This invention relates to sheet piling material and to methods of making sheet piling. More particularly, this invention relates to sheet piling panels of the type that can be driven into the ground and connected to other similar panels to form a wall system, such as a sea wall or a retaining wall.
Sheet piling material, or sheet piling, is used to form continuous earth retaining walls or sea walls. Some of the uses of such walls include anchored bulkheads, shore-protection walls, soil retaining walls, water-control structures, cut-off walls to control ground water or hazardous chemical seepage, and trenching. The retaining walls or sea walls are typically formed by driving the elongated, planar sheet piling material vertically into the ground, with adjacent sheets being joined to each other to form a sturdy structure. The sheets are typically driven into the ground by pile driving, and the sheets must have sufficient stiffness to withstand the pile driver without buckling or otherwise failing.
Usually, the sheet piling material has a panel side edge configuration that enables interlocking of the panel edges with the edge of an adjacent panel. Sheet pilings can be made of many different types of material, including steel, aluminum, treated timber, extruded vinyl sheet material, and fiber-reinforced pultruded polymer material. Sheet pilings are used in different cross-sectional configurations, such as Z-shaped, U-shaped, and arch-shaped configurations, as well as a straight flat configuration. There are currently more than ten US-based and international steel sheet piling manufacturers who produce nearly 200 different sheet piling configurations.
Steel pilings are widely used for sheet piling material due to the superior strength and ductility of steel, the efficient use of the material in various cross-sectional configurations, and the ease of installation due to interlocking. However, there are two major drawbacks to using steel: corrosion and high weight. An alternative to steel is aluminum. While more corrosion-resistant than steel, aluminum sheet pilings are more expensive than steel. Another choice for sheet pilings is preservative-treated timber. While timber retaining structures are less expensive than metallic systems, they are coming under increased environmental scrutiny because of the preservatives used in the timber. Extruded vinyl sheet pilings can also be used for sheet pilings. The vinyl pilings are more durable that either the steel or the wood pilings, but they are expensive and suffer problems related to low strength and low stiffness. Pultruded fiber-reinforced polymer sheet pilings are stronger and stiffer than their extruded counterparts, but are more expensive.
The predominantly-used steel piles are typically made using hot rolling or cold forming, although other methods can be used. Hot rolled panels are produced by a steel hot-mill procedure in which the shape is reduced during a series of rolling stages to the final form. The thickness of flanges and webs can be adjusted and interlocks that connect one sheet pile to the other are shaped by the flow of hot metal. The shape of cold formed sheet piles is obtained by passing cold sheet steel through a series of rolls. The interlock is formed, for example, by bending the flange ends into a hook-and-grip cross-sectional configuration or a male-female ball and socket joint configuration. While there is no standard interlock design, interlocks are usually designed to provide a permanent connection of individual sheets in order to form a continuous, relatively water-tight or earth-tight wall, and to allow reasonably free sliding to facilitate installation. Also, the sheet piling material is designed to provide adequate pull strength in applications where the sheet material is under tension, and to provide a certain amount of swing.
It would be advantageous if there could be developed an improved sheet piling material, taking into consideration such factors as structural strength requirements, cost, ease of installation, durability, and absence of environmental problems.
The above objects as well as other objects not specifically enumerated are achieved by an elongated sheet piling panel having a length and width, and opposed side edges, and having elongated voids positioned within the interior of the panel, with the voids being oriented in the direction of the length of the panel, and the edges of the panel being configured to be connected to the edges of additional similar panels.
According to this invention there is also provided a plurality of elongated sheet piling panels connected into a sheet piling wall, the sheet piling panels each having a length and width, and opposed side edges, and having elongated voids positioned within the interior of the panel, with the voids being oriented in the direction of the length of the panel, and the edges of each panel being connected to the edges of adjacent panels.
According to this invention there is also provided a method of installing sheet piling panels, including providing a plurality of elongated sheet piling panels having a length and width, and opposed side edges, and having elongated voids positioned within the interior of the panel. The voids are oriented in the direction of the length of the panel, and the edges of the panel are configured to be connected to the edges of additional similar panels, with the voids extending from end to end of the panel, thereby forming through passageways. The panels are installed while advancing a fluid through the voids, from end to end of the panels.
According to this invention there is also provided a method of installing sheet piling panels, including providing a plurality of elongated sheet piling panels having a length and width, and opposed side edges. The panels have elongated voids positioned within the interior of the panel, with the voids being oriented in the direction of the length of the panel. The edges of the panel are configured to be connected to the edges of additional similar panels. The panels are aligned during installation by inserting an alignment protrusion into the voids of the panels.
Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.
