• 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.
    • Fuel Cell Power Plants in Rural Alaska

      Malosh, J. B. (1983-04)
      On the basis of fuel efficiency alone, the methanol fueled phosphoric acid fuel cell (PAFC) is a very attractive replacement for the diesel electric generator, especially in the bush regions of Alaska. However, because of the transportation costs for liquid fuel to the bush combined with the lower heating value of methanol, the PAFC looses this advantage and produces electricity that in some instances is more costly than the diesel generator. Although the PAFC is at the highest state of development of all fuel cell power plants, it is still not a commercially mature technology. The present cost of a PAFC power plant is on the order of ten times the price of an equivalent diesel electric generator. There is also no large body of published, long term data on fuel cells of any type larger than 1 kw from which an accurate assessment of reliability, maintenance and operating costs can be made. Considering this and the lack of electrical production cost advantage, the evaluation of the methanol fueled PAFC for buch applications should be suspended until more operational data is made public and units are commercially available.
    • Furnace Efficiency Testing

      Durrenberger, Joe (1983-08)
    • Heat Loss Factors for Insulated Building Foundations

      Zarling, J. P.; Braley, W. A. (1984-05)
      Steady-state and nonsteady-state finite element analyses of the heat loss occurring from basement and slab-on-grade constructions have been performed. The amount of rigid foam insulation was varied on the perimeter of the walls and slab to determine the effectiveness of various insulation configurations. Annual heat losses per linear foot of wall or slab are reported for weather conditions and soil types of both Anchorage and Fairbanks, Alaska.
    • Highway Right-of-Way Sludge Disposal

      Tilsworth, T.; Manning, D. (1986-05)
      This report encompasses a proposal to consider application of wastewater sludge to highway right-of-way. Conventional disposal of this sludge is a complex and expensive process and in some areas is severely restricted by land use and regulations. The report includes a literature review, a national survey of highway organizations and a hypothetical design analysis. Application of sludge to highway ROW can be beneficial by supplying nutrients required for plant growth, subsequent erosion stabilization and ultimate disposal of a waste resource. Disadvantages include negative public reaction, potential for contamination of ground and surface water, aesthetics, and relatively high costs. Preliminary findings of the report indicate the process is marginally feasible and recommends that a small pilot project should be conducted prior to full-scale consideration
    • Implementation of CALINE4

      Johnson, R.A.; Anderson, M.; Lilly, E.; Hok, C. (1988-11)
      To help gauge the environmental impacts of proposed highway projects, computer models are commonly used to predict both CO emissions and the resultant concentrations of CO in the atmosphere. This study has focused on an assessment of MOBILE3 as a mobile source emissions model and CALINE4 as a line source dispersion model in Alaska. We have used limited data obtained in Fairbanks o evaluate CALINE4 here. We have modified MOBILE3 to allow it to predict emissions at ambient temperatures below 0(degrees)F and have incorporated available meteorological data for Fairbanks to evaluate CALINE4. We find the use of these models does allow one to approximate trends over time in CO levels in Fairbanks, but a lack of more detailed data precludes our being able to make global statements about the abilities of the models to predict peaks and detailed spatial trends. However, the results to data indicate that these models have the potential to accurately predict CO levels in Alaska. In particular, results from a 37-hour calibration run made near an intersection indicates that CALINE4, using emissions generated by MOBILE3, can predict peak one-hour and eight-hour values within a factor of two of measured values. Conservative peak value predictions occur when the intersection option is used with the wind blowing from the intersection toward the receptor. However, the nonmodeled CO contributions may be significant if only major roads near a receptor are modeled. For worst case predictions, the limited data analyzed corroborates prior work linking worst case scenarios with cold stable meteorological conditions. In particular, a G stability case and wind speed around 0.5 m/s are appropriate. We also suggest the receptor be located downwind from an intersection. For the input emissions, we suggest the use of MOBILE3 using an average vehicle speed of 20 mph and a temperature around -20(degrees)F for Fairbanks and 10(degrees)F for Anchorage. For ambient CO levels, we suggest the user consult with local environmental agency personnel.
    • Improving Performance, Knowledge, and Methods to Provide Quality Service and Products

      Connor, Billy; Bennett, Larry (2015-12)
      The objectives of this study were to educate staff about the impact of research in Alaska, enhance communication and coordination amongst stakeholders, and formulate a long-term research and implementation research plan for pavement and materials. Education begins with an overview of pavement design, construction and maintenance in Alaska since the 1900’s through a series of webinars. Interviews with five state materials engineers were used to explore best practices. Finally, a workshop focused on developing a coordinated research program and improve implementation activities. The workshop provided a series of recommendations to The Alaska Department of Transportation and Public Facilities which will enhance the value of the departments research program.
    • Juvenile Fish Passage Through Culverts in Alaska: A Field Study

