Bridge System and Method Including Four Sided Concrete Bridge Units Adapted for Promoting Sedimentation
A method of providing an environmentally appealing region for water flow along an surrounded pathway tunnel involves providing a plurality of four-sided concrete bridge units in abutting relationship to create a surrounded pathway tunnel, one end of the tunnel located upstream along a water path and an opposite end of the tunnel located downstream along the water path; allowing water to flow through the surrounded pathway tunnel during a rain or other flow event; and providing a multiplicity of the four-sided bridge units with a corresponding bottom wall structure that interacts with the flowing water and earthen material in the flowing water such that capture and settling of the earthen material at locations along the tunnel occurs to produce a more natural water flow pathway along the tunnel.
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This application claims the benefit of U.S. Provisional Application Ser. No. 61/535,565, filed Sep. 16, 2011, which is incorporated herein by reference.
TECHNICAL FIELDThe present application relates to the general art of precast concrete bridge and culvert units, and to the particular field of four-sided bridge and culvert units.
BACKGROUNDOverfilled bridge structures are frequently formed of precast reinforced four-sided concrete units commonly referred to as arch units, arch culverts, box units or box culverts. As used herein the terminology four-sided bridge unit encompasses all of such structures. The units are used in the case of bridges to support one pathway over a second pathway, which can be a waterway. Four-sided bridge units have a bottom wall structure that facilitates on-site placement with reduced need for foundation preparation.
In the past, the four-sided bridge units of overfilled bridge structures have been constructed with bottom wall structures having a generally planar and continuous top surface and a generally uniform thickness. There is an increasing demand for construction efforts to provide more natural environments and/or to decrease impact on wildlife.
A four-side bridge unit adapted to create a more natural environment through the pathway defined by the bridge units and/or adapted to reduce impact on fish migrations would be desirable.
SUMMARYIn one aspect, a method of providing an environmentally appealing region for water flow along an surrounded pathway tunnel is provided. The method involves: providing a plurality of four-sided concrete bridge units in abutting relationship to create a surrounded pathway tunnel, one end of the tunnel located upstream along a water path and an opposite end of the tunnel located downstream along the water path; allowing water to flow through the surrounded pathway tunnel during a rain or other flow event; and providing a multiplicity of the four-sided bridge units with a corresponding bottom wall structure that interacts with the flowing water and earthen material in the flowing water such that capture and settling of the earthen material at locations along the tunnel occurs to produce a more natural water flow pathway along the tunnel.
The bottom wall structure of each of the multiplicity of the four-sided bridge units may be provided with a plurality of through openings such that at least forty percent of the bottom wall structure is open. For example, at least fifty percent of the bottom wall structure of each of the multiplicity of the four-sided bridge units may be open.
A lip structure may be provided at a top portion of at least some of the through openings, the lip structure facing upstream.
The plurality of openings of each bottom wall structure may be arranged in rows that extend along a span of the respective four-sided bridge unit.
The plurality of openings may be formed in the shape of elongated slots, each elongated slot defining a row, such that multiple beams are formed in the bottom wall structure and also extend along the span. At least one beam with a height that is greater than a height of another beam, the higher beam interacting with the flowing water and earthen material to reduce flow velocity and thereby enhance settling out of earthen material. By providing a lip structure along at least one beam, the lip structure extending in an upstream direction into an adjacent elongated slot, wash out of earthen material that has settled in the adjacent elongated slot can be limited.
The plurality of openings may be provided as multiple series of openings, each series of openings forming a respective row. By staggering openings of adjacent rows, nesting of the openings is achieved. By providing upper lip structure along one or more edges of at least some of the openings, the lip structure extending into its respective opening, wash out can be limited.
By providing the bottom wall structure of each of the multiplicity of the four-sided bridge units with a recessed portion, a low flow channel through which marine life can travel is created.
Referring to
The bottom, top and side walls are preferably precast as a single monolithic structure in a single casting operation. However, in certain implementations, one or more walls may be cast separately and then connected together by suitable connecting structure (e.g., reinforcing bars or by casting one or more elements separately and then placing that cast element in the formwork that is used to cast the final structure).
