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P N DE N G I N E E R S, I NC.

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E N G I N E E R S, I NC.

P N D

ARCTIC ENGINEERING

PND Engineers, Inc., founded in 1979, is a full-service consulting engineering firm that provides civil, marine, geotechnical, structural, and construction inspection services for a wide variety of projects. Our Arctic and cold regions design experience ranges from the Russian and Canadian Arctic regions, and throughout Alaska, for more than 30 years.

PND | Arctic Engineering


P N D

PND’s Alaskan roots have enabled the firm to be at the forefront of Arctic engineering. Working in the world’s Arctic regions requires more than traditional engineering skills. Special obstacles created by the climatic, geological, and logistical conditions of the Arctic and subarctic require knowledge and techniques that are rarely encountered in conventional engineering. PND’s vast Arctic experience enables us to deal with the challenges of design, construction, and operations in Arctic regions of the world.

Our expertise in this field covers many aspects of engineering, ranging from building and bridge design to site civil and geotechnical design. It includes the design of Arctic marine facilities and offshore drilling islands. It also involves Arctic hydrology studies and permafrost foundation design, as well as ice-structure interaction. We routinely design for severe environmental conditions, including heavy snow loads, both continuous and discontinuous permafrost, ice interaction loads, and extreme temperatures. PND’s broad Arctic experience has emphasized the importance of dealing with a host of critical issues such as cold-temperature material toughness; the effects of spring break-up on rivers for both flooding and bridge design; remote access utilizing ice roads and pads; and construction logistics associated with the Arctic.

PND has successfully completed projects in the Arctic and subarctic areas of Alaska, Canada, and northern Russia. Schedules and quality have been tightly maintained despite extremes in weather and logistical conditions. Our Arctic experience is underscored by a “can-do” attitude regardless of any technical, extreme environmental, or logistical problems. Since the founding of the company, PND has provided professional services tailored to the needs and schedules of its clients, utilizing state-of-the-art technology and skills. Many of our Arctic projects have won prestigious awards for their innovative design and construction, including the West Dock Causeway and Endicott Causeway breaches; Kuparuk River Bridge and Low Water Crossing; the Oliktok Point Dock; and pile foundations in permafrost for the Napaaqtugmuit School in Noatak, Alaska.

PND designed this award-winning, four-story restraint tower built to stabilize an oilfield separator by devising a remarkably stiff, axially-loaded structure where deflection from bending stress is virtually eliminated. Using high-grade, 48-inch- diameter surplus pipeline pipe from the Trans-Alaska Pipeline, a 48-foot-tall, two-legged, welded pipe structure was developed that would transmit loads axially to a frozen foundation. Dubbed a bi-pod, the structure utilized a massive prefabricated steel weldment as a cap to which the crude oil piping system was anchored. This innovation earned a Lincoln Arc Welding Bronze Award.

Kuparuk Pipe Restraint Tower | North Slope, Alaska PND designed all structural framing for a new drill rig on the North Slope of Alaska, which at the time was reported by the tire manufacturer to be the largest rubber tire vehicle in the world. At more than 3 million pounds, Drill Rig 6 utilizes welded steel components, including a backbone of twin 6-foot by 10-foot box girders to form a self-mobilizing unit. This project won a Lincoln Arc-Welding Award for Best of Program.

The rig is capable of moving at speeds of 2.5 mph in both longitudinal and transverse directions. This mobility is made possible by six sets of hydraulic drive bogies, each of which has twin 11-foot-diameter rubber tires. Each bogie is capable of supporting a load of 300 to 400 tons.

Drill Rig 6 | North Slope, Alaska

ARCTIC STRUCTURES DESIGN

PND provided civil and structural engineering design for this single-story, 50,000-square-foot building, including cafeteria, gymnasium, and two classroom wings for grades K-12. PND designed a pile foundation for the structure in permafrost soils. The building is elevated above the permafrost to prevent thawing of marginally frozen soils. Significant consideration was given to developing a lightweight structure, since all materials had to be flown in to the site. The remote location made clarity of design and ease ofconstruction critical for this project. The structure was built with steel-braced frames designed to resist lateral wind and seismic loads.

