• Cordova Floating Ferry Dock

      Metzger, Andrew T. (2014-12)
      This study began the evaluation of the Cordova floating ferry dock using the ANSYS AQWA software. The AQWA software models the effects of waves, wind and current on floating structures. Floating bodies are modeled as a point-mass with inertial and hydrostatic characteristics. As part of the study, the critical wave characteristic was defined. During the modeling it was found that AQWA can only model rigid bodies and that the Cordova floats experience a wide range of wave periods and directions. Consequently, AQWA requires adaptation to fully model the ferry dock at Cordova.
    • Corrosion of Steel in Calcium-Magnesium-Acetate (CMA) Deicier

      Venkatesh, Eswarahalli S.; Kutterer, Stephanie (1985-01)
      The corrosiveness of a new road deicer, Calcium Magnesium Acetate (CMA), was determined under various conditions of temperature, pH, and concentration. The corrosion rates of steel in CMA solutions were generally found to be of the order of 2 mils per year (mpy). In comparison, for the currently used chloride salt deicers the corrosion rates can range from 25-80 mpy. CMA is generally found to be a non-corrosive medium compared to sodium and calcium chloride. Although this preliminary corrosion research indicates that CMA is less corrosive to steels than salts, further work is necessary to confirm the corrosion characteristics of CMA on other materials. Additional studies should be performed on environmental and aesthetic aspects before widespread application of CMA as a road deicier.
    • Creep Behavior of Shallow Anchors in Ice-rich Silt

      Zhang, Xiong; Chen, Liangbiao; Lin, Chuang; McHattie, Robert (2013-07)
      Grouted anchors have become a common technique in the application of earth retention systems, slope stability problems and tie-down structures in unfrozen soils due to its cost and time efficiency. However, within much of Alaska area, permafrost is a common type of soil and might contain large amount of visible ice. The highly time and temperature dependent properties of ice-rich soil make it a challenge for the application of anchors in permafrost area. This project valuates the effect of water content and temperature on the creep behavior of shallow anchors in cold room lab. Also, field test was conducted to determine effectiveness of three types of grouting materials, including Bentonite clay, Microsil Anchor Grout and special cement formula. The temperature along the anchor was monitored to evaluate the degradation of the surrounding frozen soil. Research results may be applicable in the design of shallow anchors in ice-rich permafrost at various ice content and temperature range. Also, the load distribution and the pullout test results could give a general guidance for the shallow anchor design in permafrost area.
    • Current thermal state of permafrost and potential impact on the El Niño Southern Oscillation (ENSO) in the Southern Peruvian Andes

      Yoshikawa, Kenji; Úbeda, Jose; Masías, Pablo; Pari, Walter; Vásquez, Pool; Apaza, Fredy; Callata, Betto; Luna, Gonzalo; Concha, Ronald; Iparraguirre, Joshua; et al. (2018)
      Tropical, high-mountain permafrost has a unique thermal regime due to its exposure to strong solar radiation and to the rougher surface snow morphology (due to an increased occurrence of penitentes -- that is, snow spikes and ridges ranging from centimeters to meters in height) which reduce convective sensible heat transfer from the surface. Latent heat transfer and higher albedo occurring during the wet season contributes to positive feedback that supports the presence of permafrost. This preliminary study reports on the thermal state of Peruvian permafrost. It evaluates the potential combined impact of the El Niño Southern Oscillation (ENSO), along with the eleven-year solar cycles of Coropuna (15°32′S; 72°39′W; 6,377 m a.s.l.), and the Chachani volcanic complexes (16°11′S; 71°31′W; 6,057m a.s.l.); both mountains are located in the western Central Andes (e.g., west edge of the Altiplano). Temperature monitoring boreholes were established at 5217m on Coropuna and 5331m at Chachani, and electric resistivity was surveyed to better understand permafrost spatial distribution in these locations. This seven-year record of permafrost temperature data encompasses historically extreme El Niño and La Niña events. Our results show that the current lower-altitude permafrost boundary (ca. 5100m) is critically influenced by the balance of wet and dry seasons: permafrost tends to deplete during drought years. Typical permafrost thickness was 10-20 m and contained ice-rich pore spaces. The presence of permafrost and its thermal resistance depends on ice content and on higher albedo, usually due to pyroclastic materials (especially pumice) which are ideal materials for supporting permafrost resilience.
    • Datalogger Evaluation

