US20040221532A1

US20040221532A1 - Prefabricated concrete support mechanism for a railroad track with integral rubber boot and method of manufacture

Info

Publication number: US20040221532A1
Application number: US10/430,690
Authority: US
Inventors: Tom Shillington; Clint Brookhart; James Baker
Original assignee: Individual
Current assignee: Oldcastle Precast Inc
Priority date: 2003-05-05
Filing date: 2003-05-05
Publication date: 2004-11-11

Abstract

A precast, concrete slab rail system is provided which includes a resilient boot positioned around at least one rail, and which can be reversibly installed or removed from the concrete slab without the use of attachment hardware or destruction of the concrete slab.

Description

FIELD OF THE INVENTION

The present invention relates to a rail support mechanism used for railroad mass transit roadway intersections, street running track and more specifically precast concrete structures with a removable rubber boot assembly.

BACKGROUND OF THE INVENTION

Existing rail support structures for mass-transit or railroad systems typically utilize timber or cast-in-place construction that is both relatively expensive to construct and difficult to repair. More particularly, where time consuming timber construction is not used, construction is often preformed using cast-in-place methods, which are also time consuming and therefore, expensive. Thus, there exists a need to minimize the time at the construction site. In addition, for cast-in-place systems, current rail replacement techniques typically involve using a jack-hammer to chip away the concrete in the vicinity of the rail that is to be replaced. This technique is both time consuming and expensive, and exposes the rail line, construction crew and any associated railroad or nearby automobile traffic to extended periods of construction repair. Other types of rail support systems have previously utilized rubber on polymer boots on sleeves around the rail. However, these systems are generally positioned within the concrete while curing, and are thus not removable, or require attachment hardware to retain the boot in operable position.

In addition, to the above problems, there is also a need to provide a rail support apparatus that minimizes noise generated by rail cars traversing the rails. Similarly, there exists a need to reduce and minimize vibrations associated with passing rail cars, and thus to improve the quality of the ride for passengers.

Finally, there is a significant need for a method of manufacture and construction which can streamline the construction schedule by offering precast concrete rail support structures that are manufactured in a controlled environment, can be easily transported to an installation, and can be quickly repaired. Thus, the present invention addresses these problems and industry needs, as described below.

SUMMARY OF THE INVENTION

In a first aspect of the present invention, an apparatus is provide that is a precast slab that includes at least one shaped trough for receiving a rail and a resilient rail support device. The precast nature of the slab allows the time consuming process of curing the concrete that forms the slab to occur in a controlled manufacturing facility. Precast slabs of customized or standardized dimensions can then be produced at a location remote from the construction site, and subsequently delivered for speedy installation, thereby reducing the time and associated cost of having construction crews located at the construction site.

It is another aspect of the present invention to provide a combination resilient rail support device, or boot, that holds the rail within the precast slab. Proper retention of the resilient boot and rail is achieved because the slab is made with a shaped trough that includes a recess with a pronounced shoulder for receiving and engaging a predetermined geometric profile on the resilient boot. Noise and vibration dampening is achieved by isolating the metallic rail within the precast slab by surrounding it with the resilient boot. Vertical retention of the resilient boots within the shaped troughs is achieved because the lateral recesses of the shaped troughs feature upper shoulders that prevent vertical dislodgement of the resilient boot and rail from the shaped trough during normal rail car operating conditions. The resilient boot also lends itself to easy future repairs of the rail, because the resilient boot can be removed from the precast slab by withdrawing it using properly sized equipment with the rail intact, thereby eliminating the need to jack-hammer or otherwise remove the rail from the rail support using difficult, time consuming and expensive techniques. Thus, in one aspect of the present invention, an apparatus is provided comprising a substantially concrete slab that includes a least one shaped trough comprising a first lateral recess and having an upper shoulder. The apparatus also includes a resilient boot shaped for insertion into the shaped trough, the resilient boot including a bottom portion and two side support portions, at least one of the side support portions including a lateral projection that inserts into the first lateral recess to impede vertical travel. In addition, the apparatus includes a rail positioned within an interior opening in the resilient boot, wherein the resilient boot supports the rail when the resilient boot and the rail are installed within the shaped trough.