Napaaqtugmiut School | Noatak, Alaska


PND provided design services for the Northstar oil drilling and production island in the Beaufort Sea over two phases. The first phase consisted of a 320-foot by 140-foot OPEN CELL SHEET PILE dock with fenders, foundations, and various structural elements at the south end of the island. The dock was built in two separate halves with a central trench section to allow the installation of pipelines onto the island. The pipeline transition trench was later closed by a sheet pile closure wall, resulting in a solid dock face. Other aspects included heliport design; foundation design for the processor, compressor, turbine and fuel tank buildings; budgetary, administrative, project management and alliance support; and design services for temporary island access during the first year of a two-year construction program.

During the second phase of the project, PND developed, reviewed, and tested new shore protection alternatives for the island, including an OPEN CELL SHEET PILE perimeter wall and rock berm alternatives. The PND effort included extensive and simultaneous physical and numerical modeling to test and refine concept alternatives and ensure accuracy. The work included physical modeling in wave tanks at Oregon State University and Texas A&M University, as well as physical modeling of ice effects in tanks in Newfoundland and Finland. Computer modeling included ice simulations, CGWAVE and COBRAS wave modeling, and structural finite element modeling.

Additionally, as part of an enhancement project, PND designed an enlarged sheet pile-protected area for a new operations center/living quarters, a high-capacity module barge dock designed for 4,300-ton module offload, seawater intake and sump, offshore dredging, and an ARKTOS emergency vehicle egress ramp. The scope included concept through final design, permitting, assistance, physical/numerical modeling of wave/ice interaction, cost estimating, constructability reviews, construction inspection/QA, and project management.

Northstar Offshore Island | Prudhoe Bay, Alaska

OIL & GAS DEVELOPMENT

PND performed a study of mechanical ice strength properties in the Colville River. A series of tests, including ice beam bending tests and confined compressive strength measurements using a calibrated borehole jack, were conducted to establish the bending and compressive strength as well as mechanical characteristics of the ice for design purposes. The test procedures involved jacking a series of cantilevered beams of ice and pulling upward on the ice beam to break the ice in a way similar to the expected mode of failure for design use. The test results were in the anticipated range and served to validate the design.

Ice Beam and Borehole Jack Testing

Model testing using both numerical (computer) and physical models are often done for Arctic and ocean structures. PND has tested designs for Beaufort Sea artificial islands in both 3-D ice tanks and large wave basins. For one particular project, slope protection improvements for an existing petroleum development Arctic island were developed by PND. Both sloping armor rock and vertical wall steel bulkhead designs were tested. The island is approximately 1,400 feet across on the diagonal, in about 40 feet water depth, and was modeled in ice tank facilities in Finland and Newfoundland. Wave tank testing was conducted at facilities at Oregon State University and at Texas A&M University. The physical models helped answer key questions about the risk of both ice and wave overtopping, ice behavior, wave deflector design, and the stability of the armor rock slope protection.

Wave Tank and Ice Tank Physical Models

Pile Testing In Permafrost Soil

PND performed long-term pile creep tests in Alaska’s Arctic region. Twelve piles were tested in gravelly and silty permafrost soils. These tests characterized the adfreeze bond developed by a new pile installation process that is considerably more economical than traditional Arctic pile installation procedures. The testing system applied pile loads of more than 800,000 pounds and was designed for remote use to function autonomously, keeping a constant load without manpower for maintenance.

RESEARCH & DEVELOPMENT


Endicott Causeway | Prudhoe Bay, Alaska

With an overall length of 700 feet, this causeway bridge, over a breach in a previously earth-filled ocean causeway, is supported by two in-water conical pile-supported piers and features abutments protected by OPEN CELL SHEET PILE® bulkheads. The breach is designed for up to 38-foot scour below existing seabed, and the design ice load on the piers is 500 kips. This project won a Third-Place Bronze Award in the James F. Lincoln Arc Welding Foundation Professional Awards Program, as well as an Award of Merit in the American Institute of Steel Construction Competition for Special Purpose Bridges.

