JP7364393B2 - How to update the girder flange that supports the swing rail - Google Patents

Description

The present invention relates to a method for updating a girder flange that supports a swing rail for running swing wheels of a large structure such as port cargo handling equipment.

An example of a large structure equipped with a turning wheel is an unloader of port cargo handling equipment (equipment for handling cargo from a cargo ship to the ground). As shown in FIGS. 5 and 6, an unloader generally includes a portal frame 1 that can run on a straight rail installed on the ground, and a cargo handling device such as a bucket, crane, or conveyor. It consists of a rotating section 3 that is pivotably mounted on a rotating rail 2 that is installed in a circular shape on the upper surface of the rotating section 1.

Generally, the height of the top surface of the portal frame 1 is increased in order to reduce the height of the swing section to reduce the load applied to the swing rail 2, or to install a passageway or a conveyor for transporting loads between the ground. Since this is often the case, a portal shape is adopted.

Furthermore, the swing rail 2 that swings above the swing section 3 is supported by an annular girder flange 4, and the girder flange 4 that supports the swing rail 2 directly receives the load of the swing section 3. Since they are installed in harsh environments, they will need to be replaced if deterioration such as cracking, deformation, or corrosion progresses.

Generally, when updating the girder flange 4 of a large structure, the load capacity of the swing section 3 is removed from the top of the swing rail 2, since the load capacity will decrease if the girder flange 4 is partially cut or removed. It is done in the state. Unloading the swinging part 3 from above the swinging rail 2 means lifting or pushing up the swinging part 3 to reduce the load on the swinging part 3 applied to the swinging rail 2 and the girder flange that supports the swinging rail 2. It is to remove it.

However, the weight of the rotating parts of large unloaders and the like ranges from several hundred tons to several thousand tons, and in order to unload the rotating parts from the swing rails, a crane ship or crawler crane, etc. weighing several thousand tons or more is required. The normal method is to lift the swing part or to construct a foundation on the ground that can withstand the load of the swing part and then lift it while supporting the swing part, but in either case, the construction period is long. This process inevitably took a long time and cost a huge amount of money, and it was also difficult to secure a location for the crane. Such defects are not limited to equipment equipped with portal frames, but are a common problem in large structures equipped with swing rails, when updating girder flanges by unloading the swing section from the swing rail. .

An object of the present invention is to provide a novel structure in which a part or all of a girder flange can be renewed without unloading the swing part from the swing rail in a large structure in which the swing part is mounted on a swing frame. This is where the update method is proposed.

The present invention is a method for updating a part or all of an annular girder flange that supports on the upper surface a swing rail on which a swing wheel of swing equipment runs, and the method includes updating a part or all of the girder flange. This is a method for updating a girder flange supporting a swing rail, which is carried out with the equipment mounted on the swing rail.

In the above method, the girder flange is divided into a plurality of areas along the direction in which the swing wheel runs, and when a part of the divided area adjacent to the area to be updated is an existing part, the girder flange is A reinforcing member is installed at the boundary edge of the part to reinforce the existing part, the area to be updated is cut and removed, and the updated part reinforced with the reinforcing member is installed and fixed in the cut and removed area. updating a part or all of the girder flange at least once; and the reinforcing member is at least one reinforcing member arranged and fixed on the lower surface of the girder flange and extending from an inner end to an outer end thereof. In addition, by performing FEM analysis, we divided the girder flange into sections and designed reinforcing members to be used to reinforce the existing parts, and when updating the girder flange, we used strain gauges The amount of strain measured at the cut point of the girder flange was compared with the calculated strain amount of the cut point of the girder flange determined by FEM analysis, and the ratio of the measured strain amount to the calculated strain amount was used in the design. If the safety factor is greater than the safety factor, adding a reinforcing member is preferable as a specific means for solving the problem.

According to the present invention, it is possible to renew a part or all of the girder flange without unloading the swing section from the swing rail, and there is no need to use a crane ship, crawler crane, etc. to lift the swing section. . Additionally, there is no need to construct a foundation that can withstand the load of the swing section or to secure space for a crane, and the construction period can be shortened, thereby reducing the cost of updating the girder flange.

FIG. 3 is a diagram showing a vertical section of the girder flange together with the swing rail. (a) to (g) are diagrams showing the procedure for updating the girder flange. FIG. 3 is an external perspective view showing the reinforcement status of the existing portion of the girder flange. FIG. 3 is an external perspective view showing the reinforcement status of the existing portion of the girder flange. FIG. 2 is a diagram schematically showing an unloader of port cargo handling equipment. 4 is a diagram schematically showing main parts of the unloader shown in FIG. 3. FIG.

