Hydraulic and earth engineering – Fluid control – treatment – or containment – Flow control
Reexamination Certificate
2001-03-23
2002-11-05
Will, Thomas B. (Department: 3671)
Hydraulic and earth engineering
Fluid control, treatment, or containment
Flow control
C405S132000, C403S338000
Reexamination Certificate
active
06474907
ABSTRACT:
TECHNICAL FIELD
This invention relates to a novel archway apparatus which is useful for building in wilderness areas, access roads, such as logging roads and secondary roads, over waterways such as streams and creeks, while causing little or not impact to sensitive wilderness environment.
BACKGROUND
Typical road building processes in wilderness areas require the use of culverts in watershed areas to enable water to flow under the roadways built in those areas. Such culverts are typically constructed of corrugated steel pipe (CSP) or polyethylene-(HDPE) pipe. Installing these culverts requires that the creek or stream bed be disturbed or altered. This silt disruption upsets the natural habitat of the creek bed and causes harmful silt to move downstream. This can damage sensitive fish (including salmon) spawning beds. Once a culvert is installed, further problems arise. Water flowing through the confined interior of the culvert has higher than normal velocity. This occurs particularly during high water levels. Water flowing from the outlet (downstream) side of the culvert is turbulent and causes erosion in the creek bed area downstream of the culvert. Furthermore, since movement of the water through the culvert is restricted, water tends to back-up on the inlet (upstream) side of the culvert. This can cause erosion on the banks upstream of the culvert.
The use of corrugated steel pipe (CSP) in building road culverts has been widespread. Such culverts rust over time, thereby causing an unnatural form of iron oxide pollution in the streams. CSP pipes are usually galvanized with zinc to reduce rusting. However, the zinc, in itself, as a natural process of erosion, releases a certain amount of zinc metal toxins to the waterways. This is in addition to the rust that is imposed on the environment after the zinc galvanization has corroded away. In many cases, old rusted CSP installations deteriorate structurally in strength to a point where they must be replaced. Replacement further disturbs the creek and stream beds.
Over the years, numerous attempts have been made to avert such damage to creek and stream beds. Furthermore, there has been increasing pressure to preserve the environment and provide a managed balance between industrial and recreation use and conservation of natural resources. The Federal Department of Fisheries and Oceans (D.F.O.) and the British Columbia Ministry of Environment are in the process of changing their policy so as not to allow the replacement of CSP culverts with any product that disrupts the stream or creek beds. See a complete report of these requirements: Harper, D.J. and Quigley, J. T. 2000. No Net Loss of Fish Habitat: An Audit of Forest Road Crossings of Fish-Bearing Streams in British Columbia, 1996-1999.
Canadian Technical Report of Fish and Aquatic Sciences
2319 (a 44 page report identified as CTR 2319).
Alternatives such as suspended wooden trestle bridges, arches of rolled plate steel, and culverts of HDPE cut in half, and, of late, a material similar to CSP, have been used to overcome the typical problems associated with road building in environmentally sensitive areas. However, some of these alternative systems are costly and span distances are limited. Steel structures of any design suffer from the problem of rusting and thus contamination. In most cases, it is necessary to use heavy equipment for placement of the new heavy structures. This causes further disruption.
The Federal Government of Canada has embarked on a program known as “Harmful Alterations, Disruption or Destruction of Fish Habitat”(H.A.D.D.), 1998.
A search of the art reveals that different culvert attempts and designs have been published. A recent design is the use of ¾″ plate steel that has been developed by Sanders & Company Contracting Ltd., sold under the trade-mark ENVIRO-PIPES. A simple calculation of the weight of ½″ plate steel confirms that a mobile crane is required to place this plate structure in a creek bed or remove this structure from the creek bed once the road requires decommissioning. Furthermore, a structure of this size would require a low bed and truck for transport to and from the installation site.
Another product on the market comprises a non-corrugated plastic arch. This arch is discussed in the December 1999 issue of
Forest Engineering Research Institute of Canada—Eastern Division.
This product is manufactured by KWH Pipe (Canada) Ltd. and is known as the KWH Arch. This product is available to a maximum diameter of 2.3 meters. Once the pipe is cut in half, it expands to 24% larger than its original diameter. Thus the structure becomes somewhat less than half-circle. Since there are no footings along the edges that contact the ground, and with the tension placed on the structure upon installation, the product would tend to sink or be depressed into the banks of the creek bed. This therefore causes further deflection of the pipe from its original less than half circle configuration and compromises the integrity of the structure. There is a real possibility of collapse of the structure under load.
A further culvert product is supplied by Armtec Construction Products. Their product is called a “Mini Span Bridge”. The Mini Span I has a maximum width of 1800 mm. The Mini Span is brought to the site as a one-piece assembled structure. The Mini Span II is available to a width of 3660 mm, making transport of this structure difficult and costly. Required footing and structural support demands trained installers and heavy equipment for installation. This product is also made of galvanized material and other steel components that require treatment to avoid rusting.
An article by Soleno Inc. in the November/December 1999 issue of the
Canadian Forest Industries
describes a product referred to as “SolArc”. Installation of the SolArc product requires 8 to 10 cubic meters of logs (one load) to use as backfill. This is most likely required to avoid collapse of the structure under normal use as a crossing. Great difficulty would be encountered removing these logs and structure during road decommissioning. It would be difficult to avoid disturbing the creek bed with falling debris. Furthermore, the footings that are part of the SolArc structure would reduce the area of flow of the water.
SUMMARY OF INVENTION
The invention is directed to an environmentally compatible archway module for creek or stream construction comprising: (a) a curved body; (b) a first flange on a first end of the body; (c) a second flange on a second end of the body; (d) a first footing contact area at the base of a first side of the body; (e) a second footing contact area at the base of a second side of the body; and (f) a reinforcing member in a region of the body between the first flange and the second flange.
The curved body can be semi-cylindrical, the first and second flanges can have bolt holes therein, the first and second footing contact areas can be semi-cylindrical and concave, and the exteriors of the first and second footing contact areas can be planar.
The module can include a semi-circular protective cap for fitting over adjacent flanges when two archway modules are placed adjacent one another. The archway can include bolts securing the flanges of adjacent modules together. In one embodiment, the first and second flanges may be parallel to one another. In an alternative embodiment, the first and second flanges may be at an angle with one another.
There can be at least three modules and some adjacent flanges can be bolted together, and some adjacent flanges not bolted together, but having protective caps over the flanges.
The archway can include a first headwall at a first end of the adjoining modules and a second headwall at a second end of the adjoining modules. The first and second headwalls can be planar and congruent with the first and second flanges and can be bolted to adjacent flanges of the proximate modules.
REFERENCES:
patent: 832017 (1906-09-01), Hummel
patent: 838263 (1906-12-01), Moore et al.
patent: 1197966 (1916-09-01), Sweney
patent:
Nybo Barry C.
Semotiuk Robert A.
Mayo Tara L.
Oyen Wiggs Green & Mutala
Will Thomas B.
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