Kuparuk River Module Crossing | North Slope, Alaska

Engineered to accommodate module and carrier load combinations in the range of 2,300 tons and to resist forces generated by ice floes up to 5.5 feet thick, this North Slope steel box-girder bridge exhibits one of the heaviest load capacities in the world for its construction type. Careful design minimized bridge length, with a 1,500-foot-long paved low water roadway section designed to withstand overflow during flood events without damage. The bridge utilizes OPEN CELL SHEET PILE bulkhead abutments and won First Place in Alaska Construction & Oil magazine’s “Heavy Construction Project of the Year” contest, and a Bronze Award from the Lincoln Arc Welding Foundation.

PND designed these innovative submersible bridges with combined paved low water crossings on the North Slope of Alaska. This design saved the owner approximately 50 percent ($10 million) over the cost of elevated bridges for the crossing of two river channels in a flood plain nearly two miles wide. Extreme environmental conditions, design vehicle weights approaching 4 million pounds, impact loading from river ice 5 feet thick, and discontinuous permafrost soil conditions posed interesting and unusual design and construction challenges. The strength, resilience, and construction flexibility of welded steel were fundamental in providing the most cost-effective solution for this project. The project won the following: James F. Lincoln Arc Welding Award, AISC/NSBA Bridge Special Award, and the Deep Foundations Institute Special Recognition Award.

Kuparuk River Low Water Crossings | North Slope, Alaska

ARCTIC BRIDGE & CIVIL DESIGN

© JUDY PATRICK

PND was responsible for all of the civil work associated with developing this multi-billion dollar project’s transportation and infrastructure systems consisting of water access; module off-load marine facilities; a service pier; bridges; gravel and ice roads and pads; hydrology; upland and bathymetric surveys; met-ocean investigations and associated coastal engineering; airstrip and associated facilities, including instrument landing systems; all containment, including tank truck and fuel tank farms; water supply; and material sources. The project is located on Alaska’s North Slope near the Arctic National Wildlife Refuge (ANWR) and is underlain by permafrost 2,000 feet deep throughout the project site.

Gas Cycling Project Infrastructure Development | North Slope, Alaska

PND led the civil team for this North Slope development, which evaluated geotechnical data; identified material sources; utilized aerial photography for road and bridge layout; conducted hydrology and hydrological studies, met-ocean studies, and sea ice encroachment studies; developed design ice criteria; engineered road and pipeline bridge designs; and assisted in environmental and cultural/archaeological studies for various project development alternatives.

The alternative selected for construction involved an expansion of an existing offshore drilling pad utilizing 2,000 feet of OPEN CELL SHEET PILE shore protection in up to 10 feet of water and the replacement of an existing bridge’s superstructure. The island expansion and barge dock were designed for very heavy oilfield drill rig loads and self-propelled module carrier loads to support the planned ultra-extended-reach drill rig equipment (longest in the world, and largest). PND also designed the conductor piles and well cellar lids that were specialized for the very high loads and particular needs of this development. PND provided construction inspection, QA and management of the construction of the island expansion, gravel material source development, and existing bridge demolition and replacement.

Liberty Island Offshore Development | North Slope, Alaska



PND has designed four separate waterfront structures around City of Nome property. Three of these are dock facilities, each approximately 200 feet long. These structures are designed to withstand and be overrun by 4-foot-thick sea ice floes (see above) and resist 16-foot waves.

Port Facilities | Nome, Alaska

One of the largest docks north of the Arctic Circle, this sheet pile wall structure is capable of resisting ice forces greater than 140 kips per foot of wall, and it was designed to accommodate the loading footprint developed by a 2,350-ton module and carrier. The offshore mooring dolphins, the first of their kind used offshore in Alaska, resist forces generated by 400-foot barges, as well as those from infinite ice sheets up to 6 feet thick. Special Alaska-manufactured revetments protect critical areas around the dock and approach roadway during extreme wave movements. The project won several awards, including a Third Place Award from the Lincoln Arc Welding Foundation, and a Merit Award from Alaska Construction & Oil magazine.

Oliktok Point Dockhead and Dolphins | North Slope, Alaska

MARINE DESIGN

PND provided engineering and construction oversight for construction of this 3.8-mile gravel road and 10-acre gravel drill pad located within the Colville River Delta. This facility lies within the Colville River Unit on the North Slope of Alaska and is located on permafrost in a large river delta. PND’s design efforts included optimizing the road route with analysis of aerial photography and field investigations in order to minimize exposure to the annual spring floods and impacts to the surrounding tundra habitat. In addition to the facility’s operational requirements, the project’s design considerations include thermal protection of the permafrost, integration and protection of the facility within a complex floodplain, and coordination with federal, state, and local permitting efforts.

