PRECAST CONCRETE WALL WITH ELEVATED ROADWAY AND METHOD FOR CONSTRUCTING WALL

Abstract

A precast concrete wall on a prepared subgrade, comprises standardized, precast, reinforced concrete foundation, wall and cap modules. The cap modules include parapets on opposed sides and an elevated roadway therebetween. A plurality of tie down rods, each extending through the cap modules, two or more courses of wall modules and at least partially into the foundation modules. An optional anti-tunneling barrier is provided in the subgrade, below the foundation. A method of constructing the wall includes specifying standardized reinforced concrete foundation, wall and cap modules so that they can be manufactured by multiple suppliers, and providing a logistical model to minimize shipping costs by matching each point of fabrication with the appropriate point of delivery.

Description

PRIORITY

Priority is claimed to U.S. provisional patent application Ser. No. 62/480,908 filed Apr. 3, 2017, which is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present disclosure relates to precast concrete wall structures and methods for constructing the same.

BACKGROUND OF THE INVENTION

Many existing wall structures can be readily circumvented by scaling over or tunneling under the wall, or by breaching or bypassing the wall. Some wall structures are unsuitable for rugged or remote sites. Others are prohibitively expensive to construct, or require specialized materials or highly skilled labor. Further existing wall structures frequently suffer from poor aesthetics. Finally, some wall structures require significant and costly maintenance. For these reasons, there is a recognized, but as yet unfulfilled need, for a wall structure that provides an effective barrier to the movement of people, animals and/or prohibited substances such as narcotics, that that can be constructed using conventional construction materials and non-specialized labor forces, and that can be efficiently constructed and maintained.

SUMMARY OF THE INVENTION

In accordance with the present invention, a wall structure is provided having three standardized, precast, reinforced concrete modules, namely 1) base or foundation slabs, 2) wall blocks, and 3) cap modules that include parapet walls on opposing sides and an elevated roadway therebetween. The three precast modules are secured together with tie down rods that extend from the cap, through plural courses of wall units and into the foundation slab or subgrade. The precast concrete modules can be fabricated at multiple locations remote from the job site and shipped efficiently to transloading points near to the site where the wall will be constructed. Barges, freight rail, and trucks can be utilized to efficiently move the modules from the sites of fabrication to the point of placement. Concrete batch plants on or near the job site are not required.

The method of the invention includes specifying standardized reinforced concrete foundation, wall and cap modules so that they can be manufactured by multiple suppliers. More specifically, drawings will be provided to detail the forming standards and appropriate methods to safely transport units to transloading points. The modular design enables the basic units to be fabricated by concrete contractors, not just established precast producers. Precasters may have some established advantages in some respects, but concrete contractors with yard cranes and laydown areas can fabricate forms to cast these units efficiently. A logistical model is provided to minimize shipping costs by matching each point of fabrication with the appropriate point of delivery. “Just-in-Time” delivery management can be employed to minimize the need for double handling and warehousing/storage of components. The three precast components can be manufactured by many businesses, which will allow for competitive pricing (reducing the cost of the wall) and involvement of small businesses, small disadvantaged businesses, woman owned businesses, HUBZONE businesses, and Service Disabled Veteran Businesses.

The wall is constructed by preparing a subgrade for the wall and an access road on at least one side of the wall, placing foundation modules end to end on the prepared subgrade, placing wall modules in courses, a first course being placed on the foundation modules, placing cap modules on an upper course of wall modules, and securing the cap, wall and foundation modules with a plurality of tie rods.

The elevated roadway enables observation on both sides of the wall from above, and reduces the need to maintain access road(s) at ground level. Thereby, the cost of building and maintaining roads on each side of the wall can be eliminated. Should brush or trees grow up adjacent to the wall, they can be removed with conventional chainsaw cutters on booms from tractor vehicles situated atop the wall. Also weed killer can be sprayed from atop the wall to control vegetation if desired. Another advantage of the elevated roadway is that no dust is created by the patrol vehicles traversing along the wall. The dust raised by patrol vehicles on unpaved roads is a maintenance issue and signals the location of patrol agents. Furthermore, the parapets on each side of the roadway provide safety for personnel and vehicles, and protection or cover in defense situations. At specific secure locations ramps permit access from ground level up to the roadway.

