AU782839B2 - A connection assembly - Google Patents

Description

AUSTRALIA

Patents Act COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: Name of Applicant: Worley Pty Limited Actual Inventor(s): Shane McCarthy Donohoo Address for Service: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Invention Title: A CONNECTION ASSEMBLY Our Ref: 634767 POF Code: The following statement is a full description of this invention, including the best method of performing it known to applicant(s): -1fofaptflor\cMCpfor.doc A CONNECTION ASSEMBLY The present invention relates generally to a connection assembly and has been designed especially, but not exclusively for connecting a fender to a marine berth for protecting the berth from impact loads from vessels.

When mooring a vessel to a berth one must ensure that the berth has been designed to withstand the loads applied by a vessel of that size. In recent times there has been a trend in the merchant shipping industry towards larger vessels.

Thus, many of these newer, larger vessels exceed the design capacity of many older berths. Significant cost is involved in replacing or upgrading these berths.

S: 10 It is an aim of the present invention to ameliorate the above problem.

Accordingly, in a first aspect the present invention provides a fender connection le assembly for use in mounting a fender to a supporting structure, the fender including an outer engaging surface, and wherein said assembly includes a first end adapted to be connected to, or integrally formed with, the fender, and a second end adapted to be connected to a supporting structure, said connection assembly including at least one sacrificial member which is operative to plastically •ee* deform when a force applied to said fender outer surface exceeds a threshold level.

In use, the fender connection assembly according to the present invention is disposed between a supporting structure, such as a berth, and a fender. The assembly includes one or more sacrificial members which plastically deform when an overload force is applied to the fender by a vessel. The assembly is designed so that plastic deformation occurs at a load less then the maximum load capacity of the berth, but greater than the normal operating load capacity of the berth. This plastic deformation absorbs energy and thus serves to protect the berth from overload forces such as impact forces applied by vessels.

The above arrangement has substantial practical benefit. In particular, it provides a means by which an existing berth may be protected from loads imparted by vessels larger than those for which the berth was originally designed.

Moreover, the assembly according to the invention may be easily fitted to existing berths.

N:IRN\634767\IRN634767completel 10302.doc In addition, the sacrificial members of the assembly according to the invention may be readily inspected for evidence of plastic deformation occurring, thus indicating that an overload force has been applied to the fender. Traditionally, the major indicator that an overload had occurred was evidence of damage to the berth itself. Such damage is often only evident below the water line and thus can only be identified by skilled workers carrying out costly inspections.

In a preferred form, the sacrificial members are formed as elongate metal struts. Further, each member preferably includes a deformation zone wherein the plastic deformation is operative to occur. The advantage of this arrangement is 10 that the behaviour of the connection assembly under plastic deformation may be more easily predicted and controlled.

oPreferably the sacrificial member has a low shape factor such that there is little difference between the yield and plastic deformation loads. This maximises the energy absorption capacity of the assembly as a whole.

To provide the low shape factor, preferably the connection assembly is designed so that the combined axial and eccentrically generated bending stresses at the deformation zone yield at the top and bottom flanges at approximately the same load. This further improves the action of the deformation zone to act as a ***plastic hinge and to deform in a controlled manner.

To induce bending stresses within each sacrificial member, it is arranged to be disposed at an angle to the direction of the design loading. In this arrangement, preferably the deformation zone is located approximate to the supporting structure where the bending stresses are maximised. The actual angle of inclination to the direction of the design loading may be varied so that the member exhibits the yield characteristics identified above.

Preferably the sacrificial member includes a central beam which has a generally I profile having opposite flanges which are interconnected by a central web. Preferably the member includes a first reinforcing member which is fixed to the inward flange (when the sacrificial member is inclined to the direction of loading). This reinforcing member strengthens the inward flange so that the sacrificial member will exhibit the yield characteristics identified above where the top and bottom flanges yield at approximately the same load.

N:\IRN\634767\dRN634767complete 1 0302.doc 4 The sacrificial member may also include side plates which are disposed on either side of the web and which are affixed to both the upper and lower flanges.

These side plates are designed to keep the flanges apart during failure so as to further control the plastic action of the deformation zone.

In a preferred form, the fender connection assembly includes four sacrificial members which are operative to interconnect the fender to the supporting structure. Preferably the connection assembly further includes a mounting plate and the sacrificial members are disposed around and connected to the plate, which in turn is connected to the fender.

10 In a further aspect, the present invention relates to a fender for a marine 0 0.0 berth which includes a connection assembly according to any form described o.

above.