CD-4 Road | North Slope, Alaska


This road is in northwestern Alaska, about 80 miles north of Kotzebue, and extends approximately 54 miles from the coast of the Chukchi Sea to the Red Dog Mine, one of the world’s largest and richest lead and zinc mines. Based on in-depth analysis, PND designed a road alignment that maintained close proximity to borrow sources, minimized the number and size of stream crossings required, and provided the best available foundation. Although the majority of the route traverses frozen soils, which become weak when thawed, the finished road safely conveys 1,600-ton modules and large ore carriers year-round. This was accomplished by way of a combination of gravel and high-strength geotextile fabric.

Red Dog Road | Kotzebue, Alaska

PND earned a Silver James F. Lincoln Arc Welding Foundation Award for its design of the West Dock Causeway breach bridge on Alaska’s North Slope. The structure is a single-lane, torsionally resistant steel box-girder bridge with a 700-foot-long, four-span main bridge and 80-foot-long, single-span approach trestles at each end, for an overall length of 900 feet. The vertical piers are supported by eight 36-inch-diameter batter piles designed to resist ice loads of up to 1,200 kips with 40-foot scour.

West Dock Causeway | North Slope, Alaska

PND has been responsible for numerous marine projects in Cook Inlet that have required general and site-specific ice studies and monitoring. Some of these projects include: Port MacKenzie deep draft and fill docks, the Knik Arm Bridge development, the Cook Inlet Ferry Landings, and the Chuitna Coal project. Cook Inlet tides produce fast-moving tidal currents exceeding 3 feet per second. These tidal currents carry typical 2-foot-thick ice floes in excess of 1,000 feet long with occasional rafted floes twice that thickness. Loads on piles can exceed several hundred thousand pounds, and revetments with 3- to 4-foot-diameter keyed armor rock have been severely plowed from large floes.

PND has provided ice monitoring, including: measurement of ice forces on strain gauge instrumented dolphin structures, ice thickness measurements, salinity and silt measurements, 4-foot sample flexural tests, and current studies to determine flow patterns, as well as provided numerous site observations. PND reviewed one year of web camera footage, producing a timelapse movie of the ice floes around the port of Anchorage.

Cook Inlet Ice Studies | Alaska

PND performed studies of port facilities, access roads, bridges, fill pads, module staging, upland tank farm storage, shipping logistics, and airport facilities for the Hope Bay Gold Mine project. The project is located in the Canadian Arctic, requiring consideration of ice forces on dock facilities and design of transportation infrastructure on ice-rich permafrost terrain. PND designed an OPEN CELL SHEET PILE jetty to serve as a supply berth, allowing transport of large modules in excess of 2,000 tons. Upland mooring points and camp barge access floats were also evaluated as part of the design process.

Hope Bay Mine Site Development | Hope Bay, Nunavut, Canada

MARINE DESIGN


For the Tarn Field project, PND designed seven ultra-high-load- capacity steel bridges over several small North Slope streams. Extreme environmental conditions, design vehicle weights approaching 2,000 tons, and permafrost soil conditions posed design and construction challenges. These structures have played a critical role in providing drill rig access at accelerated schedules, with construction occurring only within the three-month ice road season. The designs utilized innovative OPEN CELL SHEET PILE abutments and piles founded in permafrost. Bridge lengths range from 40 feet to 120 feet.

Tarn, Meltwater, and Palm Field Development | North Slope, Alaska

PND provided engineering design, permitting support, construction planning, and construction inspection services to substantially upgrade the existing gravel runway at Kuparuk with subbase improvements, runway extensions, asphalt pavement, in-pavement centerline and touchdown zone lighting, new edge lighting, new MALSR approach lighting, all new instrument landing systems (ILS) and weather systems, five new equipment shelters, and a new air traffic coordination building in order to accommodate the needs of a new fleet of Boeing 737 aircraft and improve safety of the facility. This project was complex in that the runway is founded upon permafrost, and thermal analysis was an important aspect of the project because the design needed to ensure long-term stability of the embankment. As part of these design services, several alternative project configurations were developed, including runway, taxiway, and apron expansions, runway relocation, obstruction mitigation and/or relocation, airport lighting alternatives, and ILS alternatives. Our design conformed to the latest industry practices as specified by the Alaska DOT&PF, AASHTO, and the FAA.