In another aspect of the invention, a method is provided for manufacturing the precast slab portion of the precast rail support. The method of manufacture includes providing a form with a bock-out that properly forms the shaped troughs of the precast slab. The method includes providing block-outs with proper projections to create lateral recesses in the shaped troughs that will then receive the lateral projections of the resilient boot when the resilient boots and rails are installed in the precast slabs at the construction site. Other steps of the manufacturing process include placing structural reinforcement in the form prior to adding concrete to the form, and properly finishing the surface of the concrete for providing high quality, precast structural slabs for future placement at the construction site, and wherein the slabs are designed to withstand significant compressive loads. Thus, in one aspect of the present invention, a method of manufacturing a precast slab is provided comprising the steps of attaching at least one block-out to a precast form, the at least one block-out corresponding to a shaped trough in the precast slab, wherein the at least one block-out includes at least one recess projection corresponding to a lateral recess in the shaped trough and also includes a shoulder projection corresponding to an upper shoulder in the lateral recess of the shaped trough. Additional steps include applying a not-stick coating to the at least one block-out and an interior region of the precast form, and then adding concrete to the precast form to form the precast slab. Subsequently, additional steps include allowing the concrete to cure and then removing the at least one block-out and the precast form to expose the precast slab.

In yet a separate aspect of the present invention, a method of installing at the construction site is provided by preparing a subgrade to receive the precast slabs. The precast slabs are then lowered onto the prepared subgrade, and the resilient boots with the rail contained therein are lubricated and forced downward into the shaped troughs of the precast slab. Upon forcing the lubricated resilient boot and rails downward, the side projections of the resilient boot engage the lateral shoulders of the shaped troughs to hold the resilient boots in place without the need for accessory hardware. Thus, in one aspect of the present invention, a method for installing a precast rail system is provided, comprising the steps of preparing a subgrade to receive the precast rail support apparatus, followed by placing a precast slab of the precast support apparatus onto the prepared subgrade, wherein the precast slab includes at least one shaped trough extending along a longitudinal orientation of the precast slab, and wherein the shaped trough has a lateral recess that further includes an upper shoulder. Additional steps include positioning a resilient boot around a rail and then installing the resilient boot and rail into the shaped trough, wherein the resilient boot has a lateral projection to engage the lateral recess of the shaped trough under the upper shoulder, and wherein the resilient boot is impeded from being disengaged from the precast slab.

Additional advantages of the present invention will become readily apparent from the following discussion, particularly when taken together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of a completed concrete slab of the present invention; [0010]
FIG. 2 is a cross-sectional view of the embodiment shown in FIG. 1; [0011]
FIG. 3 is a detailed cross-sectional view of one of the two rails shown in FIG. 2; and [0012]
FIG. 4 is an alternate detailed cross-sectional view of one of the two rails shown in FIG. 2.[0013]

