Geotechnical drilling and sampling in steep rocky terrain for a proposed pump storage project. Borings were accessed by custom track equipment, and downhole imaging and packer testing were completed.
Drilling, sampling and instrumentation of one 250-foot borehole from within a resort parking garage.
115 kV transmission line rebuild involving design-build micropile foundations for twelve tubular steel pole structures and three H-frame structures. Structures were located on moderately to extremely steep slopes and required helicopter-supported construction.
Pre-construction exploration services, including drilling 2 borings upstream of the existing structure near each pier.
Land and overwater drilling to investigate the option of widening a dangerous stretch of road. Challenges included working in fast, spring runoff water, with in excess of 5 feet per minute.
Geotechnical investigation drilling in advance of solar panel installation.
Overwater borings to support future railway design, with challenges including brackish water and caving borehole conditions.
Geotechnical drilling and sampling services for one 950-foot boring steep terrain and culturally protected areas. In-situ testing included downhole imaging, packer testing, hydro fracturing and hydro jacking.
Geotechnical drilling and sampling services to aid in the design phase of the proposed hydroelectric expansion project. This included drilling fifteen boreholes and a total of more than 1800 feet.
Crux’s scope of work included a foundation grouting program, rock anchor installation and micropile installation. Consolidation grouting was completed, followed by curtain grouting in the left and right dam abutments to reduce the permeability of rock formations. All grouting activities required access utilizing a 400-ton crane, adding to the challenges at this remote dam site.
Micropile foundation design and construction for replacement structures located in extremely steep, rocky terrain. Challenges included the alignment traversing challenging geotechnical conditions featuring talus slopes, and very little data available prior to construction.
Procurement and construction services to install a permanent top-down soil nail/shotcrete shoring system to stabilize an active landslide. The shoring system required 150 epoxy-coated soil nails and 5,000 square feet of permanent reinforced shotcrete facing.
100% design-build services for four micropile foundations within the Cabot Substation. Lattice tower structures were replaced with new double-circuit monopoles the relocate the 115 kV circuits.
Multiple phases of work including a downhole imaging data acquisition program, and horizontal coring through the existing concrete dam with tight tolerance specifications.
Construction of a new water treatment plant to provide for growth in surrounding counties. Geotechnical work consisted of drilling two deep core holes to provide information regarding rock mass and groundwater conditions along the proposed tunnel alignment.
Complex geotechnical conditions and ground water prevented the use of traditional excavation methods, and Crux was contracted to provide drilling services for a ground freezing approach. Crux installed 80, 3.5-inch diameter freeze pipes that extend 25 to 30 feet from within the 18-foot diameter tunnel.
Drilled shaft and driven pile design for replacement structures on either side of the Cerritos Channel in the Port of Long Beach, CA. Challenges included designing for lateral spread displacement for a tall, heavily loaded four-legged structure.
Shallow hard rock at several planned structure locations necessitated a deep foundation alternative to drilled shafts, and Crux provided concrete cap micropile foundation design-build services for 3 H-Frame structures and 52 monopoles.
Overwater geotechnical drilling and sampling services, including drilling 15 borings to depths of between 15 and 100 feet.
Drilling and sampling 13 vertical overwater borings for a proposed intake tower. Borings were accessed by barge, with water depths ranging from 25 to 135 feet, and geophysical testing and water pressure testing were completed at select locations.
Crux provided geotechnical drilling services as part of an emergency response by Caltrans. Borings were accessed by track rig; instrumentation included TDR cables, inclinometers and standpipe piezometers.
Landslide mitigation along steep slopes unsuitable for conventional drilling equipment. Crux built custom work platforms and utilized equipment capable of setting up on tundra slopes without excavation.
Two new 500 kV transmission lines built within existing corridors. Crux was contracted to provide design-build micropile foundation services for 32 lattice tower structures in mountainous terrain and National Forest Land.
Two new 500 kV transmission lines built within existing corridors. Crux was contracted to provide design-build micropile foundation services for 32 lattice tower structures in mountainous terrain and National Forest Land.
Core drilling and sampling at nine borehole locations in close proximity to residential homes. Subsurface conditions proved challenging, consisting of glacial outwash deposits, glacial tills, and highly fractured siltstones and sandstones.
Crux provided horizontal core drilling and permeation grouting for the 1,500 foot long, deep tunnel crossing alignment of the Las Vegas Wash.
Replacement of 80 deteriorating wood poles with 15 steel poles through the wetland habitat. Crux used marsh buggies and buoyant tracked pontoon carriers to install 132 total micropiles to support challenging access structures.
Upgrading an existing 115 kV line to 220 kV. Crux provided turnkey micropile foundation services for a portion of the 36-mile alignment utilizing a combination of medium-lift helicopters and Morooka rubber track carriers.
Swapping transmission line positions between two 500 kV transmission lines. Crux designed and constructed concrete cap micropile foundations at three of the four structures, where difficult access and shallow hard rock necessitated a foundation alternative to drilled shafts.