In yet a further aspect, the present invention relates to a fender assembly for a marine berth, said berth having an operating load capacity and a maximum load capacity which is greater than said operating load capacity, said assembly including a fender having an outer engaging surface, and a connection assembly 00. 0which is operative to connect said fender to said berth, said connection assembly includes at least one sacrificial member which is operative to plastically deform when a force applied to said fender outer surface reaches a threshold load, said threshold load being greater than said berth operating load capacity and less than said maximum load capacity.

It is convenient to hereinafter describe an embodiment of the present invention with reference to the accompanying drawings. It is to be appreciated that the particularity of the drawings and the related description is to be understood as not superseding the generality of the preceding broad description of the invention.

In the drawings: Figure 1 is an elevation view of a fender connection assembly disposed between a fender and a berth; Figure 2 is a cross sectional view of the fender connection assembly along line A of Figure 1; Figure 3 is a partial elevation view of the fender connection assembly of Figure 2 connected to a berth; NAIRNM634767\IRN634767complete 10302.doc Figure 4 is a cross sectional view along section line B of Figure 3; Figure 5 is a cross sectional view along section line C of Figure 3; Figure 6 is a partial view of one end of a sacrificial member used in the fender connection assembly of Figure 1; Figure 7 is a cut away partial view of the connection between the fender connection assembly and a berth; and Figure 8 is a graph obtained by testing a specimen sacrificial member of the assembly of Figure 1.

Referring firstly to Figures 1 and 2, a fender connection assembly 10 is 10 connected to both a fender 20 and a berth 30. The fender connection assembly includes a fender connection plate 11 and four sacrificial members 12. The fender connection plate 11 includes four hinge brackets 13 and slotted holes 24 to suit fender fixings. The hinge brackets engage with pivot holes provided at one end of each sacrificial member 12. The slotted holes are used to couple the plate to the fender The construction of the individual sacrificial members is shown best in Figures 3 to 6. Referring firstly to Figure 3, the sacrificial member 12 is shown engaged with a hinge bracket 13 and connected to the berth 30 via end coupling 22. Each member 12 is inclined to the direction of design loading P applied to the outward face of the fender 20. In the illustrated form, the angle of inclination is approximately 60 degrees although this may vary depending on the design loading. Typically the angle of inclination could vary between 10 degrees to degrees and more preferably from 30 degrees to 70 degrees. The sacrificial member 12 is formed as a metal strut and is configured so that, when plastic deformation occurs in an overload situation, it does so in a deformation zone 31 near to its end coupling 22 where the bending stresses are maximised. The sacrificial member includes a central beam 32 of I cross-section having a web 14, an upper flange 15 and a lower flange 16.

An intermediate section of the beam 32 includes side plates 17 connected to the upper 15 and lower 16 flanges on both sides of the web 14. The incorporation of the side plates 17 form a triple web section with the side plates keeping the flanges 15 and 16 apart. The side plates 17 are primarily designed to assist in N:\IRN\63476T\IRN634767completeI 1 0302.doc 6 controlling the failure of the sacrificial member by maintaining the flanges generally parallel under plastic deformation in the deformation zone 31. Further, the thickness of the web 14 of the beam varies along its length with deformation zone 31 having a thinner web 14 than the opposite end section 33 of the beam 32.

As shown in Figure 6, the end section 33 includes a reinforced hole 19 which is operative to engage with one of the hinge brackets 13 via a pin (not shown).

In use, forces P applied to the fender 20 are transmitted to the sacrificial member at reinforced hole 19. These forces which are at an angle to the axis of the control beam 32, induce a moment at the deformation zone 31 and place each sacrificial member in compression.

A further reinforcing flange21 is affixed to the upper flange 15. The 0* *"dimensions of the reinforcing flange and the angle of inclination of the sacrificial member to load P are chosen such that the combined axial and eccentricity generated bending stresses in the deformation zone 31 reach yield at the top and bottom flanges at substantially the same load. Further, the configuration of the sacrificial members 12 exhibit a low shape factor so that there is minimal difference between the yield and plastic deformation loads. This arrangement allows accurate prediction of the plastic deformation load of the sacrificial member and maximises the energy absorption capacity of the sacrificial member.

A full moment connection needs to be provided between the berth 30 and the end coupling 22. Referring to Figure 7, the sacrificial member 12 is connected

C

o=o° to a berth 30 via end coupling 22. J-bolts 23 are cast into the berth 30 during its construction. Bolts 24 pass through holes in the end coupling 22 and engage with J-bolts 23. To improve the durability of this connection, a layer of epoxy non-shrink grout 25 is provided between the end coupling 22 and berth 30. It is appreciated that alternative fixing arrangements may be used to secure the sacrificial member 12 to the berth Whilst not shown, shear chains or other restraining devices may be used to accommodate lateral forces applied to the assembly 10 so that the amount of lateral forces transferred to the sacrificial members 12 is controlled.

