Port Of Anchorage Research Articles

Stiffness and strength anisotropy of overconsolidated Bootlegger Cove clays

This paper presents the evaluation of the stiffness and strength anisotropy of overconsolidated (OC) Bootlegger Cove Formation (BCF) clays at the Port of Alaska, formerly known as the Port of Anchorage. The stiffness and strength anisotropic material response was evaluated based on triaxial samples equipped with internal instrumentation including a submersible load cell and three subminiature linear variable displacement transducers (LVDTs). Three sets of bender elements were used in this research to measure shear wave velocities for different propagation and polarization directions. The effects of reproducing the stress history of the soil deposit on the stiffness cross-anisotropic behavior of the material are discussed. The laboratory test results are compared with in situ measurements of shear wave velocities based on suspension logging and crosshole and downhole soundings. The results of the experimental program showed that BCF clay is a cross-anisotropic material. Mean stiffness anisotropy ratios ranged from 0.90 to 1.22 and 0.93 to 1.46 for lightly OC and OC conditions, respectively. Strength anisotropy ratios, defined as the ratio of undrained shear strength under triaxial extension to compression, varied between 0.8 and 0.5. It is found that reproducing the stress history of the OC soil deposit during the laboratory reconsolidation stage did not have a significant impact on the initial stiffness anisotropy ratios of the BCF clay.

Effects of Construction-Induced Stresses on Dynamic Soil Parameters of Bootlegger Cove Clays

This paper presents the influence of construction-induced stress changes on the dynamic soil parameters of Bootlegger Cove Formation (BCF) clays at the site of the Port of Anchorage (POA) expansion project. Results are presented based on numerical simulations of the POA wharf construction and laboratory experimentation where both free-field and postconstruction conditions are reproduced. The postconstruction stability of the foundation clay is considered under both static and dynamic loadings. For the dynamic case, a cyclic triaxial loading equivalent to the contingency-level earthquake (CLE) established for design was used, whereas for the static case, undrained triaxial compression and extension loadings to failure were employed. The results from numerical simulations and laboratory experiments are presented and compared with field measurements and performance data collected during the project construction. The results obtained from specially designed cyclic triaxial probes show the large effects that the construction-induced stresses can have on the dynamic soil parameters and illustrate the importance of adequately considering such effects. Testing protocols and procedures are proposed for quantifying postconstruction soil parameters to better reflect field values and values at small (and otherwise appropriate) strain levels.

Hydrodynamics of Knik Arm: Modeling Study

An adaptive hydraulics (AdH) model was applied to lower Knik Arm near the Port of Anchorage, Alaska, to assess its ability to model a macrotidal system with complex hydrodynamics, including the formation and evolution of numerous gyres that are prominent at this site. Lower Knik Arm is an ideal system for this model evaluation because of the large tide range (approximately 10 m at Anchorage) and complex geometry of the system, which results in high velocities and the formation of numerous eddies throughout the study area. One eddy of primary importance is the one generated by Cairn Point, which occurs near the Port of Anchorage. Limitations of previous modeling studies and the availability of recent field data enabled this evaluation. The AdH results were compared with field data (water surface elevations, fluxes, and velocities) collected in August of 2002 and 2006, and favorable comparisons obtained for tidal amplification and eddy generation indicate that AdH reasonably reproduces the complex hydrodynamic conditions in lower Knik Arm. Simulations were also performed to investigate the importance of eddy viscosity specification, frictional specification, and bathymetry on the generation/evolution of eddies present in the system. Upon completion of the model validation, simulations were performed with modified Cairn Point configurations to investigate the impact to the eddy generated at the port. These results illustrate the variation in eddy generation through lengthening, lowering/reducing, or raising Cairn Point.

Anthropogenic noise and sound production by beluga whales (Delphinapterus leucas) in Cook Inlet, Alaska during early August 2007.

