Patent Application
20170191268
The invention relates to a structural concrete body, and more particularly to a pre-stressed concrete body.
Concrete cast bodies, and particularly posts, are known and commonly used to provide support in construction and building applications. The concrete that forms the post is strong in resisting compressive forces, but is weak in tension. In order to use concrete posts in tensile applications, manufacturers reinforce the concrete post with additional material, commonly steel rebar, which bears the tensile load. Rebar can take many different forms and is placed in a myriad of orientations within the post depending on the application. The cost to manufacture such a reinforced concrete post dramatically increases in proportion to the quantity of rebar used.
Emeca SPEusa (http://www.emeca-speusa.com/pre_casting_jointed_piles.shtml) thus discloses a concrete post and method of manufacturing a concrete post containing pre-stressed reinforcing material. Pre-stressing, or placing the reinforcing material under a tensile load while the concrete is curing, results in a compressive load applied to the concrete body once the concrete has cured and the reinforcing material is separated from the tensile force. For a given quantity of reinforcing material, the additional compressive load resulting from pre-stressing offers added tensile strength in comparison to typical non-stressed applications. Pre-stressing thus lowers material cost for creating a similarly strong or stronger concrete post.
Emeca SPEusa further discloses a face plate cast to the concrete post as it cures during the manufacturing process (http://www.emeca-speusa.com/jointed_pile_installation.shtml). The face plate permits connection to another concrete post already installed in a foundation, and includes a separate mirrored, interlocking face plate at the installation surface. The face plates are fastened via locking pins driven into the concrete and face plates (http://www.emeca-speusa.com/jointed_pile_installation.shtml; https://en.wikipedia.org/wiki/Pile_splice).
The locking pins of known pre-stressed concrete posts are not removable; an attached concrete post cannot be un-attached and re-attached in a different location. This severely limits the versatility and usefulness of pre-stressed concrete posts.
An object of the invention, among others, is to provide a removable pre-stressed concrete body. The concrete body is elongated with a first end and an opposite second end. A plurality of reinforcement strands within the concrete body extend from the first end to the second end and impart a compressive force. A baseplate is disposed on the first end, and has a plurality of first fastener receiving holes and a plurality of second fastener receiving holes.
The invention will now be described by way of example with reference to the accompanying figures, of which:
The invention is described in detail below with reference to embodiments of a pre-stressed concrete body and a method of manufacture of a pre-stressed concrete body. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and still fully convey the scope of the invention to those skilled in the art. Each of the described examples are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the invention by referring to the figures.
The concrete portion 20 forms an elongated shape with a first end 21 and a second end 22, as shown in
The reinforcement strands 30 run from the first end 21 to the second end 22. The strands 30 may, for example, be high tensile steel, or any other similar material known to those with ordinary skill in the art.
The baseplate 50, as depicted in the plan view of
In an alternative embodiment shown in
A method of manufacturing the pre-stressed concrete body 10 will now be described primarily with reference to
The manufacturing process begins with the formation of a mold structure including temporary plates 81 and 82 at each end to create an elongated form with an open top. Both first temporary plate 81 and second temporary plate 82 have a first plurality of holes 83, while first temporary plate 81 additionally has a second plurality of holes 84.
Next, reinforcement strands 30 are strung through the first plurality of holes 83 on temporary plate 81, within and along the length of the mold, and through the first plurality of holes 83 on temporary plate 82, extending outside of the mold on both ends.
Hydraulic jacks (not shown) supported and restrained by the mold are then used to apply tension to the reinforcement strands 30. In an exemplary embodiment, the jacks stretch the strands 30 to between seventy and eighty percent of their ultimate strength. With the strands 30 under tension, concrete is poured into the mold. Before the concrete cures, first fasteners 40 are inserted through the second plurality of holes 84 on temporary plate 81 and into the concrete contained within the mold. As shown and described above with reference to
The mold may be used to form one concrete portion 20 containing the reinforcement strands 30, as shown in
The strands 30 are severed at the temporary plates 81 and 82 when the concrete hardens. When removing the hardened concrete 20 from the mold, the temporary plates 81 and 82 are also removed, leaving a concrete portion 20 containing reinforcement strands 30 with a portion of first fasteners 40 extending out of the first end 21.
Lastly, the baseplate 50 is permanently installed on the first end 21 of the pre-stressed concrete portion 20. The first fastener receiving holes 51 of the baseplate 50 fit over the portion of the first fasteners 40 extending out of the first end 21, and the baseplate 50 is fastened to the first end 21 using the washers 53 and nuts 54 as depicted in
The completed pre-stressed concrete body 10 can be used in a wide variety of applications, including, but not limited to, support for highway noise barriers, support for an earth retaining wall, as elements of building construction, and as a free-standing pole support. The body 10 is installed on a surface, for example, an existing foundation. As shown in
In another embodiment of the pre-stressed concrete body 10, the circumference of the concrete portion 20 includes indentations 110, as depicted in
The embodiments of the invention described above offer a number of advantages in comparison with the prior art. The pre-stressed concrete body 10, by virtue of including the pre-tensioned reinforcement strands 30, can bear a same or greater load at a lower cost than a conventional non-stressed concrete body. The decreased quantity of reinforcing material required also lessens the weight of the concrete body, improving maneuverability. Furthermore, the baseplate 50 does not require damaging the concrete in order to fasten the body to a surface or foundation, and can be undone without affecting the future load-bearing performance of the body. This removability can save costs and ease the use of pre-stressed concrete bodies in myriad ways, including recycling previously used concrete bodies and lessening the time required to remove and replace a damaged body. Additionally, the embodiment of the mold permitting the simultaneous pouring of multiple concrete bodies conserves time while limiting reinforcement strand waste.
Although embodiments of the present invention have been shown and described, the present invention is not limited to the described embodiments. Suitable results may be achieved if the described techniques are performed in a different order, and/or if components in a described system, architecture, device, or circuit are combined in a different manner, and/or replaced or supplemented by other components or their equivalents. It would be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