Various phases of work over multiple years, including difficult access geotechnical drilling at the top of the active slide, as well as exploration services to support the design of an earth stabilization system when the slide blocked the primary access road to Yosemite National Park. Access included track mounted drills and helicopter, and instrumentation was completed at the request of the client.
Upgrading 2.8 miles of aging infrastructure on steep slopes and other access challenges. Crux designed steel cap micropile foundations for these 8 structures, installing a total of 44 micropiles using helicopter support.
The foundation of a single-story commercial building was in need of repair due to differential settlement issues. Crux provided 100% design-build services for micropile installation as a means of settlement mitigation.
Exploratory drilling along the proposed tunnel alignment, which included deep vertical, angle, and horizontal borings in highly fractured bedrock. Six boreholes were drilled to depths of up to 800 feet.
Crux was contracted to install micropile foundations for a structure location with liquefiable soils near the Willamette River. After reviewing the available geotechnical information, lateral spread design requirements, and liquefiable soils, Crux provided multiple foundation solutions and associated risks of each type, ultimately determining that vibratory caissons would be the most cost and schedule effective.
Multiple phases of work for different clients, providing exploratory drilling for the feasibility of California’s proposed High Speed Rail project. Scopes included geotechnical drilling within a national forest, packer testing, groundwater sampling, hydraulic jacking, in-situ rock testing, pressure meter testing, and downhole imaging. Access to borings required helicopter support in multiple locations.
Crux completed more than 10,000 feet of exploratory drilling to aid in the design of the Bypass and its supporting structures. Several borings were drilled along steep canyon walls to depths up to 250 feet.
General Electric commissioned the project to prevent contaminated PCB ground water from flowing into the Hudson River in upstate New York. Crux completed upward angled borings through rock to install drain wells and piezometers.
Rock slide stabilization to assist in opening a busy roadway during the thanksgiving holiday. Equipment for installing rock bolts was craned into place due to continuing rock fall exposure and limited access.
Jackson Hole Mountain Resort planned the construction of a new tram to replace their existing 40-year-old line. Crux installed five tower foundations, requiring micropile/rock anchors with concrete caps, and two terminal foundations, consisting of large footings and highly reinforced foundations.
Drilling and sampling of one 40-foot horizontal boring from within the confined power tunnel. Packer testing was completed and a graduated marker was installed.
Geotechnical drilling and in situ testing in challenging conditions. Packer testing and VWP installs completed.
Micropile foundation design and construction for replacement structures located in steep, rugged terrain on the island of Oahu. Crux provided helicopter supported installation equipment capable of drilling under in-service overhead lines.
Various phases of work relating to construction of a third intake tunnel. Scopes included core drilling from surface land, from a specialty barge, and from within the starter tunnel, as well as installation of gravity dewatering holes and slick line tremies for grout placement.
Exploration drilling services, completing 12 exploratory vertical boreholes to 600 foot depths. Drilling was also performed from the face of the entrance to the starter tunnel, including the installation of gravity dewatering holes and the drilling of long-range, horizontal exploratory core holes to lengths of 400 feet.
Core drilling and sampling in difficult-to-access locations and challenging subsurface conditions. Borings were accessed by both track drills and helicopter, and testing and instrumentation included Standard Penetration Testing (SPT), permeability testing, pressure meter testing, suspension logging, downhole imaging, and multi-level vibrating wire piezometer (VWP) and inclinometer installations.
Crux provided 100 % design-build micropile foundation services for one structure and an adjacent 60-foot by 30-foot steel maintenance platform. Located on a 45 degree slope, helicopter transport was required for all materials, equipment and personnel.
Overwater drilling from custom barge system to determine feasibility of adding a second bridge. Challenges included substantial variations in water speeds.
Micropile design and construction services for four three-legged monopole structures located in remote areas. All four were river crossing structures, and would be too heavily loaded for direct embeds.
Multiple phases of work for various clients, with scopes including borings on the dam structure, from within the power tunnel, and for slope stability investigations. Packer testing, dye testing and downhole imaging were completed, and inclinometers, standpipe piezometers and VWPs installed. Access included track, crane and helicopter.
Variable bedrock depths and boggy ground conditions created challenges for grillage and driven pile foundations at a number of sites, and Crux was engaged to provide a micropile design-build alternative. Designs were developed for self-supporting and guyed structures, and factored in variable bedrock quality as well bog up to 25 feet.
Rock core borings from steep slopes, requiring crane access for equipment. Specific project challenges included winter weather, which created slippery conditions.
Emergency rehabilitation services due to the failure of an existing bridge abutment. Crux was contracted to design and install six micropiles at this abutment. Piles were drilled through the existing bridge deck to supplement deteriorating timber piles.
Design-build foundation services for eleven monopoles and one lattice tower structure along Segment 16DCT of the MPRP. Micropiles were selected as a deep foundation alternative at these structure locations due to high groundwater and the need to minimize the disturbance area of foundation construction activities on private lands.
Crane-supported geotechnical drilling within the bridge’s concrete piers to assist in identifying structural deficiency.