The beluga whale population in Cook Inlet, Ak, has a limited range centered near the Port of Anchorage and was declared endangered in 2008. One potential threat to the belugas recovery is anthropogenic noise, which may disrupt communication and normal behaviors. This project used a boat‐based single hydrophone system to evaluate noise levels at several locations in Cook Inlet on 6 days from 2–14 August, 2007. Belugas were encountered twice, at the Port of Anchorage and near the Little Susitna River. Recorded vocalizations were analyzed to develop a provisional description of the whales’ repertoire. Call frequencies ranged from 381 Hz to 24 kHz (the limit of the recording system), with most energy at frequencies above 2 kHz. Most vocalizations were similar to call types of other beluga populations. Broadband and 1/3‐octave band levels were evaluated for noise from tidal flow and ships at the Port of Anchorage. Vessel noise levels were highest below 0.5 kHz, but frequencies ranged to greater than 8 kHz (dis...

Pursuing Free Trade

IN RECENT YEARS, THE CANADIAN GOVERNMENT has emerged as a leading proponent of western hemispheric trade liberalization and transatlantic free trade. Its efforts to transform the North American Free Trade Agreement (NAFTA) into a Free Trade Area of the Americas (FTAA) and to promote free trade between NAFTA and the European Union (EU), however, have not been successful. Ottawa's ability to lead regional and inter- regional initiatives is constrained because Canada lacks the political and economic weight of the major powers, whose support is critical to bring such projects to completion. Ottawa should continue to promote free trade, but it should focus its efforts on broadening and strengthening its own relations within the hemisphere and with Europe.THE WESTERN HEMISPHEREWhen Brian Mulroney's Progressive Conservative government announced in 1989 that Canada would join the Organization of American States, Canada's role in the region was enhanced. But it was Ottawa's decision the following year to join Mexico and the United States in negotiating NAFTA that gave economic substance to Canadian policy.The NAFTA negotiation was the result of Mexico's decision to seek free trade with the United States. The administration of George Bush incorporated the Mexican initiative into its Enterprise for the Americas Initiative, the focus of which was to reinforce economic growth and political reform in Latin America through trade, debt relief, and investment. The key element of the programme was the willingness of the United States to begin to create a hemispheric free trade area 'stretching from the port of Anchorage to the Tierra del Fuego.'(f.1) Although the Canada-United States Free Trade Agreement negotiated three years earlier would become a model for NAFTA, Ottawa was not eager to join the talks. Canada's trade and investment ties with Mexico were limited and the government was not anxious to reopen the divisive domestic debate that had accompanied free trade with the United States. It decided to participate in order to avoid a 'hub and spoke' arrangement that would leave the United States as the only country with privileged access to the others' markets. After the negotiations began, Ottawa's main objective was to protect and improve upon the gains it had achieved in the Canada-United States pact.By the time the bruising United States debate over ratification of NAFTA, which pitted labour and environmental groups against free trade supporters, ended in 1993 American enthusiasm for hemispheric free trade had faded. Deepening divisions in Congress over the place of labour and environmental standards in trade pacts prevented President Bill Clinton's administration from securing renewal of 'fast track' authority to negotiate future agreements that would not be subject to legislative amendment. The result was that the United States was no longer able to play its crucial leadership role in trade matters.(f.2)As the United States commitment to hemispheric free trade weakened, Canada's commitment increased. Jean Chretien's Liberal government, which had been highly critical of NAFTA while in opposition, reversed itself when it came to power and became a leading supporter of the agreement's expansion as a stepping stone to free trade in the hemisphere. A hemispheric accord would allow Ottawa to diversify its trade and to broaden the basis of its interaction with the United States while extending support for the multilateral trade system.The Canadian government, which had been encouraging the Clinton administration to continue its trade liberalization course, was therefore pleased when, at the December 1994 Summit of the Americas, thirty-four countries endorsed the president's proposal to negotiate a Free Trade Area of the Americas by 2005. In the meantime, Canada, the United States, and Mexico would explore ways to bring other countries into NAFTA. Chretien, Clinton, and the Mexican president, Ernesto Zedillo, announced that negotiations would begin the following month to bring Chile, which was seen as a key link between North and South America, into the agreement by 1 January 1996. …