DETAILED DESCRIPTION OF THE INVENTION

While the present invention will be described more fully hereinafter with reference to the accompanying drawings, in which particular embodiments and methods of implantation are shown, it is to be understood at the outset that persons skilled in the art may modify the invention herein described while achieving the functions and results of this invention. Accordingly, the description which follows is to be understood as illustrative and exemplary of specific structures, aspects and features within the broad scope of the present invention and not as limiting of such broad scope. [0014]
In general, the present invention is a precast structural slab that is subsequently fitted with a resilient boot supporting a railroad track or mass-transit line. The combined slab/rail system is installed at road intersections, street running track and thus is heavily traveled. Referring now to FIG. 1, a perspective view of one embodiment of the precast rail support is shown. The present invention may be used for a mono-rail track or for a track arrangement having a plurality of rails. For explanatory purposes, FIG. 1 depicts a two track arrangement. The [0015] precast rail support 10 shown in FIG. 1 includes a precast slab 12 that is preferably formed of concrete, and more preferably, is formed of concrete having structural reinforcement members, such as, without limitation, steel rebar and/or wire mesh reinforcement, carbon fiber, or fiberglass. The precast rail support 10 shown in FIG. 1 includes two substantially parallel steel rails 14. Each rail 14 is situated within a shaped trough 16 where the slab material was blocked-out during manufacture of the precast slab 12. Each shaped trough 16 is shaped to receive a resilient boot 18 (not shown in FIG. 1), which in turn, serves as structural support and vibration damping for the rail 14.
Referring now to FIGS. 2 and 3, a side elevation view of the [0016] precast rail support 10 is shown in FIG. 2, with FIG. 3 illustrating an enlarged view of the left rail of FIG. 2. The shaped trough 16 preferably includes at least one lateral recess 20, and more preferably, a plurality of lateral recesses, with at least one lateral recess 20 situated on each side of the shaped trough 16. Each lateral recesses 20 preferably includes an upper shoulder 22 that serves to provide structural resistance and support for the resilient boot 18 assembly after insertion into the shaped trough 16.
Still referring to FIG. 3, the [0017] resilient boot 18 is preferably made of hard rubber, polymer, plastic or other type of resilient material, which is well known in the art and has a shape that upwardly supports the rail 14 after the boot 18 and rail 14 combination are inserted into the shaped trough 16. More particularly, the resilient boot 18 includes an interior opening 24 that holds the rail 14. In addition, the resilient boot 18 further includes a bottom portion 26. The bottom portion 26 serves to cushion the rail 14 within the shaped trough 16, thereby assisting with noise reduction and vibration dampening when the rail is being traversed by an overlying railcar or vehicle. The resilient boot 18 also includes two side support portions 28 that are preferably contiguous with bottom portion 26. The side support portions 28 preferably include lateral projections 29 that interlock with the lateral recesses 20 of the shaped troughs 16. The side support portions 28 resist lateral deflection of the rails 14 and further assist with noise reduction and vibration dampening when the rail 14 is being traversed by an overlying vehicle.
In a separate aspect of the invention, the [0018] side support portions 28 of the resilient boot 18 include at least one, and more preferably, a plurality of void spaces 30. In addition to aiding the noise reduction and vibration dampening characteristics of the precast rail support 10, the void spaces 30 allow the resilient boot 18 to be temporarily compressed during installation of the rail 14 and the boot 18 into the shaped trough 16. This feature allows the combination of the rail 14 and the resilient boot 18 to be lubricated, and subsequently squeezed and pushed into the shaped trough 16. Upon being pushed to the bottom of the shaped trough 16, the rail 14 and the resilient boot 18 expand to occupy the space of the shaped trough 16, including the lateral recesses 20 that are occupied by the lateral projections 29 of the side support portions 28. As shown in FIGS. 3 and 4, the void spaces 30 can be any variety of shapes, number, and orientation.