Geotechnical drilling and sampling at both abutments of an approved new bridge across the South Fork of the American River. Boring locations were accessed exclusively by helicopter and were both vertical and horizontal.
Various phases of work for multiple clients. Scopes included installing permanent horizontal casings to support future ground freezing prior to tunnel construction. Drilling was completed below the water table from within a confined tunnel shaft.
Design and installation of nine micropiles to retrofit existing foundation columns to support the higher building loads required for new retail space. Micropiles were installed from within the existing structure, and in close proximity to offices and business operations.
Design-build micropile foundation services for seven lattice towers along the alignment. These towers were located in rugged terrain not accessible to track vehicles, and required helicopter support to transport equipment, materials and crews.
Geotechnical drilling and sampling on the inspection walkway of the Emergency Spillway. Boring were accessed by crane, and VWPs were installed. Challenges included low overhead clearance.
Soil remediation and micropile installation for underpinning to mitigate structural settlement issues.
Crux served as Foundation Contractor on the project, responsible for foundation selection, design and installation Several structures were located in close proximity to a canal wall and required additional analysis for foundation design. Ultimately, 18 structures were supported on micropiles and 22 on drilled shafts.
Crux mobilized quickly, providing track and helicopter supported geotechnical drilling within the footprint of the failing bridge. Instrumentation included TDR cables, inclinometers and standpipe piezometers.
Geotechnical exploration drilling and instrumentation to assist in the design of a safer, shorter realignment.
Four replacement structures were located in close proximity to protected wetland habitat, and required a foundation alternative with a small installation footprint that could also accommodate variable subsurface conditions. Crux was selected to design and construct micropile foundations at these four structures.
Micropile design-build services for a portion NorthWestern Energy’s a new 50-mile, 100 kV transmission line. The scope of work included the installation of 74 micropiles to support 10 new H-Frame towers in rugged, high elevation terrain.
100% design-build micropile foundation services for 13 replacement poles located in remote, high-altitude terrain. Helicopter supported construction methods were used.
Crux was awarded design-build foundation work for 19 tubular steel pole structures located on steep slopes and requiring helicopter support.
Various phases of work including geotechnical drilling and sampling prior to the dam raise, as well as post construction coring and inclinometer installs. Access included helicopter and crane.
The scope of work included 6-inch diameter coring at a variety of challenging locations across the dam. Three boring locations at the left abutment were accessed exclusively by helicopter, and employed helicopter portable cranes to assist in core handling and drill movement.
Geotechnical drilling in off-road, challenging locations requiring custom Morooka carriers for equipment, material and crew transport. Slope indicators, standpipe piezometers and vibrating wire piezometers were installed as directed by the client, and packer testing was completed using single and straddle packers.
Geotechnical drilling services at remote and environmentally sensitive locations to assist in foundation design for the Sunrise Powerlink Transmission Line.
Drilling and sampling to depths up to 400 feet for design of the planned facility. Borings were located on steep slopes 35 miles from the nearest road and were accessed by helicopter.
Construction of a 57.5 mile, 138 kV transmission line. For the 360 total tower foundations, approximately 45,000 lineal feet of micropiles and 9,000 feet of guy anchors were installed using micropile installation methodology.
Challenging access geotechnical exploration, requiring a combination of track and helicopter access due to higher-than-average snow levels and muddy conditions. Additional challenges included highly fractured and disjointed rock.
Drilling and geophysical services to determine potential pipeline alignments, provide information for the tunnel system, and develop a foundation design for the diffuser.
Vertical and angle borings, both overwater from Crux’s custom barge system, and land borings on rocky, undulated terrain from specialty track-mounted equipment.
Design and construction of micropile foundations to support seven replacement structures in protected wetland habitat. Crus used helicopter supported construction methods and employed a unique closed cell cofferdam setup to successfully complete installation.
Geotechnical exploration, consisted of drilling 81 geotechnical borings and a total of 4,800 feet for new transmission tower sites.
Crux provided the design and construction for micropile foundations at 56 tower locations. These sites were located within the USFS Angeles National Forest, where road construction was prohibited and conventional track vehicle access was limited.
Design-build concrete cap micropile foundations for 37 lattice tower structures. All sites were accessed by helicopter due to the rugged and environmentally protected terrain.
Crux assisted the contractor in providing preventative maintenance, installing twenty-seven 18-foot-deep pressure relief drains in the downstream apron of the dam.
Crux provided difficult access exploratory drilling to evaluate the improvement/realignment of US Route 60. Access included helicopter and track rig, and challenges included working in close proximity to the existing roadway.
Emergency core drilling and instrumentation for a landslide under US 89. Borings accessed by helicopter; scope included downhole imaging and inclinometer installation.
Geotechnical borings and standpipe piezometer installs utilizing track mounted equipment.
Limited space core sampling and instrument installation from within the interior gallery of the dam requiring equipment to accommodate access points as little as 45×79″. A combination of vibrating wire piezometers and standpipe piezometers were then installed in each boring.
