Naval Facilities Engineering Command - Ford Island

• LocationAiea, Hawaii
• Timeline2017-2018
• Construction
  MethodsHorizontal Directional Drilling
  Percussion Hammer
  Steel Casing Pullback Installation
  Pulled PVC Plastic Liner

Scope

Michels Trenchless, Inc. performed Horizontal Directional Drilling (HDD) operations to replace 3,500 linear feet (lf) of deteriorated 24-inch cast iron waterline with new 24-inch fusible PVC pipe spanning across the southwest portion of Pearl Harbor.

Special precautions were implemented to not disturb the runway that was parallel to the pipe lay-down area, as it was of historic value having sustained heavy gunfire from Japanese Zeros during the surprise attack on Pearl Harbor. Ordinance became embedded into the asphalt runway and is now being preserved.

Due to expectant variable geological conditions consisting of low blow count material mixed with cobble and volcanic tuff, the engineered drawings called for installation of a larger diameter steel protective casing (30" O.D. 0.500" wt) for the entire length of the crossing to house the 24-inch PVC liner as the plastic pipe was not expected to withstand impacts caused by unfavorable soil conditions.

Pullback of the steel casing pipe required an orchestrated placement of heavy iron elevating the 162 pound-per-foot steel pipe up to 15 feet in the air, using cradles and rollers positioned along the radius configuration necessary for maintaining integrity of the steel pipe and providing smooth transition into the opened hole.

Additional assist equipment was also staged along the pullback alignment to support the pipe on rollers around the curve. This maintained stability on the supports while negotiating the tight radius to mitigate buckling of the casing all while conforming to the highly restricted right of way.

Accomplishments:

• Michels Trenchless was presented with the 2020 Construction Risk Partners Build America Award for Best New Utility Infrastructure by the Associated General Contractors of America. The award program honors some of the toughest, most innovative and successful projects completed in 2019.
• The crossing is the final link in the U.S. Navy's Joint Base Pearl Harbor-Hickam regional water distribution pipeline system, delivering updated water service to all base facilities.