The fender connection assembly 10 provides protection to the berth 30 from impact loads. The sacrificial members are designed to plastically deform at the N:IRN\634767\IRN634767complete 10302.doc deformation zone 31 when a load applied to the fender 20 in the direction of the berth 30 exceeds a threshold load. This threshold load is set above the normal operating load of the berth 30, but below the maximum load capacity of the berth 30. During plastic deformation, energy is absorbed by the sacrificial members 12, thus protecting the berth The performance of a sacrificial member 12 loaded under test conditions is detailed in the following example. The objectives of these tests were as follows: STo apply a slowly increasing horizontal force onto the front of the specimen and to show unloading after the maximum load occurred.

10 o To observe the behaviour of the specimen under maximum load and deflection and to inspect for permanent set after the removal of the load.

To obtain force v deformation graph for the specimen.

The equipment used for these tests was as follows: Raripress electric pump with Fantinelli pressure gauge 2 MPa resolution; e One, one hundred tonne solid core double acting hydraulic jack; Two Rotary Pots (displacements measuring devices); One LVDT's (linear variable displacement transformer); One 100t pressure transducer; Macintosh computer with Lab VIEW for Windows, hardwired to National Instruments terminal block.

The central beam 32 of the specimen was made of 150UC37 with a partly replaced web of 28PL. A single reinforcing flange 21 of I2PL was welded to the upper flange 15. Side plates 17 of 8PL were positioned on either side of the web, welded on each side to the flanges. The end coupling 22 was 40mm thick and formed an angle of 59 degrees with the central beam 32 of the sacrificial member 12.

The specimen was tested on the reaction floor of a structures laboratory.

Two steel bollards spaced 1,200mm apart and bolted to the floor were used as a closed system to load and react against. The bollards were "tied" together using 5-VSL 26mm CT stress bars. The hydraulic jack was positioned to apply load to the specimen at reinforced hole 19 in a direction perpendicular to and towards end NA:IRM63476TURN634767completel 10302.doc 8 coupling 22. This enabled the transfer of the load to the specimen as required by the design.

A heavy-duty load skate was used to enable the applied force to follow the specimen as it deformed horizontally. The deformation of the specimen was measured using two rotary pots; in the horizontal position, parallel to the end coupling and approximately 900 to the specimen incline angle. An LVDT was set up to measure any movement at the coupling end 22.

The conditions for these tests were for the applied force to follow the specimen in order to be able to calculate the energy absorbed from the S 10 force-deformation curves. As the load was applied, the specimen would deform and due to the translation at the tip, the skate would follow.

The force was applied at a constant rate. Once the maximum load was reached, and the curve started to show signs of failure (rapid deformation under the same or lower load) in the specimen, the load was maintained allowing the specimen to deform in a gentle manner. This was allowed within the limits of :safety for these particular tests. A secondary jack was used to maintain the load skate at 900 to the applied force.

Referring to Figure 8 one can determine the behaviour of the specimen sacrificial member under load. The area under the curves represents the energy absorbed by the sacrificial member during deformation. It can be seen that a substantial amount of energy was absorbed during the tests with the increase in energy being in the order of 35%. Furthermore, as these tests did not deflect the sacrificial member to its full extent. Thus, the maximum energy absorbing capabilities of the specimen sacrificial member will exceed the results shown at Figure 8.

The dimensions of the sacrificial members of the assembly will change after plastic deformation has occurred. Such a change in dimension can be identified by visual inspection or simple measurement. Thus, the fender connection assembly provides an indication that the normal operating load has been exceeded.

After plastic deformation occurs the fender connection assembly 10 may be readily restored to its original condition by simply replacing one or more of the sacrificial members 12. The sacrificial members are relatively cheap to produce N:\IRM634767\IRN634767completel 1 0302.doc and may be replaced quickly, thus minimising disruption to the operation of the berth.

Thus, the present invention provides a device which allows a berth to safely cater for vessels larger than those for which it was originally designed. In addition, the device provides an indication that an overload has occurred and may be subsequently repaired at relatively low cost.

Finally, it is to be understood that alterations, modifications and/or additions may be introduced into the constructions and arrangement of parts previously described without departing from the spirit or ambit of the invention.

N:\IRN\634767\1RN634767completel 1 0302.doc

Claims (28)

1. A fender connection assembly for use in mounting a fender to a supporting structure, the fender including an outer engaging surface, and wherein said assembly includes a first end adapted to be connected to, or integrally formed with, the fender, and a second end adapted to be connected to a supporting structure, said connection assembly including at least one sacrificial member which is operative to plastically deform when a force applied to said fender outer surface exceeds a threshold level.

