How to Measure and Calculate Center of Gravity Using Loadcells

Why is it important? Because you need to Know the Load before any large object is lifted or transported.

Once fabrication and manufacture is complete, large structures, for example, an offshore module, need to be transported to their final destination for installation.

 Center of gravity is typically used to ascertain the load of:

• Topsides
• Offshore modules
• Absorbers
• Generators
• Turbines
• Reactors
• Boilers
• Wind turbine towers
• Locomotives
• Boats
• Military equipment

Before cranes, rigging and transport (could be a truck, SPMT or floating barge) you need to know the total load of the item, the balance of the load, and the position of the center of gravity so that you can safely lift and move it.

To enable this Straightpoint wireless LoadSafe compression loadcells are used. Often used in 3, 4, 6, 8… at a time, they connect to Insight software (which in fact can record data from a maximum of 126 loadcells!) and allow the weighing process to be done safely and accurately.

Each LoadSafe is positioned below the object (generally it will be raised using hydraulic jacks, preferably all connected so the lift is synchronized) and the location of the loadcell is then entered into Insight to include X and Y co-ordinates.

Once all loadcells are in position and you are happy the load is safe and stable (take into consideration metrological factors) Insight software will then require you to weigh the load three times in accordance with ISO19901 (petroleum and natural gas). Note that the LoadSafe loadcell should be rotated between each of the weighing captures.

 A real time view allows you to see the center of gravity.

Once complete, Insight will generate an html report detailing:

• Project info such as client and operator
• Wind speed and temperature
• LoadSafe co-ordinates
• Three weight values for each LoadSafe loadcell
• Three C of G values for each LoadSafe loadcell
• Total weight and standard deviation

After all, IF YOU DON’T KNOW THE LOAD, HOW CAN YOU LIFT IT SAFELY?