, the temporal variability and spatial distribution of snow and warm season precipitation were extensively measured. Snowpack patterns were established using over 1000 snow surveys from end-of-winter field campaigns. The snowpack distribution patterns were similar from year to year and relatively independent of elevation, with roughly an average of 100 mm of snow water equivalent (SWE) from the Arctic Coast to the Brooks Range divide. For the same 1500 m change in elevation, warm season precipitation has a large orographic change, which increases more than 240 mm. Warm season precipitation was evaluated using 31 meteorological stations and although a strong spatial distribution was found, no discernible long-term trends were identified in the somewhat limited 29 year data set. The accumulation of end-of-winter SWE and warm season precipitation measurements were combined to evaluate the distribution of annual precipitation. Annual precipitation varies temporally and spatially over the Alaska Central Arctic. At high elevations, 70% of the annual precipitation is liquid, while at low elevations, liquid precipitation only represents 40% of the annual budget and end-of winter SWE becomes the dominate precipitation contributor. Moisture responsible for snow-producing storms was found to originate from different sources depending on the time of year and ice cover conditions. North originating moisture is three times more likely to occur during the fall when sea ice is thin, or nonexistent. Mid-winter moisture was found to advect into the Arctic from the south. The timing and travel pathways of snowfall events were determined using an atmospheric model (HYSPLIT) and supplemental surface analysis charts.
    • Synergistic effects among leading indicators of construction safety management

      Calhoun, Matthew E.; Schroeder, Herbert P.; Perkins, Robert A.; Bennett, F. Lawrence; Baker, Elisha R. IV (2015-12)
      Safety performance in the construction industry has improved significantly since the Occupational Safety and Health Act was enacted in 1970. Despite these improvements, annual accident statistics indicate the construction industry remains one of the most dangerous for workers. However, there are some construction companies that defy these statistics and have an exemplary safety record. Many of these companies have adopted a zero-accident vision and measure their safety performance using both leading and lagging indicators. Safety performance has traditionally been measured with only lagging indicators that have included recordable injury rates, experience modification rates, days-away-restricted-transferred, among many others. Unfortunately these indicators are recorded after an accident has occurred, resulting in management only being able to take a reactive approach. Conversely, a proactive approach uses leading indicators to alert management before an accident occurs. Previous research has found thirteen leading indicators that are connected to a strong safety performance for construction projects. However, several researchers and safety management experts recommend only monitoring and measuring two to three indicators on a project due to the resources required. Determining which leading indicators to monitor can be a difficult process for management new to this proactive approach. In an effort to help the construction industry, the first phase of data collection for my dissertation benchmarked the knowledge and use of leading indicators by interviewing twenty-five small contractors. The purpose of the interview was to identify leading indicators used by each small contractor and identify challenges to implementation when an indicator was not being used. The results were analyzed to find the total percentage of use for each indicator and their relationship to the contractor's total recordable injury rates. Two leading indicators were found to be linked with a safer total recordable injury rate and both indicators included having high percentages of workers employed for more than five years. The second and third phase of data collection for my dissertation focused on large owner and contractor companies who typically have had a better safety performance in comparison to small contractors. The Delphi method was used to assemble two separate expert panels to quantify the pairwise synergistic effects among thirteen leading indicators from the perspective of an owner and a contractor. The expert panel from the perspective of the owner found the leading indicators with the greatest synergistic impact included pre-task planning, project management team safety process involvement, housekeeping program, owner safety walkthroughs, worker observation process, owner participation in worker orientation sessions, and stop work authority. The other panel from the perspective of a contractor found the indicators with most synergistic impact were pre-task planning, near-miss reporting, worker observation process, an auditing program, and project management team safety process involvement. The results from this study can serve as an aid to all management that are beginning to take a more proactive approach towards measuring and monitoring safety performance.
    • Alternative project delivery in rural Alaska: experiences, quality and claims

