Hydraulic and earth engineering – Fluid control – treatment – or containment – Flow control
Reexamination Certificate
1999-06-30
2001-03-20
Bagnell, David (Department: 3673)
Hydraulic and earth engineering
Fluid control, treatment, or containment
Flow control
C405S124000, C138S107000
Reexamination Certificate
active
06203245
ABSTRACT:
FIELD OF INVENTION
This invention relates to a guard for protecting the exterior end portions of culverts which are commonly employed for subterranean stream or water drainage purposes and which are frequently found under roads, driveways or the like where water drainage is of concern.
BACKGROUND OF INVENTION
Tubular steel culverts are well-known in the art and are commonly employed as an underground conduit for water. A long-recognized shortcoming of conduits of this nature and others constructed from different types of material, is that the extremities of the culverts are susceptible to breakage or deformation as a result of increased loading in this area. This normally is attributable to the weight of traversing vehicles travelling over culverts which have not been buried deeply.
A further shortcoming of tubular culverts, no matter what their cross-sectional shape may be, is the collection of unwanted debris at the culvert ends which impedes the flow of water and which commonly results from material in the slope or embankment, through which the culvert extends, collecting at the lower portion of the water inlet or discharge ends of the culvert. In situations where embankment subsistence is regarded as a problem that must be addressed, a common practice is to reinforce the embankment area surrounding the free ends of the conduit by a retaining wall formed from stonework, wire mesh or the like.
Parker, in U.S. Pat. No. 546,245, issued Sep. 10, 1889, discloses a sectionalized tubular culvert or pipe conduit with provision, at the exterior ends of the culvert or pipe, for providing for a retaining wall constructed from sectionalized end wall sections, including sections which interlock with the grooves provided in the exterior ends of the conduit. A variation on this is also disclosed by Parker in U.S. Pat. No. 567,653, issued Sep. 15, 1898. In yet another variation, Simpson, in U.S. Pat. No. 786,059, issued Mar. 28, 1905, discloses an arched subway structure constructed from semi-circular shell sections and which, at its free ends, is provided with an outwardly-projecting semi-circular flange, and against the interior face of which, reinforcing wall sections abut.
While the foregoing prior art references are also representative of other types of retaining walls used with conduits, tunnels or the like, they are not concerned with protecting the end portion of a conduit which, as a result of its installation or location, is exposed to periodic loading which can break, or in the case of metal culverts, deform at the ends of the culvert, and which can also result in the collection of unwanted debris in the inlet and discharge areas of the culvert.
SUMMARY OF INVENTION
The novel culvert guard of my invention is designed to surround and protect the exterior end portion of a culvert from excess loading and simultaneously create a retaining wall section about the culvert end, and particularly on either side of the culvert end, to thereby assist in reducing the collection of embankment debris in the inlet and outlet areas of the culvert. Additionally, because each culvert end guard of my invention is assembled from two substantially identical or like half sections, when guards are used at either end of a conduit, at the time the conduit is laid down in a trench, it can conveniently and advantageously be positioned in location on the bottom half sections of the guards prior to the placement of the upper mating half sections, and then backfilling the trench.
In accordance with my invention, the end guard which is used to surround and protect an exterior end portion of a culvert is assembled from first and second like half shell sections. Each half shell is T-shaped, including a control limb portion and two end limb portions, imparting to it its T-shape configuration and also having an exterior surface and an interior surface. The interior surface is characterized by an open-ended channel of predetermined size and shape that is centrally disposed in and which extends in a direction along the central limb portion. The balance of the interior surface is made up of contact areas located on either side of the channel, such that when the first and second half shell sections are brought together in opposed and closed shell relationship, they engage one another along their respective contact areas and form from their respective channels, a passageway for the culvert.
The size and shape of the open-ended channel is dictated by the cross-sectional shape and dimensioning of the culvert two half shells are intended to surround and which, for example, can be oval or square but, most commonly, are circular in cross-section. Thus, when used with a conduit having a circular cross-section, the open-ended channel of each half shell is in the form of a half pipe which has a radius that is no less than the exterior radius of the tubular culvert, so as to receivingly accommodate at least half of the conduit when positioned therein.
The half shell sections, while being identical or substantially identical one to the other, are preferably separately formed from any suitable material, such as precast concrete. In this regard, the exterior surface of each half shell can include a T-shaped face and a surrounding side wall. The contact areas forming part of the interior surface and which are located on either side of the open-ended channel, may be offset relative one to the other, but preferably lie in the same plane and in a plane parallel to the plane of the T-shaped face.
The first and second half shell sections can be identical or substantially identical. In this latter regard, the first half shell section when used as the top half shell section, may slightly differ from the second, lower, half shell section, by having that portion of its is sidewall which extends from one free end to the other free end of its two end limb portions (and which forms one half of the outermost sidewall of the culvert guard when installed), extend downwardly and outwardly from its T-shaped face rather than perpendicular to the T-shaped face. In other words, the outermost sidewall of the top half shell section can project outwardly over the outermost sidewall of the underlying or lower half shell section and by doing so, provides a zone adjacent the outermost sidewall of the lower half shell section which is lees susceptible to water blockage by embankment subsistence.
When the two half shells are brought together in opposed and closed shell relationship to thereby surround and protect the exterior end portion of the culvert, means can also be provided for maintaining the two half shells in this relationship. Suitable means includes the provision of a plurality of rod receiving holes which each extend fully through the exterior surface and the contact areas of the interior surface. Once interconnecting rods are inserted through the holes of mating half shells, lateral movement of one shell section relative to the other is not possible.
Another form of maintaining the two half shells in opposed and closed shell relationship is to provide for, on each half shell, at least one rib which projects outwardly from the contact area on one side of the open-ended channel, and an equal number of rib receiving depressions which are correspondingly located in the contact area on the other side of the channel. When the rib of one half section is inserted into the rib receiving depression of the other half section, the two sections become interlocked and resistant to relative lateral displacement.
As will be appreciated, the two end limb portions of each T-shaped half shell which extend laterally on either side of the end of the culvert, function as a reinforcing wall for the embankment about the culvert and also create an enlarged water collection area or basin at the ends of the culvert.
REFERENCES:
patent: 546245 (1895-09-01), Parker
patent: 567653 (1896-09-01), Parker
patent: 786059 (1905-03-01), Simpson
patent: 915266 (1909-03-01), Boyd
patent: 1098766 (1914-06-01), Scully et al.
patent: 2958200 (1960-11-01), Russell
patent: 5971663 (1999
Bagnell David
Klotz Trevor C.
Pechhold Alexandra K.
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