The bottom wall 12 of the unit 10 is shaped and configured to facilitate both sedimentation within and passage of marine life once the unit is installed. Specifically, the bottom wall 12 includes a plurality of elongated, spanwise extending through openings that extend completely through the thickness of the bottom wall 12. As shown, each elongated opening 24 has a length LO that is at least about sixty percent of the overall width of the unit LU (e.g., LO is at least about 70% of LU, such as for example, between 80% and 95% of LU). However, other variations are possible. Intermediate beams 26 separate the elongated openings 24 and serve to maintain a rigid connection between the lower ends of the side walls 14 and 16. Edge located beams 28 are also provided, thereby providing a continuous peripheral support surface at the lower side of the bottom wall. The lower surface of each beam 28 is preferably in common plane with the continuous peripheral support surface to provide added stability and distribution of loads. As shown, roughly about 40% to 60% (e.g., about 45% to 55%) of the lower side of the bottom wall makes up the support or resting surface of the bridge unit and the remainder (about 60% to 40%) is open via the openings 24. However, other variations are possible. Lengthwise extending reinforcement may be provided in each of the beams for structural integrity, with some continuity provided between that reinforcement and the reinforcement of the vertical side walls.
As seen in
As seen in
Referring to
In the illustrated embodiment, the connection of every other beam to the vertical side wall includes a haunch 46, which may include reinforcement, to resist the moment loads in the corners. Placing the haunches in a spaced apart manner, rather than providing a continuous haunch, can also help promote sedimentation. However, continuous haunches are also contemplated for some applications, as reflected in the embodiment of
While the embodiment of
Referring again to
An alternative embodiment of a four-side bridge unit 50 adapted for sedimentation is shown in
A further embodiment of a four-sided bridge unit 70 is shown in
It is to be clearly understood that the above description is intended by way of illustration and example only and is not intended to be taken by way of limitation, and that changes and modifications are possible. For example, other possible unit configurations are reflected in
Other embodiments are contemplated and modifications and changes could be made without departing from the scope of this application.
Claims
1. A method of providing an environmentally appealing region for water flow along a surrounded pathway tunnel, the method comprising:
- providing a plurality of four-sided concrete bridge units in abutting relationship to create a surrounded pathway tunnel, one end of the tunnel located upstream along a water path and an opposite end of the tunnel located downstream along the water path;
- allowing water to flow through the surrounded pathway tunnel during a rain or other flow event; and
- providing a multiplicity of the four-sided bridge units with a corresponding bottom wall structure that interacts with the flowing water and earthen material in the flowing water such that capture and settling of the earthen material at locations along the tunnel occurs to produce a more natural water flow pathway along the tunnel.
2. The method of claim 1, further comprising providing the bottom wall structure of each of the multiplicity of the four-sided bridge units with a plurality of through openings such that at least forty percent of the bottom wall structure is open.
3. The method of claim 2, wherein at least fifty percent of the bottom wall structure of each of the multiplicity of the four-sided bridge units is open.
4. The method of claim 2, further comprising providing a lip structure at a top portion of at least some of the through openings, the lip structure facing upstream.
5. The method of claim 2, further comprising arranging the plurality of openings of each bottom wall structure in rows that extend along a span of the respective four-sided bridge unit.
6. The method of claim 5, further comprising providing the plurality of openings in the shape of elongated slots, each elongated slot defining a row, such that multiple beams are formed in the bottom wall structure and also extend along the span.
7. The method of claim 6, further comprising providing at least one beam with a height that is greater than a height of another beam, the higher beam interacting with the flowing water and earthen material to reduce flow velocity and thereby enhance settling out of earthen material.
8. The method of claim 7, further comprising providing a lip structure along at least one beam, the lip structure extending in an upstream direction into an adjacent elongated slot and acting to limit wash out of earthen material that has settled in the adjacent elongated slot.
9. The method of claim 5, further comprising providing the plurality of openings as multiple series of openings, each series of openings forming a respective row.
