Can v use two 50 T cranes to lift a 75 T equipment...?
From United Arab Emirates, Abu Dhabi
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From United Arab Emirates, Abu Dhabi
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If you are planning to lift and shift within a short distance in a static position, and the operators are capable of coordinating with each other, then it can be possible. However, if you are planning to erect at some height, the capacity of the lift will be reduced based on the boom length and height.
Let us wait for the opinion/guidance from our safety expert members.
From India, Kumbakonam
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1189Let us wait for the opinion/guidance from our safety expert members.
From India, Kumbakonam
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Tandem Lift Guidelines
A tandem lift is permitted provided that the cranes are of the same type. For example, using one side hydraulic crane and the other side mechanically operated crane is not permitted.
Before conducting a tandem lift, a lifting plan and rigging study must be conducted. The radius of the lift and the Safe Working Capacity (SWC) of the cranes should be known before deciding on the usage of cranes. Without the radius and the load chart details of the cranes, we can't provide you with any suggestions.
Regards,
Pon
From India, Lucknow
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A tandem lift is permitted provided that the cranes are of the same type. For example, using one side hydraulic crane and the other side mechanically operated crane is not permitted.
Before conducting a tandem lift, a lifting plan and rigging study must be conducted. The radius of the lift and the Safe Working Capacity (SWC) of the cranes should be known before deciding on the usage of cranes. Without the radius and the load chart details of the cranes, we can't provide you with any suggestions.
Regards,
Pon
From India, Lucknow
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Hello! It’s my opinion that it can be harmful to use two different cranes cause it can be dangerous at any time. Thanks & regards... Sourav Chandra
From India, Kolkata
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From India, Kolkata
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Sometimes, it is dangerous to lift long or oversized materials with a single crane. Tandem lifts are a universally accepted practice. In one of our projects, we used three cranes to erect a long gallery due to ground situations. The only thing is we have to follow all safety procedures and the lift plan.
Regards,
Pon
From India, Lucknow
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Regards,
Pon
From India, Lucknow
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We have erected a 42-ton raft with two 75-ton cranes at a height of 27 meters. In this scenario, the weight of the girder/raft and the required height for placement must be considered when selecting the cranes for lifting and erection.
From India, Kumbakonam
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From India, Kumbakonam
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My view is similar to those expressed above. Two cranes can be used, provided it is for transfer operation at the ground level. To use at elevated levels, it has to be decided after seeing the LIFT vs. LOAD chart of both the cranes and with the knowledge of an expert. You should also consider the type of load. If it is a uniformly distributed load, the lifting task is relatively easy. Otherwise, the uneven distribution (lopsided objects have CG - Centre of Gravity - away from the geometric centre) will pose a challenge. Synchronization between the two operators is also a very important aspect.
Regards,
V. Raghunathan
From India
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Regards,
V. Raghunathan
From India
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Positioning Cranes for Lifting Operations
Position the cranes and booms at the initial position where the material is to be lifted. Determine the safe working load (SWL) of the cranes. Then, reposition them to where the material is to be shifted. Again, find out the SWL. If the SWLs of both cranes do not exceed the actual load of the material, then lifting with a tandem or critical plan is possible.
Note: In our project, 7 cranes of 30-ton capacity were used several times.
From Kuwait, Kuwait
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Position the cranes and booms at the initial position where the material is to be lifted. Determine the safe working load (SWL) of the cranes. Then, reposition them to where the material is to be shifted. Again, find out the SWL. If the SWLs of both cranes do not exceed the actual load of the material, then lifting with a tandem or critical plan is possible.
Note: In our project, 7 cranes of 30-ton capacity were used several times.
From Kuwait, Kuwait
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You have provided a good suggestion. I need clarification on one point. You mentioned, "if both SWLs of both cranes do not exceed the actual load of the material," I believe the combined SWL of both cranes should be greater than the actual load to ensure safety.
