RSS 1.0Theses (Civil and Environmental Engineering)
Recent Submissions
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TEST College of Engineering & Mines 9/25/17TEST College of Engineering & Mines 9/25/17
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A geohydrologic analysis of an upland-bedrock aquifer system: applications to interior AlaskaEster Dome, an upland-dome bedrock aquifer system, located nearby Fairbanks, Alaska, was studied to identify important geohydrologic processes occurring in Interior upland aquifer systems. The ground-water dynamics at Ester Dome are complex due to the fractured nature of the aquifer system. The geology at Ester Dome consists of metamorphic and igneous rocks. Valley bottom deposits include gravels and loess. The flow pattern of the dome aquifer system is radial. Ground-water flows from a central high elevation recharge area and discharges into lakes, streams, and wetlands in the valley bottoms. The primary form of recharge to the bedrock aquifer is from spring snowmelt. Snow water equivalent and snow depth increases with elevation. Ground-water levels were observed at fifty sites on Ester Dome for two years. Water levels in wells at high elevations or locations with no silt or permafrost coverage show seasonal fluctuations. However, ground-water levels in the valley bottoms show little seasonal fluctuations, except wells that penetrate gravel deposits and have no overburden. A ground-water flow model was developed to aid in the understanding of these geohydrologic processes. The ground-water flow model shows recharge and bedrock hydraulic conductivity as the most sensitive parameters.
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Disinfection by-product experiences in Alaskan village drinking water systems and the Caribou-Poker Creek watershedThe purpose of this research was to study the disinfection by-product formation potential (DBPFP) in small drinking water systems in Alaska. As per the US. E.P.A's disinfectants/disinfection by-products (D/DBP) rule, the maximum contaminant limit (MCL) for the two major DBPs namely, total trihalomethanes (TTHMs) is 80 micrograms (ug) per liter (L) and 60 micrograms/liter for the five 5 halloacetic acids (HAA5). It was decided to conduct research on the total trihalomethane formation potential (TTHMFP) and the 5- haloacetic acid formation potential (HAA5PF) of the 17 Alaskan village drinking water systems with reportedly high TTHM and HAA5 values. It was found that specific UV absorbance (SUVA) had excellent correlations with TTHM/DOC and HAA5/DOC. These correlations were used to aid in drinking water source selection in a sub-arctic watershed named the Caribou-Poker Creek Research Watershed (CPCRW).
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Fuel penetration rates in frozen and unfrozen soils: Bethel, AlaskaAlaska fuel-storage facilities are required by law to provide secondary containment for their largest tank-volume. Secondary containment commonly includes berms, catchment basins and ditches. Fuel-penetration rates on site soils are needed to predict potential fuel-penetration depths. Field and lab tests quantified fuel-penetration rates for three site soils in Bethel, Alaska. In-situ tests following ASTM D 5093-90 allowed measurement of fuel infiltration rates using a falling-head permeameter allowed quantification of hydraulic conductivities, permeabilities and infiltration rates in frozen and unfrozen soils prepared at various moisture contents. Unfrozen samples were tested at room temperature, 19.8-24.0C̊ (67.6-75.2F̊). Fuel-penetration rates were similar regardless of moisture contents. Tests for frozen samples occurred at -4C̊ (25F̊). Fuel-penetration rates decreased as ice-saturation increased. The permeant used for each test was a Diesel #2/Jet A-50 fuel mixture (heating fuel) consisting of predominately Jet A-50.
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Ice, bedload transport, and channel morphology on the upper Kuparuk RiverThe objective of this study was to quantify the impact of bottom ice on sedimentation processes at a study site on the Upper Kuparuk River, in Northern Alaska. The approach taken was to use the Meyer-Peter and Mueller (1948) and Parker (1990) equations to determine bedload rating curves at four cross sections within the study reach, and to apply these rating curves to the ten year flow history of the study site to determine the total potential bedload transport that was suppressed during snowmelt runoff. In conjunction with this analysis, a tracer rock study was performed at the study site. During the first two years of the project, the field study yielded little bedload transport information, as there were no competent flows during this time. However, the storm of record occurred in August 02 2002, which provided an opportunity to observe the geomorphic response to a major event, to estimate an average bedload transport rate based on the virtual velocity of the recovered tracer rocks, and to compare the predictive methods to the tracer data based calculations. The results suggest that the potential bedload transport (500 m³) over the ten-year flow history is comparable to the amount of transport that occorred during the extreme event of August 2002 (870 m³), and that the suppression of bedload transport, due to an ice covered bed surfaces, likely affects the morphology and sediment supply of the river.
