Greenfield 500/230kV switchyard with 40+ acres of development, scope included all grading, drainage system, final surfacing, fencing, just under 1,000 foundations of various types (spread footings, slab on grade and drilled piers) and oil containment liner systems with vaults
Installed (6) drilled pier foundations for new transmission line. Drilled pier size for all foundations was 6.5’ diameter x 21’ deep. Drilled pole and anchor holes through rock. Project challenges included steep terrain, long travel times for concrete, wet working conditions in rainy Oregon coastal mountains, having to pump concrete 600’ down a hill because access roads were too steep for a concrete truck.
Installed drilled pier foundations, CMPs for direct embed pole and plate anchors. Drilled pier foundation sizes 6’ to 7.5’ diameter up to 27’ deep. (41) CMPs for direct embed poles & (41) plate anchors. Project challenges included varying ground conditions consisting of solid bedrock, boulders over 5’ in diameter and loose caving sands that required temporary shoring and polymer slurry for hole stabilization.
Installed (2) drilled shafts (7’ diameter x 34’ deep & 8’ diameter x 38’ deep) and (1) CMP for direct embed pole. The subsurface conditions consisted of poorly graded sands & silts with a high ground water level requiring the use of polymer slurry for hole stabilization.
Installed (15) Transmission structure foundations comprised of a mixture of drilled pier and micropile with concrete cap. Drilled pier foundations ranged in size of 8’ to 10’ in diameter up to 38’ deep. Micropile counts from 12 to 20 per structure with concrete caps in size of 15’ to 22’ in diameter and up to 7.75’ thick. Unique project challenges included subsurface conditions of basalt bedrock with strengths over 20,000psi, round pile caps created challenges with rebar installation, concrete pile caps required thermal control plans for mass concrete pours.
Installed (1) drilled pier foundation for new transmission structure. Pier size was 6.5’ diameter x 33’ deep. Site was located next to the Willamette River which led to high groundwater and caving soils requiring the use of polymer slurry for hole stabilization.
Installed foundations, CMPs for direct embed steel poles and drilled pole holes for wood poles. Foundations included mixture of drilled piers and micropile w/ concrete cap. (9) drilled pier foundations at 6’ to 7’ diameter up to 25’ deep. (2) micropile foundations with (28) individual micropiles in each foundation with 21’x21’x6’deep square concrete cap. (12) CMPs for direct embedded steel poles, 4.5’ to 5’ diameter up to 18’ deep. (95) wood pole holes. Project challenges included work along highly traveled roadways, varying ground conditions including large boulders and caving soils, thermal control plan and procedures for mass concrete pours on micropile caps including ice being added to concrete mix to bring overall temperature down at time of placement.
Greenfield 230/115kV switchyard with 17+ acres of development. Site development scope included grading, base rock, road & sidewalk improvements, drainage improvements including large detention pond. Foundation scope included over 560 foundations consisting of a mixture of slab on grade and spread footings. Other scope included roughly 3,000ft of 12’ tall perimeter CMU wall with strip footing consisting of over 800cy. Two large oil containment shield areas with piping to pit area. Scope also includes large open excavations for getaway duct banks and feeder vault installation. Final yard surfacing consisting of switchyard surfacing rock and roadway top course. Project challenges included extremely aggressive phased project schedule that was completed two weeks ahead of time, excessive amounts of ground & surface runoff water management and highly sensitive environmental concerns.
Installed foundations, ground grid, conduit & cable trench for (5) new 115kV bays, control house, switchgears, transformers, and cap banks at the existing substation site. Foundation types included drilled piers, slab on grade and spread footings. Replace mesh and barb wire on existing fence. Oil containment system including shield areas around transformers, piping and pit with discharge into detention pond. Installation of new surfacing rock over entire substation once the project was complete. Challenges included large cable trench installed in very tight working conditions between switchgears and fence, very soft caving soils in drilled pier construction and excessive groundwater and runoff management.
Rebuild of existing Reedville Substation with conversion to GIS layout. Scope highlights include installation of foundations, ground grid, conduit, duct banks, oil containment system and final surfacing rock. Foundations included spread footings, slab on grade and specialized GIS foundations requiring extremely tight horizontal and vertical tolerances for embed placement. Project challenges included complex GIS foundation construction, excessive ground and surface runoff water and a tight worksite inside an existing energized substation.