Without limiting the scope of this disclosure, in one preferred embodiment the two rail assembly shown in FIG. 1 is prepared in units having a length of approximately 17.5 feet and a width of approximately 8.0 feet, with the outer top edge of each shaped [0019] trough 16 positioned about 1.2 feet from the outside top edge of the precast slab 12. Each shaped trough 16 is about 0.7 feet wide at its top, with about 4.3 feet separating the inside top edge of each shaped trough 16. In addition, the precast slab 12 has an overall thickness of about 1.2 feet, with each shaped trough 16 occupying a depth of about 0.6 feet. Each long side edge of the precast slab 12 has a side edge taper of about 0.25 inch from top to bottom, with the top of the slab 12 having a narrower width than the bottom of the slab. Each rail is preferably, but not limited to, about 115 pound A.R.E.A., and the resilient boot 18 is preferably made of a non-conductive material.
In a separate aspect of the present invention, a method of manufacturing the [0020] precast slab 12 is provided and is now described. Initially, the block-outs that form the shaped troughs 16 are bolted into place with the precast forms that are used to form the precast slab 12. The block-outs include recess projections corresponding to the what will become the lateral recesses 20 of the shaped troughs. In addition, the recess projections include shoulder projections which correspond to what will become the upper shoulder 22 of the lateral recesses 20.
The interior surfaces of the precast forms including the exterior block-out surfaces are then oiled or otherwise receive a non-stick coating. Preferably, the forms are stood on edge during oiling to prevent the buildup of oil during its application. In addition, if necessary, the forms are also optionally cleaned prior to oiling to dislodge previously adhered concrete. This optional cleaning step is preferably performed while the form is placed in an upright position. After oiling, the form is placed in a horizontal position if not already in such an orientation, and the reinforcing materials, such as a rebar cage, carbon fiber, etc., is placed into position. In addition, lifting devices are preferably positioned such that they are cast into the [0021] precast slab 12. Concrete is then added to the forms. This step preferably includes vibrating and/or otherwise consolidating the concrete to prevent air voids.
Preferably, the surface of the concrete is then smoothed in the form using a device such as a screed or a straight edge. In addition, as the concrete goes into its initial set, the surface may optionally be troweled smooth, with burrs and high spots eliminated. In addition, it is also optional to slightly round what will be the bottom edges. Further optional steps include conducting quality assurance and/or quality control to check for items such as proper dimensioning of the forms prior to adding the concrete to the forms, as well checking proper finishing and flatness to the concrete surface prior to letting the concrete fully cure. After the concrete is allowed to cure, the form is turned over and all bolts and any accessories are removed from the forms as necessary. Hook cables or lifting means are then attached to the lifting devices, and the [0022] precast slab 12 is removed from the forms. Additional optional steps include spraying the cured precast slab 12 with a sealer to aid in inhibiting the detrimental impact of potential future environmental influences, such as chloride ions that may contact the precast slab 12 after salting. The finished slab is then placed into storage or shipped to a construction site.
In yet a separate aspect of the present invention, a method of installing the [0023] precast rail support 10 is provided. More specifically, installation is initiated by preparing or otherwise ensuring that the subgrade is prepared to receive the precast rail support 10. The precast slab 12 is then placed onto the prepared subgrade. Next, the rail 14 and the resilient boot 18 are fitted together. The exterior of the resilient boot 18 is then lubricated, such as by the application of a lubricant, for example grease or soapy water. The lubricated resilient boot 18 with the rail 14 in place is then downwardly forced into the shaped trough 16. Additional optional steps include placing a plurality of precast slabs 12 prior to installation of the resilient boot 18 and rail 14 assemblies into the precast slabs 12. In addition, quality assurance and/or quality control steps may be performed at any point during the installation process, to check such items as proper grade, proper lubrication, proper insertion of the resilient boot 18 and rail 14 assembly into the shaped trough 14, and proper rail alignment, etc.
The present invention lends itself to easy repair of the [0024] rail 14 and/or resilient boot 18. Repair is achieved by removing the resilient boot 18 and rail 14 form the shaped trough 16 by grasping the resilient boot 18 and rail 14 combination with equipment and vertically lifting the resilient boot 18 and rail from the shaped trough 16. Subsequently, a new rail 14 and or resilient boot 18 can be placed back into the shaped trough by lubricating the exterior of the resilient boot 18 and forcing the resilient boot 18 with the rail positioned therein down into the shaped trough. Thus, repairs can be made to the rail 14 or resilient boot 18 without the destruction of the concrete, and complete replacement of the slab.

