Technical Field
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The present disclosure relates to a method of deconstructing a container gantry crane particularly, but not exclusively, a method of deconstructing a ship-to-shore container gantry crane.
Background
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Cranes are extensively used around the world for transporting goods between vehicles and land, and between heights (e.g. to the top of a building under construction). Ship-to-shore gantry cranes are used at docks to transport containers between ships and the shore and to load ongoing vehicles such as lorries and trains. Cranes, like most machinery have a finite lifetime, after which they are no longer serviceable due to wear and tear, damage or other factors which render the cranes redundant.
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When a crane becomes redundant, it must be removed from its site to allow a replacement to be put into place and remove the safety risk posed by a redundant crane. Gantry cranes are removed by deconstructing the crane piece-by-piece using heavy lift mobile/crawler cranes working in a top-down manner to remove sections from the crane and remove the sections from site, until none remain.
Summary
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There is provided a method of deconstructing a container gantry crane, the method comprising:
- weakening structural members of the gantry crane by cutting partially through each of the structural members at cut points, the cut points comprising a leg cut point on each leg of the crane,
- applying a lateral force to the gantry crane above the cut points, thereby causing the gantry crane to collapse.
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The structural members are weakened at the cut points so that when the lateral force is applied, the structural members pivot about the cut points and the crane folds. This process is referred to as a controlled collapse. This method vastly improves the safety, speed and efficiency of the deconstruction process by greatly reducing the time that operators spend working at height and over water. Further, this method eliminates the lifting operations required by the piece-by-piece method, further improving safety.
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The crane may comprise four legs. A container gantry crane usually comprises a frame including legs and a boom extending from a front side, which may be described as a waterside, of the frame. The boom may be raisable and a lifting apparatus for lifting and lowering containers can move along the boom. The boom of a ship-to-shore gantry crane is positioned over a body of water. On a back, or landside of the frame, a back boom and machinery house is generally positioned, along with mechanisms for controlling the travel and operation of the lifting apparatus. In this specification, the terms back, or backside and landside are used interchangeably and the terms front, or frontside and waterside are used interchangeably.
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Optionally, the lateral force is provided in a direction from the front to the back side of the crane and/or in a direction away from the closest body of water. The crane will then be folded in the backwards, and/or landside direction, away from the closest body of water.
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Optionally, the leg cut points are each within 10 metres of the height of the underside of a boom of the crane, and preferably within 5m of the height of the underside of a boom of the crane. Optionally, the cutting partially through a respective one of the legs at each of the leg cut points comprises forming a horizontal cut partially through the respective leg. Optionally, the legs are girders and cutting partially through the legs comprises cutting through a land side and land-water sides of the girder, leaving the waterside at least partially uncut.
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Optionally, the cut points further comprise two girder cut points on one or each land-water horizontal girder(s), the horizontal girder(s) connecting two of the legs. Optionally, the one or more land-water horizontal girders comprise two primary land water horizontal girders between the height of the ground and the height of the boom of the crane.
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Optionally, cutting partially through the structural members comprises cutting through all except one face/side of each of the structural members to leave one side of each structural member intact.
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Optionally, the structural members comprise box girders and cutting partially through the box girders comprises cutting through all except one side of each of the box girders to leave one side of each box girder intact. Optionally, when the cut is a horizontal cut, the landside and land-water sides are cut and the waterside of the structural member remains intact.
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Optionally, when the cut is a vertical cut, the sides are cut through and one of the top and bottom side is cut through to leave the bottom or top respectively intact. Optionally, a vertical cut closer to the landside legs than the waterside legs comprises cutting the top and leaving the bottom intact Optionally, a vertical cut closer to the waterside legs than the landside legs comprises cutting the bottom and leaving the top intact.
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Optionally, cutting partially through each of the structural members at cut points comprises performing each cut in a top-down sequence, from the uppermost part of the cut to the lowermost part of the cut. Optionally, cutting partially through each of the structural members at cut points comprises performing a portion of each cut from an internal side of the structural members, and then completing each cut, from an external side of the structural members. In this way, cuts in which operatives are located within the confines of the portal structure are made first, followed by safer cuts in which operatives are outside the structure. Optionally, the final cuts made are on the upper waterside of the crane on an external side of the structural members.
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Optionally, the lateral force is applied in a landside direction. Optionally, applying a lateral force comprises using ropes attached to an anchor point on the gantry crane to pull the gantry crane in a landside direction. Optionally, the lateral force is applied by plant machinery such as a demolition excavator. Optionally, the ropes comprise hoist ropes of the gantry crane. Optionally, the ropes are attached to the machinery house of the gantry crane.
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Optionally, cutting partially through the structural members is performed less than 10 hours, preferably less than 8, 6 or 5 hours before applying the lateral force. Optionally, cutting partially through the structural members is performed using oxygen and propane cutting equipment.
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Optionally, the method further comprises laying sand in a collapse path of the crane, the sand being over 1m deep, preferably more than 1.5m and preferably up to 2m in areas of the collapse path in which the heaviest portions of the crane land during the collapse.
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There is further provided a method of disposal of a gantry crane, the method comprising: deconstructing the gantry crane according to the method described above and removing the collapsed gantry crane to one or more disposal facilities.
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Optionally the one or more disposal facilities comprise a recycling facility, a manufacturing facility, a land fill facility, or any other waste processing facility.
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Further features and advantages of the above-described aspects of the present disclosure will become apparent from the claims and the following description.
