This disclosure relates generally to water-management infrastructure such as pipes and corrugated steel culverts, and more particularly to an environmentally benign system and method for rehabilitating and extending the useful life of such infrastructure.
For over a century, more than a third of the drainage culverts installed in the United States have been corrugated steel pipe (CSP) in round and pipe-arch shapes. The service life of a corrugated metal culvert varies, depending on factors such as coatings, material thickness, climate, maintenance, pH on water flows, and the condition of the surrounding soil. Since this type of culvert came into widespread use by the 1950s, many are now reaching the end of their useful life and need to be repaired, replaced, or refurbished before they fail. Metal culverts can fail in different ways. For example, rust and corrosion can cause the pipe to leak, or even disintegrate and collapse. Leaks can lead to erosion around the pipe and the resulting lack of structural support can cause the pipe to break, often unexpectedly. Pipe failure can wash out roads and bridges and cause environmental damage to the waterways they drain into.
Of course, culverts can be replaced by building a new culvert close to the existing one or by digging up the existing pipe and replacing it. Unfortunately, these methods can be very costly and time-consuming. Further, open cut methods may be impractical due to the impact they have on vehicular traffic, since the road above the culvert will likely have to be closed during culvert replacement, or because of limitations imposed by terrain, and/or climate.
Culverts can sometimes be rehabilitated without digging them up using a process that is referred to in the industry as trenchless replacement technology. In this method, a new pipe is attached to a tool that is pushed or pulled through the existing damaged pipe. The tool head intentionally breaks or splits the old pipe as it drags the new liner pipe behind it, and therefore this technique is also referred to as “pipe bursting.” Such trenchless methods allow culverts to be replaced with minimal disruption to traffic flow on the roadways above the culvert and with less impact on the waterways the culvert drains into. However, such “pipe bursting” techniques are “destructive” to the pre-existing host pipe, i.e., the culvert that is being replaced, thereby rendering the host pipe effectively useless for providing support or peripheral protection, for example, to the new liner pipe.
Another technique for rehabilitating old culverts is to use a slipliner, wherein a plastic liner is pulled through the interior of the host pipe without breaking it. Unfortunately, difficulties may be encountered with pulling the liner through a corrugated pipe, especially if the pipe is damaged or partially collapsed. The process of pulling the plastic liner through the pre-existing host pipe also places the liner under strain, which may weaken the liner and lead to premature failure.
Yet another technique for rehabilitating old culverts is to use a technology called cured in place pipe, or CIPP. In this technique a wet lining is pulled in place and then induced to harden in the field. Unfortunately, some CIPP materials and their installation methods can pose environmental risks, including the release or leaching of toxic materials into the environment, which has been known to cause fish kills, negatively affect wastewater treatment plants, and has even resulted in daycare center, school, and government building evacuations.
As will be apparent, rehabilitating damaged culverts, heretofore, has been difficult. Furthermore, the environmental cost of replacing rusted, corroded, or damaged metal corrugated steel pipes (CSPs) in the form of culverts is extremely large due to their prevalence throughout the United States and other countries around the world. Many solutions have been proposed but none are entirely without drawbacks including negative impacts on fish, wildlife, plant life, soil, and water in and around the culvert that is being rehabilitated. It would therefore be beneficial to provide a system and method that overcomes at least some of the above-mentioned drawbacks.
In accordance with an aspect of at least one embodiment, there is provided a method for in situ rehabilitation of a host pipe, comprising: disposing a support frame within the host pipe and adjacent to an inner surface of the host pipe, the support frame providing a plurality of attachment points spaced away from the inner surface of the host pipe; attaching a plurality of longitudinal planks to the support frame via the plurality of attachment points, each longitudinal plank of the plurality of longitudinal planks having an inwardly facing surface that forms a portion of a liner surface within the host pipe, and each longitudinal plank of the plurality of longitudinal planks having an outwardly facing surface opposite the inwardly facing surface with at least one longitudinal protrusion extending away therefrom; and at least partially filling a space that is defined between the inner surface of the host pipe and the plurality of longitudinal planks with a cementitious grout material, to form a grout layer upon curing of the cementitious grout material, wherein the cementitious grout material flows around and surrounds the at least one longitudinal protrusion during the step of filling the space, such that the at least one longitudinal protrusion is embedded within the grout material upon curing of the cementitious grout material.