10. The method of claim 9, further comprising staggering openings of adjacent rows to provide nesting of the openings.
11. The method of claim 10, further comprising providing upper lip structure along one or more edges of at least some of the openings, the lip structure extending into its respective opening.
12. The method of claim 2, wherein in each of the multiplicity of the four-sided bridge units haunch sections connect the bottom wall structure with side walls of the respective four-sided bridge unit.
13. The method of claim 1, further comprising providing the bottom wall structure of each of the multiplicity of the four-sided bridge units with a recessed portion to create a low flow channel through which marine life can travel.
14. An overfilled bridge system, comprising:
- a plurality of four-sided concrete bridge units arranged in abutting relationship to create a surrounded pathway tunnel, one end of the tunnel located upstream along a water path and an opposite end of the tunnel located downstream along the water path;
- wherein each of a multiplicity of the four-sided bridge units includes a corresponding bottom wall structure that is configured to interact with the flowing water and earthen material in the flowing water such that capture and settling of the earthen material at multiple locations along the tunnel occurs to produce a more natural water flow pathway along the tunnel.
15. The system of claim 14, further comprising:
- earthen material, deposited from flowing water, settled at the multiple locations.
16. The system of claim 14, wherein the bottom wall structure of each of the multiplicity of the four-sided bridge units includes a plurality of through openings such that at least forty percent of the bottom wall structure is open.
17. The system of claim 16, wherein at least fifty percent of the bottom wall structure of each of the multiplicity of the four-sided bridge units is open.
18. The system of claim 16, wherein at least some of the through openings include an upper lip structure at least part of which faces upstream.
19. The system of claim 16, wherein the plurality of openings of each bottom wall structure are arranged in rows that extend along a span of the respective four-sided bridge unit.
20. The system of claim 19, wherein the plurality of openings are configured as elongated slots, each elongated slot defining a row, such that multiple beams are formed in the bottom wall structure and also extend along the span.
21. The system of claim 20, wherein at least a first beam of each of the multiplicity of four-sided bridged units has a height that is greater than a height of another beam, the first beam configured to interact with the flowing water and earthen material to reduce flow velocity and thereby enhance settling out of earthen material.
22. The system of claim 21, wherein the first beam includes an upper lip structure extending in an upstream direction into an adjacent elongated slot and is configured to limit wash out of earthen material that has settled in the adjacent elongated slot.
23. The system of claim 19, wherein the plurality of openings are arranged as multiple series of openings, each series of openings forming a respective row.
24. The system of claim 23, wherein the openings of adjacent rows are staggered to provide nesting of the openings.
25. The system of claim 24, wherein multiple openings of each of the multiplicity of four-sided bridge units includes an upper lip structure along one or more edges, the lip structure extending into its respective opening.
26. The system of claim 16, wherein the bottom wall structure of each of the multiplicity of the four-sided bridge units includes a recessed portion to create a low flow channel through which marine life can travel.
27. A structure, comprising:
- a four-sided concrete unit buried in earthen material, the four sided bridge unit having a top wall, a bottom wall and first and second side walls connecting the top wall to the bottom wall, wherein the bottom wall includes multiple openings therein for allowing water to infiltrate through the bottom wall into the earthen material.
28. The structure of claim 27, wherein the plurality of openings of the bottom wall are arranged in rows that extend along a span of the four-sided bridge unit.
29. The structure of claim 28, wherein the plurality of openings are in the shape of elongated slots, each elongated slot defining a row, such that multiple beams are formed in the bottom wall structure and also extend along the span and act to transfer load to the ground below the unit.
Type: Application
Filed: Sep 13, 2012
Publication Date: Mar 21, 2013
Applicant: Contech Engineered Solutions LLC (West Chester, OH)
Inventors: Scott D. Aston (Liberty Township, OH), Michael A. Blank (Tacoma, WA), Edward H. Zax (Miramar Beach, FL)
Application Number: 13/613,710
International Classification: E01F 5/00 (20060101);