Hereinafter, a procedure for updating a girder flange that supports a revolving frame will be described using an unloader of port cargo handling equipment as a representative example of a large structure equipped with a revolving rail.

FIG. 1 is a diagram showing a vertical cross section of the girder flange 4 together with the swing rail 2. As shown in FIG. The girder flange 4 has a cylindrical T-shaped reinforcing joint 5 located on its lower surface to hold the girder flange 4, and a cylindrical belly plate (web) 6 connected to the lower part of the T-shaped reinforcing joint 5. It is made up of the following:

To update the girder flange 4, as shown in FIG. (Example is shown below.) If a part of the divided area adjacent to the area to be updated is an existing part, a reinforcing member 7 is installed and fixed at the boundary edge of the existing part as shown in FIG. 2(b). At the same time, as shown in FIG. 2(c), the area to be updated is cut and removed by fusing or the like. Then, as shown in FIGS. 2(d) and 2(e), a renewal member 8 provided with a reinforcing member is installed in the cut and removed area and fixed by joining by welding or the like. The turning rail 2 is omitted in FIGS. 2(a) to 2(g).

The area to be updated is cut away together with a portion of the T-shaped reinforcing joint 5. The reinforcing member 7 is at least one plate-like member having a width extending from the inner end to the outer end of the girder flange 4, and whose upper end surface has a height that does not exceed the upper end surface of the T-shaped reinforcing joint 5. The existing portion is reinforced by placing it on the lower surface of the girder flange 4 and joining and fixing it by welding or the like. The reinforcing member of the renewal member 8 is basically the same as that of the reinforcing member 7. The updating work is performed using the spaces formed at the upper and lower parts of the swing section.

To further update the existing part of the girder flange 4, divide the girder flange 4 into sections as shown in FIG. 2 (f) and move the swinging wheels 3a of the swinging section 3, as shown in FIG . 2 (g). Then, the reinforcing member 7 is installed to reinforce the existing portion, and the area to be updated is cut and removed, and the girder flange 4 is updated in the same manner as described above. In addition, in order to update the entire girder flange 4, all existing parts may be removed and the updated member may be placed in the removed part.

The present invention updates part or all of the girder flange by performing the above-mentioned operation at least once while leaving the swing part 3 on the swing rail 2.

The updating procedure for the girder flange and the design of the reinforcing member can be specifically determined by performing FEM analysis. The allowable stress used in the girder flange renewal procedure and the design of reinforcing members should preferably be set based on the yield point, rather than the tensile strength, in order to reduce residual strain (permanent strain) after construction (after renewal).

The safety factor of the allowable stress relative to the yield point (yield point/allowable stress) can be a relatively small value, for example, around 2, because the load is static and the time required for updating is short. can do.

This safety factor can be set to an even smaller value, for example, about 1.15, if strain monitoring is also carried out using a strain gauge during renewal construction.

The position and range in which the girder flange is cut and removed is determined by calculating the Mises stress that occurs when the girder flange is cut and removed, so that even the portion where the Mises stress is the largest is below the allowable stress.

When updating the girder flange, there is a possibility that stress or strain that differs from the FEM analysis due to unforeseen factors such as defects in the material may occur. It is best to set a high safety factor in order to keep deformation within an allowable range, but in partial renewal work on site, it is difficult to carry out construction based on a high safety factor in terms of space and time. There are cases.

Generally, the safety factor of a steel structure under a static load environment is designed to be about 3, but the safety factor can be set to about 2 only when the construction period is about several tens of days.

In the present invention, when updating a girder flange, by measuring and monitoring the amount of stress and strain on the girder flange, it is possible to detect at an early stage the occurrence of stress or strain that occurs due to unexpected factors and differs from that found in FEM analysis. For example, if the stress or strain amount is larger than 1.1 times the amount of stress or strain determined by FEM analysis, update of the girder flange is stopped, reinforcement members are added, and the existing part of the girder flange is further strengthened. By taking reinforcement measures, it was possible to lower the safety factor to less than 2.

As the reinforcing member 7, a plate-like member having a flat surface as shown in FIG. 3 can be used, but as shown in FIG. It is also possible to use one having at least one bent part, and in this case, there is an advantage that the reinforcing member 7 can be made thinner because the reinforcing effect can be enhanced. Note that the reinforcing member 7 is fixed to the T-shaped reinforcing joint 5 by welding or the like.

Work was carried out to update the entire circumference of the girder flange that supports the swing rail of an unloader with an unloading capacity of 3000 t/h, which unloads ore etc. from ships. The unloader has a total height of 49 m, a portal frame height of 15 m, a swing part height of 34 m, and a swing part weight of 2000 tons.The swing rail has a swing diameter of 12 m, and the girder flange has a thickness of 40 mm and a width (from The dimension up to the outer end) is 600 mm.