In accordance with an aspect of at least one embodiment, there is provided a method for in situ rehabilitation of a host pipe in the form of a corrugated culvert or other conduit, comprising: applying a preparation treatment to an inner surface of the host pipe to at least partially fill in at least some corrugated indentations in the inner surface of the host pipe; disposing a support frame within the interior of the host pipe and adjacent to the host pipe inner surface, and coupling said support frame to the host pipe; assembling a plurality of longitudinal planks within the interior of the host pipe to form a liner, comprising attaching the longitudinal planks to the support frame and further comprising coupling together adjacent longitudinal planks via coupling structures that are arranged along each of the opposite longitudinal edges of each of the longitudinal planks, wherein each longitudinal plank has an inwardly facing surface that forms a portion of an inner surface of the liner and an opposite outwardly facing surface having at least one longitudinal protrusion extending away therefrom; and, at least partially filling a space that is defined between the preparation treatment applied to the inner surface of the host pipe and the assembled plurality of longitudinal planks with a cementitious grout material, to form a grout layer upon curing of the cementitious grout material, wherein the cementitious grout material flows around and surrounds the at least one longitudinal protrusion during the step of filling the space, such that the at least one longitudinal protrusion is embedded within the grout material upon curing of the cementitious grout material.
In accordance with an aspect of at least one embodiment, there is provided a system for in situ rehabilitation of a host pipe in the form of a corrugated culvert or other conduit, comprising: a support frame, which is sized for being received within and coupled to an inner surface of the host pipe, the support frame configured to provide a plurality of attachment points spaced away from the inner surface of the host pipe; a plurality of interconnected longitudinal planks forming a liner within the host pipe, each longitudinal plank of the plurality of longitudinal planks having an inwardly facing surface that forms a portion of an inner surface of the liner, and each longitudinal plank of the plurality of longitudinal planks having an outwardly facing surface opposite the inwardly facing surface with at least one longitudinal protrusion extending away therefrom; and a layer of a cured cementitious grout material filling or substantially filling a space between the inner surface of the host pipe and the plurality of interconnected planks, wherein the at least one longitudinal protrusion of each longitudinal plank is embedded within the cured cementitious grout material.
In accordance with an aspect of at least one embodiment, there is provided a rehabilitated culvert, comprising: a corrugated steel pipe (CSP) having an outer corrugated surface and an inner corrugated surface; a preparation treatment applied to the inner corrugated surface; a layer of cured cementitious grout material bonded to the preparation treatment; a support frame embedded within the layer of the cementitious grout material; and a plurality of interconnected longitudinal planks arranged side-by-side and end-to-end, each longitudinal plank having at least one longitudinal protrusion on a surface thereof facing the inner corrugated surface, the at least one longitudinal protrusion of each longitudinal plank being imbedded within the layer of cured cementitious grout material, the interconnected longitudinal planks cooperating to form an inside liner of the CSP that is spaced away from the inner corrugated surface of the CSP.
Exemplary embodiments will now be described in conjunction with the drawings in which:
While the present teachings are described in conjunction with various embodiments and examples, it is not intended that the present teachings be limited to such embodiments. On the contrary, the present teachings encompass various alternatives and equivalents, as will be appreciated by those of skill in the art. All statements herein reciting principles, aspects, and embodiments of this disclosure, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure.
As used herein, the terms “first”, “second”, and so forth are not intended to imply sequential ordering, but rather are intended to distinguish one element from another, unless explicitly stated to the contrary. Similarly, sequential ordering of method steps does not imply a sequential order of their execution, unless explicitly stated.
Installation of the system that is shown in
Referring still to
Prior to rehabilitating the host pipe 100, the surrounding site conditions should be surveyed to identify abnormalities or additional problems that may exist on site and appropriate remediation steps should be taken. Optionally but preferably, a LIDAR (Light Detection and Ranging) survey should be conducted to record initial conditions to be compared with conditions that are measured after rehabilitation is complete. Key survey points to be studied are at, for example, 12 o'clock, 3 o'clock, 6 o'clock, and 9 o'clock positions within the host pipe 100. Of course, different positions and/or additional positions may be surveyed.