Core drilling and sampling for a feasibility study to construct a new dam and related facilities. Borings accessed by track rig; packer testing completed and VWPs installed.
Design-build services for steel cap micropile foundations on a number of segments. Challenges have included accurately orienting the foundations, working within 6 feet of existing in-service foundations, low overhead clearances due to energized lines, and environmentally sensitive work areas.
The West Fort McMurray (WFMAC) 500 kV Transmission Line Project includes over 310 miles of high voltage transmission line. Crux provided geotechnical profiling and foundation design for approximately 2,600 structures between two potential alignments.
Design-build micropile foundations for two lattice tower structures, as well as micropile foundations and rock anchors for two guyed towers in remote British Columbia.
The project involved the rebuild of a 21-mile, 69 kV ATC transmission line in Marinette County, Wisconsin. Crux was selected to design and construct steel cap micropile foundations for three tubular steel pole structures.
Crux was contracted as the EPC foundation engineer of record and responsible for execution of foundation designs and oversight of the contractor’s QC & Crux’s QA programs.
Crux was contracted as the EPC foundation engineer of record and responsible for execution of foundation designs and oversight of the contractor’s QC & Crux’s QA programs.
Micropiles as an alternative to helical piles where geotechnical investigations revealed shallow bedrock.
Soil strand anchor installation in steep terrain to secure the dam’s debris boom.
Installation of direct embedment poles, anchors drilled shafts and micropile on the Avista line, crossing the steep, rugged terrain of I-90’s Fourth of July Pass.
Micropile foundation design-build for one challenging H-Frame structure, located on extremely steep slopes and requiring helicopter access.
Micropile foundations for a three-legged pole structure located on steep terrain and requiring helicopter access.
Micropile foundations for 12 highly challenging structures requiring helicopter support.
Micropile foundations for new lattice poles and to retrofit existing structures within federally-owned lands requiring helicopter access.
Micropile foundations for two tubular steel poles on the alignment featuring challenging access and subsurface conditions.
Micropile foundation construction at select locations along the alignment requiring helicopter support due to road permitting challenges.
Installation of steel cap micropile foundations and grouted anchors to support self-supported and guyed lattice towers.
Engineering and construction of two micropile foundations for new tubular steel poles in challenging topography.
Micropile design-build for two 3-pole structures and six H-Frames as an alternative to drilled shafts to assist the project team in meeting schedule.
Micropile foundations for structures located on steep, rocky slopes and requiring helicopter support.
Micropile foundations at nine locations featuring challenging drilling conditions and/or challenging access, as well as oversight of drilled shaft foundation construction at seven locations.
Helicopter supported micropile installation to support a new 69 kV transmission line through an environmentally sensitive national park.
Geotechnical drilling and instrumentation services, completing 3,460 feet of drilling between two angle borings.
Helicopter-supported geotechnical drilling, entailing 39 borings at 31 separate locations spread across the unlined spillway and on top of a 40-foot bench on the west side of the spillway.
Crux provided limited access and overwater geotechnical exploration for the project, which entailed a geotechnical investigation to design improvements for the Black River Pump Station, located in Renton, Washington. The limited access portion of the program involved eight borings to between 50 and 70 feet from within the pump house utilizing specialized, compact equipment. Cone Penetration Test probe explorations were completed and vibrating wire piezometers were installed in select borings. The overwater scope included drilling and sampling seven borings to up to 70 feet from a custom barge system both upstream and downstream of the pump house.
The project involved exploration for a new fish passage facility at Albeni Falls Dam, which is located approximately 50 miles northeast of Spokane, WA on the Pend Oreille River. Crux’s scope included eight geotechnical borings, two of which were in highly challenging locations. These borings were located on a rock outcrop on the intake side of the dam and required a 30-ton crane to mobilize drilling equipment. The remaining borings were accessed by low-pressure rubber track carrier. Borings ranged from vertical to 20 degrees from vertical, and were drilled to between 68 and 109 feet. Packer testing was completed on 10-foot intervals in all borings, downhole imaging was performed in all borings, and vibrating wire piezometers were installed in six of the eight borings. Project challenges included working in confined spaces next to existing infrastructure, working during a time of significant snowfall, and remaining flexible when unexpected spill gate repairs required the project team to relocate the crane on short notice. All work was completed safely and on schedule.
The USACE project entailed a geotechnical investigation to assess the rock conditions and stability of the Libby Dam, a concrete gravity dam located on the Kootenai River in Northwestern Montana. Crux was contracted to provide the full drilling scope, which included nine borings ranging in depth from 25 to 188 feet on and around the structure of the dam, as well as packer testing and downhole imaging. Six of the borings were angled, and six were in hard rock while the remaining three were in soil. Project challenges included access, with multiple boring locations situated on steep slopes and requiring a winch setup and specialty drilling equipment. In addition, artesian conditions were encountered in one boring, which were mitigated by grout packer use during installation. Finally, winter weather conditions were encountered late in the project; the impacts of which were mitigated by the owner maintaining road access despite the snow.