2. A connection assembly according to claim 1, wherein the or each sacrificial 10 member is formed as an elongate metal strut.

3. A connection assembly according to either claim 1 or 2, wherein the or each l S•sacrificial member includes a deformation zone wherein the plastic deformation is ogo operative to occur. S.i

4. A connection assembly to claim 3, wherein said deformation zone is located adjacent said second end.

5. A connection assembly according to any preceding claim, wherein the or each sacrificial member has a low shape factor.

6. A connection assembly according to any preceding claim, wherein the at least one sacrificial member includes a central beam having opposite first and second flanges which are interconnected by a web, wherein along at least a portion of said sacrificial member, the first flange is stronger than said second flange.

7. A connection assembly according to claim 6, wherein the first flange includes a first reinforcing member fixed along its length so as to increase the strength of that flange over the second flange.

8. A connection assembly according to either claim 6 or 7, wherein the first flange is stronger than said second flange in said deformation zone.

9. A connection assembly according to any one of claims 6 to 8, further including side plates which are disposed on either side of said web and which are affixed to both the first and second flanges. A connection assembly according to claim 9, wherein said side plates do not extend into said deformation zone.

N:'JRN634767\1RN634767completel 1 0302.doc

11. A connection assembly according to any one of claims 6 to 10, wherein the central beam has an I profile.

12. A fender assembly for a marine berth, said berth having an operating load capacity and a maximum load capacity which is greater than said operating load capacity, said assembly including a fender having an outer engaging surface, and a connection assembly which is operative to connect said fender to said berth, said connection assembly includes at least one sacrificial member which is operative to plastically deform when a force applied to said fender outer surface reaches a threshold load, said threshold load being greater than said berth operating load 10 capacity and less than said maximum load capacity.

13. A fender assembly according to claim 12, wherein the or each sacrificial member interconnects said fender to said berth so that on the application of said threshold loading to said fender, said fender assembly is caused to compress with the fender being caused to move towards said berth as the or each sacrificial member is plastically deformed.

14. A fender assembly according to either claim 12 or 13, wherein the or each sacrificial member extends at an angle to said fender so that combined axial and eccentrically generated bending stresses are induced in the or each sacrificial member on loading being applied to said fender outer surface.

15. A fender assembly according to claim 14, wherein the or each sacrificial member has a top and bottom flange and wherein the angle at which the or each sacrificial member extends from said fender is such that the induced combined axial and eccentrically generated bending stresses cause yielding at said top and bottom flanges at approximately the same loading.

16. A fender assembly according to any one of claims 12 to 15, wherein the or each sacrificial member includes a deformation zone where that member is operative to deform under the threshold loading.

17. A fender assembly according to claim 16, wherein the deformation zone of the or each sacrificial member is located at an end region of that member adjacent said berth.

18. A fender assembly according to either claim 16 or 17, wherein the at least one sacrificial member includes a central beam having opposite first and second N:\IRN\634767\IRN634767compIete1 10302.doc flanges which are interconnected by a web, wherein along at least a portion of that member, the first flange is stronger than second flange.

19. A fender assembly according to claim 18, wherein the first flange includes a first reinforcing member fixed along its length so as to increase the strength of that flange over the second flange.

A fender assembly according to claim 18 or 19, wherein the first flange is stronger than said second flange in said deformation zone.

21. A fender assembly according to any one of claims 18 to 20, further including side plates which are disposed on either side of said web and which are fixed to 10 both the first and second flanges. .e

22. A fender assembly according to claim 21, wherein the side plates do not .i e extend into the deformation zone.

23. A fender assembly according to any one of claims 18 to 20, wherein the central beam has an I profile.

24. A fender assembly according to any one of claims 12 to 23, wherein the .i connection assembly includes a plurality of said sacrificial members which are Oleo disposed about an inner surface of said fender.

A fender assembly according to claim 24, wherein the sacrificial members ***are secured onto a mounting plate which in turn is connected to said fender.

26. A fender assembly according to any one of claims 12 to 25, wherein the or each sacrificial member is formed as a metal strut.

27. A connection assembly for use in mounting a fender to a supporting structure substantially as herein described with reference to the accompanying drawings.

28. A fender assembly substantially as herein described with reference to the accompanying drawings. DATED: 11 March 2002 PHILLIPS ORMONDE FITZPATRICK Attorneys for WORLEY PTY LIMITED N:\IRN\634767\IRN634767complete1 1 0302.doc