The wall itself is designed and constructed to prevent easy penetration using hand held power tools and/or vehicles. The shape of the wall is designed to make climbing or scaling the wall difficult if not impossible. At secure locations passage can be made through the wall using gates or other measures to limit access from one side to the other. Drainage as needed can be maintained or diverted through the wall via heavy grates that are integral to the wall. Undermining of the wall or tunneling under can be prevented by installing an optional but preferred cutoff barrier of steel or concrete panels in the subgrade below the foundation modules.

The size of the wall, e.g., height of the wall, width of the roadway, can vary depending on the location and purpose of the wall. The wall secures one area to be secured and separated from another area by intrusion of humans or animals from the other area. The footprint of the wall is less than if a wall is constructed and roadways maintained on both sides. The wall of the invention provides an effective barrier to the movement of people, animals and/or prohibited substances such as narcotics, can be constructed in rugged or remote sites using conventional construction materials and non-specialized labor forces, and can be efficiently constructed and maintained.

Further objects and advantages of the invention will become apparent from the following detailed description when read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a precast, steel-reinforced modular concrete wall under constructions in accordance with the invention.

FIG. 2 is a partial elevational view of an embodiment of the wall of the invention.

FIG. 3 is a horizontal plan sectional view of the wall.

FIG. 4 is vertical cross-sectional view of the wall.

FIG. 5 is a plan view of an embodiment of a wall module.

FIG. 6 is a transverse cross-sectional view of the wall module taken along line 6-6 of FIG. 5.

FIG. 7 is a longitudinal cross-sectional view of the wall module taken along line 7-7 of FIG. 5.

FIG. 8 is a plan view of an embodiment of a cap module.

FIG. 9 is a cross-sectional view of the cap module taken along line 9-9 of FIG. 8.

FIG. 10 is a plan view of an embodiment of a foundation module.

FIG. 11 is a cross-sectional view of the foundation module taken along line 11-11 of FIG. 10.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Turning now to the drawings, a precast concrete wall 10 is constructed on a prepared subgrade SG, as shown in FIGS. 1-4. The wall 10 comprises a plurality of precast, steel-reinforced concrete foundation modules 12, arranged end to end in a foundation course 14; a plurality of precast, steel-reinforced concrete wall modules 16 arranged in two or more courses 18; a plurality of precast, steel-reinforced cap modules 20 arranged end to end on the top of the wall modules; and a plurality of tie down rods 22. The tie down rods extend through the cap modules 20, two or more wall modules 16, and at least partially into the foundation modules 12. In one embodiment, the tie down rod comprises a 1-inch diameter (#8) grade 60 rebar with threaded ends.

To deter tunneling under the wall, an optional but preferred barrier 24 is inserted in the subgrade before the foundation modules 12 are placed. In relatively flat terrain a trenching wheel with cutting teeth can be used to cut a narrow slot in the underlying soil. The barrier 24 can comprise a reinforced concrete slab and/or steel sheets abutting at each joint. The annular space between the slot and the barrier can be backfilled with soil or more preferably filled with injected cement grout. In more rugged terrain (up to 45-degree slopes), where the subgrade is not comprised of competent bedrock, the aforementioned slot construction can be continued or sheet piles can be driven to provide an anti-tunneling barrier. Where competent bedrock is found immediately below the surface, the barrier may be unnecessary. The type of system used will depend on proximity to the required materials and the actual terrain and geology.

Turning now to FIGS. 10 and 11, the foundation for the wall comprises precast foundation modules 12 that are preferably connected together end to end. The foundation modules can be laid in a straight line or curved along a radius R as shown in FIG. 3. The subgrade SG on which the foundation modules 12 will rest will be graded and compacted and stabilized as necessary. Soft or unstable materials can be remediated using conventional techniques. The module 12 includes steel reinforcing bars 26 as shown in FIG. 11. The precast foundation modules 12 incorporate rod anchors 28. One embodiment of an anchor 28 comprises a threaded terminator mounted to an anchorage plate embedded in the foundation module and configured to receive and secure a threaded tie down rod 22. The ends of each foundation module preferably include pairs of tongue and groove connectors 30 whereby adjacent foundation modules can be connected together. Similarly, a top surface of module 12 preferably include male/female tongue and groove connectors 32 configured to receive connectors on the bottom of the wall units 16. Although tongue and groove connector are shown, other alternative connecting systems can be utilized. The foundation modules can be further secured to the subgrade with soil or rock anchors 34, as shown in FIGS. 2-4. Anchors can be installed at any angle.

