Trinity River Vision Project – Part 7: Gateway Park Site E Sanitary Sewer Relocation

Project Details

Open Shield Pipe Jacking

  • 48″ steel casing for 16″ gravity sewer
  • 325′ drive beneath Interstate 30


  • HDPE siphons (12″ and 18″)
  • Two 740′ bores beneath Trinity River

Geotechnical Conditions

  • Lean clay and clayey sand
  • Limestone bedrock


  • Flat grade (0.20%) for IH-30 crossing
  • Mixed face soil conditions

Project Overview

As a trenchless subconsultant to Kimley-Horn, Bennett Trenchless Engineers provided design assistance for two trenchless crossings for utility relocations associated with the Trinity River Vision Project.  The Part 7 – Gateway Site E Project involved the relocation and replacement of 2,200 feet of existing sanitary sewer, including major crossings of the existing Trinity River and Interstate Highway 30 (IH-30).  The project used a mixed-bag of trenchless construction methods including HDD, open-shield pipejacking, and auger boring.  BTE selected HDD for construction of the twin, inverted siphon crossings of the Trinity River, and open-shield pipejacking for the gravity sewer crossing of IH-30.  Challenges on the project were varied and included mixed conditions of soils overlying limestone bedrock; work area and site access constraints; and coordination with USACE regarding environmental risk mitigation for hydrofracture.