Mature trenchless method has a history in pipe replacement
As municipalities continue to grapple with aging infrastructure, they need to be aware of effective and efficient methods of replacing failing, outdated or undersized sewer and water line. Here, W&WD Managing Editor Elisabeth Lisican discusses the viability of pipe bursting as an adequate trenchless technology with Matt Timberlake, vice president of Ted Berry Co. Inc.
Elisabeth Lisican: How is pipe bursting an economic pipe replacement method?
Matt Timberlake: Pipe bursting is especially effective if the existing pipe has inadequate capacity and has substantial structural defects preventing other trenchless methods from being utilized. This method can be used advantageously to reduce damage to pavement and disruptions to traffic, hence reducing the social costs associated with pipeline replacement, as well as providing a significantly smaller environmental footprint. The pipe bursting method results in an existing pipe being replaced with a new factory-manufactured pipe in the same location that will have the same or larger inner diameter. This method is considered a favorable alternative to other trenchless rehabilitation methods, such as cured-in-place pipe, which relines an existing pipe with a liner that conforms to the profile of the existing pipe inner diameter while reducing it by the thickness of the lining material installed. Pipe bursting is often used in comparative analysis with other rehabilitation methods; however, it should be considered a replacement method, as a new pipe is installed.
Lisican: What are the different types of pipe bursting systems?
Timberlake: Pipe bursting systems are primarily classified into two classes: 1. pneumatic pipe bursting and 2. static pipe bursting, which is based on the type of bursting tool used. The basic difference between these systems is in the source of energy and the method of breaking the old pipe, and some consequent differences in operation. The selection of a specific replacement method depends on geotechnical conditions, degree of upsizing required, type of new pipe, construction of the existing pipeline, depth and profile of the existing pipeline, availability of experienced contractors and equipment, risk assessment and other possible site-specific issues.
Lisican: What specific types of applications in particular would lend themselves well to trenchless methods such as pipe bursting?
Timberlake: The advantages are especially notable in pipeline replacement for deeper line, where the greater depth of line increases the cost of open-cut replacement through extra excavation, shoring and dewatering, etc., while it has minimal effect on the cost of pipe bursting. Additionally, as the underground utility network becomes even more congested through the advancement and expansion of services like gas, high-speed cable and fiber optic, the need to preserve space underground for future growth becomes a necessity.
Lisican: In an industry where cost savings are especially critical, how do you make the business case for pipe bursting and other trenchless methods?
Timberlake: Pipe bursting is a mature technology with a proven history for trenchless replacement of existing pipe. As the lifecycle of the existing underground infrastructure expires, and failures occur at an alarming rate, pipe bursting is one of the methods that will be used to effectively provide long-term service for critical utilities that are essential to public life and health. As the only trenchless method that can increase the size of the existing pipe, pipe bursting is well suited to a growing need for additional capacity, whether it be in the sewer, water, gas or other utility market sectors. With an increased public awareness and limited funding available for critical infrastructure rehabilitation, it is necessary that we utilize methods that offer reduced social disruption and reduced environmental impact, and prepare for future capacity needs while leveraging technology that provides a better product both short and long term.