Abstract
This patent provides designs for an ecologically friendly gravity retaining walls using a wide variety of building materials. This patent provides a method to build gravity walls using random fill. Where fill material is placed and then grouted in a specific way to form a solid mass. The primary problem with grouting loose fill to form a solid mass is that it needs confinement. This patent presents steps to create a confined space for grouting a structural section to provide horizontal support of an external mass. This is accomplished by dividing the wall into three sections. From front to back, these are the face, the structural section, and the back drainage sections. By grouting these separately and tying them together with modified concrete covered rebar a complete wall can be built in a very efficient manner. Initially planter blocks were included, now those claims are submitted under application Ser. No. 18/507,899.
Claims
1. A method of forming concrete on steel rebars for a retaining wall, comprising: Providing a plurality of steel rebars covered with concrete elements molded in a series of undulating shapes within a grouted fill to form a gravity mass retaining structure behind a concrete wall face; wherein concrete nodes of the concrete elements are molded around all or part of a respective rebar to make modified rebars; wherein the concrete cures until reaching a minimum compressive strength of 2000 psi prior to being used for the purpose of structurally tying the grouted fill; wherein each of the rebars used to attach the g routed mass to the concrete wall face contain a non-modified portion free of concrete nodes; wherein the undulating shapes of the concrete of each modified rebar has a minimum section of 1.5 inches over the steel rebar and a maximum section of at least 1.5 times the minimum section and the slope of the undulating shapes between the minimum and maximum sections are sloped at between 20 and 45 degrees measured from the longitudinal axis of the rebar; and Attaching non-modified portions of the respective rebars within the wall face of the retaining structure to create a gravity retaining wall within an area between a back cut in the ground to be supported by the retaining structure and the wall face using cohesive soil fill and large debris fill; wherein the large debris fill is concrete rubble from demolition projects or boulder and cobble size rocks; wherein the large debris fill is made of large debris fill elements which leaves large void spaces between the large debris fill elements; wherein the large void spaces are initially filled with gravel size rocks to make a mechanical connection between the concrete nodes of each rebar and the large debris fill elements; wherein the non-modified portions of the respective rebars are attached within the wall face and then bent towards the grouted fill behind and supported by the wall face; and Placing grout pipes simultaneously with the rebars and the grouted fill; wherein the grout pipes are placed at designed locations to communicate with the large void spaces; grouting material is then injected through each of the grout pipes into the large void spaces to lock the cohesive soil fill and large debris fill with the concrete nodes and rebars to form a solid reinforced mass that support horizontal and vertical loads from the material behind the gravity retaining wall.
2. The method of claim 1, further comprising wherein the grouted fill of the gravity retaining wall functions as a single unit due to the inclusion of said modified rebars to tie the entire mass together to provide uniform support to the supported ground behind said gravity retaining wall.
3. The method of claim 1, further comprising wherein the gravity retaining wall is tested by first testing the strength of each proposed fill to determine which fill material has the lowest strength and then creating selective grout zones around the modified rebars within the lowest strength fill material and performing pull out tests on said modified rebar that are g routed into the lowest strength material for that particular project.
4. The method of claim 1, further comprising verifying that the gravity retaining wall performs as designed.
5. The method of claim 1, further comprising providing for an environmentally friendly option of constructing the gravity retaining wall by using inert debris fill generated by demolition of existing structures and placing the inert debris within the grouted fill of the gravity retaining wall.
6. The method of claim 5, further comprising wherein the use of inert debris fill reduces the noise and vibration cause by compaction equipment due to the inert debris fill being placed loosely along with the gravel sized rocks and modified rebars and then grouted in place to form the solid reinforced mass of the gravity retaining wall.
7. The method of claim 1, further comprising using fine grained soils as the cohesive soil fill and placing horizontal or near horizontal layers of modified rebars laid out in a grid pattern along with a covering of gravel size rocks and grout pipes to provide the necessary reinforcing.
