Universal Framed Cofferdam

Abstract

Universal Framed Cofferdam has prefabricated skeletal steel space framing formed from multiple steel vertical pipes and two levels of horizontal diaphragm trusses rigidly connected to pipe columns. Beams of each diaphragm truss are attached to vertical pipes of the framing with rigid moment connections creating a rigid space frame of the perfectly round form that is used as a false work of the Cofferdam. Wales of the Cofferdam and short pieces of the flat sheet piling are attached to the vertical pipes forming a skeleton of the Cellular structure. The Skeleton of the Universal Framed Cofferdam is prefabricated in the convenience of the Dry Dock and than floated to the site. Buoyancy of the framing allows Cofferdam skeleton transportation without using the barge or otherwise necessary floating devices. Once brought to the site of installation Cofferdam skeleton is installed vertically in position and leveled on the bottom of the river bed. If necessary river silt can be jetted and pumped out of pipe annular space and pipe columns of framing can be simultaneously lowered in position by using vibro—hummer. After space framing installation, rock sockets are predrilled through the annular space of vertical pipes and rock anchors installed. Sheet pile skin of the Cofferdam installed between pipe columns concludes Cofferdam Can erection. Universal Framed Cofferdam Can than filled with compacted gravel and becomes a Hybrid Gravity Caisson/Columnar water front or marine structure that has the best features of the Conventional Cellular Cofferdam and of Columnar Dolphin structure. It has enhanced sliding and overturning stability provided by Rock anchors preloaded by Cofferdam granular fill and has effective mechanism that prevents concave or convex surface of rupture failure that may be suffered by conventional Cellular Cofferdams, and has mechanism that more effectively resists deep surface sliding failure of the Cofferdam base.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is a hybrid of Cellular Cofferdam and of Columnar Dolphin structure. More specifically, it is a prefabricated Columnar structure that is floated to the site and built as Rock Anchored gravel filled Cellular Cofferdam structure after on site installation of perimeter sheet pile skin.

That type of structure can be utilized for many types of waterfront projects like:

Mooring or Breasting Dolphins

Quay Wall And most notably

Bridge Pier Fender system where extremely high lateral load application from the Ship Collision impact makes open Columnar Fender Structure or conventional Cellular Cofferdam construction unviable and/or uneconomical solution.

2. Description of the Prior Art

Numerous structures that were designed for similar tasks include Pile supported Dolphins, Open (Pile supported) or Closed (Cellular Cofferdam) Marginal Wharfs.

While benefits of present invention were long recognized and some attempts were made to advance in that direction, none of them had resolved the problems that were addressed by present invention. While present day Cellular Cofferdams are well suitable for the purposes for which they were designed, they would not be suitable for the purposes of present invention where magnitude of the lateral load far exceeds the load level that conventional Cellular Cofferdams were designed for. The present invention addresses these issues. Two of the most significant benefits of the present invention are:

• • Creation of prefabricated cofferdam framing that can be built in the dry and floated to the site of installation.
  • Creating the structure with enhanced stability level that is significantly higher than that of conventional Cellular Cofferdam.

The following is the description of the prior Art.

U.S. Pat. No. 1,398,221

Inventor: Charles S. Boardman

Issued: Nov. 29, 1921

Invention was designed to permit the assembly of the caisson with co-acting interior bracing in any convenient location from which it can be lifted as a unit and set into the position where sheet piles are released from separable reinforcing cage or bracing form and driven to final tip elevation. The separable reinforcing cage is formed of a series of annular bracing members connected by vertical spacing members and having a central unobstructed opening that permits removing the material from the bottom of excavation.

SUMMARY OF PRESENT INVENTION

The present invention relates to open ended Caisson structures or Cellular Cofferdams and to pile supported Dolphins at the same time. The new structure consists of a prefabricated spaced Columnar framing with rigid horizontal truss diaphragms and large annular opening that allow jetting and pumping out the river silt from the bottom of excavation. At least two of such horizontal truss diaphragms are rigidly connected to vertical pipes along the height of the framing. A primary object of the present invention is to create a rigid prefabricated Cellular Cofferdam structure that will overcome the shortcomings of prior art devices used by industry.

Another, primary objective of the present invention is to create a self floating structure that can be built in the convenience of the Dry Dock and than floated to the site of construction.

