A guide to trenchless technology
Imagine if you had to close or divert roads, highways, rail lines, utility lines or bike paths every time a pipeline or culvert system needed to be installed. Trenchless construction is the solution that allows for safe installation of storm drains and culvert systems with minimal disruption to the public or the environment.
Joints provide large bearing surfaces to transfer jacking loads from one precast section to the next, RCP and RCB can withstand large jacking forces. This makes it an ideal pipe for trenchless installations.
There are three primary methods of trenchless installations; pipe jacking, tunneling (both micro and large tunnel) and jack and bore.
Pipe jacking
Like micro-tunneling, but usually requires workers to guide the cutter head and bring back spoils with a conveyor system or even by hand. In both cases, powerful hydraulic jacks are used to push specially designed reinforced concrete pipe through the ground behind a cutter head or shield at the same time the tunnel soil is being excavated. A range of mechanical and remote-control excavation systems are available from many manufacturers and pipe jacking companies.
Micro-tunneling
Defined as a remote controlled and guided pipe jacking technique that does not require tunnel entry by any workers. It usually provides an excavation face that is continuously supported. With this type of installation and equipment the pipe is remotely jacked, with exact guidance, and the ability to control the support of the excavation face. Having a manufactured pipe with a smooth and continuous outside diameter allows the installation to be easier.
Jack and bore
Defined as using an auger boring technique that uses a steel auger attached to a cutting head that is rotated to cut through the soil as a steel pipe is jacked through the soil. As the cutting head advances, it excavates the soil while the flights of the auger move the soil back to the pit with no worker access needed within the pipe.
Pipe choice for pipe jacking projects stems from a combination of durability and sustainability; for example, reinforced concrete pipe that can withstand the thrust or axial forces during installation. If a pipe material is not specified by the engineer, a cost comparison based on installation speed and risk, material availability at the project location, and life cycle assessment of the pipe become principal issues; in other words, a thorough review on pipe suitability should be done.
The benefit of our jointed pipe is its ability to withstand loads applied by the live load from vehicles driving over it and the soil load under deep fills as well as required specifications to control pipe tolerances through a rigorous quality control and assessment at the manufacturing plant. One of the most important requirements for pipe material is to keep the jacking forces to a minimum by manufacturing each piece of pipe to be straight and have the exact exterior shape as the pipe in front of it. Also, the joint must be able to withstand the axial loads, even with cushioning material. If the jacking force is expected to exceed the axial thrust the pipe is designed for intermediate jacking stations or IJS can be added at intermediate points in the pipeline.
All Rinker Materials products are produced in accordance with American Association of State Highway and Transportation Officials (AASHTO) or American Society for Testing and Materials (ASTM) specifications. Our rigorous quality control protocols ensure a well-manufactured product based on national as well as state and/or local standards, such as American Society of Civil Engineers (ASCE) 27-17 Standard Practice for Direct Design of Precast Concrete Pipe for Jacking in Trenchless Construction, ASTM C1885 Standard Specification for Circular Precast Concrete Culvert, Storm Drain, and Sewer Pipe for Pipe Jacking, or ASCE 28 Standard Practice for Direct Design of Precast Concrete Box Sections for Jacking in Trenchless Construction.
Eliminating or reducing the need to open cut a road for pipe placement means there is no need to detour traffic and inconvenience the public while delivering significant cost savings.
Additionally, RCP and RCB combine the reinforcement benefits of steel and the structural benefits of concrete to form a pipe that can take the robust forces needed to push it forward through an excavated tunnel as well as withstand the loads from above, such as a highway, airport, or railroad.
Knowing the head that will be used, the length of the push or jack, the project’s soils, and other information help guide the design and installation process.
It is usually better to tunnel or jack through cohesive soils, these are soils that have a high clay content. Cohesive soils do not crumble and they are hard to break up. However, construction methods are available for non-cohesive soils which are more granular and do not clot together. In this instance different cutter heads may be used, or chemical stabilization. Using square thrust rings and a square capable cutter or hand digging under a square protective cover to make just enough room to push large box culvert sections under highways and turnpikes.
With a variety of Pipe and Box sizes and joint types available from Rinker, pipe can be produced to use with jacking equipment or tunneling equipment and project requirements.
Rinker’s reinforced concrete pipe can be jacked or tunneled without the added cost of a casing pipe. Using a casing pipe means extra cost of a second pipe, additional time welding each junction, and twice the feet of pipe to push.
Rinker Materials has also assisted with design of a jacked installation that was pushed on a radius. Working with Rinker Materials on how to design your RCP pipe to be jacked under a busy thoroughfare without disruption of the traveling public gives you a required RCP class strength determined by an engineer.
We work with both engineers and contractors, if you are considering pipe jacking, working with Rinker Materials as well as the contractor early in the concept process helps move the project forward successfully and in a more cost-effective manner.
In a collaborative design relationship, Rinker works with a project owner to streamline the design process with the engineer and expedite construction services with the contractor. This simple, but fundamental project approach saves money and time by transforming the relationship between Rinker Materials, the designers, and the contractors into a mutually beneficial alliance grounded in teamwork.
Rinker Materials adds immediate value on design-build projects by providing assistance with the layout, budget estimates, structural and hydraulic design, special fitting design, and joint and gasket design during the proposal, technical submittal, design development, and construction document phases.