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Estimation of operation time for soil vapor extraction systemsSince the inception of Soil Vapor Extraction (SVE) as a viable contaminated soil restoration strategy, operators of these systems have struggled with determining the best date to terminate operation of their systems. Using principles of soil-gas flow and mass transport through unsaturated soils, stochastic hydrogeology, uncertainty analysis, and a cost/risk decision model, a procedure that can determine the appropriate time to discontinue operation of SVE systems was developed. Modeling of physical characteristics and determination of mass removal of a SVE system was accomplished using statistical realizations of permeability (uncertainty model) and a 2D advective-dispersive finite element vapor transport program (VapourT). The results from subsequent Monte Carlo analysis of the mass removal simulations are then subjected to a cost/risk analysis (decision model) to determine the appropriate termination time for the system based on costs and the probability that the system will fail to reach the regulatory standard. The decision model provides information on the cost benefits associated with either the continued operation of a SVE system, or its replacement with a more economically feasible remediation system. The intention of this research is to validate a framework for the estimation of termination time for the operational phase of a selected soil vapor extraction system.
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Water quality from rainwater catchments throughout Alaska: looking at contaminants in catchment materialsA field study which focused on linking materials used in rainwater catchments to the quality of water they produce was conducted throughout Alaska in the summer of 2003. The importance of this project stems from the fact that many families throughout Alaska depend on rainwater catchment systems to provide water for washing, cleaning, cooking and/or drinking purposes. After a core group of participants were identified, samples were periodically collected from participants' water taps and were analyzed for a suite of contaminants that included metals (e.g., Pb and Zn), organics (e.g., volatile organic compounds) and bacteria. Based on variables, such as construction materials, the frequency of rainfall, the amount of water collected and the duration of storage, we evaluated the effectiveness of various catchments for providing safe drinking water. This fieldwork, coupled with a companion document addressing best management practices for rainwater catchments, provides valuable information for owners of small systems seeking to use rainwater catchments in Alaska. The conclusions of the study were that zinc concentrations of water collected at the tap were affected by roof and tank material, lead concentrations of water collected at the tap were affected by roof material, and copper concentrations of water collected at the tap were affected by pipe material.
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Hydrologic comparisons and model simulations of subarctic watersheds containing continuous and discontinuous permafrost, Seward Peninsula, AlaskaMauze Gulch (4.9 km²), and Niagara Creek (6.5 km²), located near Zougarok, Alaska and Melsing Creek (80.6 km²), and Clyde's Gulch (2 km²), located near Council, Alaska were studied to quantify the hydrologic response of these watersheds. They have been studied extensively as part of the NSF Arctic Transitions in the Land-Atmosphere System (ATLAS) study. These watersheds demonstrate a progression from a continental subarctic to a marine moderated subarctic environment. Each contains varying proportions of permafrost. Mauze Gulch and Niagara Creek are underlain by continuous, warm, thin permafrost (1̃5-50m thick). Melsing Creek and Clyde's Gulch are underlain by discontinuous permafrost. The Swedish HBV-96 model was applied to these watersheds. The model requires minimal input of meteorological data (temperature and precipitation) to generate hydrographs. Examining the basic stream hydrology showed that differences in hydrologic response based on permafrost distribution can be identified. By changing parameters, such as field capacity and the percolation to the groundwater, it is possible to reflect physical differences between watersheds using the model. Results of this study were compared with previously studied basins in Alaska. Comparisons showed that model parameters can be used to distinguish differences in hydrologic response in basins with varying amounts of permafrost.
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Floodplain assessment for the Teklanika and Toklat River project reaches in Denali National Park and Preserve, AlaskaThe National Park Service (NPS) is required to assess risks of flooding to existing and proposed structures within the boundaries of the NPS system. Within Denali National Park and Preserve (DNP & P), there are several large, braided rivers that require floodplain management. The objective of this investigation is to provide DNP & P with guidelines and methods that apply fluvial geomorphic, hydrologic, and hydraulic analysis in order to delineate flood hazard zones on this type of stream. Data collected from Teklanika and Toklat Rivers were used to develop a return period versus flood depth/bankfull depth curve and assess potential streambank erosion. Site specific data combined with this curve will enable NPS personnel to easily approximate flood hazard zones for the project reaches. The method can be applied to assess other flood hazard zones associated with other braided rivers with similar characteristics.