Kuparuk Runway Upgrades | North Slope, Alaska

CD3 Pipeline Bridges | North Slope, Alaska

PND was responsible for design and construction oversight of three pipeline bridges located in the Colville River Delta. All bridges were two-span steel box structures with lengths of 455 feet to 690 feet. The center pier was designed with an inclined face to resist ice floes approaching from various angles. Since 2006 PND has performed the biennial inspections of these structures and provided detailed inspection reports outlining recommended maintenance.



PND has designed four separate waterfront structures around City of Nome property. Three of these are dock facilities, each approximately 200 feet long. These structures are designed to withstand and be overrun by 4-foot-thick sea ice floes (see above) and resist 16-foot waves.

Port Facilities | Nome, Alaska

One of the largest docks north of the Arctic Circle, this sheet pile wall structure is capable of resisting ice forces greater than 140 kips per foot of wall, and it was designed to accommodate the loading footprint developed by a 2,350-ton module and carrier. The offshore mooring dolphins, the first of their kind used offshore in Alaska, resist forces generated by 400-foot barges, as well as those from infinite ice sheets up to 6 feet thick. Special Alaska-manufactured revetments protect critical areas around the dock and approach roadway during extreme wave movements. The project won several awards, including a Third Place Award from the Lincoln Arc Welding Foundation, and a Merit Award from Alaska Construction & Oil magazine.

Oliktok Point Dockhead and Dolphins | North Slope, Alaska

MARINE DESIGN

PND provided engineering and construction oversight for construction of this 3.8-mile gravel road and 10-acre gravel drill pad located within the Colville River Delta. This facility lies within the Colville River Unit on the North Slope of Alaska and is located on permafrost in a large river delta. PND’s design efforts included optimizing the road route with analysis of aerial photography and field investigations in order to minimize exposure to the annual spring floods and impacts to the surrounding tundra habitat. In addition to the facility’s operational requirements, the project’s design considerations include thermal protection of the permafrost, integration and protection of the facility within a complex floodplain, and coordination with federal, state, and local permitting efforts.

CD-4 Road | North Slope, Alaska


This road is in northwestern Alaska, about 80 miles north of Kotzebue, and extends approximately 54 miles from the coast of the Chukchi Sea to the Red Dog Mine, one of the world’s largest and richest lead and zinc mines. Based on in-depth analysis, PND designed a road alignment that maintained close proximity to borrow sources, minimized the number and size of stream crossings required, and provided the best available foundation. Although the majority of the route traverses frozen soils, which become weak when thawed, the finished road safely conveys 1,600-ton modules and large ore carriers year-round. This was accomplished by way of a combination of gravel and high-strength geotextile fabric.

Red Dog Road | Kotzebue, Alaska

PND earned a Silver James F. Lincoln Arc Welding Foundation Award for its design of the West Dock Causeway breach bridge on Alaska’s North Slope. The structure is a single-lane, torsionally resistant steel box-girder bridge with a 700-foot-long, four-span main bridge and 80-foot-long, single-span approach trestles at each end, for an overall length of 900 feet. The vertical piers are supported by eight 36-inch-diameter batter piles designed to resist ice loads of up to 1,200 kips with 40-foot scour.

West Dock Causeway | North Slope, Alaska


Endicott Causeway | Prudhoe Bay, Alaska

With an overall length of 700 feet, this causeway bridge, over a breach in a previously earth-filled ocean causeway, is supported by two in-water conical pile-supported piers and features abutments protected by OPEN CELL SHEET PILE® bulkheads. The breach is designed for up to 38-foot scour below existing seabed, and the design ice load on the piers is 500 kips. This project won a Third-Place Bronze Award in the James F. Lincoln Arc Welding Foundation Professional Awards Program, as well as an Award of Merit in the American Institute of Steel Construction Competition for Special Purpose Bridges.

