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PROJECTS:  INFRASTRUCTURE TECHNOLOGIES

Specialty Civil Construction

With a substantial history of large scale excavation and earthwork, Forgen has developed specialty civil construction capabilities to provide innovative solutions for our clients’ clean construction challenges. We selectively pursue specialty civil and geotechnical construction projects that are ideally suited to our in-house resources and expertise. We seek opportunities that competitively add value, using our own experienced staff and fleet of equipment. Typically, this includes large scale excavation, shoring, grading and/or trenching, or projects with an environmentally sensitive component.

    • Deep excavations
    • DMMAs/DSMAs
    • Earthwork and Grading
    • Landfill expansion and closure/capping construction
    • Stormwater management
    • Stream/river diversion and restoration
    • Structural earth retention systems
    • Water management and control – STAs, canals, infiltration galleries, retention basins, reservoirs

SANTA ANA RIVER LEVEE IMPROVEMENT
Santa Ana, California

  • Installation of approximately 800 20 ft and 24 ft long
    post-tensioned SuperRockBolts™
  • Road protection with trench plates and k-rail
  • Repaved the road and sealed slurry before reopening

North Star, the prime 8(a) contractor, selected two primary subcontractors, Forgen and Landslide Solutions, Inc. (LSI), to assist with stabilizing a failing rock slope near Eastman Lake. Both subcontractors were selected based on extensive experience and excellent reputations.

The U.S. Army Corps of Engineers made a rock cut during the road construction for the Eastman Lake park headquarters access road in the early 1970s. Although the road cut is nearly continuous in this area, episodic rock failures had occurred since its construction. The rock cut slope consisted of 980 lf of near vertical weathered schist and sandstone, from which some wedges had fallen and blocked the roadway below. The rock cut was broken into lower and upper vertical sections. The lower section consisted of the bottom of the entire 980 lf face. The upper section consisted of an upper 280 lf crown in the cliff face. A bench containing a v-ditch separated the upper and lower sections. The average height of the sections was 35 ft. The total estimated surface area of both sections was 51,000 sf.

The North Star team conducted mechanical scaling, requiring an equipment combination consisting of a long reach excavator and a traditional excavator with a scaling blanket attachment. Following the mechanical scaling process North Star hand scaled the slope to insure removal of any loose rock material. Approximately 800 20 ft and 24 ft long post-tensioned SuperRockBolts™ were then installed across the rock face and were used to anchor high strength steel rock fall mesh. The road below was protected against damage by placing trench plates and k-rail to catch potential rock fall debris. In addition the road was repaved and slurry sealed before reopening to the public for the July 4th weekend.

SFWMD RS-G341 CONVEYANCE IMPROVEMENTS
SEGMENTS 1&2
Belle Glade, Florida

  • Dewatering of canal and farm ditches to elevation 0.0 using 24 in hydraulic pumps
  • Blasting of 12,700 lf of 40 ft wide canal 
  • Excavation of 12,700 lf of canal to elevation -2.0
  • Placement of muck on rock core spoil pile embankment to minimum elevation of 15.5
  • Installation of drainage culverts

Forgen was contracted to provide services for the RS-G341 Conveyance Improvements project for the South Florida Water Management District (SFWMD) in Belle Glade, Florida. Dewatering of the project area was completed after the installation of cofferdams to block off water from the existing Bolles Canal to the east and west of the project. Four cofferdams were constructed and dewatering was completed in three sections using 12 to 24 in diameter hydraulic pumps. Following dewatering of each section, muck within the proposed excavation and spoil pile embankment footprint was removed and stockpiled outside the proposed embankment footprint. Muck was removed to expose a limestone rock layer beneath the muck. Once muck was removed, the proposed canal excavation cross section was drilled and blasted to break up the limestone rock layer within the proposed footprint of the new canal.

Following blasting, the canal was excavated using a Caterpillar 374 excavator to an elevation -2.0 (depth of approximately 8 ft from surface of rock layer). Excavated material was used to construct the rock core for the spoil pile embankment adjacent to the canal for flood control, and rock material was placed in lifts using a Caterpillar D6 bulldozer. Dewatering during the excavation of the canal was maintained at an elevation 0.0. Using smaller Caterpillar 330 size excavators and D6 dozers, stockpiled muck was placed and compacted atop the rock core to increase the spoil pile embankment elevation. The minimum elevation of the completed spoil pile embankment was elevation 15.5. Farm ditches were blasted and excavated in a similar manner, with rock excavated from the farm ditches used to construct adjacent farm roads. Drainage culverts were installed at the ends of the farm ditches to facilitate the movement of irrigation water to and from fields adjacent to the project.