After completing the initial survey, for best results, the inner surface of the host pipe 100 is cleaned using e.g., high pressure water blasting to remove bond breaking substances disposed thereon. For instance, a water pressure of at least 3000 psi and more preferably at least 5000 psi may be used for the initial cleaning step. Now referring also to
In this specific and non-limiting example, a preparation treatment 200 is applied to an inner surface of the host pipe 100. As is shown most clearly in
Now referring also to
In an alternative implementation, the preparation treatment 200 may be formed entirely from the repair mortar VELOSIT® RM 202 or another suitable material, optionally with a waterproof layer applied on top thereof. The repair mortar or other suitable material in this case serves to fill in the corrugation indents and to provide the bonding surface to which another cementitious grout material can adhere during subsequent steps of the installation process. Advantageously, the layer of repair mortar or other suitable material filling the corrugation indents is structurally strong and increases support within sections of the host pipe 100 that are badly corroded or damaged.
Referring again to
The system shown in
The support frame 300 may be formed in a single continuous section or alternatively it may be formed in a plurality of sections that are arranged end-to-end, with each section including rod elements 302 (e.g., 6 m lengths of 10 mm rebar arranged at 3 o'clock, 6 o'clock, 9 o'clock, and 12 o'clock positions within the host pipe 100) and hoop elements 304 that are spaced approximately 300 mm apart. The support frame 300 may be fabricated from common construction materials, such as for instance steel rebar, in which case the rod elements 302 and hoop elements 304 may be welded together, during installation within the host pipe 100, to form the support frame 300. Alternatively, the rod elements 302 and the hoop elements 304 may be clipped and secured in place, to form the support frame 300 without the need for welding, using clips 306 as shown most clearly in
Additional rod elements 308, which optionally may have a diameter smaller than that of the rod elements 302, may be arranged at 1 o'clock, 2 o'clock, 4 o'clock, 5 o'clock, 7 o'clock, 8 o'clock, 10 o'clock, and 11 o'clock positions within the host pipe 100, or at another suitable spacing depending on the diameter of the host pipe 100. As shown in
The support frame 300 provides a plurality of attachment points along a curved plane that is spaced away from the inner surface of the host pipe 100. As shown in
Now referring also to
Now referring also to
The number, size, shape and orientation of the longitudinal protrusions is selected to be suitable for attaching the longitudinal planks 402 to the support frame via clips or other suitable fasteners, and for allowing cementitious grout material to flow around and embed the longitudinal protrusions therein after the cementitious grout material has cured, and to increase the torsional and/or longitudinal rigidity of the longitudinal planks 402 to resist movement and shifting during installation.
During installation of the system according to the instant embodiment, individual longitudinal planks 402 are placed side-by-side, with the male coupling rail 406 at the edge of one longitudinal plank being 402 slidingly inserted into and coupled with the complementary female coupling groove 408 at the edge of an adjacent longitudinal plank 402. The longitudinal male coupling rail 406 slides into the longitudinal recess of the female coupling groove 408 to form a grout-tight seal between the two longitudinal planks 402. The longitudinal planks are “locked” together when they are coupled in this fashion. However, the longitudinal planks can be “unlocked,” if necessary, before they are grouted in place by relatively sliding the longitudinal planks 402 in a reverse direction.
As shown most clearly in
In the instant example, the longitudinal planks are curved in a direction transverse to their length. Since the cross-section of the assembly 400 of interconnected longitudinal planks 402 installed within the host pipe 100 will form substantially a circle, it is advantageous for the longitudinal planks 402 to have a slight curve conforming approximately to the curved wall of the host pipe 100, especially if the host pipe 100 is only a few meters or less in diameter. Alternatively, the longitudinal planks 402 are substantially flat and result in a polygon like cross-sectional profile that merely approximates a circle, especially when the diameter of the host pipe 100 is more than a few meters in diameter.
The assembly 400 of the longitudinal planks 402 may be built in stages, after the support frame 300 has been fully or partially assembled and suitably anchored inside the host pipe 100. A first plurality of the longitudinal planks 402 are fastened to some of the plurality of attachment points provided along the support frame 300. For instance, each attachment point is provided using a clip 1300, which is shown in isolation in
Sliding-block wedges 1400, which are shown in isolation in
Of course, the sliding-block wedges 1400 may be omitted if the longitudinal planks 402 can be secured to the support frame 300 with sufficient rigidity to avoid significant movement or shifting during introduction of the cementitious grout material during subsequent steps. Alternatively, expanding ring-shaped support members may or other suitable reinforcement members may be temporarily installed within the assembly 400 of longitudinal planks to maintain a desired cross-sectional shape of the assembly 400 during introduction of the cementitious grout material. Once the grout material has cured, and the assembly 400 of longitudinal planks is locked into the desired configuration, the temporary support members may be removed. Further, the longitudinal planks 402 may be attached to the support frame 300 using other fasteners or differently configured clips.