Kuparuk River Module Crossing | North Slope, Alaska

Engineered to accommodate module and carrier load combinations in the range of 2,300 tons and to resist forces generated by ice floes up to 5.5 feet thick, this North Slope steel box-girder bridge exhibits one of the heaviest load capacities in the world for its construction type. Careful design minimized bridge length, with a 1,500-foot-long paved low water roadway section designed to withstand overflow during flood events without damage. The bridge utilizes OPEN CELL SHEET PILE bulkhead abutments and won First Place in Alaska Construction & Oil magazine’s “Heavy Construction Project of the Year” contest, and a Bronze Award from the Lincoln Arc Welding Foundation.

PND designed these innovative submersible bridges with combined paved low water crossings on the North Slope of Alaska. This design saved the owner approximately 50 percent ($10 million) over the cost of elevated bridges for the crossing of two river channels in a flood plain nearly two miles wide. Extreme environmental conditions, design vehicle weights approaching 4 million pounds, impact loading from river ice 5 feet thick, and discontinuous permafrost soil conditions posed interesting and unusual design and construction challenges. The strength, resilience, and construction flexibility of welded steel were fundamental in providing the most cost-effective solution for this project. The project won the following: James F. Lincoln Arc Welding Award, AISC/NSBA Bridge Special Award, and the Deep Foundations Institute Special Recognition Award.

Kuparuk River Low Water Crossings | North Slope, Alaska


© JUDY PATRICK

PND was responsible for all of the civil work associated with developing this multi-billion dollar project’s transportation and infrastructure systems consisting of water access; module off-load marine facilities; a service pier; bridges; gravel and ice roads and pads; hydrology; upland and bathymetric surveys; met-ocean investigations and associated coastal engineering; airstrip and associated facilities, including instrument landing systems; all containment, including tank truck and fuel tank farms; water supply; and material sources. The project is located on Alaska’s North Slope near the Arctic National Wildlife Refuge (ANWR) and is underlain by permafrost 2,000 feet deep throughout the project site.

Gas Cycling Project Infrastructure Development | North Slope, Alaska

PND led the civil team for this North Slope development, which evaluated geotechnical data; identified material sources; utilized aerial photography for road and bridge layout; conducted hydrology and hydrological studies, met-ocean studies, and sea ice encroachment studies; developed design ice criteria; engineered road and pipeline bridge designs; and assisted in environmental and cultural/archaeological studies for various project development alternatives.

The alternative selected for construction involved an expansion of an existing offshore drilling pad utilizing 2,000 feet of OPEN CELL SHEET PILE shore protection in up to 10 feet of water and the replacement of an existing bridge’s superstructure. The island expansion and barge dock were designed for very heavy oilfield drill rig loads and self-propelled module carrier loads to support the planned ultra-extended-reach drill rig equipment (longest in the world, and largest). PND also designed the conductor piles and well cellar lids that were specialized for the very high loads and particular needs of this development. PND provided construction inspection, QA and management of the construction of the island expansion, gravel material source development, and existing bridge demolition and replacement.

Liberty Island Offshore Development | North Slope, Alaska



PND provided design services for the Northstar oil drilling and production island in the Beaufort Sea over two phases. The first phase consisted of a 320-foot by 140-foot OPEN CELL SHEET PILE dock with fenders, foundations, and various structural elements at the south end of the island. The dock was built in two separate halves with a central trench section to allow the installation of pipelines onto the island. The pipeline transition trench was later closed by a sheet pile closure wall, resulting in a solid dock face. Other aspects included heliport design; foundation design for the processor, compressor, turbine and fuel tank buildings; budgetary, administrative, project management and alliance support; and design services for temporary island access during the first year of a two-year construction program.

During the second phase of the project, PND developed, reviewed, and tested new shore protection alternatives for the island, including an OPEN CELL SHEET PILE perimeter wall and rock berm alternatives. The PND effort included extensive and simultaneous physical and numerical modeling to test and refine concept alternatives and ensure accuracy. The work included physical modeling in wave tanks at Oregon State University and Texas A&M University, as well as physical modeling of ice effects in tanks in Newfoundland and Finland. Computer modeling included ice simulations, CGWAVE and COBRAS wave modeling, and structural finite element modeling.