8. The method of claim 1, wherein the retaining structure is an improved mechanically stabilized earth (MSE) wall.
Description
(1) A quick list of the Figures is:
(2) FIG. 1. shows a perspective view of the wall at the beginning of the construction process prior to any fill being placed. This also shows the location of two cross sections for FIGS. 2A, 2B, 2C, 2D, and 2E in contrast to FIGS. 3A, 3B, 3C, 3D, and 3E.
(3) FIG. 2A Shows the three fill sections relative to the wall and the back cut along with the back-drain details.
(4) FIG. 2B Shows the preparation of the back-drain and back cut relative to the original slope.
(5) FIG. 2C Shows the beginning of the random fill being placed and initially grouted into place.
(6) FIG. 2D Shows the random fill placed to its full height and the final stages of the three fill process.
(7) FIG. 2E Shows the final grouted gravity wall with both layers of grouting and the three fill sections. Also shown is the detail for the drainage presented on FIG. 4.
(8) FIG. 3A Shows the same three fill sections as shown in FIG. 2A but this section shows how the grouted fill will interact with the horizontal modified rebar attaching the wall face to the grouted random fill. In addition the typical detail of the modified rebar shown in FIG. 14.
(9) FIG. 3B Shows the open wall sections where the modified rebar will be inserted into the wall face.
(10) FIG. 3C Shows the first layer of random fill being grouted to the wall face modified rebar.
(11) FIG. 3D Shows the full height of the random fill with the grout pipes in place for all three sections of the grouting process.
(12) FIG. 3E Shows the final grouting of the gravity wall and the modified rebar to ensure that the wall face and the three sections function a one unit.
(13) FIG. 4 Presents a typical perspective of the back cut and the concrete covered drainage material. The concrete cover is to prevent the grout from entering the drainage material. Also, shown is the FIG. 5 section of the concrete and drainage material.
(14) FIG. 5 Provides a section view of the drainage material and the concrete cover along with the grouted random fill.
(15) FIG. 6 Provides a possible method to test the minimum strength of the grouted random fill using a sacrificial test modified rebar.
(16) FIG. 7 Shows a typical concrete block with a minor modification to allow for the installation of a modified rebar into the wall face.
(17) FIG. 8 Presents a perspective view of a planter block that is designed to work with the modified rebar used for the grouted random fill gravity wall.
(18) FIG. 9 Shows the same planter block from a vertical view and it shows the location of the vertical cut of FIG. 10.
(19) FIG. 10 Shows a sectional view of the same planter block.
(20) FIG. 11 Presents a cross sectional view of a random fill grouted gravity wall that uses the planter blocks for a wall face.
(21) FIG. 12 Is a perspective view of a planter block gravity wall in construction.
(22) FIG. 13 Presents an alternative block design that could be used for a planter box wall face with a hole for the attachment of the modified rebar.
(23) FIG. 14 Provides a detail showing how the rebar is modified with undulating concrete cast on to the rebar such that weaker grouted gravel can transfer load to and from the rebar to ensure that the wall face and the random fill will function as a unit.
FIGURES
(24) The following discussion describes the enclosed Figures which are provided to show how the Green Gravity Wall would be constructed. It is important to follow the steps of the construction to ensure that all parts of the wall function as designed. First is a list of the numbered items that can be referred to when examining the figures.
