Yesterday was a big success for APE China and APE USA. We successfully drove the world’s largest sheet pile (shell pile wall) in 11 minutes of drive time. The pile was 11.3 (37 feet) wide and 22m (72 feet) tall and 16mm (.62″) thick. The pile was driven with a tandem APE 200-6 hammer (built at APE China) powered by two 1050HP Cummins engine power units (also built in APE China). The hammers were mounted to a special beam designed by Casper, Phillips and Associates. The clamping system was also made at APE China using 4 short cassion beams and 4 APE model 200 caisson clamps.
These shell pile walls will be used on the Hong Kong-Macau Bridge project, currently the largest construction project in China. The decision to use a single shell-pile-wall instead of sheet piles came about for several reasons. The first reason being that driving sheet piles out at sea is very difficult and time consuming process. In order to fit the time line of the bridge construction completion date they will need to complete 2 shell pile walls per day. Driving sheet piles would be drastically slower. The second reason to use shell-pile-walls instead of sheet piles is due to margin of error of the large diameter cassions that these shell-pile-walls will be interlocked to. In our test situation, the interlocks that the pile was to fit into were .5m (1.64 feet) wider at the top than at the bottom. This means that as the pile was driven into the ground it was literally being compressed by 1.64 feet, causing the pile to bulge out and create added resistance. If this job were to use sheet piles it would be extremely difficult to custom shape each sheet pile to fit the unknown margins of error between each interlock.
The importance of the success of this project are far higher than we originally expected. The fact of the matter is that if this shell-pile-wall pile failed than it would delay the entire Hong Kong Macau bridge project and also create engineering nightmares to think of a new design that can meet the time line given. All of the top officials in charge of the entire bridge project were present to verify with their own eyes the success or failure of the APE tandem 200-6 system. It is now safe to say, even in the most difficult conditions that will be given during the project, this pile can be driven with success.