Liebherr Middle East and Dutco Balfour Beatty (DBB) have worked together to modify a standard duty-cycle crawler crane to power a vibro hammer without a separate power pack – saving time and money in the execution of piling works at the Expo Village in Dubai.
It is estimated that the modification to allow the new 100t HS 8100 HD crane to drive the vibro hammer that installs pile casing using its own engine has resulted in a 20% increase in the productivity of the operation.
“Instead of using two engines to run the vibro hammer setup, we have only one, and this is controlled by the crane operator,” explained Ibrahim Hamdy, DBB’s plant and transport manager.
“We therefore do not have the frame and power pack that is normally mounted on the crane, and so we save on weight and manoeuvrability.”
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The application also saved on the purchase or rental of the power pack as well as on diesel and other running costs.
Hamdy notes: “We don’t need a separate operator for the power pack, so we save on manpower costs, and we save time because we eliminate the lost time required for communication between crane operator and vibro hammer operator.”
DBB has a six-month programme to complete the piling and foundations work for its contract, but is now well ahead of schedule and set to complete the piling within four and a half months instead.
This is substantially due to a modification designed by ourselves and Liebherr. Hamdy affirms: “Overall, we have calculated that in time, money and efficiency, we have improved productivity by 20% compared to the conventional two separate equipment of vibro hammer and crane setup.”
He added: “This is the first time this modification has been used in the UAE, and we shall be using this on the next project where we deploy the Liebherr duty cycle crawler cranes.”
Aside from the HS 8100 HD, DBB is using two 50t-capacity Liebherr HS 8050 HD cranes taken to install the steel cages and a fourth Liebherr unit, an LR 1130 crawler crane with a maximum load capacity of 137t.
Rotary drills supplied by another manufacturer are being used to bore the holes, with the Liebherr units driving the casing and then placing the steel rebar cage, in one length, into the hole.
The contract requires 1,900 piles, ranging in depth between 15m and 26m, and with diameters of 1,000mm, 900mm and 750mm. The soil is sand for the first four metres, with mixed rock of varying hardness below that, and a water table nearly seven metres below the surface.
“The speed at which we are able to work has been significantly increased by operating the vibro hammer directly from the crane engine,” said Tamer Shalash, DBB’s ground engineering manager.
“We are working to a 24-hour cycle, and our highest rate of pile installation has been 43 piles during one cycle.
“Using this configuration, we are saving up to six minutes per pile. We are actually calculating that during one cycle we can save two or three hours. This is a real achievement, and we are very happy to have worked with Liebherr to arrange such a satisfactory performance,” he detailed.