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It can be seen that the voids 36 are positioned within the interior 44 of the sheet piling panel 12 rather than on the front face 46 or rear face 48 of the sheet piling panel 12. By positioning the voids 36 in the interior 44 of the panel 12, an I-beam type structure can be created between adjacent voids 36. The front and rear faces 46, 48 form the flanges of the I-beam configuration, and the material 50 between adjacent voids 36 form the column linking the flanges. The structure is similar to that of a truss. The areas of greatest stress on the sheet piling panel 12 during installation and operation of the panel are at the front and rear surfaces 46, 48, whereas the interior portion 44 of the sheet piling panel 12 is not subjected to the same amount of stress. Furthermore, the spacing between cells can be designed to optimize strength, stiffness and drivability. By positioning the voids 36 in the place where the stress is the lowest, savings in material can be realized without sacrificing overall stiffness and strength properties. The use of the voids 36 in the low stress area, i.e., interior portion 44, not only saves the cost of the removed material that would otherwise been in the interior 44 of the panel, but also reduces the weight of the panel without sacrificing overall strength or stiffness. The spacing between the voids 36 can be designed or configured as needed to optimize the strength, stiffness and driveability of the sheet piling panels for particular structural requirements.
Preferably, the voids are concentrated in the middle portions 54 of the sheet piling panel 12 or the middle portions 54 of the segments 22, 24, 26, rather than in the edge portions 56 of the panel 12 or in the intersection portions 26, 28. By configuring the panel 12 with the voids 36 present in the middle portions 54 of each wall segment 22, 24, 26, and with an absence of voids 36 in the edge portions 56 and intersections 26, 28 of the wall segments, the areas of greatest stress will be substantially void-free for improved structural integrity. It can be seen that by selecting where the elongated voids 36 are positioned within the sheet piling panels 12, the panels can be made stronger, and without increasing the amount of material or weight. For example, in a particular embodiment of the invention, the panel 12 has one or more voids 36 in the middle wall segment 22, and has none of the voids 36 in the flange wall segments 20 and 24. Other configurations with advantageous void placement can be used.
The sheet piling panels 12 can be made of any suitable material, including welded steel and aluminum. Preferably the sheet piling panel is made of a polymeric material. In one particular embodiment of the invention the sheet piling panels 12 are made using an extrusion process, with the voids 36 being created continuously as the panel is extruded. Although any extrudable material can be used, a preferred material is a thermoplastic material, and more preferably a vinyl material. Wood/plastic composites can also be extruded to make the sheet piling panels. In another particular embodiment of the invention the sheet piling panels 12 are made using a pultrusion process, with the voids 36 being created continuously as the panel is pultruded. Although any material capable of being pultruded can be used, a preferred material is a thermosetting resin, such as a polyester material.
It is to be understood that the sheet piling panels 12 can be provided with external reinforcement material. For example, fiber-reinforced polymer composite material can be applied directly to the sheet piling panels to augment the bending strength and bending stiffness. Preferably, this external reinforcement material is applied to the areas needing additional strengthening, such as, for example, at the top and bottom exterior surfaces of the panels 12. Other reinforcement materials can be used.
Regardless of how the panels are formed, if they are of a polymeric material they can be filled with any suitable filler, and can be reinforced with any suitable reinforcement material. Fillers and reinforcements suitable for filling and reinforcing polymeric materials for use in extrusion and pultrusion processes are well known to those skilled in the art. Examples include, but are not limited to, sawdust, natural fillers such as hemp or flax, chopped glass fibers, continuous glass fibers, glass mats, and glass fabrics.
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One of the benefits of providing the sheet piling panel 12 with the voids extending from end-to-end of the panel, thereby forming through passageways, is that a drilling fluid can be pumped through one or more of the voids to assist in driving the sheet piling panel 12 into the ground. The fluid can be a drilling mud, or air, as well as other materials. Other types of fluids, such as protective fluids or anchoring fluids can also be pumped through the voids. One method of pumping the drilling fluid through the voids is shown in
The sheet piling panels made according to the invention can be used to make sheet piling walls for such uses as sea-walls, anchored bulkheads, shore-protection walls, soil retaining walls, water-control structures, cut-off walls to control ground water or hazardous chemical seepage, and trenching, as well as other uses.
The principle and mode of operation of this invention have been described in its preferred embodiments. However, it should be noted that this invention may be practiced otherwise than as specifically illustrated and described without departing from its scope.
This application claims priority from U.S. Provisional Patent Application Ser. No. 60/529,712, filed Dec. 15, 2003, and entitled SHEET PILING PANELS WITH ELONGATED VOIDS.
Number | Date | Country | |
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60529712 | Dec 2003 | US |