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Measurement of effective diffusion on andesite rock, Amchitka Island, AlaskaBetween 1965 and 1971 three nuclear weapon tests were conducted on Amchitka Island, Alaska. Currently research is being conducted to understand the possible movement of radionuclides through the Island subsurface into the marine environment so that a monitoring system can be developed. The possibility of radionuclide diffusion into matrix rock surrounding facture pathways needs to be better understood. This thesis presents ongoing research with the goal of determining the effective diffusion coefficients for andesite rock found in the Island subsurface. These studies are being conducted in a bench scale reactor consisting of two chambers separated by a sliced rock core obtained from the Island. The increase in conservative tracer over time is measured in the receiving chamber. The effective diffusion coefficients are then determined by applying these results to a solution to Fick's Second Law. Results from these studies will be used in the development of a long term monitoring program for the island.
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Single lane live load distribution factor for decked precast / prestressed concrete girder bridgesThe Alaska Department of Transportation (AKDOT) uses the decked precast, prestressed concrete bulb-tee girder for most of its bridge construction. The live load distribution factor (DF) equations provided by the American Association of State Highway and Transportation Officials (AASHTO) for the decked bulb-tee girder system do not differentiate between a single or multilane loaded condition. This practice results in a single lane load rating penalty for decked bulb-tee girder bridges. The research objective of this thesis is to determine DF simplified equations that accurately predict the distribution factor of the decked bulb-tee girder system when it is only subjected to single lane loading. Eight decked bulb-tee bridges were instrumented. Each bridge was loaded with a single load vehicle to simulate the single lane loaded condition. The experimental data were used to calibrate grillage models of the decked bulb-tee girder system. The calibrated grillage models were used to conduct a parametric study of the bulb-tee girder system subjected to single lane loaded condition. Eight new simplified equations that describe the single lane loaded distribution factor for both shear and moment forces of these bridges are developed in this thesis.
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Experimental investigation of fiber-reininforced polymer composite bridge deck panel in cold regionsTo build highway bridges in cold regions like Alaska, cast-in-place concrete has been found to be difficult and expensive, especially in winter seasons. Decked Bulb-Tee bridge members can be heavy and the deck cannot be replaced. On the other hand, fiber-reinforced plastic (FRP) composite materials offer a great opportunity in this area. The primary technical barrier to the use of composite materials in infrastructure applications is lack of data on environmental durability. The present study presents experimental load and strain results of a FRP composite panel that was subjected to cold temperatures. The FRP panel consists of an upper and a bottom laminate tied by a honeycomb core, which was produced by sequentially bonding a flat sheet to a corrugated sheet. Specifically, the objective of this research was to understand the effects of low temperature and low-temperature thermal cycling on the performance of FRP composite bridge deck panels in cold regions. This was achieved by analyzing static tests and results for a FRP deck panel. The research results reported herein showed an increase in stiffness as temperature was lowered up to a certain point, and a reverse trend at a further lower temperature.
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Three dimensional finite element analysis of decked precast, prestressed concrete girder bridgesThe speed of construction has become the key issue for bridges. This is especially true in cold regions like Alaska, where you face a very short summer season. The speed of construction can be expedited by connections. As there are advantages in connections there are also disadvantages. One of the primary advantages of the connectors is that it makes the load transfer mechanism very efficient. However everything comes for a price. Maintenance of connections is very difficult. Routine inspections are to be made to ensure proper functioning of the system. This becomes a very important factor in Alaska where extreme winter conditions exists. Another issue is that the current connector design is based on an empirical approach. A rational design method is needed. In this study an effort has been made to find the presence of ISD on the live load distribution factor for single lane loading. Using ABAQUS CAE, 3D finite element (FE) models have been developed and analyzed with different parameters. By varying the parameters, different distribution factors corresponding to the reaction, strains (flexure and shear) as well as the forces originating from the connectors are evaluated and compared. This paper provides a basis for future connector design.