NUMBERED ITEMS FOUND ON THE FIGS
(25) 1. Concrete Block Wall Face 2. Temporary Back Cut 3. Fully Grouted Cell 4. Rebar Inside Fully Grouted Cell 5. Open Cell Where the Back Side of the Block Was Cut Open 6. Modified Rebar Inserted into the Hole #5 or Hole #38 7. Concrete Foundation Structurally Designed 8. Gap Between the Back of Footing #7 and Back Cut #2 for the Subdrain 9. Concrete Cover to Protect Back Drain Material 10. Back Drain Material 11. Subdrain Perforated Pipe 12. Gravel Fill Around the Subdrain 13. Subdrain Filter Cloth 14. Wall Grout for the Modified Rebar 15. Non-modified Section of Rebar 16. Ground Surface in Front of Wall 17. Fill Zone Behind the Block Wall to be Lightly Grouted 18. Structural Fill Zone Tightly Grouted 19. Fill Zone Adjacent to Back Cut #2 may need to be Lightly Grouted 20. Ground to be Supported by the Retaining Wall 21. Original Slope Prior to Back Cut being Made 22. Demolition Concrete or Cobbles and Boulder Size Rocks 23. Gravel Fill Between Demolition Concrete and Rocks 24. Initially Lightly Grouted Zone Along the Back Side of the Block Wall 25. Excess Grout Foam to be Trimmed Off 26. Grout Injection Pipes Installed Along with the Gravel, Concrete, and Cobble and Boulder size Rocks 27. Grouted Gravel Fill Around Modified Rebar #6 or Test Rebar #30 28. Secondary Level of Lightly Grouted Zone along the Back Side of the Wall 29. Primary Grouted Zone for Strength 30. Test Rebar 31. Concrete Nodes Around Rebar for Testing the Grouted Fill 32. Test Load 33. Test Section Limits 34. Rebar Connecting Foundation to the Planter Blocks 35. Planter Blocks 36. Planter Box to be Filled with Soil and Plants 37. Drain Hole 38. Rebar Hole for Both Block #35 to Block #35 Connection and Modified Rebar to Tie Blocks #35 to the Grouted Fill 39. Horizontal Hole for Modified Rebar 40. Planter Block with alternate design of hole for the rebar 41. Elongated hole for the rebar 42. Horizontal Modified Rebar to tie the #17 Grouted Fill together along the length of the wall #1 43. Boundary between the grouted layers 44. Concrete cover cast upon the #15 rebar
FIG. 1
(26) This figure shows a gravity wall in the process of being constructed. This is a perspective view from above, and behind the gravity wall. The block wall 1 has been constructed on top of a concrete foundation 7 with steel rebar 4 with cement grout 3 in some of the wall cells. Horizontal Modified Rebar 42 to tie the #17 Grouted Fill together along the length of the wall #1 The original slope has been trimmed removing loose topsoil to expose the back cut 2. Between the back of the foundation 7 and the base of the back cut 2 is a gap 8 for the proposed subdrain pipe 11 (not Shown). On the back cut is the back drain material 10 such as J Drain covered with concrete 9 to protect the back drain material from intrusion by the grout. This perspective shows the locations of three section cuts which will show the method of construction and how to test the strength of the structural fill. Section 2 shows the cross section through the back drain and the block wall and the fill sections. Section 3 shows the cross section through the area where the modified rebar 6 will attach the wall face to the structural fill. Section 6 will show how during construction a test section can be built into the fill and tested to determine its minimum strength.
FIG. 2 A
(27) FIG. 2A shows the basic layout of the wall fill sections. The area adjacent to the block wall fill Zone 17 will be lightly grouted to prevent large expansive forces from damaging the block wall. This Zone 17 will not be part of the structural fill zone. Zone 19 is also lightly grouted to protect the back drain material 10 by ensuring that the grout does not penetrate the soil to be supported to the extent that it flows into and around the concrete cover 9. It should be noted that in the event that the retaining wall is designed to support full hydrostatic pressure then this would not be necessary. Once the block wall 1 and the back drain material 10 are protected by the grout Zones 17 and 19, then the structural zone can be grouted to form Zone 18. This Zone 18 is to be grouted to its full extent to build the primary structural gravity wall. It should be noted that these same zones will be given different identification numbers in later figures as they become grouted zones.
