Hong Kong ranks as the city with the highest number of skyscrapers in the world. Yet it is still being developed in many areas. In this article we bring you an update on a project located in the heart of Central, Hong Kong Island’s most vibrant and densely built-up area. Located right next to a fresh market, navigating through a crowd of shoppers was the only way to get to the jobsite. The construction site itself had such a small footprint that unloading the equipment was a challenge. It took the client quite a while to position the ICE-600 power pack and 18RF vibratory hammer so that handling of the piles and machinery would be possible.

Like the 20RF, the 18RF is light and compact and can be lifted by a 35t mobile crane. Easy to set up, quick to get operational.

Specifications:

Eccentric moment: 0-18 kgm

Max. centrifugal force: 0-1015 kN

Max frequency: 2300 rpm

Weight: 4120kg

K.H. Foundations LTD. was looking for a vibratory hammer that does not disturb the residents and avoids vibration damage to adjacent structures. ICE Hong Kong dealer Face Machinery suggested resonance free vibrating technology as the solution for working under these conditions. RF hammers operate at a high frequency and can vary the moment of the spinning eccentric weights, effectively eliminating the low and disruptive resonance vibrations typical for the start-up and stop of regular vibratory hammers. Although the technology has been widely used for decades in Europe and is very popular in cities like Shanghai, RF vibrating technology is largely unknown in Hong Kong. This was a first rental job and a good chance to prove the concept as safe and reliable for use in heavily urbanized areas of Hong Kong.

The socket H-beam foundation was installed by rotating a 610mm 12-meter-long steel casing into the ground with a piling rig, emptying the casing with a Kelly bar, lowering a H-beam into the hole and filling it up with grout. Finally, before the grout has completely set, the 18RF extracts the temporary casing and moves to repeat these steps for the next foundation pile.

When the hammer arrived on site the client had already completed 5 piles in the center of the site, away from existing structures, and was ready to extract these with the vibro. Hong Kong construction sites are supervised by building authorities who control what technology is safe to use on site. As this was the first major job for Resonance Free vibrators concern was raised for the impact on adjacent buildings and power utilities. As the first five piles were away from sensitive areas, permission was granted to demonstrate the performance of the 18RF. After a satisfactory performance the 18RF was cleared for use. The client was happy they had grasped the opportunity to rent the 18RF as it allowed them to continue with a well-established foundation method without having to worry about possible vibration damage. Face machinery’s service team was available on site until the clients operators felt confident in operating the equipment correctly.

The client was impressed with the performance of the hammer and received no complaints or claims from the neighborhood. This project successfully demonstrated the capability of RF technology and opens the door for further acceptation in the market. Visit the www.icevibro.com website for more application stories and to download results from vibration impact studies or contact a technical expert to discuss your next urban piling job.