StifPipe™ is a truly revolutionary product in that it allows construction of a "custom-size" and "custom-shape" strong and stiff pipe to fit the needs of a variety of repair needs in the pipeline and culvert industry. There are many ways to install StifPipe™ including the three installation approaches described in more detail below:
Method A: Cast-In-Place – This approach is ideal for pipes with relatively smooth surfaces. Installation steps (after the pipe surface has been prepared and cleaned) include the following:
a) A first layer of carbon fabric is applied on the pipe surface
b) The special honeycomb core is applied on top of the first layer of carbon fabric; the thickness of this hollow core can be 1/4 inch or more depending on the diameter of the pipe being repaired
c) Additional layers of carbon fabric will be applied on the honeycomb core; these layers will be designed to resist the full internal pressure of the pipe
Method B: Precast Segmental Construction – This approach is ideal for corroded and/or collapsing culverts that are made with corrugated metal pipe (CMP) and have an uneven interior surface. The technique is similar to the segmental construction method that has been successfully used in construction of long span bridges for decades. Based on consideration of the diameter and shape of the pipe (i.e. circular, oval or egg-shaped cross section) as well as the size and number of access points, the pipe segments will be constructed off-site. These segments will be a few feet long and will have a cross section that is slightly smaller than the pipe. Once the pipe is made available, the construction sequence can consist of the following steps:
a) The pre-manufactured segments will be delivered to the job site in advance
b) Client will have the opportunity to inspect & validate the strength of each pipe segments prior to installation
c) The crew will carry the lightweight segments into pipe
d) The segments will be positioned sequentially along the pipe
e) Adjacent segments will be connected together with a special detail to create a long continuous pipe
f) The small annular space between the StifPipe™ and the host pipe will be filled with resin or grout to join these two pipes together.
Method C: Continuous Precast – This technique is ideal when there is a large open space at least at one end of the pipe; this could, for example, be the case for a culvert buried deep and crossing a roadway. The construction sequence could be as described below:
a) A mandrel several feet long with a cross section the same shape but slightly smaller than the pipe cross section is placed outside the pipe such that its axis is aligned with that of the pipe
b) A portion of StifPipe™ several feet long is constructed on the mandrel and is partially cured
c) The partially-cured portion is slipped away from the mandrel and is pushed into the host pipe
d) Additional portion of StifPipe a few feet long will be constructed on the mandrel such that it will be continuous with the previously constructed StifPipe™; this new portion will also be partially cured
e) The new longer piece is moved a few feet into the pipe
f) The above steps b) through e) will continue until the desired length of pipe has been manufactured
g) The annular space between the StifPipe™ and the host pipe is filled with grout or resin