The Saguaro Ranch Tunnel was planned as the entrance to an exclusive residential development. Crux provided geotechnical services by drilling a single 700-foot horizontal boring through the ridge transected by the tunnel. Geologic conditions consisted of a protomylonite granite that was highly sheared and altered from faulting. Crux used an HQ3 triple tube coring system and systematic drilling mud program to achieve 100% core recovery in zero RDQ rock conditions despite a large, 82-foot-wide major fault zone that was encountered within the tunnel alignment. The boring was drilled from the crown of the south portal to the north portal, resulting in continuous rock mass data from portal to portal. The borehole was used as the pilot tunnel for the rest of the work and as a “burn” hole with the blast pattern.
The United States Park Service required landslide mitigation along the primary access road within Denali National Park. The project sites were located along steep slopes unsuitable for conventional drilling equipment. In order to complete work, Crux built custom work platforms and utilized equipment capable of setting up on tundra slopes without excavation.
The project entailed road rehabilitation and wall preservation along the historic highway, Going-To-The-Sun, located in Glacier National Park. Numerous horizontal holes were drilled below road grade to determine wall integrity, backfill materials, and depth to bedrock. This was accomplished by designing a platform attached to an excavator on the road above. Crux completed this project with minimal effect on traffic and zero impact to the wall.
Gibbons Falls, located in Yellowstone National Park, contained several hundred feet of old history masonry rock walls in need of reinforcement. The project involved the drilling and installation of reinforcement through existing masonry walls, requiring the use of an air rotary system. After the borings were drilled through the 18 inch walls, a tubular steel pile was placed in the hole and grouted into the bearing unit and masonry wall. In order to develop capacities for a soil nail wall, several soil nails of varying lengths were installed using a DTH hammer system. Nails were installed through the casing and pressure grouted in the bond zone on 5 foot intervals as the casing was extracted.
Portland General Electric operates the Round butte Dam in Central Oregon and made plans to construct a selective water withdrawal structure. Crux provided geotechnical foundation investigation for the project, including drilling six HQ3 boreholes within and adjacent to the selective water withdrawal structure. The boreholes were located in water depths of up to 270 feet and were advanced 100 feet beyond the mudline. Boreholes were completed using a 30 foot barge and imaging was completed using Crux’s optical televiewer. The project was successfully completed despite challenges from the water depth and current.
The project consisted of the development of several bridge structures, roadways and housing lots for a 400-home community. General site conditions consisted of steep foothills and drainages, and surrounding lands were designated as a sensitive recreation areas. Crux provided specialty coring systems to the project, obtaining high-quality core samples in weak/weathered sandstone formations. Feature orientation was also obtained using Crux’s customized optical televiewer system, Crux Oriented Borehole Logging (COBL). Boring depths ranged from 50 to 300 feet and were located on ridge tops and in steep valleys.
Core drilling and sampling at sloped locations along the dam, requiring helicopter transport and a custom leveling platform setup.
The project entailed constructing a roadway to provide access between Juneau and the continental road system. The only access to Juneau prior to construction was by air, ferry or barge service. Crux provided geotechnical drilling services at proposed bridge sites. Boring locations were accessed using helicopter and barge support due to limited access. Geologic conditions varied from deep glacial deposits in the river banks and deltas, to shallow bedrock along river valleys. Borings were drilled to depths of 250 feet in deep alluvial deposits. Challenges to the drilling program included winter weather and short daylight hours. Crux worked closely with the Forest Service and ADOTPF to ensure that environmental protection standards were met.
Crux provided drilling and instrumentation services for the project, located in Powder River Basin, South Dakota. The scope of exploration drilling entailed the completion of 18 borings along a proposed rail alignment. Subsurface conditions consisted of sands with fines (overburden) overlying clay, shale and sandstone. Boring locations presented additional challenges, as they were located away from roadways, and on steep ridges, ravines and hillsides. Access to within 2000 feet of borings was feasible by unimproved farm roads. Beyond this, all equipment, materials and personnel were transported to sites by helicopter or track vehicle depending on site-specific conditions. The scope of instrumentation included the installation of standpipe piezometers, vibrating wire piezometers and inclinometer casings.
This project involved evaluating the feasibility of constructing two road tunnels and one transit tunnel between Riverside and Orange Counties. Crux provided geotechnical exploration drilling, completing a series of boreholes that ranged in depth from 800 to 1,300 feet. Drilling was completed within the Cleveland National Forest, restricting road access and requiring the use of a helicopter portable drill equipment. Crux completed hydraulic conductivity testing in each borehole at the completion of drilling utilizing wireline pneumatic and fluid packer systems. Test intervals ranged from 10 feet to 20 feet. Crux also provided the contractor with vibrating wire transducer and observation well installation.