Additionally, as part of an enhancement project, PND designed an enlarged sheet pile-protected area for a new operations center/living quarters, a high-capacity module barge dock designed for 4,300-ton module offload, seawater intake and sump, offshore dredging, and an ARKTOS emergency vehicle egress ramp. The scope included concept through final design, permitting, assistance, physical/numerical modeling of wave/ice interaction, cost estimating, constructability reviews, construction inspection/QA, and project management.

Northstar Offshore Island | Prudhoe Bay, Alaska


PND performed a study of mechanical ice strength properties in the Colville River. A series of tests, including ice beam bending tests and confined compressive strength measurements using a calibrated borehole jack, were conducted to establish the bending and compressive strength as well as mechanical characteristics of the ice for design purposes. The test procedures involved jacking a series of cantilevered beams of ice and pulling upward on the ice beam to break the ice in a way similar to the expected mode of failure for design use. The test results were in the anticipated range and served to validate the design.

Ice Beam and Borehole Jack Testing

Model testing using both numerical (computer) and physical models are often done for Arctic and ocean structures. PND has tested designs for Beaufort Sea artificial islands in both 3-D ice tanks and large wave basins. For one particular project, slope protection improvements for an existing petroleum development Arctic island were developed by PND. Both sloping armor rock and vertical wall steel bulkhead designs were tested. The island is approximately 1,400 feet across on the diagonal, in about 40 feet water depth, and was modeled in ice tank facilities in Finland and Newfoundland. Wave tank testing was conducted at facilities at Oregon State University and at Texas A&M University. The physical models helped answer key questions about the risk of both ice and wave overtopping, ice behavior, wave deflector design, and the stability of the armor rock slope protection.

Wave Tank and Ice Tank Physical Models

Pile Testing In Permafrost Soil

PND performed long-term pile creep tests in Alaska’s Arctic region. Twelve piles were tested in gravelly and silty permafrost soils. These tests characterized the adfreeze bond developed by a new pile installation process that is considerably more economical than traditional Arctic pile installation procedures. The testing system applied pile loads of more than 800,000 pounds and was designed for remote use to function autonomously, keeping a constant load without manpower for maintenance.

RESEARCH & DEVELOPMENT



P N D

PND’s Alaskan roots have enabled the firm to be at the forefront of Arctic engineering. Working in the world’s Arctic regions requires more than traditional engineering skills. Special obstacles created by the climactic, geological, and logistical conditions of the Arctic and subarctic require knowledge and techniques that are rarely encountered in conventional engineering. PND’s vast Arctic experience enables us to deal with the challenges of design, construction, and operations in Arctic regions of the world.

Our expertise in this field covers many aspects of engineering, ranging from building and bridge design to site civil and geotechnical design. It includes the design of Arctic marine facilities and offshore drilling islands. It also involves Arctic hydrology studies and permafrost foundation design, as well as ice-structure interaction. We routinely design for severe environmental conditions, including heavy snow loads, both continuous and discontinuous permafrost, ice interaction loads, and extreme temperatures. PND’s broad Arctic experience has emphasized the importance of dealing with a host of critical issues such as cold-temperature material toughness; the effects of spring break-up on rivers for both flooding and bridge design; remote access utilizing ice roads and pads; and construction logistics associated with the Arctic.

PND has successfully completed projects in the Arctic and subarctic areas of Alaska, Canada, and northern Russia. Schedules and quality have been tightly maintained despite extremes in weather and logistical conditions. Our Arctic experience is underscored by a “can-do” attitude regardless of any technical, extreme environmental, or logistical problems. Since the founding of the company, PND has provided professional services tailored to the needs and schedules of its clients, utilizing state-of-the-art technology and skills. Many of our Arctic projects have won prestigious awards for their innovative design and construction, including the West Dock Causeway and Endicott Causeway breaches; Kuparuk River Bridge and Low Water Crossing; the Oliktok Point Dock; and pile foundations in permafrost for the Napaaqtugmuit School in Noatak, Alaska.