Referring again to
The process of extending the assembly 400 of longitudinal planks 402 continues as described above until a desired length of the host pipe 100 that is being rehabilitated is lined with longitudinal planks 402. In many cases, substantially the entire length of the host pipe 100 is lined with longitudinal planks 402. As each additional plurality of longitudinal planks 402 is installed, the individual longitudinal planks 402 are coupled to one another and are attached to the support frame 300 and optionally shimmed, as described above. For better certainty, the process of assembling the longitudinal planks 402 may be paused at various points prior to extending the assembly 400 of longitudinal planks 402 to the final desired length. For instance, as described in more detail below, after completion of approximately 30 m of the assembly 400 of longitudinal planks 402 a cementitious grout material is pumped into the just-completed section to form a grout layer 500. After pumping and at least partial curing of the grout material within the completed section, the process of extending the assembly 400 of longitudinal planks 402 continues for another 30 m, etc.
Referring again to
After a section of the assembly 400 of longitudinal planks 402 has been assembled, such as for instance a 30 m section of the assembly, secured to the support frame 300, and optionally shimmed, a grout layer 500 is formed by pumping a grout material into the annular space between the assembly 400 of longitudinal planks 402 and the preparation treatment 200 that is applied to the inner surface of the host pipe 100. For instance, 20 mm grout hoses are wrapped at 45-degree angles through the interior of the host pipe. Two hoses may be used, one installed with a right (spiral) lay and one left (spiral) lay. Pumping is done through an inflatable bulkhead. The bulkhead is preferably installed at the 10 o'clock and 2 o'clock positions. Entry points are preferably at the 4 o'clock and 7 o'clock positions of the bulkhead. Valves control a ‘T’ in the grout hoses. Grouting will take 2 hours to complete a 30 m section. The grout material fills the annular space between the assembly 400 of longitudinal planks 402 and the preparation treatment 200. By way of a specific and non-limiting example, VELOSIT® NG 511 or an equivalent grouting solution is pumped into the annular space to form the grout layer 500. VELOSIT® NG 511 has minimal shrinkage, has slight volume increase in the plastic stage to ensure good bonding to metal, has corrosion inhibitor, adequate working time (60-minute working time) and 1740 psi (12 MPa) compressive strength after 6 hours, excellent adhesion to properly prepared concrete and steel, and minimal water penetration. As noted above, in host pipes 100 having a length greater than 30 m, the pumping of the grout takes place in multiple stages as groups of the longitudinal planks 402 are inserted. By way of a specific and non-limiting example, as discussed above, approximately 30 m of the assembly 400 of longitudinal planks 402 may be installed, including the pumping of grout material, per day. Additional segments of 30 m or less may be installed during subsequent days until the full length of the host pipe 100, or at least a predetermined portion thereof, has been rehabilitated.
The grout layer 500 bonds to and extends from the preparation treatment 200 to the surface 404 of the longitudinal planks 402 in the assembly 400 of longitudinal planks 402. Due to the interconnection of the longitudinal planks 402 via the male coupling rail 406 and the female coupling groove 408, and the use of appropriate end connectors 602 or 652, the grout material does not leak through the assembly 400 of longitudinal planks 402. The pumped-in grout material therefore can fill entirely or substantially entirely the annular space that is defined between the preparation treatment 200 and the assembly 400 of longitudinal planks 402. As shown in
As will be apparent, the grout layer 500 serves to fix the components of the system shown in
In an alternative implementation, the assembly of longitudinal planks 402 may extend circumferentially only part of the way around the inside of the host pipe 100. For instance, a trough-shaped assembly of longitudinal planks 402 may be installed within approximately the bottom half of the host pipe 100. In this case, the grout material is pumped into a generally U-shaped space between the assembly of longitudinal planks 402 and the preparation treatment 200 applied to the inner surface of the host pipe 100. Alternatively, if the host pipe 100 is an arch shaped structure rather than a full cylinder host pipe, then a substantially arch shaped assembly of longitudinal planks 402 may be constructed and the grout material may be pumped into a generally inverted U-shaped space between the assembly of longitudinal planks 402 and the preparation treatment 200 applied to the inner surface of the host pipe 100.
