Aerial view of a trenchless construction site with two excavation pits, equipment, and vehicles along a roadway.

Case Studies

Des Moines WRA Ingersoll Run Outlet Sewer Segment 1

Project Details

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Project Name
Des Moines WRA Ingersoll Run Outlet Sewer Segment 1
General Contractor
Minger Construction Co., Inc. - Jordan, MN
Location
Des Moines, IA
Ground Conditions
Wet clay
Akkerman Equipment
4800 GBM System, P250D Power Pack, PCH 44
Pipe
42-in Hobas™ FRP - Jacking Pipe
Total Length/Hard Rock Section
3 x 60-LF crossings with minimal clearance

Project Overview

These (3) – 0% grade crossings were installed by Minger Construction in just two weeks leaving a mere 7-inches of horizontal clearances between each of the 42-in pipes. Although short in length, pilot tube microtunneling was selected to directly install the final product pipe underneath an existing box culvert so that flow would not be disturbed.

Challenges

  • Required three 60-LF trenchless crossings with only 7 inches of horizontal clearance between each 42-in pipe
  • Crossings were installed at 0% grade, demanding extreme precision
  • Installation took place beneath an existing box culvert, requiring careful planning to avoid disrupting flow
  • Wet clay conditions added complexity to line control and stability during installation

Solution

  • Minger Construction used the Akkerman 4800 GBM System with a P250D Power Pack and PCH 44 for guided pilot tube microtunneling
  • Directly installed final product pipe to avoid a second pass, improving efficiency and reducing disturbance risk
  • Pilot tube technology enabled highly accurate line and grade control despite wet clay conditions and tight spacing
  • Completed all three crossings in just two weeks, with no disruption to the existing culvert infrastructure

Outcome

  • Successfully installed all three 60-LF 42-in. crossings with only 7 inches of separation between pipes
  • Maintained precise 0% grade alignment under tight spatial constraints and challenging wet clay conditions
  • Completed trenchless installation in just two weeks, minimizing impact to surrounding infrastructure
  • Prevented disruption to existing box culvert flow through accurate, single-pass pilot tube microtunneling
  • Demonstrated the effectiveness of Akkerman’s guided boring technology in precision-critical urban sewer applications

Photo Gallery

Aerial view of a trenchless construction site with two excavation pits, equipment, and vehicles along a roadway. Pipe jacking equipment positioned in a shored excavation pit with concrete pipe sections ready for installation.