PND designed this award-winning, four-story restraint tower built to stabilize an oilfield separator by devising a remarkably stiff, axially-loaded structure where deflection from bending stress is virtually eliminated. Using high-grade, 48-inch- diameter surplus pipeline pipe from the Trans-Alaska Pipeline, a 48-foot-tall, two-legged, welded pipe structure was developed that would transmit loads axially to a frozen foundation. Dubbed a bi-pod, the structure utilized a massive prefabricated steel weldment as a cap to which the crude oil piping system was anchored. This innovation earned a Lincoln Arc Welding Bronze Award.

Kuparuk Pipe Restraint Tower | North Slope, Alaska PND designed all structural framing for a new drill rig on the North Slope of Alaska, which at the time was reported by the tire manufacturer to be the largest rubber tire vehicle in the world. At more than 3 million pounds, Drill Rig 6 utilizes welded steel components, including a backbone of twin 6-foot by 10-foot box girders to form a self-mobilizing unit. This project won a Lincoln Arc-Welding Award for Best of Program.

The rig is capable of moving at speeds of 2.5 mph in both longitudinal and transverse directions. This mobility is made possible by six sets of hydraulic drive bogies, each of which has twin 11-foot-diameter rubber tires. Each bogie is capable of supporting a load of 300 to 400 tons.

Drill Rig 6 | North Slope, Alaska

ARCTIC STRUCTURES DESIGN

PND provided civil and structural engineering design for this single-story, 50,000-square-foot building, including cafeteria, gymnasium, and two classroom wings for grades K-12. PND designed a pile foundation for the structure in permafrost soils. The building is elevated above the permafrost to prevent thawing of marginally frozen soils. Significant consideration was given to developing a lightweight structure, since all materials had to be flown in to the site. The remote location made clarity of design and ease of construction critical for this project. The structure was built with steel-braced frames designed to resist lateral wind and seismic loads.

Napaaqtugmiut School | Noatak, Alaska

B R I D G E A B U T M E N T S AC C E SS U RV E Y H E AV Y- L OA D FAC I LB R I D G E S S H I P P I N G T E R M I NP I E R S H Y D R O L O G Y C AU S E WP E R M A F R O S T P R E D R I L L I N G D O L P H I N S F E N D E R S Y S T E MB U L K H E A D S E N V I R O N M E N TI M PAC T S T U D I E S S I T E D E V EB R I D G E A B U T M E N T S AC C E SS U RV E Y H E AV Y- L OA D FAC I LB R I D G E S S H I P P I N G T E R M I NP I E R S H Y D R O L O G Y C AU S E WP R E D R I L L I N G D O L P H I N S FS Y S T E M S B U L K H E A D S E N V II M PAC T S T U D I E S S I T E D E V EB R I D G E A B U T M E N T S AC C E SS U RV E Y H E AV Y- L OA D FAC I L

Seattle Office

1736 Fourth Avenue S, Suite A

Seattle, Washington 98134

Phone: 206.624.1387

Fax: 206.624.1388

Houston Office

10497 Town and Country Way, Suite 210

Houston, Texas 77024

Phone 832.930.4830

Juneau Office

9360 Glacier Highway, Suite 100

Juneau, Alaska 99801

Phone: 907.586.2093

Fax: 907.586.2099

Headquarters:

Anchorage Office

1506 West 36th Avenue

Anchorage, Alaska 99503

Phone: 907.561.1011

Fax: 907.563.4220

c Copyright 2015, PND Engineers, Inc.

P N DE N G I N E E R S, I NC.

For additional information please visit our website.www.pndengineers.com

Palmer Office

550 S Alaska St., Suite 207

Palmer, Alaska 99645

Phone: 907.707.1081

PND Engineers Canada, Inc.

Vancouver Office

Suite 2000, Oceanic Plaza

1066 West Hastings Street

Vancouver, BC Canada V6E 3X2

Phone: 604.601.5247


P N D

ARCTIC ENGINEERING

PND Engineers, Inc., founded in 1979, is a full-service consulting engineering firm that provides civil, marine, geotechnical, structural, and construction inspection services for a wide variety of projects. Our Arctic and cold regions design experience ranges from the Russian and Canadian Arctic regions, and throughout Alaska, for more than 30 years.

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