Brief Description of Drawings
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Embodiments of the present disclosure will now be described by way of example only, with reference to the following diagrams, in which:-
- Fig. 1 is a side view of a gantry crane;
- Fig. 2 is a partial side view of the gantry crane of Fig. 1;
- Fig. 3 is a side view of the gantry crane of Fig. 1 and its collapse path; and
- Fig. 4 is a side view of the gantry crane of Fig. 1 during controlled collapse.
Detailed Description
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An embodiment of the disclosure is described subsequently.
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Fig. 1 shows a container, ship-to-shore gantry crane 100 comprising a frame including four legs 102, 103 (of which two are shown) and a front boom 101 extending on a front side, which may be described as a waterside, of the frame. The boom 101 is raisable as shown by the additional possible positions 101a, 101b shown in Fig. 1. A lifting apparatus 104, otherwise known as a crane trolley, for lifting and lowering containers can move along the boom 101. The boom 101 of a ship-to-shore gantry crane is positioned over a body of water. On a back, or landside of the frame, a back boom 105 and machinery house 106 is generally positioned, along with mechanisms for controlling the travel and operation of the lifting apparatus 104. Two water-land horizontal girders 107 (one shown) attach legs 102, 103 at a position between the ground and the boom 101. The back, backside/landside of the crane is signified by the L in Fig. 1 and the front/frontside/waterside is shown as W.
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A method will now be described for deconstructing the container gantry crane shown in Fig. 1.
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The method comprises: weakening structural members of the gantry crane by cutting partially through each of the structural members at cut points, and applying a lateral force to the gantry crane above the cut points, thereby causing the gantry crane to collapse.
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Fig. 2 shows the position and orientation of each cut point. The cut points include leg cut points 201, 202 on each leg of the crane (two of four shown). The cut points further include horizontal girder cut points 203, 204 (two of four shown). The structural members are weakened at the cut points so that when the lateral force is applied, the structural members pivot about the cut points and the crane folds as shown in Fig. 3 and Fig. 4 to be discussed in more detail later. This process is referred to as a controlled collapse.
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As shown in Fig. 2, the leg cut points are each within 10 metres of the height of the underside of the boom 101 of the crane. As shown in the close-up top-view cut diagrams 201a and 202a, cutting partially through a respective one of the legs at each of the leg cut points comprises forming a horizontal cut partially through the respective leg. The cut sides are shown by dashed lines. The legs 102, 103 are box girders and cutting partially through the legs 102, 103 comprises cutting through a land side and land-water sides of the girder, leaving the waterside W of the box girders at the leg cut points at least partially uncut.
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The cut points further comprise two horizontal girder cut points 203, 204 on each land-water horizontal girder 107 (one of the two horizontal girders are shown). The cuts made at the cut points 203, 204 are vertical cuts, in which the sides are cut through and one of the top and bottom side is cut through to leave the bottom or top respectively intact.
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Vertical cut 203 is closer to the landside legs 102 than the waterside legs 103 and so the top is cut leaving the bottom intact. Vertical cut 204 is closer to the waterside legs 103 than the landside legs 102 and so the bottom is cut leaving the top intact.
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Each vertical cut is performed in a top-down sequence, from the uppermost part of the cut to the lowermost part of the cut. Cutting is performed in a sequence in which all internal cuts, where operatives are located within the confines of the portal structure, are made first, followed by external cuts and the final cuts are on the upper waterside of the crane. In this example, the cuts may be performed in the following order: 202a Internal, 202b Internal, 201a Internal, 201b Internal, 204a Internal, 204b Internal, 203a Internal, 203b Internal, 201a External, 201b External, 203a External, 204a External, 203b External, 204b External, 202a External, 202b External. Where necessary, stability braces may also be removed from the crane.
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Fig. 3 shows crane 100 with the boom 101 raised and shows an example collapse path 310. The lateral force is provided in a direction from the front W to the back side L of the crane and in a direction away from the closest body of water. As shown by the collapse path 310, the crane will then be folded in the backwards, and landside L direction, away from the closest body of water.
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Before applying the lateral force, the method includes laying sand 311 in a collapse path of the crane, the sand being over 1.5m deep and up to 2m in areas of the collapse path in which the heaviest portions of the crane will land during the collapse.
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Cutting partially through the structural members is performed using oxygen and propane cutting equipment, less than 5 hours before applying the lateral force, to avoid accidental collapse.
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Fig. 4 shows the crane 100 during controlled collapse. The crane folds at the cut points 201, 202, 203, 204 and the crane follows the collapse path to the ground on which sand is laid (sand not shown in Fig. 4). The lateral force is applied using ropes attached to an anchor point on the gantry crane to pull the gantry crane in a landside direction L. The lateral force is applied by plant machinery such as a demolition excavator via the hoist ropes of the gantry crane which are advantageously already fixed to the crane.
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Once collapsed, the gantry crane is removed to one or more disposal facilities. In many cases, a large proportion of the crane is recycled at a recycling facility.
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Although particular embodiments of the disclosure have been disclosed herein in detail, this has been done by way of example and for the purposes of illustration only. The aforementioned embodiments are not intended to be limiting with respect to the scope of the appended claims.
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It is contemplated by the inventors that various substitutions, alterations, and modifications may be made to the invention without departing from the scope of the invention as defined by the claims. Examples of these include the following:-
Further cuts and deconstruction may be performed prior to collapse of the gantry crane.