      Zarling, John P.; Kinney, Thomas C.; McGilvary, Randy; Briggs, Rick (1986-01)
    • A Design of an nterface Board between a MRC Thermistor Probe and a Personal Computer

      Raskovic, Dejan (2013-09-30)
      The main purpose of this project was to design and build a prototype of an interface board between an MRC temperature probe (thermistor array) and a personal laptop computer. This interface board replaces and significantly improve the capabilities of an existing MRC RD100 readout instrument. The new interface board provides the user to test a new installation as well as read instantaneous thermistor array. The report also documents the outputs of the the MRC temperature probe for future and the operational characteristics of both the MRC RD100 and the new interface board.
    • Determination of Seasonal, Frequency and Durational Aspects of Streamflow with Regard to Fish Passage Through Roadway Drainage Structures

      Ashton, William S.; Carlson, Robert F. (1984-11)
      Optimal design of culverts for fish passage for each stream crossing requires the magnitude, duration, frequency and seasonal relationship of the flow and the timing of fish movement. Although previous studies have measured fish swimming abilities and culvert water velocity profiles, there are limited studies in northern regions of the hydrologic relationship among magnitude, duration, frequency and season of discharge for the design of culverts for fish passage. We analyzed streamflow records from 33 gaging stations in southcentral, western, interior, and arctic Alaska (from watersheds with a drainage area less than 100 sq. miles each) to determine the highest consecutive mean discharge with one-, three-, seven and fifteen-day durations, and the lowest consecutive mean discharge with three-, seven-, fourteen- and thirty-day durations. Streamflow during three seasons were analyzed: spring, April 1 to June 30; summer, July 1 to August 31; and fall, Septermber 1 to November 30. The lognormal distribution, using the Blom plotting position formula, was used to estimate flows at recurrence intervals of 1.25, 2, 5, 10 and 20 years. Multiple linear regression equations were developed to predict flows from ungaged watersheds. Significant basin and climatic characteristics for high flows were drainage area, mean annual precipitation and percent of the drainage basin with forest cover. Significant characteristics at low flows were drainage area, mean minimum January temperature, mean annual precipitation and percent of drainage basin covered by forests. This report provides the culvert designer with equations to predict flows, other than the instantaneous peak flow, for use in designing culverts for fish passage. Two example problems are given to show the application of these equations.
    • Development of a Design Method for H2Ri Wicking Fabric in Pavement Structures

      Lin, Chuang; Zhang, Xiong; Han, Jie (2016-11)
      A new roadway drainage design concept is proposed to reduce the roadway water content and enhance the overall pavement performance by implementing H2Ri geotextile with lateral wicking ability. Compared with conventional drainage materials, this type of geotextile has high tensile strength and higher specific surface area, which enable to continuously transport water under unsaturated conditions. SEM (Scanning Electron Microscope) images indicated that the geotextile functions effectively for soils with particle size larger than 12 microns. A series of tests were performed to establish the relationships among different parameters, including resilient modulus test, large-scale direct shear test, salt concentration test and pressure plate test. Test results indicated that the soil-geotextile system can work effectively to reduce the water content within the pavement structure by 2%. By doing so, the corresponding resilient modulus can be increased by 3 times and the permanent deformation can be reduced to half of that value. Meanwhile, the interface frictional strength between geotextile and soil was not sensitive to water content change.
    • Diesel Fuel Additives: Use and Efficacy for Alaska's Diesel Generators

      Kemp, Chandler; Williams, Frank; Holdmann, Gwen; Witmer, Dennis (2013-05)
    • Direct Satellite Communications

      Hills, Alex (1985-06)
      Mobile radio communications in Alaska are not always effective along our highways, marine system, and remote field sites. This ineffective mobile radio communications coverage is due in part to the lack of repeaters in appropriate locations and an excess of users on certain frequencies. Lower frequencies can propogate over hilly areas whereas higher frequencies tend to travel in straight lines and are shielded by hills, ridges, and tall buildings. A new communications system called Mobile Satellite Service (MSS) may be available for use in the State in three or four years. The MSS system utilizes a satellite link between the transmitting station to the receiving station. The system is best suited for areas with few path obstructions therefore use in remote, rural areas where other forms of communication are unavailable or unreliable is very appropriate. This interim report identifies candidate applications in the state and determines coverage which will be provided in Alaska by each of the proposed satellites. The final report will give specific recommendations for feasible applications and include a technical and economical analysis of mobile satellite operations in Alaska, specifying technical requirements and defining potential operating difficulties.
    • Effect of Radiant Barriers in Wall Construction