A further object of the present invention is to create a space frame that can effectively engage force of the barge impact or force coming from the Mooring device by using mechanisms provided by both conventional Cellular Cofferdam structure and Columnar structure of the Dolphin.

Yet, another objective of the present invention is to use the benefits coming from the Rock Anchor devices that incorporate concrete rock sockets with HP Anchor sections or reinforced concrete rock or soil anchors preloaded by gravity of the Cellular Cofferdam granular fill. Such Rock Anchor devices solve several shortcomings of prior art. Such shortcomings (as shown on FIG. D3) include:

• • Low Block Rotational stability
  • Low Sliding Resistance to large horizontal forces
  • Concave or convex surface of rupture failure through the granular fill of Cofferdam.
  • Deep Surface rotational sliding typical for Cofferdam Quay Walls formed on deep clay deposits.

Objective of that invention is to use preloaded anchor devices for additional Cofferdam stability and prevention of drift and erosion of Cellular Cofferdam granular fill. (FIG. D1; FIG. D2; FIG. D3)

And still further objective of the present invention is to provide a composite Cellular Cofferdam that is economically viable and simple in production.

Additional objects of the present invention will appear as the description of the invention proceeds.

To the accomplishment of the above and related objects, this invention may be embodied in the form illustrated in the accompanying drawings and the following description of the present invention and of construction sequence. Attention, however, being called to the fact that the drawings are illustrative only, and that changes may possibly be required in any specific construction that illustrated and described within the scope of the appended claims.

The foregoing and other objects and advantages will appear from the description to follow. In the description all references are made to the accompanying drawings, which form a part hereof, and which illustrate specific embodiment where the invention may be practiced.

That embodiment is described in sufficient detail to enable those skilled in the art to practice the invention. It is also shall be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of invention. In the accompanying drawings, alike reference characters designate the same parts throughout all views. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims.

The present invention overcomes the shortcomings of the prior art by providing prefabricated framing that is also used as a template for Cellular Cofferdam sheet pile skin installation. and for positioning of

the rock sockets predrilled for Rock Anchor installation. Prefabricated framing also allows easy transportation of the Cofferdam from the manufacturing facility to the site of construction. It allows ease of installation of the sheet pile skin in the river environment where high speed currents can affect sheet pile installation.

The framing of the Universal Cofferdam is manufactured in the convenience of the Dry Dock where each end of the pipe column is sealed (FIG. 3 & FIG. 4). After completion of the frame fabrication Dry Dock is flooded, Cofferdam framing brought into horizontal position (FIG. 1A) and floated from the Dry Dock facility to the site of construction where seal is removed from the pipe ends and Cofferdam framing is brought into vertical position with the help of floating cranes. Finally, Cofferdam framing is lowered into position until it firmly touches the river or sea bed in a perfectly vertical position (FIG. 5). Jetting through the river silt can be utilized to aid that process. In the next step rock sockets are drilled through the vertical pipe annular spaces and rock anchors installed. In the following steps flat sheet pile skin of the Universal Framed Cofferdam is installed and Cofferdam is filled with compacted gravel. That concludes the process of cofferdam construction.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Features and advantages of the present invention will become more fully appreciated and understood when reviewed in conjunction with accompanying drawings. All drawings have similar parts referenced by alike characters in all details and views.

FIG. 1 3-D View of Universal Prefabricated Cofferdam Framing.

FIG. 2 Top and bottom flange connection detail between star truss and pipe column

FIG. 3 Bottom seal plate assembly detail.

FIG. 4 Top seal plate and lifting device assembly detail.

FIG. 5 Section A-A. Prefabricated cofferdam framing in vertical position.

FIG. 6 Plan. Erected cofferdam framing with rock anchors and sheet pile installed.

FIG. 7 Section B-B. Cofferdam with installed rock anchors and sheet pile skin.

FIG. 8 Cofferdam utilization in Bridge Protection Device.

FIG. 9 Section C-C. Bridge Protection Device.

FIG. D1 Rock Anchor Load Diagram.

FIG. D2 Rock Anchor Load Diagram.

FIG. D3 Failure Mechanism Diagram of the prior Art.

DESCRIPTION OF THE REFERENCED NUMERALS

The numerals characters shown in different views that are illustrated in different Figures denote similar elements of the Bridge Pier Fender that was selected for illustrative purposes of Universal Cofferdam application. The following numbering is used throughout the various drawing Figures.

