PRE-STRESSED CONCRETE FOUNDATION FOR A MARINE BUILDING STRUCTURE

A pre-stressed marine foundation includes a concrete base to be placed on a sea bed, a body placed over the concrete base, and a concrete platform. The body includes closed sections, each closed section composed of a pre-stressed concrete segmented column that has an upper extreme and a lower extreme joined at the base, and opened sections joined at sides of the closed sections, each open section composed of a structured beam frame. The concrete platform is joined at the upper extremes of the concrete columns.

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Description
PRIORITY STATEMENT

The present application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application Ser. No. 61/352,296 to the inventors, filed Jun. 7, 2010 and entitled “PRE-STRESSED CONCRETE FOUNDATION FOR A MARINE BUILDING STRUCTURE”, the entire contents of which is hereby incorporated by reference herein.

BACKGROUND

1. Field

The example embodiments in general relate to the foundation for a marine building structure, and more specifically to a pre-stressed foundation to support off-shore marine structures such as wind power generators.

A portion of the disclosure of this provisional patent application document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office file or records, but otherwise reserves all copyrights associated with this document.

2. Related Art

Certain prior art teaches diverse marine foundations, for example, U.S. Pat. No. 4,304,506 which describes a marine structure that has a base and foundation means projecting itself deep in the base to set itself in a deep marine bed, the foundation comprising a system of walls with means to hold it in both sides of the wall.

U.S. Patent Application Publication No. US-2009/0191004 describes a design method and construction of a cubic formed marine foundation structure. The method includes a first stage having a design phase and a second stage having an installation phase. In the first stage, design parameters are given relative to the weights set on the foundation structure, the profile of the grounds over its installation location, allowable tolerances in installation, certain parameters utilized to calculate the minimum diameter and longitude of the cube's borders. The size of the cube is utilized to simulate load situations and penetration in the foundation terrain. The foundation, as the majority of the foundations of the prior art, relates to marine currents and therefore are designed to resist these currents.

SUMMARY

An example embodiment is directed to a pre-stressed marine foundation. The foundation includes a concrete base to be placed on a sea bed, and a body placed over the concrete base. The body includes a plurality of closed sections, each closed section composed of a pre-stressed concrete segmented column, each column having an upper extreme and a lower extreme joined at the base, and a plurality of opened sections joined at sides of the closed sections, each open section composed of a structured beam frame. A concrete platform is joined at the upper extremes of the concrete columns.

Another example embodiment is directed to a pre-stressed marine foundation comprising a concrete base, a body placed on the concrete base, the body having a triangular cross-section formed by three equally-spaced segmented pre-stressed vertical concrete columns with three beam frames joined in an open space between the three spaced segmented vertical concrete columns, and a concrete platform joined to upper ends of the vertical concrete columns.

Another example embodiment is directed to a pre-stressed marine foundation comprising a base having a sloped side surface, a tower placed on the base, the tower having a triangular cross-section formed by a plurality of spaced segmented pre-stressed vertical concrete columns with a plurality of reinforcing beam frames joined in open spaces between the spaced segmented vertical concrete columns to realize a tower with annular structure and said triangular cross-section, and a platform joined to upper ends of the vertical concrete columns.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments will become more fully understood from the detailed description given herein below and the accompanying drawings, wherein like elements are represented by like reference numerals, which are given by way of illustration only and thus do not limit the example embodiments.

FIG. 1 shows a perspective view of the pre-stressed concrete marine foundation in accordance with an example embodiment.

FIG. 2 shows an elevated lateral view of the pre-stressed concrete marine foundation in accordance with an example embodiment.

FIG. 3 shows an upper view of the pre-stressed concrete marine foundation in accordance with an example embodiment.

FIG. 4 shows a lower view of the foundation according to an example embodiment.

FIG. 5 shows a view of a concrete segment according to an example embodiment.

FIG. 6 shows a view of the joint of the column with the beam frame according to an example embodiment.

DETAILED DESCRIPTION

As to be shown and described in more detail hereafter, the pre-stressed (post-tensioned) concrete marine foundation of the example embodiments, due to its structural design and combination of materials of which it is made, is designed so as to provide a stronger resistance, durability and support than concrete and steel marine foundations of the prior art.