Installation of the system that is shown in
Referring still to
Prior to rehabilitating the host pipe 100, the surrounding site conditions should be surveyed to identify abnormalities or additional problems that may exist on site and appropriate remediation steps should be taken. Optionally but preferably, a LIDAR (Light Detection and Ranging) survey should be conducted to record initial conditions to be compared with conditions that are measured after rehabilitation is complete. Key survey points to be studied are at, for example, 12 o'clock, 3 o'clock, 6 o'clock, and 9 o'clock positions within the host pipe 100. Of course, different positions and/or additional positions may be surveyed.
After completing the initial survey, for best results, the inner surface of the host pipe 100 is cleaned using e.g., high pressure water blasting to remove bond breaking substances disposed thereon. For instance, a water pressure of at least 3000 psi and more preferably at least 5000 psi may be used for the initial cleaning step.
In this specific and non-limiting example, a preparation treatment 200 is applied to an inner surface of the host pipe 100. The preparation treatment 200 has already been discussed above with reference to
The preparation treatment 200 may include a plurality of different materials, which are applied in a plurality of separate layers. As discussed above, in the specific example that is shown in
In an alternative implementation, the preparation treatment 200 may be formed entirely from the repair mortar VELOSIT® RM 202 or another suitable material, optionally with a waterproof layer applied on top thereof. The repair mortar or other suitable material in this case serves to fill in the corrugation indents and to provide the bonding surface to which another cementitious grout material can adhere during subsequent steps of the installation process. Advantageously, the layer of repair mortar or other suitable material filling the corrugation indents is structurally strong and increases support within sections of the host pipe 100 that are badly corroded or damaged.
The system shown in
Referring still to
It should be noted that by interlacing the lengths 902 and 904 of FRP rebar they alternately cross over each other—length 902 crossing over length 904 and then length 904 crossing over length 902, etc. Plastic clips or ties 908 are installed during creation of the support frame 900 to secure the lengths 902 and 904 of FRP rebar and to couple together the portions which cross over each other, as shown most clearly in
It should be noted that although preferably two separate lengths 902 and 904 of FRP rebar are used, it is possible to use a single length of FRP rebar where the middle of the length is secured at one end of the host pipe 100 and the two lengths on either side of the secured-middle overlap each other in spirals, one overlapping with the other in an alternating pattern.
The support frame 900, in a manner similar to support frame 300 as discussed above, provides a plurality of attachment points along a curved plane that is spaced away from the inner surface of the host pipe 100. As shown in
Now referring also to
As shown most clearly in
The number, size, shape and orientation of the longitudinal protrusions is selected to be suitable for attaching the longitudinal planks 1202 to the support frame via clips or other suitable fasteners, and for allowing cementitious grout material to flow around and embed the longitudinal protrusions therein after the cementitious grout material has cured, and to increase the torsional and/or longitudinal rigidity of the longitudinal planks 1202 to resist movement and shifting during installation.
During installation of the system according to the instant embodiment, individual longitudinal planks 1202 are placed side-by-side, with the male coupling rail 1206 at the edge of one plank inserted into and coupled with the complementary female coupling groove 1208 at the edge of an adjacent longitudinal plank 402, as shown in
As shown most clearly in
In the instant example, the longitudinal planks 1202 are curved in a direction transverse to their length. Since the cross-section of the assembly 1200 of interconnected longitudinal planks 1202 installed within the host pipe 100 will form substantially a circle, it is advantageous for the longitudinal planks 1202 to have a slight curve conforming approximately to the curved wall of the host pipe 100, especially if the host pipe 100 is only a few meters or less in diameter. Alternatively, the longitudinal planks 1202 are substantially flat and result in a polygon like cross-sectional profile that merely approximates a circle, especially when the diameter of the host pipe 100 is more than a few meters in diameter.
The assembly 1200 of the longitudinal planks 1202 may be built in stages, after the support frame 900 has been partially or fully assembled and suitably anchored inside the host pipe 100. A first plurality of the longitudinal planks 1202 are fastened to some of the plurality of attachment points provided along the support frame 900. For instance, each attachment point is provided using a clip 1300, which is shown in isolation in
Sliding-block wedges 1400, which are shown in isolation in
Of course, the sliding-block wedges 1400 may be omitted if the longitudinal planks 1202 can be secured to the support frame 900 with sufficient rigidity to avoid significant movement or shifting during introduction of the cementitious grout material during subsequent steps. Alternatively, expanding ring-shaped support members or other suitable reinforcement members may be temporarily installed within the assembly 1200 of longitudinal planks to maintain a desired cross-sectional shape of the assembly 1200 during introduction of the cementitious grout material. Once the grout material has cured, and the assembly 1200 of longitudinal planks is locked into the desired configuration, the temporary support members may be removed. Further, the longitudinal planks 1202 may be attached to the support frame 900 using other fasteners or differently configured clips.