      Monta, Katrina L.; Pehrson, Gerald S.; Cryer, Matthew N. (2015-12)
      The popularity of alternative project delivery systems has expanded beyond the private sector and into the public sector. Alaska embodies unique challenges that may present obstacles while using alternative project delivery systems. This analysis will provide an understanding of alternative project delivery systems in Alaska and how local experiences, quality and claims are affected. Alaska's unique characteristics present both challenges and opportunities for implementing alternative project delivery systems. This report begins with a discussion of experiences from several rural Alaska projects, and how alternative project delivery systems can be utilized. Some impacts that alternative project delivery systems have on quality are then presented, including a perspective on quality and recommendations for achieving customer satisfaction. A treatment of construction claims is then provided, followed by conclusions and recommendations for stakeholders in selecting an appropriate project delivery system. Alternative project delivery systems were researched by means of scholarly literature reviews, professional interviews and seminars. The report of these findings is intended to provide owners and contractors with a concise presentation of the challenges and advantages for using alternative project delivery systems in Alaska.
    • Preliminary assessment of effectiveness of precut technique in controlling transverse cracks for asphalt pavement in Interior Alaska

      Netardus, John Jaro; Liu, Juanyu; Zhang, Xiong; Shur, Yuri; Saboundjian, Steve (2016-05)
      Transverse thermal cracking is one of the most common pavement distresses on asphalt pavements in cold climates. Transverse cracks are costly to maintain and unpleasant to drive over. The State of Alaska Department of Transportation and Public Facilities must seal cracks every summer to prevent further road damage from occurring. A simple solution that is gaining support is the precut technique where saw cuts are installed perpendicular to the road centerline shortly after construction to help relieve thermal stresses that cause cracking. This technique has effectively reduced the effects of natural transverse thermal cracking in other states as well as in Fairbanks, Alaska. This study investigates two road construction projects that include precuts with variable factors including three precut spacing intervals, five precut depths, and five pavement structures. Costs to install precuts are also compared against the cost to maintain a section without precuts in a preliminary cost effective analysis. Crack survey data from both projects have revealed that precutting does reduce transverse thermal cracking. Shorter precut spacing, placing precuts where natural cracks existed prior to construction, deeper precuts, and stronger pavement structures provided the best results. Further observations and more accurate cost data are recommended for an absolute determination of cost effectiveness.
    • Numerical analysis of structural behavior of welded wire reinforcement in reinforced concrete beams

      Balasubramanian, Radhakrishnan; பாலசுப்ரமணியன், ராதாகிருஷ்ணன்; Hulsey, J. Leroy; Ahn, Il-Sang; Perreault, Paul V.; Lin, Chuen-Sen (2016-05)
      Modernization and industrialization have paved the way for the construction industry of India to expand. On the other hand the Indian construction industry is set to face an acute workforce shortage. The shortage of construction workers has in fact slowed down the growth of this industry in major cities across the country and escalated its cost by 40 percent. An alternative way to replace the labor force is by automation techniques. This study is a numerical analysis to evaluate structural behavior of simply supported concrete beams reinforced with welded wires in comparison with mild steel reinforced concrete beams. Welding conventional steel bars (60 ksi) reduces their shear strength by 50 percent. Welded Wire Reinforcement (80 ksi), with its greater strength, higher durability, significantly lower placing and overall cost, provides an alternative and perhaps a better substitution for mild steel bars. The commercial finite element analysis program, ABAQUS, was used to model the non-linear behavior of reinforced concrete beams. In order to evaluate the structural behavior of welded wire reinforced concrete beams, different configurations of longitudinal and transverse wires have been considered. First, different types of stirrup configurations in a rectangular reinforced concrete beam are compared with a conventional reinforced beam. Second, a structurally performing welded wire configuration is compared with a Mexican chair styled reinforcement configuration. This part of the analysis is evaluated for a T–beam, used for building roof applications.
    • 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.
    • 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.
    • 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.