Trenchless Technology

TrenchlessTechnologyAn Alternative Solution – Trenchless technology is the generic term for processes of construction, rehabilitation and replacement of buried pipelines and utilities via minimally intrusive means, resulting in substantially lessened surface and subsurface disruptions. These types of technologies are usually used in areas where cutting of traditional trenches for pipe-laying is not practical, such as in highly urbanized centers.

Other applications where trenchless technology is utilized regardless of congestion are crossings of highways and railroads, to traverse water bodies such as rivers, or to bypass environmentally sensitive zones. When undergoing trenchless installation, the joints of a pipe are typically either under compression, as in jacking applications, or under tension, as in pull-in applications such as directional drilling. The effectiveness of trenchless pipe products are therefore heavily related to joint types.

Solutions with Steel Pipe – Various types of jacking applications include microtunneling, auger boring, and pipe ramming, amongst others. Steel pipes installed by jacking methods include the Permalok® T-5 or T-7 joints, or field welded traditional steel casing pipe. The jacking of steel pipes results in high positional accuracy and low disturbance of the soil in the embedment area so that optimum bedding is achieved and any type of surface disturbance such as heave or settlement is avoided.

Since the compressive strength of steel is the same as its tensile strength, steel cylinders are ideal for withstanding high jacking forces. For pull-in applications where pipe joints are under tension, trenchless technology provides opportunities for the direct installation of steel pipelines with restrained joints, thereby also reducing possibilities of leaks and joint misalignments and settlements.

The Steel Pipe Advantage – For the most challenging horizontal directional drilling (HDD) projects, steel pipe is selected for its ability to be fully engineered, from selection of wall thicknesses accurate to a thousandth of an inch, availability of various restrained joints such as single or double lap welded or butt-welded joints, to a wide array of flexible bonded dielectric coatings and linings. The distance to which a steel pipeline can be directionally drilled is limited only by the available installation equipment. The same cannot be said of alternate materials such as thermoplastics.

Permalok® steel casing pipe is used for double and single pass systems using microtunneling, while shorter highway and railroad crossings may be completed using pipe ramming or auger boring. If specified, Northwest Pipe Company’s beveled-by-square edge joints can also be supplied for traditional butt-welded casing pipe use. Our AWWA C200 steel water pipes are regularly specified for challenging river crossing and other HDD applications. Through our wide array of products, we continue to contribute to the growth of trenchless technology nationwide.