10. cofferdam framing.

11. pipe column filled with concrete.

12. steel wide flange beam of the horizontal truss.

13. sheet pile perimeter wale wide flange beam.

14. sheet pile interlock connector with web stiffeners welded to the pipe column in the Dry Dock 15. flat sheet pile Cofferdam skin.

16. HP section of the rock anchor

17. headed studs

18. horizontal truss connection plates

19. bottom seal plate assembly detail

20. top seal plate with lifting device

21. air relieve opening

22. lifting hole

23. air relieve opening plug plate

24. predrilled rock socket

25. gravel fill.

26. concrete cap

27. Bridge Protection Device piles along the side of the Bridge Pier

28. Bridge Protection Device horizontal struts along the side of the Bridge Pier

29. corner wheel rubber fender

30. panel rubber fender

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to an improved method of construction and installation of sheet pile Cellular Cofferdams. It also relates to improved design of Cofferdam structure itself, creating a new subclass that can be called Columnar Cofferdam structure. The following discussion describes in detail one embodiment of invention. This discussion, however, should not be construed, as limiting the invention to this particular embodiment. Practitioners skilled in the art will recognize other numerous embodiments as well. The drawings show similar elements of the invention denoted by the same numerical character in all views and sections shown in FIG. 1 through FIG. 9 where the present invention generally depicted by the numeral 10.

FIG. 1 is a 3-D View of Universal Prefabricated Cofferdam Framing.

FIG. 1A is an illustrative view of the prefabricated Cofferdam framing in a floating position. The prefabricated Cofferdam framing 10 includes six pipe columns 11 with lifting devices attached to the top of each pipe, two levels of horizontal trusses composed of wide flange beams 12, sheet pile perimeter wales 13 and sheet pile interlock connectors 14. Both ends of the pipe columns are sealed.

FIG. 2 shows rigid connection of the horizontal truss diaphragm to the pipe columns.

Flange connection plate 18 is welded to the flanges of the truss beam 12 and to the pipe columns 11.

FIG. 2 also shows connection of the sheet pile connector 14 to the pipe column 11. It shall be noted that sheet pile connector 14 is not only connected to plate 18 but has its own stiffener plates welded to the pipe column and to connector 14 for alignment and transportation purposes.

FIG. 3 shows bottom seal plate column assembly. Seal plate 19 is bolted to the pipe column 11 through stiffener plates welded to the pipe. Elastomeric seal may be applied to upper face of the plate to aid in providing water-tightness of the seal plate connection.

FIG. 4 shows top seal plate with lifting device. Seal plate 20 has air relieve opening 21 and air relieve opening plug 23 attached to the plate 20 with machine bolts. Seal plate assembly is bolted to the column 11 through stiffener plates welded to the pipe. Elastomeric seal may be applied to the bottom face of the seal plate assembly to aid in providing seal water-tightness. Bottom seal plate assembly 19 shall be removed from the Prefabricated Cofferdam Framing 10 at the site of erection prior to sinking the framing in vertical position. Only air relieve opening plug plate 23 shall be removed from the top seal assembly prior to rotating the framing in a vertical position at the site of erection. The whole top plate assembly 20 can be removed only after framing is brought in nearly vertical position.

FIG. 5 shows Prefabricated Cofferdam Framing 10 in a vertical position, bearing on top of bedrock or other type of firm base. Section A-A shows arrangement of all framing elements along the framing elevation. Two sets of horizontal truss diaphragms (elements 12) connected to columns 11 through connector plates 18. Wales 13 are shown connected to columns 11 and sheet pile connectors 14 are shown attached along the length of the columns 11.

Section A-A shows framing installed with top and bottom seal plate assemblies removed.

FIG. 6 shows the same framing in plan with rock anchors 16 and sheet pile skin 15 installed.

FIG. 7 shows Section B-B that is cut from plan shown on FIG. 6. Rock anchors 16 are shown to be grouted or concreted into rock socket 24 and extended through the pipe column 11. Rock anchors are grouted within length of the pipe column making a composite section consisting of pipe pile, confined concrete and of embedded rock anchor section 16. In some cases HP section of anchor 16 can be replaced with reinforced concrete section.

FIG. 8 shows one of the preferred embodiments of the present invention—Bridge Protection Device or Bridge Fender.