As to be shown and described in more detail hereafter, the example embodiments are directed to a ring-shaped or annular pre-stressed concrete marine foundation structure that is designed to resist marine currents, and which may offer a stronger resistance, settling, support to mount and/or place or mount different structural elements thereon.

The following parts list is provided to aid the reader and should be occasionally referred to for convenience of understanding.

PARTS LIST

    • 10 pre-stressed marine concrete foundation;
    • 11 concrete base;
    • D1 greater diameter of the base;
    • D2 lesser diameter of the base;
    • 116 base sloped surface;
    • 117 aperture in the base;
    • 118 step in the base;
    • 12 body;
    • 13 closed sections;
    • 13a, 13b and 13c pre-stressed concrete columns;
    • 130 concrete segment;
    • 14 opened sections;
    • 14a, 14b and 14c beam frames;
    • 15 platform;
    • 132 external face;
    • 133 internal face;
    • 134a and 134b lateral faces;
    • 135 upper side;
    • 136 lower side;
    • 137 vertical ducts;
    • 138 horizontal ducts; and
    • 140 beams.

FIG. 1 shows a perspective view of the pre-stressed concrete marine foundation in accordance with an example embodiment; and FIG. 2 shows an elevated lateral view of the pre-stressed concrete marine foundation in accordance with an example embodiment. The pre-stressed concrete marine foundation 10 is a ring-shaped reinforced and post-tensioned concrete structure in combination with a framework of beams (See FIG. 1, opened sections 14, for example). The pre-stressed concrete marine foundation 10 is designed to support loads to which it is subject, such as the weight of the load, the movement of the waves and/or seismic events. The example embodiments thus are designed to overcome all of the drawbacks of prior art previously discussed.

As illustrated in FIGS. 1 and 2, the base 11 comprises a body of frusto-conical shape, having a determined thickness. Base 11 has a diameter D1 that is reduced gradually to a diameter D2 from which rises a body 12 of the foundation 10. Diameter D1 at the bottom of the base 11 is greater that the diameter of the body 12, whilst diameter D2 at the top of base 11 where it meets body 12 and the diameter of the body 12 are substantially the same. The amplitude of the base 11 provides stability to foundation 10 against frontal loads resulting from waves and marine currents. The shaped section of the base 11 provides a surface 116 that has a slope.

The surface 116 serves two purposes. Referring to FIG. 2, on the one hand, the angled slope of surface 116 has a purpose of deflecting water currents that it faces upward, thus reducing the risk of horizontal displacement of the foundation 10. In addition, surface 116 is pressed by the weight of the water over it. This weight assists in maintaining the base 11 on the marine bed, and counteracts the inertial moment that is caused by the superficial marine currents that might tend to overturn the foundation 10.

FIG. 3 shows an upper view of the pre-stressed concrete marine foundation in accordance with an example embodiment. Referring to both FIGS. 2 and 3, the surface of diameter D2 of base 11 includes a step 118 that serves as a guide for the placement of the columns and frames of body 12. In addition, the base 11 incorporates the necessary means to allow pre-stressing of concrete columns (closed sections 13) of body 12 with base 11, such that the base 11 and the closed sections 13 work as a monolithic structure.

Foundation 10 includes the base 11, the body 12 and a platform 15 that are built and assembled in a wharf or at the coast and is taken assembled to the site where the construction will be set. There are different techniques for the transportation of constructions over floating structures. At the construction site, the marine bed is cleaned and leveled; thereafter the foundation 10 is sunk and set. The leveling of the terrain can be carried out by known methods in this matter, for example, with rocks. In other embodiments, the marine foundation may be equipped with a net of horizontal and vertical pipes, interconnected and embedded within the concrete base 11, including nozzles in their ends for injecting a pressurized water jet to remove the sand under the footing and clean the marine bed. Such pressurized water jet is produced whilst the marine foundation 10 is being sunk.

FIG. 4 shows a lower view of the foundation 10. As best shown in FIG. 4, base 11 has an aperture 117. Aperture 117 facilitates the sinking of the foundation 10. In addition, the aperture permits the anchoring of the foundation 10 on the marine bed. Once the foundation 10 has been placed, concrete is strained over the base 11 and the aperture 117 to form a concrete layer thus providing an additional weight to the foundation 10 to ensure it does not move.

