With no readily available lifting system in the current market that can lift a weight of 1100t on a crane barge with millimeter accuracy, DQS approached Mammoet to provide a customized solution for the replacement of a pintle bearing located at the bottom of the crane.
The customized gantry was first designed by the Breda office and made from gantry components which are readily available at multiple Mammoet locations in Europe and Asia.
The system comprised of four tower gantries, four SJ850 strand jack model each with 850t lifting capacity. As for the millimeter precision required, this was delivered by the team using a special software to operate and control the strand jack model.
Overall manpower for the team consisted of specialists from Mammoet Breda and local expertise from Mammoet Vietnam. Despite this operation being the first for Mammoet Vietnam, the local team provided the support by picking up the necessary skills required quickly.
For execution, building of the gantry itself was done mostly at various heights from 15m-36m. When the gantry was fully constructed, it was assembled onto the crane which was lifted to 20mm and then placed on stand-by for checking of the system.
Next, the crane was then lifted to 1300mm and set in a position for two weeks. DQS then proceeded to replace the pintle bearing and the crane was subsequently lowered back to its original position once the replace is complete.
The operation was successfully and safely completed despite challenges faced by the team with regards to mobilization of gantry components and manpower due to frequent changes in local COVID-19 restrictions.
Once all upgrade is completed for the crane barge, DQS will be able to use it for piles layout and lifting of modules onto platforms.