Crux provided both land and overwater drilling for the Fort Peck Field Study located at the Fort Peck Dam near Glasgow, Montana. Land drilling included ten borings to approximately 150 feet in depth. Pressure meter testing was completed and vibrating wire piezometers were installed in four select borings. The overwater scope of work included ten vertical borings to approximately 50 feet in depth in the plunge pool below the spillway. CPT testing was completed as directed by the client. Overwater drilling was completed utilizing Crux’s custom 40-foot barge system.
The King County Wastewater Treatment Division commissioned an exploration project to investigate upgrading the wastewater conveyance system in the Bellevue, Washington area. Crux provided core drilling and sampling at nine borehole locations in close proximity to residential homes. Subsurface conditions proved challenging, consisting of glacial outwash deposits, glacial tills, and highly fractured siltstones and sandstones. Several borings consisted of silts, sands and gravels near the surface, and transitioned to dense gravels and cobbles as depths increased. Crux drilled a total of approximately 3,000 feet, including one 730-foot borehole drilled at 20 degrees from vertical. Vibrating wire piezometers were installed in select holes, and Crux provided packer testing and downhole imaging services on as as-needed basis.
A geotechnical investigation was commissioned for the proposed upgrade of the Montana State Highway 82 Bridge. The bridge crosses Flathead River, just north of Flathead Lake in northwest Montana. Crux provided a 30-foot barge system to complete three overwater geotechnical borings. Water depth was approximately 40 feet and borings were drilled to depths of up to 260 feet. A rough terrain crane was utilized to place the barge into Flathead Lake, and support equipment towed it into place above boring locations. Crux completed all drilling successfully, and supported CPT testing as directed by the client.
The San Clemente Dam was an arch dam on the Carmel River about 15 mi southeast of Monterey. After years of planning and deconstruction, the dam was officially removed in 2015, making it the largest dam removal project to-date in California. During the deconstruction phase, Crux provided geotechnical exploration drilling and sampling for the project, entailing six rock core borings and four soft sediment borings for a total 1,515 feet of drilling. Borings were accessed by specialized track mounted equipment, and VWP’s and inclinometers were installed at select locations.
The Allison Creek Hydro Project entailed a proposed new hydroelectric on the south side of Port Valdez, AK. If approved, the project would significantly increase the reliability of the Copper Valley Electric Association’s transmission system and generating plants. Crux’s scope of work included drilling and sampling three vertical boreholes and two angled boreholes. All three vertical borings were drilled to 100 feet and one 1.5” piezometer standpipe was installed. One angled boring was drilled at 30 degrees to 150 feet, and the other as drilled at 10 degrees to 670 feet. All five borings were located in challenging terrain and required helicopter support to place equipment and materials.
Difficult access exploration drilling, requiring winching a specialty track 200 feet down a steep, rugged embankment.
Grant PUD commissioned an investigation at Wanapum Dam in central Washington after a horizontal crack was discovered in a pillar supporting the dam’s spillway. Diving operations confirmed the issue and Grant PUD lowered the reservoir to an elevation below the crack during investigations. An exploration plan was developed to evaluate the overall condition of the pillar and determine the extent of the fracture. Crux’s scope of work included drilling and sampling at challenging access borehole locations, requiring continuous support of a crane to set all equipment and personnel onto the spillway. Upon completion of drilling each hole to final depth, water pressure testing was performed and back flow pressures were measured with the use of pneumatic packers and pressure gauges. Acoustic and optical surveying was also required for each hole with the use of a down-the-hole televiewer survey tool (COBL).
The Denver Water Department commissioned a geotechnical investigation for the future expansion of Gross Reservoir near Boulder, Colorado. Crux was selected to provide drilling and sampling services for four vertical and two angled boreholes in granite subsurface conditions. The project was located on United States Forest Service (USFS) property and was subject to various environmental regulations and restrictions. In an effort to minimize impact to the surrounding areas, crews completed two boreholes at each of the three locations using track-mounted equipment. Road access to boreholes was limited and to alleviate access constraints, the USFS permitted the removal of 40 trees near the project site. All required water was brought in using a 1,800-gallon water truck and pumped 2,000 feet to each drill site using hydraulic pumps. Crux performed downhole imaging using Crux Oriented Borehole Logging (COBL), and all boreholes were successfully completed while following client and USFS regulations.
A Southern California development commissioned a geotechnical drilling and instrumentation program to monitor slope movement adjacent to existing infrastructure. Crux drilled 12 borings using a combination of track vehicle and crane support to accommodate the sloped, urban environment. Borings ranged in depth from 50 to 150 feet for a total of 1350 feet of drilling. Inclinometers and standpipe piezometers were installed in 6 holes each. Specific project challenges included adhering to owner requirements so as not to impact existing operations. All track and crane work was completed outside business hours, and boring locations were selected to be clear of sensitive operational areas.
As part of a continued Caltrans emergency response effort to mud and landslides causing numerous highway closures in Big Sur, CA, Crux provided geotechnical drilling and instrumentation. Nine boring locations were accessed by track rig and drilled to depths between 60 and 160 feet. Instrumentation included a combination of TDR cables, inclinometers and standpipe piezometers.
