Bridges – Pier
Reexamination Certificate
2001-03-19
2002-09-17
Hartmann, Gary S. (Department: 3671)
Bridges
Pier
C405S231000, C052S749100, C052S749100, C052S749100
Reexamination Certificate
active
06449791
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to structures for bridges, roadway overpasses, and the like, and more specifically to a prefabricated pier system in which both the pier bases and pier caps are prefabricated at a manufacturing facility removed from the construction site, and shipped to the construction site for assembly. The pier caps then serve as permanent forms for the casting of the concrete pier cap beams for the structure.
2. Description of Related Art
Conventionally, bridge and overpass construction involves the on site construction of a series of temporary forms for casting reinforced concrete structural members, which forms are later removed once the concrete has cured. This is generally a relatively long and drawn out process, as it is necessary initially to construct forms for the pier foundations, then wait for the concrete to cure before forming further concrete structures above the foundations, with a further delay for curing before finally forming the pier caps and upper structure.
The time required for concrete to cure to full strength can take days or even weeks, depending upon the concrete mass, the mixture used, the curing process, the weather and temperature, and perhaps other factors as well. Yet, with conventional construction where a series of concrete components are formed progressively from the footings, some delay at each step of the way is required due to the time required for constructing concrete forms for each step and the curing time for each of the several concrete castings required. As a result, conventional bridge construction is a time intensive operation, even where many prefabricated components (prestressed concrete beams and slabs, steel girders, etc.) are used. The relatively large amount of time required also greatly increases the costs of such projects, due to the necessity of keeping the required labor force on the payroll through completion of the project or at least until that labor is no longer required. Obviously, some means of reducing much of the delay in such conventional construction is a desirable goal.
Accordingly, the present invention provides a solution to the above problem by providing a prefabricated pier system which eliminates most of the above steps in the construction of a bridge or the like. The present invention comprises the fabrication of a series of pier bases and pier caps at a manufacturing site remote from the bridge construction site, with the prefabricated components then being shipped to the construction site for installation.
The prefabricated pier bases are then set into a concrete footing at the construction site, with a corresponding series of steel pier members then installed and welded in the pier bases after the concrete footing has cured. The prefabricated pier caps are then installed and welded to the tops of the piers, with the caps serving as permanently installed forms for casting the transverse pier cap beams in place. The present construction thus greatly reduces the number of pours of concrete used in conventional bridge construction, and accordingly greatly reduces the time required and corresponding labor and other costs incurred in such construction.
A discussion of the related art of which the present inventor is aware, and its differences and distinctions in comparison to the present invention, is provided below.
U.S. Pat. No. 3,100,968 issued on Aug. 20, 1963 to Thomas E. Bourdon, titled “Marine Dock,” describes a dock structure adapted to temporary, seasonal installation in a body of water. The pier foundations comprise a series of heavy metal bases with two metal columns extending upwardly from each base, with no direct connection between the bases. A transverse beam is installed between each set of columns of each pair of bases. However, the transverse beam is a continuous structure, with no prefabricated pier caps being disclosed for the fabrication of the transverse beam on site. The Bourdon structure teaches away from the present permanently installed bridge construction, as the Bourdon structure must be relatively light for portability.
U.S. Pat. No. 3,662,559 issued on May 16, 1972 to Wesley K. Swift, titled “Anchorage For Boat Docks,” describes a floating dock structure with permanently installed piers. The pier structure comprises a pair of vertical columns linked together for stability, with concrete poured around the bases and link for security. Sleeves are attached to the dock structure to ride vertically along the pier columns, with the buoyant dock structure floating on the surface of the water as is well known in the art. Swift teaches away from the present invention with his buoyant dock structure movably secured to his vertical piers. He does not disclose any form of permanently installed pier caps immovably affixed to the vertical piers, nor the use of concrete for any of the upper structure of his pier, as is done with the present prefabricated pier structure.
U.S. Pat. No. 3,798,867 issued on Mar. 26, 1974 to Benjamin F. Starling, titled “Structural Method And Apparatus,” describes a method of repairing existing, previously installed support columns and piers, rather than the fabrication of new structures as provided by the present invention. Starling provides a casing or enclosure which is installed around the existing column, with a suitable agent (epoxy or concrete) being poured into the casing to surround and reinforce the existing column. While Starling discloses such a reinforcement method in combination with an HP (H section pier) member, he does not disclose any means of installing the HP member in the first place, nor any means of providing a prefabricated pier cap for forming the pier cap beam.
U.S. Pat. No. 3,894,374 issued on Jul. 15, 1975 to Pierre Faucheaux, titled “Set Of Elements For The Construction Of Buildings,” describes provision of a base plate which is imbedded in concrete to form a foundation structure. The base plate includes upright tubular members upon which vertical support posts are installed. A series of transverse beams are then installed atop the vertical posts. The posts and beams are hollow, and comprise non-recoverable forms for pouring concrete therein. However, the Faucheaux construction does not provide a series of prefabricated pier caps which are joined together to provide a pier beam form, as provided by the present prefabricated pier system.
U.S. Pat. No. 4,349,297 issued on Sep. 14, 1982 to Terrance J. Misener, titled “Boat Dock,” describes a dock structure having a series of separate pier foundations, with each foundation having a single tubular pier extending vertically upwardly therefrom. The piers are joined longitudinally by tubular stringers essentially defining the two edges of the dock, with a series of transverse plastic planks installed over the stringers. This construction does not require the transverse pier beams of the present bridge construction, and accordingly does not provide any prefabricated pier caps, as provided in the present pier construction. Moreover, the pier foundations of the Misener dock construction are not directly connected to one another, whereas the piers of each pier assembly of the present construction are all directly connected at their upper and lower ends, respectively by the corresponding pier foundation and pier cap beam.
U.S. Pat. No. 4,409,764 issued on Oct. 18, 1983 to John A. Wilnau, titled “System And Method For Reinforced Concrete Construction,” describes a system having a series of prefabricated hollow forms which are bolted in place and to one another, with a single pouring of concrete being made to fill all of the internally interconnected forms. Wilnau does not provide a single pier foundation structure which is set into a single corresponding footing dug therefor, as in the present pier system. Rather, each column of the Wilnau construction has its own, separate foundation. Moreover, Wilnau utilizes a pair of widely spaced reinforced concrete columns to support a lateral beam of reinforced concrete thereacross
Hartmann Gary S.
Litman Richard C.
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