      Estes, Mark; Olson, Todd (1988-01)
      The performance of radiant cardboard barriers were tested and evaluated using the DOT&PF guarder hot box. Two types of insulation were used in the testing fiberglass bat and blown cellulose. The test procedure consisted of obtaining temperature measurements at designated positions throughout seven types of wall configurations. These tests showed, that the configuration with 5.5 inches of fiberglass bat insulation compressed to 4 inches with a radiant cardboard barrier allowed the least total heat flux through the wall section. An economic analysis indicated that the use of radiant barriers may be feasible in situations where insulation support is needed or an uninsulated gab is required for wiring or utilities.
    • The Effects of Load History and Design Variables on Performance Limit States of Circular Bridge Columns

      Goodnight, Jason Chad; Feng, Yuhao; Kowalsky, Mervyn J.; Nau, James M. (2015-01)
      This report discusses a research program aimed at defining accurate limit state displacements which relate to specific levels of damage in reinforced concrete bridge columns subjected to seismic hazards. Bridge columns are designed as ductile elements which form plastic hinges to dissipate energy in a seismic event. To satisfy the aims of performance based design, levels of damage which interrupt the serviceability of the structure or require more invasive repair techniques must be related to engineering criteria. For reinforced concrete flexural members such as bridge columns, concrete compressive and steel tensile strain limits are very good indicators of damage. Serviceability limit states such as concrete cover crushing or residual crack widths exceeding 1mm may occur during smaller, more frequent earthquakes. While the serviceability limit states do not pose a safety concern, the hinge regions must be repaired to prevent corrosion of internal reinforcing steel. At higher ductility demands produced by larger less frequent earthquakes, reinforcing bar buckling may lead to permanent elongation in the transverse steel, which diminishes its effectiveness in confining the concrete core. Bar buckling and significant damage to the core concrete represent the damage control limit states, which when exceeded lead to significant repair costs. Furthermore, rupture of previously buckled bars during subsequent cycles of loading leads to rapid strength loss. The life safety or collapse prevention limit state is characterized by fracture of previously buckled bars. The goal of the experimental program is to investigate the impact of load history and other design variables on the relationship between strain and displacement, performance strain limits, and the spread of plasticity. The main variables for the thirty circular bridge column tests included: lateral displacement history, axial load, longitudinal steel content, aspect ratio, and transverse steel detailing. A key feature of the experiments is the high fidelity strain data obtained through the use of an optical 3D position measurement system.Column curvature distributions and fixed-end rotations attributable to strain penetration of reinforcement into the footing were quantified. The following sequence of damage was observed in all of the cyclically loaded experiments: concrete cracking, longitudinal steel yielding, cover concrete crushing, confinement steel yielding, longitudinal bar buckling, and fracture of previously buckled reinforcement. The first significant loss in strength occurred when previously buckled reinforcement fractured. The measured data was used to refine strain limit recommendations. Particular attention was paid to the limit state of longitudinal bar buckling, since it limited the deformation capacity of all of the cyclically loaded specimens. Empirical expression were developed to predict the compressive strain at cover crushing, the compressive strain at spiral yielding, and the peak tensile strain prior to visible buckling after reversal of loading. In design, limit state curvatures are converted to target displacements using an equivalent curvature distribution. The Modified Plastic Hinge Method was developed to improve the accuracy of strain-displacement predictions. Key aspects of the proposed model which differentiate it from the current method include: (1) a decoupling of column flexure and strain penetration deformation components, (2) a linear plastic curvature distribution which emulates the measured curvature profiles, and (3) separate plastic hinge lengths for tensile and compressive strain-displacement predictions. In the experiments, the measured extent of plasticity was found to increase due to the combined effects of moment gradient and tension shift. The proposed tension hinge length was calibrated to match the upper bound of the measured spread of palsticity. The proposed compressive hinge length only contains a term related to the moment gradient effect. Expressions which describe the additional column deformation due to strain penetration of reinforcement into the adjoining member were developed. When compared to the current technique, the Modified Plastic Hinge Method improved the accuracy of both tensile and compressive strain-displacement predictions. Abstract for Volume 3: This report presents the numerical portion of the research project on the impacts of loading history on the behavior of reinforced concrete bridge columns. In well-detailed reinforced concrete structures, reinforcing bar buckling and subsequent bar rupture serve as common failure mechanisms under extreme seismic events. Engineers often use a strain limit state which is associated with bar buckling as the ultimate limit state, but the relationship between the strain demand and resultant bar buckling is not well understood. Past research has indicated large impact of the cyclic loading history on the strain demand to achieve reinforcing bar buckling. On the other hand, sectional analysis is widely implemented by engineers to relate strain to displacement. However, the cyclic load history also has potential impact on the relationship between strain limits and displacement limits. As a result, it is important to study the seismic load history effect on the strain limit state of reinforcing bar buckling and on the relationship between local strain and structural displacement. In addition, Performance-Based Earthquake Engineering (PBEE) strongly depends on an accurate strain limit definition, so a design methodology needs to be developed to identify the strain limit for reinforcing bar buckling including the seismic load history effect. Two independent finite element methods were utilized to accomplish the goal of this research work. First, fiber-based analysis was utilized which employed the Open System for Earthquake Engineering Simulation (OpenSees). The fiber-based method was selected because of its accuracy in predicting strains and its computational efficiency in performing nonlinear time history analysis (NTHA). The uniaxial material models in fiber-based sections were calibrated with data from material tests. In addition, strain data and force-deformation response from large scale testing assists selection of element types and integration schemes to ensure accuracy. The advanced beam-column elements and material models in OpenSees resulted in a very accurate prediction of strain at local sections as well as global dynamic response of structures. A number of nonlinear time history analyses with 40 earthquake ground motions were conducted to investigate the effect of seismic load history on relationship between structural displacement and strain of extreme fiber bars at the critical section. The second finite element model was established with solid elements to predict bar buckling. The model included a segment of reinforcing bar and its surrounding elements, such as spiral turns and concrete. This model separates itself from previous bar buckling research by utilizing actual sectional detailing boundary conditions and plastic material models instead of the simplified bar-spring model. The strain history is considered as the demand on this model. A series of strain histories from the experimental tests and fiber-based analyses were applied to the finite element model to study their impacts on the strain limit for reinforcing bar buckling. Initial analytical investigations have shown significant impact of load history on the strain demand to lead to reinforcing bar buckling in the plastic hinge region. This is also confirmed in the experimental observation which only included a limited number of load histories. The parametric study extended the range of load history types and also studied the effect of reinforcement detailing on bar buckling. On the other hand, analyses with fiber-based models showed that the load history rarely impacts the relationship between local strain and structural displacement. A design approach was developed to include the load history effect on the strain limit state of bar buckling.
    • Egress Window Tests