Crux provided drilling services before and after the 117-foot San Vicente Dam raise, and returned to provide inclinometer installation. The scope of work included drilling two 125-foot HQ3 borings from the crest of the dam. Both borings allowed for drive up access. An inclinometer was installed in one boring and the other was sealed at the surface for future use. In a deviation from Crux’s typical installation of inclinometer casing only, the client requested permanent equipment that would allow them to retrieve real-time data from offsite. Crux installed all inclinometer equipment, as well as all surface conduit and electronics between the borehole collar and the dam control house.
The project involved a 3,000-foot-long, 9.8 foot diameter sewer tunnel crossing Brushy Creek in Round Rock, TX. Crux provided drilling services to stabilize the tunnel alignment prior to excavation using a new stabilization method. The drilling and grouting program entailed drilling horizontally along the tunnel alignment with continuous core drilling using a wire line coring system. Techniques were developed to control the deviation of the drill string and, along with down-hole surveys, provided continuous core while maintaining a set elevation and target zone.
The project included the addition of a single-circuit 230 kV line, and the relocation of an existing 138 kV and 69 kV line onto new poles. Foundations were designed and constructed using a radial array of battered micropiles in combination with an all-bolted steel pile cap. Two micropiles were tested at each foundation site to confirm load capacities. Micropiles were selected as the preferred foundation type due to the difficulty of road construction in the area; this type of foundation allowed for each footing to be constructed using solely helicopter support.
The Theme Stream Bridge, located in Spokane’s Riverfront Park, was originally constructed for the 1974 World’s Fair. The 300-foot-long concrete structure has since deteriorated and required upgrading. Crux was contracted to design and install a total of eight micropiles at the footing locations of the replacement bridge. The original structure was built quickly to prepare for the Fair, which led to a number of unique challenges during construction. As-built drawings were unavailable or inaccurate, and unforeseen subsurface obstructions were encountered during drilling. Crux worked closely with the contractor and owner to ensure that all eight piles were successfully installed and tested to capacity.
To improve communications in the area, Verizon commissioned the installation of the Flagstaff Mountain Communication Tower in Northport, Washington, and the Cabbage Hill Communication Tower in Pendleton, Oregon. Crux was contracted to install approximately 50 rock anchors at each site to tie down the towers. All anchors were successfully proof tested and locked off to the owner’s specifications.
The project entailed a penstock repair at the Montrose Hydroelectric Facility, north of Vancouver, British Columbia, after a naturally occurring rockslide caused significant damage. The 5-km penstock supplies water to the 88-MW facility, which was off line for several months during repairs. Crux was selected to install rock bolt anchors and slope mesh above the penstock as a means of slope stabilization. 41 anchors were installed and successfully proof tested to 42 kips each. All-terrain man-lifts and forklifts were utilized to assist with the placement of drilling equipment and materials.
The Interior to Lower Mainland Transmission Line Project is a new, 155-mile alignment located in British Columbia, Canada. The project was intended to expand the capacity of the transmission system providing power to the Lower Mainland and Vancouver Island, and was completed in 2015. One structure on the alignment – lattice tower structure 3740 – was located in steep, rugged terrain and was inaccessible by road. Crux was selected to provide 100% micropile foundation design-build services at this location, transporting all personnel, equipment and materials to the site by helicopter. As no site-specific geotechnical information was available prior to foundation installation, Crux completed standard penetration tests (SPTs) to characterize the site during the drilling of the first micropile. This information determined the micropile quantity and depth required for this particular structure. A pre-fabricated steel pile cap was installed at each tower leg prior to tower setting.
ITC’s Lore to Turkey River Transmission Line upgrade involved the replacement of 108 structures across the 28-mile alignment. Crux was selected to provide micropile foundation design-build for 12 H-frame structures and one pole foundation (27 footings total). These structures were located in challenging access areas, involving steep, muddy slopes. Crux utilized flatbed Morooka carriers to transport drills to these locations, and customized Morooka-mounted cranes to set the drills onsite and assist with additional material/equipment handling. In total, 2,100 linear feet were drilled and 81 micropiles installed. One pile was successfully proof tested at each structure location, and steel pile caps were installed to prepare for structure setting. In addition to soft, unstable ground conditions, project challenges included limited onsite communication abilities due to rolling hills and remote locations.
The project was located in the Lake Mead National Recreation Area, and consisted of the partial relocation of a 230 kV transmission line. Crux provided engineering design and construction of four steel cap micropile foundations for tubular steel pole structures. Construction was supported by helicopter and required zero visible dust while drilling due to naturally occurring asbestos.
Avista Corp. commissioned the rehabilitation of Nine Mile Dam, located in Spokane, WA. Tailrace work included the forming and placement of five new pier extensions and a new tailrace deck allowing for operator access. Crux was selected to drill and install new post-tensioned anchors through the existing concrete and into bedrock. Drilling through the existing concrete brought with it the risk of potential water flow; a rick Crux identified and developed a mitigation plan for, should flowing water have been encountered at rock contact. Crane access was required for all sites, and two anchors were successfully installed at each pier.
