About 3,000m (9,840ft) of jointed glass-reinforced epoxy pipes were to be lifted into trenches during the second phase of the Ballanaboy Gas Terminal in Ireland.
Roadbridge Ltd, the civil engineering and building contractors, were contracted by Shell E & P Ireland to construct the civil works element of the terminal to receive gas from the Corrib field, which is located in the Atlantic Ocean 83km off the west coast of Ireland, for processing prior to entering the national grid.
Each pipe section came in 10m (32ft) lengths and weighed approximately 400kg (880 lbs). These were joined together on site using a joint lamination technique, with a maximum of six pipes forming one string. This required spreader lengths of 24m, 36m and 48m. Each 10m pipe was supported at two points by nylon web slings to eliminate movement at the joints during lifts.
Roadbridge rented two 24m Modulift lattice systems as well as a sling assembly to support the rigging of a single 36m lattice spreader rig, to lift varying lengths of pipes. Lifting the pipes were a 90t Tadano Faun ATF 90G-4 all terrain with 13.5t counterweight and a 50t Grove GMK 3050, both supplied by Walsh Crane Hire.
The original plan was to use excavators, says Tom Walsh, Roadbridge contracts manager. “As we had a large number of excavators already on site, we originally planned to utilise about seven to lift the varying lengths of pipe sections. We took the decision to replace these with the Modulift lattice system mainly because the lifting frame provided better support for the pipes during the lifts, minimising the risk of damage to the pipe as well as providing a safer, more efficient, lifting process.
“It is also more cost effective. For a direct comparison, the cost of hiring two cranes and the Modulift lattice system equates to the cost of using four excavators. The 36m lattice spreader
rig lifted by one crane is even more cost-effective.”
Approximately 80 pipe sections were assembled in total, with no two lifts being identical. A 56m string of pipes, weighing approximately 2,000kg, was lifted using the 48m lattice spreader and the two crane arrangement. These pipes were supported at 12 points using the nylon web slings. Due to the length of each string, a lifting plan was designed and agreed before each lift took place to ensure every load was level and under control throughout. The system was used three times a week from August to October 2007, and one of the 24m spreaders was left on site until January when the phase
of works finished.
The Modulift lattice system was originally designed to handle long roof sheets, says Modulift director Nick Latham. The spreader beam consists of blocks of two 3m-long types: a 138kg (304 lb) sling lug section, and a 110kg (220 lb) standard section. Lifting points on the spreader support the load at regular, one metre, intervals. A crane lifts the 24m spreader arrangement by a two-leg sling, providing a lifting capacity of up to 3t. Spans up to 42m long are hung from multiple slings.
Metre-long cross beams are available for lifting wider loads. The Modulift spreader system range comprises 16 systems, which provide lifting capacity for weights up to 3,000t and lengths up to 53m.