To provide clarity to the drawings, the following is a list of the components and associated numbering as found in the drawings:



	#	Component

	10	Precast rail support
	12	Precast slab
	14	Rail
	16	Shaped trough
	18	Resilient boot
	20	Lateral recess
	22	Upper shoulder
	24	Interior opening
	26	Bottom portion
	28	Side support portions
	29	Lateral projection
	30	Void spaces

While various embodiments of the present invention have been described in detail, it is apparent that modifications and adaptations of those embodiments will occur to those skilled in the art. However, it is to be expressly understood that such modifications and adaptations are within the spirit and scope of the present invention, as set forth in the following claims. [0026]

Claims

1. A precast apparatus for supporting a transportation rail, comprising:

a) a substantially monolithic concrete slab including at least one shaped trough comprising a first lateral recess having an upper shoulder;

b) a resilient boot shaped for insertion into said shaped trough, said resilient boot including a bottom portion and two side support portions, at least one of said side support portions including a substantially lateral projection that operatively engaged with said first lateral recess to impede vertical travel of said resilient boot;

c) a rail positioned within an interior opening in said resilient boot, wherein said resilient boot supports said rail when said resilient boot and said rail are installed within said shaped trough.

2. The precast apparatus as claimed in claim 1, wherein said shaped trough further comprises a second lateral recess having an upper shoulder.

3. The precast apparatus as claimed in claim 1, wherein each of said two side support portions of said resilient boot include a lateral projection.

4. The precast apparatus as claimed in claim 1, wherein said upper shoulder at least partially confines said lateral projection.

5. The precast apparatus as claimed in claim 1, wherein said bottom portion and said side support portions of said resilient boot are contiguous.

6. The precast apparatus as claimed in claim 1, wherein said substantially concrete slab includes a plurality of shaped troughs.

7. The precast apparatus as claimed in claim 1, wherein said resilient boot comprises a rubber material.

8. The precast apparatus as claimed in claim 1, further comprising a lifting means for lifting said substantially concrete slab.

9. The precast apparatus as claimed in claim 8, wherein said lifting means comprises at least one of a lifting hook, an eye-bolt, a strap material, and a rope material.

10. The precast apparatus of claim 1, wherein said substantially concrete slab further comprises at least one of a wire mesh material, a carbon fiber material and a fiberglass material.

11. The precast apparatus of claim 1, further comprising a steel reinforcing member positioned in said substantially concrete slab below said resilient boot.

12. (Cancelled)

13. (Cancelled)

14. (Cancelled)

15. (Cancelled)

16. (Cancelled)

17. (Cancelled)

18. A method of installing a precast rail support apparatus, comprising:

a) preparing a subgrade to receive the precast rail support apparatus;

b) placing a precast slab portion of the precast support apparatus onto the prepared subgrade, the precast slab portion including at least one shaped trough extending along a longitudinal orientation of said precast slab and having a lateral recess, the lateral recess further including an upper shoulder;

c) positioning a resilient boot around a transportation rail;

d) installing said resilient boot and said transportation rail into said at least one shaped trough by compressing said resilient boot to temporarily reduce the overall size of the resilient boot, the resilient boot having a lateral projection to engage the lateral recess of said shaped trough under said upper shoulder, wherein said resilient boot is impeded from being disengaged from said precast slab.

19. The method of installing as claimed in claim 18, wherein said step of installing the resilient boot and rail further comprises the steps of:

lubricating the exterior of the resilient boot; and

forcing the resilient boot and rail downward into the shaped trough of the precast slab until said lateral projection of said resilient boot engages said lateral recess of said shaped trough.

20. (Cancelled)

21. The precast apparatus of claim 1, wherein said resilient boot further comprises at least one aperture positioned within said resilient boot to facilitate temporary compression of said resilient boot, wherein said resilient boot can be positioned within said at least one shaped trough;

22. The method of claim 18, wherein said resilient boot comprises at least one aperture which allows said resilient boot to be temporarily compressed during said installing step.