      Rood, Robert (1985-08)
    • Evaluate H2RI Wicking Fabric for Pavement Application - Year 2

      Zhang, Xiong; Connor, Billy (2015-10-31)
      The Tencate H2Ri wicking fabric has proven to work well on two roadway sections on the Dalton Highway. In each the fabric has reduced the water content in the embankment resulting in a maintenance free section. This project used a 24 foot flume in the laboratory to evaluate the effectiveness of the fabric on well graded sand and organic silt. The fabric effectively removed the moisture in the well graded sand. However, the organic silt blinded the wicking fibers which eliminated the capillary moisture movement. The results also demonstrated that overlapping the fabric for joints is not efficient
    • Evaluation of Precut Transverse Cracks for an Asphalt Concrete Pavement in Interior Alaska (Moose Creek –Richardson Highway)

      Liu, Jenny; McHattie, Robert; Zhang, Xiong; Netardus, John (2015-08-31)
      Road-width thermal cracks (major transverse cracks) are perhaps the most noticeable form of crack-related damage on AC pavements throughout colder areas of Alaska. The main objective of this study is to recommend design strategies and construction practices aimed at controlling thermal cracking in AC pavements. In this report, literature review summarizes selected items of the engineering literature directly relevant to precutting of pavement-type structures and control of thermal cracking in general. Crack surveys and data collection were conducted at the test sections in an AKDOT&PF resurfacing project to compare various precut strategies (variations of cut spacing and depth), with the locations of natural major transverse cracks both before and after construction. Laboratory testing and numerical analysis were also presented to provide basic data about the physical properties of the AC and help explain some of the observed characteristics associated with natural thermal cracking. 17.