      Kane, Douglas L.; Belke, Charles E.; Gieck, Robert E.; Mclean, Robert F. (2000-06)
      In the past, culvert design where fish passage was considered generally has been based on the weakest-swimming adult fish in a river system. It has also been recognized for some time that juvenile fish are very active throughout the year, moving upstream and downstream in response to a number of environmental factors. In Alaska, many natal and nonnatal streams in southcentral and southeastern Alaska support both Chinook (Oncorhynchus tschawytscha (Walbaum)) and Coho (Oncorhynchus kisutch (Walbaum)) for one to three years, respectively, before they emigrate to sea. Are we restricting desirable habitat for these juvenile salmonids with hydraulic structures such as culverts? Unfortunately we have little information on either the behavior of juveniles in the vicinity of hydraulic structures or their swimming abilities. The objective of this study was to examine the behavior of juveniles when attempting to ascend a culvert. It was hypothesized that vertical obstacles or high velocity of opposing flow may prevent juvenile fish from moving upstream. It was also hypothesized that they would determine and take the path of least resistance to optimize their chances of successfully ascending a culvert. Four culverts were selected for intensive study regarding juvenile fish passage: Beaver and Soldotna Creeks on Kenai Peninsula and No-name and Pass Creek Tributary on Prince of Wales Island. It was postulated that fish are motivated to move upstream to obtain food if they can establish its presence. We used salmon eggs as an attractive food source both to initially capture the juveniles and then to motivate them to ascend the culvert for possible recapture. Juvenile fish were captured in a baited minnow trap and stained with a dye. They were released downstream of the culvert while the food source was placed upstream in a minnow trap. We supplemented our visual observations with underwater video cameras. We made numerous hydrologic and hydraulic measurements at each site. Although we attempted to select culverts that would prove to be quite challenging to juvenile fish passage, in three of the culverts selected, juvenile fish, of the full range of the fork length initially captured, succeeded in ascending through the culvert. For the fourth culvert, some larger juvenile fish succeeded in ascending the culvert, but not the smaller of each fish type. It was clearly established that juvenile fish were motivated to move upstream to obtain food. In the Beaver Creek culvert, fish used the large corrugations to their advantage when ascending the culverts. The Pass Creek Tributary culvert had corrugations too small for fish to utilize. No-name Creek appeared to present not problems for juvenile fish for the water levels at the time of the visit as they small along the bottom on the centerline of the culvert. In general, observations of fish attempting to move upstream through the culvert revealed that they swam very close to the culvert wall, and in the case of high velocities (Beaver Creek and Pass Creed Tributary) they swam near the surface along the sidewall where velocities are reduced. It is obvious that the juvenile fish are attempting to minimize power output and energy expenditure by taking the path of least resistance. Although not quantitavely proven, it appears that as long as fish make some headway in their upstream movement they are content. The rationale for this conclusion is that fish do not know what they may encounter upstream so they attempt to conserve as much power and energy as possible while still moving forward. They generally do so by seeking out the lowest velocities in the cross-section. In areas of steep velocity gradients along the wall (where the areal extent of low velocities is limited), it is clear in our videotapes that fish have problems maintaining their position and preferred orientation. It is apparent from our observations that because of their small size, juvenile fish are hindered by turbulence and that this area needs more study.
    • Laboratory Performance of Wicking Fabric H2Ri in Silty Gravel, Sand and Organic Silt

      Connor, Billy; Zhang, Xiong (16-05)
      The use of wicking fabric, H2Ri, is growing in its use to remove water from roadway and airport embankments. Past research has shown H2Ri to be effective in sands and fine grained materials in roadways up to 32 feet in width. However, there is a desire to use H2Ri for airports which require a minimum width of 75 ft. This project tested H2Ri in a 73-foot flume in a crushed surface course with 14 % fines. In addition, the fabric was tested in a 22-foot flume with a sand and with an organic clay. The intent was to bracket the material for which the H2Ri will work. The study showed that the fabric will easily move water 73 feet in a silty gravel. The study showed that the fabric was also able to readily remove water in sand. However, the fabric blinded when used in organic silt and proved ineffective. The study also showed that using simple overlap of the H2Ri as a splice, while effective, was not as efficient at moving water as the fabric itself. Consequently, moisture tended to build up around the splice.