Referring particularly to FIGS. 5-7, wall modules 16 comprise precast concrete blocks with one or more cavities 36. The cavities of at least a first course 18a, more preferably the lower 12 feet of the wall, are filled with sand as shown in FIG. 4 that will be extremely difficult to tunnel through should the face of the wall be penetrated. This will deter breach of the wall from either direction. Other barrier enhancing components such as steel plates 19 (see FIG. 3) or razor wire can be utilized alone or in combination with sand fill. Modules 16 included steel reinforcing bars 36. Each wall module includes one or more bores or channels 40 to receive tie down rods 22. Similar to the foundation modules, the wall modules 16 include tongue and groove connectors 42 on the ends of the modules to connect wall modules end to end. Likewise tongue and groove connectors 44 are provided on the top and bottom of each unit to connect wall modules in one course to other wall courses 18, foundation modules 12 below or cap modules 20 above. On steep slopes, the courses of precast wall modules 16 will be placed horizontally with modules cut or preformed to meet the necessary geometry as shown for example in FIG. 2.

Referring now to FIGS. 8 and 9, cap modules 20 comprise parapets 46 on opposing sides of the module with a roadway 48 formed therebetween. The geometry of the parapets as shown in FIGS. 1 and 4 are shaped, including rounded tops, so as to deter a grapple from being used to secure a rope or cable to it from either side. Contact strips or other electronic monitors optionally can be incorporated in the parapet that would alert and deter long ladders or man-lifts from being used to assist in overtopping the wall. As with the other modules, cap modules 20 comprises steel reinforcing 50. Cap modules 20 also include bores 52 for receiving tie down rods 22 and anchorage plates 54. Fasteners, such as washers and nuts (not shown) secure the upper ends of the tie down roads in pockets 56 in the cap modules. After the fasteners are secured, the pockets can be filled with grout. The cap modules 20 include tongue and groove connectors 58 on the ends of the modules to connect wall modules end to end. Likewise tongue and groove connectors 60 are provided on the bottom of each cap module to connect to wall modules 16 in a top course 18b.

Concrete specifications can vary based on the particular wall requirements. Air entrained concrete can be used. For most applications, the modules can be precast with standard 4000 psi concrete as available from established redimix plants meeting ASTM or ACI standards across the United States, which is cost efficient.

In one embodiment the width of the foundation modules is twice the width of the wall modules to spread the bearing load of the wall. The cap modules can also wider, more preferably twice as wide as the wall modules to deter scaling of the wall and to provide a roadway atop the wall. Multiple courses of wall modules are laid in running bond relative to each other and the foundation and cap modules as best shown in FIG. 2.

During wall construction temporary access roads 60 can be constructed one or both sides of the wall 10. Mobile gantry cranes 62 on caterpillar tracks, rails or wheels on flat terrain can be used to rapidly and efficiently construct the wall 10, as shown in FIG. 1.

In a preferred boarder wall embodiment, the wall modules are sixteen feet long, eight feet wide, five feet high, and weigh no more than 40,000 lbs. The wall modules include two 1-foot thick reinforced sections on both sides of the module that will significantly deter wall penetration. The foundation modules are sixteen feet wide, eight feet long and 18 inches thick. The cap modules have overall dimensions that are sixteen feet wide, eight feet long and five feet high. As such these precast modules can be shipped be conventional barge, rail and/or truck from fabrication plants across the country to the job site.

In the boarder wall embodiment, a roadway width of approximately twelve feet on top of the wall can be accessed by motorcycles, ATVs and other authorized vehicles. Autonomous vehicles and/or drones with sensors can be used to patrol the wall. At specific secure locations side, ramps can be constructed using mechanically stabilized earth or an elevator can be installed to allow access to the top of the wall with vehicles. At such locations, access will be controlled by guarded or technology controlled sensors and other devices. The vantage point from the roadway on top of the wall will reduce the need for maintaining roads on either side of the wall and can reduce the cost of aerial surveillance. The cap parapets adjacent the roadway provides safety and protection or cover in defense situations.

Where movement across or through the wall is desired, heavy retractable concrete gates on rails can provide controlled access under proper supervision.

Rainwater that falls on the elevated roadway will flow toward low points in the roadway where it can be conveyed down to drainage ways. These conveyance features are preferably located on the secure side of the wall. Surface drainage control can be provided through grading and ditches directed towards natural drainage features. Detention areas and infiltration areas will be constructed to minimize the need to provide drainage through the wall. Where such drainage is required, precast wall modules can be provided with heavily grated openings to permit the flow of water but restrict unauthorized penetration through the wall by man or beast.