(28) This figure is intended to show the final goal of the gravity wall. Also, presented is a complete back drain system showing how the drainage material 10 ties into the subdrain pipe 11. The subdrain pipe 11 is typically a 4-to-6-inch diameter PVC pipe with slots or small holes. To ensure that the pipe does not become clogged the typical design is in the form of what is commonly call a burrito drain. Where the pipe 11 is surrounded by poorly graded gravel 12 and wrapped in filter cloth 13. In this case the filter cloth needs to be protected from the grout in zones 18 and 19 by the bottom section of the concrete cover 9 as shown in FIG. 2A.
FIG. 2B
(29) FIG. 2B section shows the condition prior to the placement of fill and grout. This shows how the original slope 20 has been trimmed back to the temporary cut slope 2. Then the drainage material 10 and protective concrete cover 9 were placed on the cut slope 2. The drainpipe 11, gravel 12 and filter cloth 13 has been wrapped around the pipe 11 to protect the system.
FIG. 2C
(30) FIG. 2C section shows the condition where some fill has been placed and the lightly grouted zone 17 has started. Grout pipes 26 have been installed beyond this section. What is shown are the demolition concrete and rocks 22 in a matrix of gravel 23. If expansive grout is used then some of the grout will reach the temporary surface and expand to form a non-structural foam 25 that will need to be removed prior to placing an additional layer of fill.
FIG. 2D
(31) FIG. 2D section shows all the fill has been placed to the top of the wall. A subsequent light grouting 28 has been injected into the next layer of fill adjacent to the wall. Also, as more fill is placed additional grout pipes 26 were installed. The second grouting also has created a foam layer 25 on top of the grouted zone. It should be noted that the drawings in this presentation show only two layers of grouting. If the proposed height of the retaining wall exceeds what can be completed in two lifts, then this same procedure could be followed for as many lifts as is necessary. The primary objective is to create a thick Zone 17 of grouted material that will spread the short-term load created when the structural Zone 19 is tightly grouted.
FIG. 2E
(32) FIG. 2E shows the final stage of the grouting. The primary grouted zone 29 is shown by hatch marking where the line spacing is narrower than the initial lightly grouted zone 24 with heavy lines along the back side of the wall face. Depending on the ground conditions and the measures taken to protect the back drain material 10 a second lightly grouted zone 19 as shown on FIG. 2A may be needed along the back cut 2. The primary goal of FIG. 2E is to show that the size of the primary grouted zone 29 is critical to ensure the stability of the supported material 20. This is how all gravity walls are designed. Prior to construction the load from the supported material 20 is balanced against the resisting strength and mass of the planned primary grouted zone 29, to achieve the desired factor of safety. Again, the grouting will result in a temporary excess grout foam 25 which will need to be removed. After the grouting is complete the back drain material 10 should be tested to ensure that the grout in zone 29 does not interfere with its gravity drain capacity to elevate hydrostatic pressure.
(33) FIG. 2E shows the location of the FIG. 4 enlargement of the back drain system.
FIG. 3A
(34) FIG. 3A shows the basic layout of the wall face and the fill sections. The area adjacent to the block wall fill Zone 17 will be lightly grouted to prevent large expansive forces from damaging the block wall. This Zone 17 will not be part of the structural fill zone. Zone 17 is intended to tie the block wall 1 to the lightly grouted fill Zone 17 through the use of the modified rebar 6, as shown in Section 3 A. Zone 19 is also lightly grouted to protect the back drain system shown in the figures related to Section 2. It should be noted that in the event that the retaining wall is designed to support full hydrostatic pressure then this would not be necessary. Once the block wall 1 and the back drain material 10 are protected by the grout Zones 17 and 19, then the structural zone can be grouted to form Zone 18. This Zone 18 is to be grouted to its full extent in order to build the primary structural gravity wall. It should be noted that these same zones will be given different identification numbers in later figures as they become grouted zones.
(35) This figure is intended to show the final goal of the gravity wall. Also presented is the subdrain pipe 11 which is typically a 4-to-6-inch diameter PVC pipe with slots or small holes. To ensure that the pipe does not become clogged the typical system is to form what is commonly call a burrito drain. Where the pipe 11 is surrounded by poorly graded gravel 12 and wrapped in filter cloth 13. In this case the filter cloth needs to be protected from the grout in zones 18 and 19 by the bottom section of the concrete cover 9 as shown in FIG. 3A.