Referring again to
The process of extending the assembly 1200 of longitudinal planks 1202 continues as described above until a desired length of the host pipe 100 that is being rehabilitated is lined with longitudinal planks 1202. In many cases, substantially the entire length of the host pipe 100 is lined with longitudinal planks 1202. As each additional plurality of longitudinal planks 1202 is installed, the individual longitudinal planks 1202 are coupled to one another and are attached to the support frame 900 and shimmed, as described above. For better certainty, the process of assembling the longitudinal planks 1202 may be paused at various points prior to extending the assembly 1200 of longitudinal planks 1202 to the final desired length. For instance, as described in more detail below, after completion of approximately 30 m of the assembly 1200 of longitudinal planks 1202 a cementitious grout material is pumped into the just-completed section to form a grout layer 500. After pumping and at least partial curing of the grout material within the completed section, the process of extending the assembly 1200 of longitudinal planks 1202 continues for another 30 m, etc.
Referring again to
After a section of the assembly 1200 of longitudinal planks 1202 has been assembled, such as for instance a 30 m section of the assembly, secured to the support frame 1200, and shimmed, a grout layer 500 is formed by pumping a grout material into the annular space between the assembly 1200 of longitudinal planks 1202 and the preparation treatment 200 that is applied to the inner surface of the host pipe 100. For instance, 20 mm grout hoses are wrapped at 45-degree angles through the interior of the host pipe. Two hoses may be used, one installed with a right (spiral) lay and one left (spiral) lay. Pumping is done through an inflatable bulkhead. The bulkhead is preferably installed at the 10 o'clock and 2 o'clock positions. Entry points are preferably at the 4 o'clock and 7 o'clock positions of the bulkhead. Valves control a ‘T’ in the grout hoses. Grouting will take 2 hours to complete a 30 m section. The grout material fills the annular space between the assembly 1200 of longitudinal planks 1202 and the preparation treatment 200. By way of a specific and non-limiting example, VELOSIT® NG 511 or an equivalent grouting solution is pumped into the annular space to form the grout layer 500. VELOSIT® NG 511 has minimal shrinkage, has slight volume increase in the plastic stage to ensure good bonding to metal, has corrosion inhibitor, adequate working time (60-minute working time) and 1740 psi (12 MPa) compressive strength after 6 hours, excellent adhesion to properly prepared concrete and steel, and minimal water penetration. As noted above, in host pipes 100 having a length greater than 30 m, the pumping of the grout takes place in multiple stages as groups of the longitudinal planks 1202 are inserted. By way of a specific and non-limiting example, as discussed above, approximately 30 m of the assembly 1200 of longitudinal planks 1202 may be installed, including the pumping of grout material, per day. Additional segments of 30 m or less may be installed during subsequent days until the full length of the host pipe 100, or at least a predetermined portion thereof, has been rehabilitated.
The grout layer 500 bonds to and extends from the preparation treatment 200 to the surface 1204 of the longitudinal planks 1202 in the assembly 1200 of longitudinal planks 1202. Due to the interconnection of the longitudinal planks 1202 via the male coupling rail 1206 and the female coupling groove 1208, and the use of appropriate end connectors 602 or 652, the grout material does not leak through the assembly 1200 of longitudinal planks 1202. The pumped in grout material therefore can fill entirely or substantially entirely the annular space that is defined between the preparation treatment 200 and the assembly 1200 of longitudinal planks 1202. As shown in
As will be apparent, the grout layer 500 serves to fix the components of the system shown in
In an alternative implementation, the assembly of longitudinal planks 1202 may extend circumferentially only part of the way around the inside of the host pipe 100. For instance, a trough-shaped assembly of longitudinal planks 1202 may be installed within approximately the bottom half of the host pipe 100. In this case, the grout material is pumped into a generally U-shaped space between the assembly of longitudinal planks 1202 and the preparation treatment 200 applied to the inner surface of the host pipe 100. Alternatively, if the host pipe 100 is an arch shaped structure rather than a full cylinder host pipe, then a substantially arch shaped assembly of longitudinal planks 1202 may be constructed and the grout material may be pumped into a generally inverted U-shaped space between the assembly of longitudinal planks 1202 and the preparation treatment 200 applied to the inner surface of the host pipe 100.