The modular wall structure secured with spaced tie down rods is flexible to withstand seismic forces, elongation and contraction due to temperature changes, ramming by heavy equipment, differential settlement and weathering. The foundation slab modules are designed to reduce contact pressures to less than 2,000 psf, which will allow simple slab on grade construction; avoiding more costly deep foundations. The wall design minimizes the need for borings and geotechnical investigations by accommodating greatly varying ground conditions. Rock or soil anchors may be added in specific situations.

The wall can have varying shades of color as reflected in the color of the Portland cement used in the fabrication at each source of the precast wall components. The aggregates used in the precast elements will also represent the materials available at the location of manufacture. As an alternative, specific colors can be used and incorporated into the wall. Decorative designs, etchings or natural rock features can be stamped or molded into the exterior faces of one or both sides of the wall and cap modules if so desired. Also, notices, warnings and acknowledgements maybe be stamped or molded into exterior faces.

While particular embodiments of the wall structure and method of construction have been described herein, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the scope of invention as defined by the appended claims.

Claims

1. A precast concrete wall on a prepared subgrade, comprising:

a plurality of precast, reinforced concrete foundation modules arranged end to end in a foundation course,

a plurality of precast, reinforced concrete wall modules arranged in two or more courses, a first wall course on the foundation course,

a plurality of precast, reinforced concrete cap modules arranged end to end on an upper wall course, and

a plurality of tie down rods, each extending through one of the cap modules, two or more wall modules and at least partially into one of the foundation modules, an upper end of each tie down rod being secured to said one of the cap modules, and a lower end of each tie down rod being secured to said one of the foundation modules or subgrade.

2. A precast concrete wall as in claim 1, further comprising an anti-tunneling barrier extending into the subgrade under the foundation course.

3. A precast concrete wall as in claim 2, wherein the anti-tunneling barrier is at least one of the group of precast, steel-reinforced concrete panels, steel panels, and driven sheet piles.

4. A precast concrete wall as in claim 1, wherein the cap modules have precast bores for receiving the tie down rods and recesses in an upper surface of the cap modules for accommodating rod fasteners, wherein in the wall modules have bores for receiving the tie down rods, and wherein the foundation modules have a tie down rod anchorage elements.

5. A precast concrete wall as in claim 1, further comprising a plurality of soil or rock anchors securing the foundation modules to the subgrade.

6. A precast concrete wall as in claim 1, wherein the cap modules comprise parapet walls on opposed sides of the cap modules.

7. A precast concrete wall as in claim 1, wherein the cap module is wider than the wall module and a top surface is of the cap modules is configured as a roadway accommodating motorized vehicles.

8. A precast concrete wall as in claim 1, wherein the wall modules have one or more cavities and the cavities in at least the first wall course are filled with sand.

9. A precast concrete wall as in claim 1, wherein abutting surfaces of each of the foundation, wall and cap modules have mating connectors configured to mechanically connect adjacent modules.

10. A precast concrete wall as in claim 1 wherein the width of the foundation modules is substantially twice the width of the wall modules, and the length of the wall modules is substantially twice the length of the foundation modules.

11. A precast concrete wall as in claim 1 wherein the width of the cap modules is substantially twice the width of the wall modules, and the length of the wall modules is substantially twice the length of the cap modules.

12. A method of constructing a precast concrete wall, comprising the steps of

specifying precast, reinforced concrete foundation, wall and cap modules,

contracting with a plurality of suppliers to supply foundation, wall and cap modules in accordance with the specifications,

providing a logistical model to matching each point of supply fabrication with an appropriate point of delivery,

preparing a subgrade for the wall and an access roadway on at least one side of the wall,

placing foundation modules end to end on the prepared subgrade,

placing wall units in courses, a first course being placed on the foundation modules,

placing cap units on an upper course of wall units, and

securing the cap, wall and foundation modules with a plurality of tie rods.

13. A method as in claim 12, wherein the cap modules include parapets on opposed sides of the cap modules and a roadway for motorized vehicles between the parapets on the top of the wall.

14. The method of claim 12 wherein a mobile gantry crane is used to place wall and cap modules.

15. The method of claim 12, further comprising the step of constructing an anti-tunneling barrier in the subgrade prior to placing the foundation modules.

16. The method of claim 12, wherein the wall modules have one or more cavities and further comprising the step of filling the cavity of at least the first course with sand.

17. The method of claim 12 further comprising installing a plurality of soil or rock anchors through the foundation modules into the subgrade.