A tower of the example embodiment is composed of a body 12, whose purpose is to support the platform 15 that is placed above sea level.

As illustrated best in FIGS. 2 and 3, body 12 is formed by three closed sections 13. Each closed section includes alternated reinforced and pre-stressed concrete columns (13a, 13b and 13c); with three open sections 14, each open section comprising beam frames (14a, 14b and 14c) that in combination form an annular structure. This annular structure thus forms the body 12 which is hollow in its center.

Body 12 as illustrated in the figures, has a transversal triangular section (See FIG. 3, for example). Notwithstanding, any geometry could be used; for example, the body 12 could include more than three columns forming a polygonal body. In addition, in the center of the body 12 other columns could be incorporated. However, the triangular configuration appears to offer the desired resistance against the lateral loads produced by the waves and marine currents. In addition, a body 12 formed of three columns offers a broader surface above base 11 for the circulation of water between the columns.

The polygonal geometric configurations of body 12 that have a larger number of columns may provide a better resistance to the flow of marine currents. However, such a construction may result in a less efficient performance and its construction could be more expensive.

Body 12 of the foundation 10 incorporates three pre-stressed concrete columns (13a, 13b and 13c) spaced in between, that extend length and width wise on the marine pre-stressed concrete foundation 10 on the apexes of the triangular transversal section of body 12 joined laterally to the beam frames (14a, 14b and 14c).

FIG. 5 shows a view of a concrete segment according to an example embodiment. Each pre-stressed concrete column (13a, 13b and 13c) is formed by concrete segments 130 that have a semicircular shape. A segment of concrete 130 is shown in FIG. 5, and according to the example embodiments, have the same dimension and shape, so that each segment 130 can be fabricated in standardized formworks.

Segments 130 have the shape of a cylindrical segment that has an arch of approximately 110°. Each concrete segment 130 has an external face 132 and an internal face 133 with two lateral faces 134a and 134b of a given thickness. These segments also have an upper side 135 and a lower side 136. Within segments 130 there are a plurality of vertical ducts 137 and optionally, horizontal ducts 138 to introduce and secure within the same vertical and horizontal pre-stressing tendons, to join segments 130 that are piled vertically. Through each of these vertical ducts 137 are introduced pre-stressing tendons and through the pre-stressing tendons the concrete segments 130 remain fixed and firmly joined, forming in this manner each concrete column 13a, 13b and 13c whose structural properties are similar to one corresponding to a monolithic structure. The pre-stressing vertical tendons are introduced and secured by means and methods well known to those persons skilled in the art.

The pre-stressed concrete semicircular segments 130 are piled vertically, one on top of the other, edge to edge, to form the body 12 of the foundation 10, in accordance with the embodiment illustrated in FIGS. 1 and 2, each concrete column 13a, 13b and 13c comprising four segments 130. The segments 130 are built at the sea coast or at workshops near to the docks and taken to the off-shore construction site. However, one with ordinary skills in the pertinent art would realize that each column can be built from more or less than four concrete segments 130, the selection of which depends on the design and size of the foundation 10 and construction as well as transport considerations.

As would be evident from the present disclosure to one with ordinary skill in the art, the concrete columns 13a, 13b and 13c may also be manufactured in any geometry and not only in the shape of semicircular transversal section columns. For example, the columns 13a, 13b and 13c can have a circular, polygonal or triangular transversal section, including one in another shape such as one incorporation various lobes. In addition, columns 13a, 13b and 13c could be straight or could be shaped such that the upper segments 130 would have a lesser diameter than the lower segments 130 it forms, or could be a “bottle neck” type wherein and for example two lower segments 130 have a greater diameter than the two upper segments 130 in a same column.

FIG. 6 shows a view of the joint of the column with the beam frame according to an example embodiment. According to the example embodiments, the pre-stressed semicircular concrete columns (closed sections 13) are joined laterally to the beam frames (open sections 14) by means of a union that allows the columns and frames to work structurally as one unit.

As shown best in FIG. 5, the body 12 of the pre-stressed marine foundation 10 is preferably composed of three beam frames (14a, 14b and 14c) forming three sections termed jointly open sections 14. As shown in FIG. 6, each of these frames comprises a plurality of structured beams 140.

