Saipem and Azfen JV has contracted Module Caspi Industrial Solutions LLC (Module Caspi) to manufacture 4No. custom bulk bags with a submerged weight of 5.1mT when filled with a grout mix of 60% sand and 40% cement. The unit designed to be suitable for multiple subsea lifts.
Project name: Turning Bollards for Flowline Campaign
The basis of the turning bollard bag design by Subcon to achieve the required submerged weight of:
5.1mT utilising a bag grout mix of 40% cement and 60% sand is as follows.
- Density of a grout mix of sand and cement when activated with water; 1,875Kg/m³.
- Submerged density of a grout mix of sand and cement when activated with water; 850Kg/m³.
III. Required submerged weight; 5,100Kg (5.1mT).
- Required volume of grout to achieve submerged weight based on submerged density; 5,100 /
850 = 6m³.
The turning bollard bag to achieve the required volume has been manufactured at 2-2.5m long by 2-2.5m
wide and with a height of 1.5m.
The weight in air of the bag design prior to activation is;
- Approximate density of a aerated grout mix of sand and cement; 1,200Kg/m³.
- Volume of turning bollard bag; 6m³
III. Weight in air; 1,200 x 6 = 7,200Kg (7.2mT)
The maximum weight of the turning bollard bags is on recovery to surface from the seabed in an
undrained state.
- Density of a grout mix of sand and cement when activated with water; 1,875Kg/m³.
- Volume of turning bollard bag; 6m³
III. Weight in air; 1,875 x 6 = 11,250Kg (11.25mT)
LIFTING SLING DESIGN
The turning bollard bag is designed to be lifted with 4no. 3mt WLL certified slings in a basket lift
scenario. The basis for the use of 3mT WLL slings is as follows;
Turning Bollard Bag maximum weight; 11,250Kg (11.25mT)
DAF; 2
Number of Lift Points; 8 (4No. Slings in basket lift configuration)
Loading Factor based on 60⁰ minimum sling angle from horizontal; 1.7
11,250 x 2 / 8 / 1.7 = 1,650Kg
Recommendation is for a lift sling with a minimum WLL of 2mT.
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