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693t Proof load test completed on a Gantry crane in two days

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Country Hoboken, Belgium
Date/ Year May 2011
Service details  Unique Group’s Water Weights brand water-filled proof load bags offer varying capacities from 1 to 110-tonnes which provides an easy, safe and cost-effective means of load testing all kinds of lifting equipment and load-bearing structures.

Water-filled bags offer a significant advantage over traditional forms of solid weights because the test load is applied gradually and precisely.

A comprehensive range of products to suit all applications is available for hire or sale. Get in touch with us buoyancyballast@uniquegroup.com  

Summary of the Project
Unique Group’s Buoyancy & Ballast division completed a 693tonne test on a gantry crane using water-filled proof load bags within two days.

Client Requirement

The client wanted to upgrade a 450tonne overhead crane to 630tonne capacity, for a special project. Therefore, we were asked to perform a static test load of 693t, during which the crane had to carry the load and travel along the 400m length of its track. The job also needed to be performed during the daytime within two days.

Unique Solution Delivered


Unique Group’s solution for the client involved spreading the load over three separate hooks so we supplied three weights of our Unique Group brand Water Weights proof load bags between approximately 180t to 280t. In order to not interrupt the normal activities of the crane, the job was performed during the weekend and for safety reasons we did not perform any of the activities after sunset.

Our engineers and the equipment consisting of 24 bags, 3 load cells and several slings/shackles, arrived at the site on Friday to complete necessary preparations and begin pre-rigging. Following which on Saturday the 693t static load test was performed using proof load bags filled with water and on Sunday the dynamic 630t test was completed.

Following the successful completion of the proof load test, our personnel and equipment were demobilised from the site and we had completed our project on schedule. 

Benefits delivered

  • Customised solution – based on the operational feasibility
  • On-site Support
  • Efficient and reliable method
  • HSEQ Compliant
  • Project completed within schedule