2021 saw a historic first in Hong Kong. For the first time in the territoriy's history AZ-700 steel sheet piles have been used for permanent retaining walls. Previously the widest sheet pile section used was the 1200mm size AZ-600. The AZ- 700 has a width of 1400mm and requires 15% fewer piles to be installed leading to significant time savings. When compared to the more common No.4 or No.6 U piles the installation speed is tripled or even quadrupled. In this article you will read more about the advantages of wide AZ piles as well as about the vibro equipment that was used for the installation.

Over the last years, as the buildings in Hong Kong have become taller and larger, the requirements for construction site safety have also increased. Hong Kong is a city that pursues speed. Therefore, new construction methods and reliable machinery and equipment must be used for "fast, ruthless, and accurate" projects.

The advantage of AZ wide sheet piles are explained by the pile manufacturer Arcelor MittalZ-type sheet piles are the preferred choice for permanent applications. The AZ® series combine a section with extraordinary characteristics with the quality-proven Larssen interlock. Z-shaped sheet piles present the following advantages extremely competitive section modulus/mass relation, lighter than U-piles when comparing sections with equivalent properties, increased inertia and thus reduced deflection allowing the choice of high yield strength steels for the most economical solution, large width resulting in high installation performance and enhanced watertightness. AZ sheet piles are usually supplied and driven as double piles. The interlock is often crimped, thus improving the straightness of the wall, and reducing noise when driving with a vibratory hammer. All Arcelor Mittal AZ steel sheet piles have the proven Larssen interlock.

The advantage of AZ wide sheet piles are explained by the pile manufacturer Arcelor Mittal

Example 1

For a project in the new development area of Tung Chung the contractor was tasked to drive 38m long AZ-700 piles. The piles consisted of three sections, the first section was installed by excavator mounted vibro and finished off with the ICE 815C. After the second section was welded on, an ICE 1412C was used to drive that to depth, and the third section was installed by 1412C also. In case of refusal an impact hammer was on site to make sure the pile wall reaches design depth. All the 3 vibro’s clamped the double AZ-700 section over the interlock, using a jaw plate that wraps around the interlock and leaves the interlock undamaged. The pile sections were driven to slightly different heights so that during the welding the pile was kept in position by the adjacent piles.

Example 2

The second project we are sharing photos of, is a project at Hong Kong International Airport’s third runway. Due to the height restrictions the airport authorities set for this project, the 26m long AZ-700 piles arrived on site in three sections. An excavator mounted vibro was chosen to position the piles and do the initial driving. Then the contractor follows with an 815C and 1412C for the second and third pile section. Now that there are more references in the market and the available ICE equipment has proven to be able to install the piles, we believe this will be a future trend for the choice of foundation work.

Why do Hong Kong clients choose ICE?

After 45 years in service, ICE’s original product line-up of 416L – 815C and 1412C are still in production and well-known, well-liked, and well-recognized by users and developers all over the world. The three classic ICE models have undergone continuous improvements over the decades, using new generation parts and materials as they came available, increasing their reliability and performance.

ICE dealer Face Machinery has been providing local service from their yard in The New Territories for decades. The Face Machinery team can support ICE users with parts, repair, and overhaul. Equipment is available for rental and also for purchase from local stock.

Are you interested to increase your efficiency in a similar way? Contact your ICE representative in Shanghai or Hong Kong today to get started!