FIG. 3B
(36) FIG. 3B shows the condition prior to the placement of fill and grout. This shows how the original slope 20 has been trimmed back to the temporary cut slope 2. Then the drainage material is not continuous and therefore only the drain is presented. The drainpipe 11, gravel 12 and filter cloth 13 has been wrapped around the pipe 11 and gravel 12 to protect the system. FIG. 3B shows the open segments of the blocks 5 prior to the installation of the modified rebar 6 (not shown).
FIG. 3C
(37) FIG. 3C shows the condition where some fill has been placed and the grouting of the lightly grouted zone 17 has started. Grout pipes 26 have been installed along with the broken segments of demolition concrete and rocks 22 in a matrix of gravel 23. Both modified rebar 6 have been placed in the concrete grout 14 to tie the nonmodified section of rebar 15 to the wall. The opening in the block 5 below the fill level has been filled with gravel 23 and grouted in place by the initial grout 24. If expansive grout is used, then some of the grout will reach the temporary surface and expand to form a non-structural foam 25 that will need to be removed prior to placing an additional layer of fill.
FIG. 3D
(38) FIG. 3D shows the fill has been placed to the top of the wall. A subsequent light grouting 28 has been injected into the next layer of fill adjacent to the wall. Also, as more fill is placed additional grout pipes 26 were installed. The second grouting also has created a foam layer 25 on top of the grouted zone. It should be noted that the drawings in this presentation show only two layers of grouting. If the proposed height of the retaining wall exceeds what can be completed in two lifts, then this same procedure could be followed for as many lifts as is necessary. The primary objective is to create a thick Zone 17 of grouted material that will spread the short-term load created when the structural Zone 19 is tightly grouted.
FIG. 3E
(39) FIG. 3E show the final stage of the grouting. The primary grouted zone 29 is shown by hatch marking where the line spacing is finer than the initial lightly grouted zone 24 along the back side of the wall face. Depending on the ground conditions and the measures taken to protect the back drain system a second lightly grouted zone 19 as shown on FIGS. 2A and 3A may be needed along the back cut 2. The primary goal of FIG. 3E is to show that the size of the primary grouted zone 29 is critical to ensure the stability of the supported material 20. This is how all gravity walls are designed. Prior to construction the load from the supported material 20 is balanced against the resisting strength and mass of the planned primary grouted zone 29 by a ratio that is the factor of safety. Again, the grouting will result in a temporary excess grout foam 25 which will need to be removed. After the grouting is complete the back drain system should be tested to ensure that the grout 29 does not interfere with its gravity drain capacity to elevate hydrostatic pressure. Also shown is the boundary between the layers 43.
FIG. 4
(40) FIG. 4 shows the back cut 2 in perspective with the concrete cover 9 over the back drain material 10. Also shown is the location of a section view presented on FIG. 5. For the purposes of clarity, the fill materials 22 and 23 and the primary grout 29 are not shown in this view.
FIG. 5
(41) FIG. 5 shows a cross sectional view of the back cut 2 and the back drain material 10 and the concrete cover 9. Also shown in this view is the gravel fill 23 and the primary grout 29. This section view also includes the ground to be supported 20 which is being drained.