The beams 140 can be manufactured in steel or in concrete. Concrete beams have a better result when faced with the corrosion of sea water, while steel beams have an elasticity module that renders a better performance when faced with the efforts of traction and compression of water current and at the inertial moment generated by the structure when placed over the foundation, for example, an eolic generator that is exposed to the wind strain. In both cases, beams 140 can be pre-assembled sections, such as beam panels that are connected to the concrete segments as these are being placed.

In the event of a steel metallic frame, it is assembled by welding and/or bolts and/or screws with or without reinforcement elements. As shown in FIG. 6, in one example, it is joined by means of a welding of the metallic beams 140 to the reinforcement rods of concrete segments 130 of columns 13a, 13b and 13c, such that each of the segments 130 is joined to the beam frames 14a, 14b and 14c. In this example, a metallic beam 140 is welded to metal inserts embedded within the concrete segment 130. The metal inserts can be placed to provide a joint, either to the beam 140 and as well to join (through a ‘seam”) with vertical pre-stressing strands in the segment 130. The metallic beam 140 may be protected internally by injection of pressurized mortar and externally by applying an epoxy coating, for example. The beams 140 can be structured of any well known manner to form a determined arrangement, for example, as a honeycomb structure or an included beam structure, while each element is joined to an upper module and/or a lower adjacent module.

In the event that concrete beams 140 are used, the beams 140 may also include internal ducts, to allow the introduction of horizontal or diagonal pre-stressing tendons, such that a same horizontal or diagonal pre-stressing tendon may hold the concrete segments 130 as well as the beams 140.

The beam frames 14a, 14b, 14c have as purpose the structural support of the pre-stressed marine foundation 10 and of joining the pre-stressed semicircular cement segments 130 while it permits the flow of water through it.

The concrete base 11, and the body 12, comprising concrete segments 130 and beams 140, are assembled on a sea barge in the dock, transported to the erection site, and finally sunk in at the erection site. Once the body 12 of the marine foundation structure is placed and post-tensioned in site, it is placed over the same one concrete platform 15, preferably of a circular form, that serves as a base for other structures, for example, a petroleum platform or an eolic generator, or for example, a pre-stressed concrete tower for a wind power generator.

The ends of body 12 are raised above the sea level, such that the principal portion of body 12 is submerged in water, while only the extremes arise from the sea at a proper height above the levels of tides.

As shown in the figures, platform 15 comprises an upper circular concrete base that has a determined thickness. As shown in the figures, the diameter of platform 15 is greater than the diameter of body 12, and may include accessories and protrusions necessary to support an installation. If the installation is a concrete tower for eolic generators, this includes means to anchor the tower to the foundation. The platform 15 has proven efficient with the triangular configuration of body 12; otherwise it could prove to be overly heavy.

Additionally, the lower face could include means such as a step or grooves so that the platform 15 may adapt to body 12 of the foundation 10. The platform 15 can also include ducts to introduce pre-stressing cables such that base 11, body 12 and platform 15 are joined by means of pre-stressing cables and the entire structure functions as a monolithic structure.

In accordance with the example embodiments, the pre-stressed concrete foundation 10 is capable of supporting large forces in a lateral direction without collapsing, without inclining and without significant structural damages. Also, corrosion has a lesser effect on the concrete structure.

Since the pre-stressed marine concrete foundation 10 is designed to operate in areas subject to seismic activity, the advantage and benefit shall be that of enduring principally two types of environmental forces. These are: the forces due to waves and the forces imposed over the base 11 due to earthquakes.

In regard to those forces derived from waves, the referenced design to the body of the pre-stressed marine concrete foundation, particularly to the straight metallic beam frames (14a, 14b and 14c) upon existing a space between the beams 140 that form spaces without impacting directly on the pre-stressed marine concrete foundation 10, results in a structure not being weakened by the forces derived from waves and thereby the life span of the pre-stressed marine concrete foundation 10 shall extend beyond those of prior art foundations.

The marine foundation 10 may have an example height between 10 to 30 meters from the sea bed. The definitive location of the foundations are studied and prepared to receive the foundation with several possibilities:

ROCK BED COVERED BY A THIN LAYER OF SAND. The foundation will be lowered to the sand bed level and a water pump from the barge will inject pressurized water through the pipe system to disperse the sand and lower the foundation to the rock bed. At this time, stone wedges are used to level the foundation (plumb). A trompe is lowered to the center bottom of the base 11 and concrete is pumped to fill all the aperture 117 (see FIG. 4) of the base 11. The amount of concrete can be as much as needed to use it as a bottom weight necessary to stand the forces created by the tower and/or other causes.

