Microtunneling Bradshaw Company Maryland TUNNELING SPECIALISTS SINCE 1963      


"Recycle Age Tunneling"

Understanding Pipe Rehabilitation

In this age of increasing urban congestion, where failing sewers are buried beneath busy roadways and layers of utilities, owners are more frequently turning to trenchless pipe rehabilitation as a cost-effective means of fixing rather than replacing their sewers. We call it “Recycle Age Tunneling” because pipe rehabilitation can dramatically increase the useful life of a sewer, provided that the sewer has retained at least some of its original structural integrity.  Pipe rehabilitation (slip-lining or re-lining) using modern fiberglass or plastic materials creates a sewer pipe resistant to deterioration from hydrogen sulfide gas and other chemicals that commonly damage existing sewers.  And even though rehabbed sewer pipe have smaller IDs, the materials used have superior coefficients of friction that can preserve and often improve flow rates.  Pipe rehabilitation can be performed from relatively small work areas at the surface and even through existing manholes.  This greatly reduces disruption to the public and traffic particularly when compared to trenched pipe replacement.  Finally, the cost of trenchless pipe rehabilitation can be significantly less than a new pipe installation if additional pipe capacity is not required. 

  • Can your sewer pipe be rehabilitated?
  • What are the benefits?
  • What are the risks?
Pipe Rehabilitation Technologies

At Bradshaw Construction, pipe rehabilitation is accomplished using either slip-lined or spiral wound technologies.  Slip-lining is the process in which a smaller fixed diameter pipe is used to sleeve a failing pipe.  After the new sleeve liner is installed it is grouted in place.  By using fiberglass reinforced polymer mortar pipe, the liner can be cast into virtually any cross section to fit a limitless variety of pipe shapes, including round, horseshoe, square, etc.  Slip-lining requires an open access shaft long enough to insert the liner pipe into the existing sewer pipe.  In situations where such access shafts are not possible, spiral wound technology is an effective solution.  Spiral wound technology is an alternate method of pipe rehabilitation in which a steel-reinforced plastic profile (3”-6” wide) is either wound along the existing pipeline or wound in the manhole and pushed into the existing pipeline.  The profile is continuously fed through a surface access point such as a manhole and wound using a custom winding machine designed to the desired cross section geometry.  Like the slip-lined option, the spiral wound technology can rehabilitate pipe of any shape or size.  It is then either expanded or grouted in place.  If grouted in place, it can even incorporate steel reinforcing within the grout to create a structural pipe within the failing pipe.

  • What size and how many pits are required?
  • Can you rehab sewers with live flow?
  • What is required for a structural rehab?
Pipe Rehabilitation Solutions

Our experience with rehabilitating failing sewer pipe stretches back over 17 years.  In 1995, we undertook our first slip-lining project using HOBAS pipe.  In the time since, we have relined over 10,000’ of sewer in sizes ranging from 15” to 96”.  We have completed several emergency pipe rehabilitation projects for the City of Baltimore by slip-lining collapsed sewers with 36” and 42” HOBAS fiberglass pipe and grouting them in place.  These projects required difficult shaft and tunnel excavation of the collapsed sewer sections then cleaning of the sewer line prior to slip-lining.  We are a certified Sekisui SPR installer for the mid-Atlantic and Southeastern US.  Our experience has been capped with a 6,000’+ undertaking at the Dundalk Marine Terminal in Baltimore, MD.  The primary purpose of the project was to seal out contaminated ground water infiltration through the existing sewer pipe joints.  To do this, we relined 24” to 96” RCP pipe using Sekisui SPR and Expanda technology.  The new sewer profiles have all been installed and grouted or expanded in place.  Infiltration reduction goals were achieved even though manholes were not rehabbed. 

  • Slip-line or Spiral wound, which is appropriate?
  • How much experience does your installer need?
  • How much time does it take?

To answer these questions and any others about your next project, please  contact us.

   Click here for a listing of our Pipe Rehabilitation Projects