Referring now to
At step 1502, a preparation treatment is applied to the inner surface of the host pipe. The preparation treatment includes one or more layers of materials that are selected to provide a good support and bonding. By way of a specific and non-limiting example a layer of closed cell foam is applied initially to the inner surface of the host pipe. Preferably, the inside diameter of the host pipe is substantially uniform along the length thereof after application of the closed cell foam, which in this context means more uniform than the diameter of the host pipe before applying the closed cell foam. By way of an example, 80% to 100% of the depth of corrugation indents of the inner surface of host pipe are filled with the closed cell foam, and more preferably the layer of closed cell foam is screeded to a substantially circular cross-section. A layer of a mortar material, such as for instance repair mortar VELOSIT® RM 202, is then applied on top of the closed cell foam using a trowel or another suitable applicator. A waterproof layer, such as for instance VELOSIT® WP 120, may then be applied to complete the preparation treatment. The thickness of the layer of closed cell foam varies due to the irregular shape of the inner surface of the corrugated material of the host pipe. Suitable thicknesses of the layers of repair mortar layer and of the waterproof layer are approximately 6 mm and 2 mm, respectively.
At step 1504 a support frame is constructed and secured to the inner surface of the host pipe. For instance, first and second lengths of FRP rebar are installed running along the inner surface of the host pipe, forming respective spirals with a right lay and a left lay beginning at the discharge end of the host pipe. The two spirals of FRP rebar run in opposite directional rotations one relative to the other, so that they cross and overlap periodically. The lengths of FRP rebar are installed in the host pipe at a 22.5-degree angle (to the horizontal) thus “spiraling.”
At step 1506 an assembly of longitudinal planks is installed and secured to the support frame so as to form a liner within the host pipe. The longitudinal planks are interconnected by male coupling rails and female coupling grooves disposed along opposite longitudinal edges thereof End connectors are disposed between the butted up against one another ends of adjacent longitudinal planks in the length direction, thereby supporting the ends of the planks and sealing spaces that would otherwise allow grout material to pass through. The ends of the longitudinal planks are staggered such that there is no seam extending circumferentially around the assembly of longitudinal planks. Various wedges and clips are used at this stage to secure the longitudinal planks to the support frame and to shim the structure, so as to put equal pressure on all points around the complete plank structure and hold it in place.
At step 1508, grout material is pumped into the annular space between the liner of longitudinal planks and the preparation treatment applied to the inner surface of the host pipe. By way of an example, 20 mm grout hoses are wrapped at 45-degree angles through the interior of the host pipe. Two hoses may be used, one installed with a right (spiral) lay and one left (spiral) lay. Pumping is done through an inflatable bulkhead. The bulkhead is preferably installed at the 10 o'clock and 2 o'clock positions. Entry points are preferably at the 4 o'clock and 7 o'clock positions of the bulkhead. Valves control a ‘T’ in the grout hoses. Grouting will take 2 hours to complete a 30 m section. By way of a specific and non-limiting example, VELOSIT® NG 511 or an equivalent grouting solution is used.
Throughout the description and claims of this specification, the words “comprise”, “including”, “having” and “contain” and variations of the words, for example “comprising” and “comprises” etc., mean “including but not limited to”, and are not intended to, and do not exclude other components.
It will be appreciated that variations to the foregoing embodiments of the disclosure can be made while still falling within the scope of the disclosure. Each feature disclosed in this specification, unless stated otherwise, may be replaced by alternative features serving the same, equivalent or similar purpose. Thus, unless stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
All of the features disclosed in this specification may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. In particular, the preferred features of the disclosure are applicable to all aspects of the disclosure and may be used in any combination. Likewise, features described in non-essential combinations may be used separately (not in combination).
Number | Date | Country | Kind |
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3112125 | Mar 2021 | CA | national |
3125165 | Jul 2021 | CA | national |
This application claims priority from U.S. Provisional Patent Application No. 63/139,085 filed on Jan. 19, 2021; Canadian Patent Application No. 3,112,125 filed Mar. 17, 2021; and Canadian Patent Application No. 3,125,165 filed Jul. 20, 2021, all of which are incorporated herein by reference in their entirety.
Number | Date | Country | |
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63139085 | Jan 2021 | US |