IRREGULAR SOIL. Such types of soils need stone to support the foundation 10. The process stands lowering the foundation 10 in the marine bed and casting concrete in the aperture 117 of the base, as mentioned before. The concrete base 11 can be prepared with perforations to drill through micro piles anchored in deeper rock beds.

The example embodiments being thus described, it will be obvious that the same may be varied in many ways. For example, the body 12 of the foundation 10 could include concrete blocks placed between the concrete columns. Additionally, the platform 15 could be built in steel and it not be held by pre-stressing to body 12 of the foundation 10. Such variations are not to be regarded as departure from the example embodiments, and all such modifications as would be obvious to one skilled in the art are intended to be included within the following claims.

Claims

1. A pre-stressed marine foundation, comprising:

a concrete base to be placed on a sea bed,
a body placed over the concrete base, the body including: a plurality of closed sections, each closed section composed of a pre-stressed concrete segmented column, each column having an upper extreme and a lower extreme joined at the base, and a plurality of opened sections joined at sides of the closed sections, each open section composed of a structured beam frame, and
a concrete platform joined at the upper extremes of the concrete columns.

2. The foundation of claim 1, wherein the body has a triangular cross-section formed by three segmented pre-stressed concrete columns and three beam frames therebetween.

3. The foundation of claim 1, wherein each beam frame includes a plurality of beams selected from concrete beams or metallic beams.

4. The foundation of claim 1, wherein concrete segments forming each of the concrete columns are semicircular and have substantially the same form and same dimensions.

5. The foundation of claim 1, wherein the base includes an aperture.

6. The foundation of claim 1, further comprising a concrete layer added to the base to increase weight of the base.

7. A pre-stressed marine foundation, comprising:

a concrete base,
a body placed on the concrete base, the body having a triangular cross-section formed by three equally-spaced segmented pre-stressed vertical concrete columns with three beam frames joined in an open space between the three spaced segmented vertical concrete columns, and
a concrete platform joined to upper ends of the vertical concrete columns.

8. The foundation of claim 7, wherein the base has a bottom diameter and a top diameter and a sloped side surface, the bottom diameter greater than the top diameter.

9. The foundation of claim 7, wherein the base top diameter is approximately the same diameter of the body.

10. The foundation of claim 7, wherein the base includes a central triangular aperture.

11. The foundation of claim 7, wherein each beam frame includes a plurality of structured beams selected from concrete beams or metallic beams.

12. The foundation of claim 7, wherein concrete segments forming each of the vertical concrete columns are semicircular and have substantially the same form and same dimensions.

13. A pre-stressed marine foundation, comprising:

a base having a sloped side surface,
a tower placed on the base, the tower having a triangular cross-section formed by a plurality of spaced segmented pre-stressed vertical concrete columns with a plurality of reinforcing beam frames joined in open spaces between the spaced segmented vertical concrete columns to realize a tower with annular structure and said triangular cross-section, and
a platform joined to upper ends of the vertical concrete columns.

14. The foundation of claim 13, wherein the base includes a central triangular aperture.

15. The foundation of claim 13, wherein each beam frame includes a plurality of structured beams selected from concrete beams or metallic beams.

16. The foundation of claim 13, wherein concrete segments forming each of the vertical concrete columns are semicircular and have substantially the same form and same dimensions.

17. The foundation of claim 13, further comprising a concrete layer added to the base to increase weight of the base.

Patent History
Publication number: 20110299937
Type: Application
Filed: Jun 7, 2011
Publication Date: Dec 8, 2011
Inventors: Jose Pablo Cortina-Ortega (Col. Paseo de las Lomas), Alejandro Cortina-Cordero (Col. Paseo de las Lomas), Jose Pablo Cortina-Cordero (Col. Paseo de las Lomas)
Application Number: 13/155,080
Classifications
Current U.S. Class: With Anchoring Of Structure To Marine Floor (405/224)
International Classification: E02D 27/52 (20060101);