FIG. 6
(42) FIG. 6 shows a longitudinal section where the fill zone has been limited to gravel fill 23 only. This is to provide a test zone to determine the minimum strength of the primary grouted zone. This view is just prior to the grout being injected through the grout tubes 26. The bulk of the primary grouted zone is filled with demolition concrete and rock 22. The rock and concrete are placed in a random fashion and although they add strength to the structural gravity fill it cannot be counted upon unless there are minimum placement specifications. This figure is intended to provide a method to test the minimum strength of the design gravity fill. For the design presented herein the lowest strength material that is made up of the granular fill 23 at the maximum distance from the grout injection points 26. The figure shows two dashed lines 33 that are the limit of the test section. In the center of the test section is a rebar 30 that is covered with concrete nodes 31. After the gravel fill 23 has been grouted with grout around modified rebar 30 and its concrete cover 31, then it can be loaded with test pull out load 32. If the rebar is not pulled out with a predetermined minimum load then it is safe to assume that the remainder of the structural fill in Zone 18 forming the gravity wall has at least that amount of shear strength.
FIG. 7
(43) FIG. 7 shows a modified concrete block that forms the open cell 5 in the back of concrete block wall face 1. The blocks could either be cut to form the opening or by using a modified mold.
FIG. 8
(44) FIG. 8 presents a perspective view of an alternate block 35 that could be used as an alternative to the typical concrete block wall 1 described in FIG. 1. This block has the advantage of having a planter box hole 36 on the front side. Each planter box hole 36 has a one or more small drain holes 37 designed to drain from one block down to the next block below. Each block has grouting holes 38 that are sloped so that each row of blocks is set back from the one below so that part of the planter box 36 is exposed to allow plants to grow out of the wall. Each grout hole 38 has a smaller horizontal hole 39 that allows a modified rebar 6 to be inserted into hole 38. This is intended to tie the blocks 35 to the primary 28 and secondary 29 grouted fill, in fill Zones 17 and 18.
FIG. 9
(45) FIG. 9 is a top view of the block 35. This view shows the planter box 36 with its drain holes 37 and the grout holes 38 and the horizontal holes 39. This view also shows a section view FIG. 10.
FIG. 10
(46) FIG. 10 shows a cutaway section of block 35. This section is cut through the planter box 36 with a drain hole 37 and the grout hole 38 with its horizontal hole 39.
FIG. 11
(47) FIG. 11 shows a cross section of a wall of planter blocks 35 in front of the gap between the wall and the temporary back cut 2. The blocks are held in place by the rebar 4 in the connected holes 38. The bottom block is tied to the concrete foundation 7 by the rebar 4. In addition to the rebar 4 the blocks 35 are also tied to the grouted fill by modified rebar 6 that pass-through hole 39. From that point the rebar 6 is bent to align with the larger connecting holes 38. For clarity the figure does include the gravel 23 and rock 22 fill that would be grouted. The grout pipes 26 are shown because during construction they would be placed into the fill as the fill is placed. Also, the back cut 2 is shown with a drainage system. This is the same as discussed above where back drain material 10 is placed on the back cut 2 and protected from the grout by concrete cover 9 that leads down to a perforated pipe 11 surrounded by gravel 12 and wrapped in filter cloth 13.
FIG. 12
(48) FIG. 12 shows a perspective drawing showing the wall during construction from a point in front and slightly above the wall. On the left side there are four layers of planter blocks 35 set on top of the concrete foundation 7. The concrete foundation has rebar 34 sticking up at the same angle as the grout holes 38. The temporary back cut 2 has the back drain material 10 which is covered by the protective concrete cover 9. Also shown is one of the horizontal modified rebar 6. The fill material is not shown for clarity. As the wall is constructed it would be filled and grouted in a process similar to the method outlined for the concrete block wall above.
FIG. 13
(49) FIG. 13 Presents an alternative block 40 designed that could be used for a planter box 36 wall face with a slot 41 for the attachment of the modified rebar. This view shows two blocks 40 stacked such that the two slots 41 form a complete hole. Horizontal hole 39 is also shown.
FIG. 14
(50) FIG. 14 Provides a detail previously noted a modified rebar 6. This detail shows how the rebar 15 is modified with undulating concrete 44 cast on to the rebar such that weaker grout 24 and gravel 23 can transfer load to and from the rebar. These modified rebars are designed to ensure that the wall face 1 and the random fill will function as a unit.