FEM analysis was performed by setting the allowable stress to the yield point of the girder flange material SM490 (324 MPa for thickness ≦ 16 mm, 314 MPa for 16 < thickness ≦ 40 mm, 294 MPa for thickness > 40 mm)/2, that is, the safety factor is 2. As a result, it was found that the entire circumference of the girder flange was divided into 20 sections, and 36 flat-faced plates made of SM490 and 32 mm thick were installed as reinforcement.

When the girder flange was updated in accordance with the analysis results as shown in Figure 2 above, it was confirmed that the girder flange could be updated for 80 days without exceeding the allowable stress.

As a result of performing FEM analysis with the allowable stress set to the yield point of the girder flange material SM490/1.15, that is, the safety factor of 1.15, the entire circumference of the girder flange was divided into 16 sections, and the existing members were reinforced. It was found that 28 plate-shaped bodies made of SM490 and having a flat surface with a thickness of 32 mm should be installed.

In this example, in order to reduce residual strain (permanent strain) caused by unexpected factors and avoid deformation or breakage of the girder flange, a strain gauge is attached to the area near the cut site during construction to measure strain. However, if the actual measured value of distortion exceeds 1.15 times the value calculated by FEM analysis, we will stop updating the girder flange and carry out reinforcement, while following the results of FEM analysis. The girder flange was updated as shown in Figure 2. As a result, it was confirmed that the girder flange could be updated in 73 days without any problems.

In Example 2, FEM analysis was carried out to update the girder flank using a reinforcing member having a bent part in which the central part in the longitudinal direction was bent at an angle of θ = 30° with respect to the axis. It was found that 28 plates made of SM490 and having a thickness of 25 mm were sufficient.

In this example as well, strain gauges were installed near the cutting site during construction to reduce residual strain (permanent strain) caused by unexpected factors and to avoid deformation or breakage of the girder flange. If the actual value of distortion exceeds 1.15 times the value calculated by FEM analysis, we will stop updating the girder flange and perform reinforcement, while following the results of FEM analysis. The girder flange was updated as shown in Figure 2 above. In this case as well, it was confirmed that the girder flange could be renewed in 69 days without any problems.

Comparative example 1

We planned a method to lift the swing section using a crane ship with a lifting capacity of 3,000 tons, unload the swing section from the swing rail and garter flange, and then replace the girder flange. There are only six crane ships in Japan with a lifting capacity of 3,000 tons or more, so it was necessary to change the construction schedule. Furthermore, it was revealed that with this updating method, the construction cost would increase by about 10% compared to Example 3.

Comparative example 2

We planned to build a foundation on the ground adjacent to the unloader to withstand the load of the swivel section, and use that foundation to support the load of the swivel section and jack it up.However, it would be necessary to stop the unloader while the foundation was being constructed. Since the unloader is located on a quay, it was estimated that foundation piles would need to be installed underwater, which would prolong the suspension of operations by approximately six months.

According to the present invention, it is possible to provide an updating method that allows part or all of the girder flange to be updated without unloading the swing section from the swing rail.

1 Portal frame 2 Swivel rail 3 Swivel part 3a Swivel wheel 4 Girder flange 5 T-shaped reinforcement joint 6 Belly plate 7 Reinforcement member 8 Renewal member

Claims (3)

A method of renewing part or all of an annular girder flange that supports on its upper surface a swing rail for running swing wheels of swing equipment, the method comprising:
The girder flange is updated with the swing equipment mounted on a swing rail ,
The girder flange is divided into a plurality of regions along the direction in which the swing wheel runs, and when a region adjacent to the region to be updated among the divided regions is an existing region, the boundary edge of the existing region At least once, a reinforcing member is installed to reinforce the existing part, the area to be updated is cut and removed, and an updated member reinforced with the reinforcing member is installed and fixed in the cut and removed area. A method for updating a girder flange supporting a swing rail , which comprises updating a part of the girder flange by repeating the above operations, or updating the entire girder flange by repeating the above operation . The reinforcing member supports the swing rail according to claim 1 , wherein at least one plate-shaped member is arranged and fixed on the lower surface of the girder flange and extends from an inner end to an outer end thereof. How to update girder flange. By performing FEM analysis, we divided the girder flange into sections and designed reinforcing members to be used to reinforce the existing parts.When updating the girder flange, we analyzed the girder flange cut area measured with a strain gauge. Compare the strain amount with the calculated strain amount of the cut part of the girder flange obtained by FEM analysis, and if the ratio between the measured strain amount and the calculated strain amount is larger than the safety factor used in the design, the reinforcing member 3. A method for updating a girder flange supporting a swing rail according to claim 1 or 2 , further comprising: adding the following.

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