An unstable rock slope was discovered at the north abutment of the Post Falls Dam south channel. Crux’s scope consisted of drilling and installing eight galvanized rock dowels and four inclined angle drains through competent rock. The rock dowel solution included installation of approximately 2,700 square feet of double twist mesh. Drain holes were drilled at five degrees above horizontal and completed with three-inch slotted drain pipe. Access was challenging, and all drilling was performed from a work platform suspended by crane. All other work on the dam was temporarily suspended due to safety concerns regarding the unstable slope, and Crux was tasked with developing a design and construction approach that could be employed immediately. Additional project challenges included working in cold, snowy weather conditions.
The project included the reconstruction of the Sinnema Quaale Upper Revetment on the Snoqualmie River near Duvall, WA. The major scope of work required construction of a 750-foot long shoring wall to stabilize the slope along the riverbank in order to protect the upslope highway from future landslides and erosion. Crux provided engineering, procurement and construction services to construct the H-Pile/Sheet Pile/Tieback Shoring System. Crux’s scope was to design, install and test 119 permanent ground anchors for the shoring system. The variable geotechnical conditions provided continuous challenges during construction, as the unstable slope continued to slide and shift, requiring ongoing emergency shoring measures to arrest the slope and allow construction efforts to resume.
Crux was contracted to provide specialty foundation design and construction for two failing wood poles located on private farm land in Northern California. Attempts to install a drilled shaft was unsuccessful due to extremely soft soils, and PG&E specified steel cap micropiles as an alternative. A total 14 piles were installed deeper than expected, requiring 85 feet to find a competent geotechnical unit. Both foundations were installed under live overhead lines, and a Lineman Inspector was onsite to allow for a clearance of just 32 feet above ground level. Access to the property required partial use of an adjacent roadway, necessitating traffic control. All work was safely completed on schedule.
Badger Coulee is a new 180-mile, 345 kV transmission line in southern Wisconsin jointly developed by American Transmission Co. and Xcel Energy. The majority of the structures on the alignment allowed for conventional access, but 17 tubular steel poles required helicopter access for all equipment, materials and personnel, requiring an alternative foundation type which could accommodate these restrictions. Crux was selected to provide micropile foundation construction at these locations, installing between 6 and 16 piles per foundation in arrays ranging from 6 to 7.5 feet in diameter. Phase 1 occurred during the winter months, involving challenges associated with low temperatures, snow and wind. Phase 2 occurred during the summer months, involving challenges associated with thick mud and soft ground conditions. Both phases encountered challenging drilling conditions, with overburden and weathered rock requiring casing to be extended 20 to 50 feet below ground level. Additionally, high clays and silts in the sandstone bonding unit necessitated bond zones in excess of 30 feet.
Structure 279 on an MJ Electric Wisconsin alignment was located on an island, requiring innovative access methods and an alternative foundation design to the drilled shafts being employed on remaining structures. Crux provided micropile foundation design-build services for this H-Frame structure, accessing the structure site by barge and a customized track mounted drill rig. The materials and installation equipment utilized were lightweight and ideal for transportation by barge. Due to the location and access methods, pouring concrete to form a pile cap proved challenging. Instead, Crux introduced a unique steel pile cap alternative that could be manufactured offsite and transported to the structure location in one piece. The foundation was installed in challenging conditions featuring approximately 8 feet of loose soils over 5 feet of clay and on top of weathered bedrock.
Idaho Power’s Brownlee Dam is a hydroelectric earth fill embankment dam on the Snake River, along the Idaho-Oregon border. Crux was contracted to complete geotechnical drilling and testing on the spillway of the dam to examine the spillway to rock interface. 13 geotechnical borings were drilled vertically to either 10 or 40 feet utilizing a track mounted geotechnical drill. Additionally, two borings were drilled to 40-foot depths for proof testing. All-thread bar was installed and grouted the full 40-foot depth in the first hole, and to 30 feet in the second. This allowed for the two proof tests to effectively test strengths at different depths. Equipment and materials were mobilized onto the spillway by crane. Challenges included working on the steep spillway slope, which was covered in algae and made traction incredibly difficult. Crux mitigated this by retrofitting the drill with rubber tracks as opposed to the standard steel, and outfitting the crew with traction cleats.
Crux was contracted to drill and sample one near-horizontal boring to a depth of 1,300 feet as part of an EPA-commissioned geotechnical investigation. Drilling took place through weathered and fractured material with the end goal of collecting continuous rock core, and subsequent rock strength and fracture data. Challenges included a high elevation drill site accessed by a steep, narrow, unimproved roadway, requiring equipment which could accommodate both the challenging access as well as the required drilling depths. Crux employed a Morooka track carrier to transport the drill and telehandler forklifts to assist with materials onsite. Crux successfully provided the client with continuous samples over the full depth of the hole. Drilling stayed within the client’s allowable deviation tolerance, reaching within 8 feet of the target for a total deviation of less than 1 degrees over the 1,300 feet.