FIG. 9 shows vertical Section C-C through the Bridge Protection Device.

Framing of the Universal Framed Cofferdam is prefabricated inside of Dry Dock with both ends of the column pipes 11 sealed. In the next step Dry Dock is flooded and framing is rotated into horizontal floating position for transportation to the site.

FIG. 7 shows Cofferdam framing with rock anchors and sheet piling skin installed. Rock anchors 16 are installed through the pipe columns into predrilled rock sockets 24 and annular space of the rock socket and of the pipe column 11 is filled with concrete. Conclusion of that operation creates columnar Dolphin with internal rigid farming.

The last operation that concludes creation of the Universal Cofferdam is filling the cellular space restrained by sheet pile confinement 15 with granular fill 25.

It shall be noted that prefabricated framing of the Universal Cofferdam can be fabricated with various diameter and height parameters. Column pipe diameter and Cofferdam diameter, however, shall be adjusted to such a close dimension that projections of sheet pile interlock connector 14 were between 4″ and 6″ maximum.

Minimum column pipe 11 diameter is recommended to be 24″ (minimum pipe diameter that allows efficient installation of the HP profile rock anchor).

Optimal ratio Cofferdam (D)iameter/(H)eight ratio shall be established by qualified design professional familiar with Cofferdam and Columnar Dolphin analysis.

The present invention allows great usage flexibility of Universal Framed Cofferdam. It can be used for construction of deep water Quay Walls and Dolphins subjected to unusually high loads.

However, it becomes the most economical solution for Bridge Fenders that protects Bridge Piers from the impact of barge or ship collision, where the impact load of ship collision with Pier protecting structure is unusually high.

The present invention utilizes the ability of Rock Anchors 16 preloaded with granular fill 25 to more effectively resist Cofferdam Block Rotational stability, Sliding resistance to large horizontal forces,

Concave or Convex surface of rupture failure through the granular fill of Cofferdam or foundation base, and Deep Surface rotational sliding that is typical for Cofferdam Quay Walls formed on deep clay deposits. (FIG. D3)

From the above description it can be seen that Universal Framed Cofferdam 10 of the present invention is able to overcome the shortcomings of prior art devices by providing prefabricated framing that can be used in lieu of expensive false work conventionally utilized in cofferdam construction and at the same time has greater stability parameters that are derived from the usage of rock anchors 16 and of rigidly connected space framing stabilized by horizontal pressure of the compacted granular fill 25 and by interlock forces developing in perimeter skin sheet piling due to hoop forces that confine Cofferdam granular fill.

While certain novel features of this invention have been shown and described in the annexed claims, it is not intended to be limited to the details above, since it shall be understood that various omissions, modifications and changes to the details of the device illustrated can be made by those skilled in the art without departing in any way from the idea of the present invention.

Claims

1. Prefabricated rigid Cofferdam framing that is floated to the site of construction and positioned in place to complete and aid in Cofferdam construction. Prefabricated Cofferdam framing that comprises:

a) a skeletal frame that is formed from multiple tubular columns.

b) at least two horizontal Diaphragms rigidly connected to columns and forming rigid space framing of Universal Cofferdam.

c) perimeter wale system attached to tubular columns to form perfect circular false work for the Cellular Cofferdam Can sheet piling.

2. six end Star Truss that serves as a horizontal diaphragm and is formed from two equal sided triangles intersecting in two levels and connected together to form a rigid diaphragm structure or a truss that is formed in plan as a single piece element.

Other horizontal truss diaphragm configurations that can be used for that purpose and do not violate the concept of present invention.

3. Final Universal Framed Cofferdam product that comprises:

a) Rock or soil anchors consisting of structural steel HP sections or round reinforced concrete section.

b) Sheet pile perimeter skin connected to the tubular columns of Prefabricated Cofferdam Cell framing that forms Hybrid Gravity Caisson/Columnar Framed Space Structure.

4. Universal Framed Cofferdam as recited in claim 3a, where rock or soil anchors prevent undesired effects of Cofferdam Block Rotational movement, resist Sliding forces, prevent forming of Concave or Convex surface of rupture failures through the granular fill of Cofferdam or through the foundation base and prevent Deep Surface rotational sliding failure as shown in Failure Mechanism Diagram of Prior Art (FIG. D3)