Regards,
V. Raghunathan
From India
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Regards,
V. Raghunathan
From India
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Hello, Mr. Raghunathan,
Here is the clarification:
- **Weight of the material to be shifted:** 40.0 tons
- **SWL of crane 1 at initial position:** 30.5 tons
- **SWL of crane 2 at initial position:** 27.0 tons
- **Total capacity of cranes at initial position:** 57.5 tons
- **SWL of crane 1 at final position:** 24.5 tons
- **SWL of crane 2 at final position:** 21.5 tons
- **Total capacity of cranes at final position:** 46.0 tons
In both positions, the total capacity exceeds the weight of the material (40.0 tons). Here, a tandem/critical lift is possible. In other words, we can say that the total capacity of the cranes should be more than the weight of the material by at least 10 to 15%.
Regards,
Ramesh Dharmarajan
From Kuwait, Kuwait
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Here is the clarification:
- **Weight of the material to be shifted:** 40.0 tons
- **SWL of crane 1 at initial position:** 30.5 tons
- **SWL of crane 2 at initial position:** 27.0 tons
- **Total capacity of cranes at initial position:** 57.5 tons
- **SWL of crane 1 at final position:** 24.5 tons
- **SWL of crane 2 at final position:** 21.5 tons
- **Total capacity of cranes at final position:** 46.0 tons
In both positions, the total capacity exceeds the weight of the material (40.0 tons). Here, a tandem/critical lift is possible. In other words, we can say that the total capacity of the cranes should be more than the weight of the material by at least 10 to 15%.
Regards,
Ramesh Dharmarajan
From Kuwait, Kuwait
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Thank you for the detailed explanation with an example. The numerical example dispels any doubt one might have while lifting the job with two cranes. In the example given above, the combined SWL of both cranes is MORE THAN THE JOB WEIGHT, ensuring safety. This aspect is satisfied in the pre-lift and lift conditions. However, when you made the first post, you mentioned it the other way, perhaps due to oversight.
If both SWLs of both cranes do not exceed the actual load of the material, INCORRECT, if both SWLs of both cranes exceed the actual load of the material by about 15%,... CORRECT
Please make the correction (of the clerical error) accordingly in your first post.
Regards,
V. Raghunathan
From India
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If both SWLs of both cranes do not exceed the actual load of the material, INCORRECT, if both SWLs of both cranes exceed the actual load of the material by about 15%,... CORRECT
Please make the correction (of the clerical error) accordingly in your first post.
Regards,
V. Raghunathan
From India
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From the query, it is clear that you are not conversant with crane rigging. For God's sake, don't get carried away with the "I think..." answers in rigging. Tandem lift is a serious and dangerous operation. For that matter, every lifting operation needs to be considered as serious and dangerous. The history of crane failures says so. The consequences of a failure can be quite serious. However, by following the set procedures, every lift can be completed safely, allowing you to relax at the end.
Tandem Lift: A Critical Operation
A tandem lift (using multiple cranes) is a critical lift. It requires a lift plan.
Components of a Lift Plan
A competent rigger will draw a lift plan. A lift plan is required as part of any critical lift procedure and must provide the following:
• Type and de-rated capacity of cranes to assess SWL of the cranes (load chart) in the configuration
• Boom length
• Crane radius
• Weight and shape of the load, center of gravity, etc.
• Ground and site conditions
• Placement of the crane
• Swing and tail clearances
• Necessary communication to be used
• Explanation of hand signals
• Rigging hardware
• Rigging sketch
• Rated capacity of rigging components
• Sling angles
• Strain calculations
• Wind velocity
• Load moment indicator
• Others
Your cranes, as such, cannot lift the intended load, and no rigger/competent person will permit it.
Regards,
Kesava Pillai
From India, Kollam
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Tandem Lift: A Critical Operation
A tandem lift (using multiple cranes) is a critical lift. It requires a lift plan.
Components of a Lift Plan
A competent rigger will draw a lift plan. A lift plan is required as part of any critical lift procedure and must provide the following:
• Type and de-rated capacity of cranes to assess SWL of the cranes (load chart) in the configuration
• Boom length
• Crane radius
• Weight and shape of the load, center of gravity, etc.
• Ground and site conditions
• Placement of the crane
• Swing and tail clearances
• Necessary communication to be used
• Explanation of hand signals
• Rigging hardware
• Rigging sketch
• Rated capacity of rigging components
• Sling angles
• Strain calculations
• Wind velocity
• Load moment indicator
• Others
Your cranes, as such, cannot lift the intended load, and no rigger/competent person will permit it.
Regards,
Kesava Pillai
From India, Kollam
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