APE has developed Helical Pile systems that will change the nature of helical pile as they are seen by the deep foundations industry. Helical piles have been for most of their history produced by manufacturers who have focused on small diameter screw anchors. These anchors began as tie downs for cables supporting power poles and evolved into small diameter screw anchors used on low capacity foundations. The bolt together sections, homemade driving equipment and the lack of main stream engineering made them suspect and generally unaccepted by the deep foundation industry.
As the industry evolved a core group of manufacturers began to generate larger anchors and more sophisticated drilling equipment. Unfortunately the bolt together sections and lack of involvement by the greater community of deep foundation contractors has left helical piers or anchors, filling an insignificant niche in the industry. Coupled with engineering that is unsupported by the most of the geophysical engineering community. A push for over ten years to correlate drive torque to load capacity of the anchors has been refuted by the general community of engineers and unsupported by many of the people involved in the larger diameter higher energy helical pile industry.
APE has embarked on a program that encompasses material manufacture and supply, equipment development and engineering that relies on the standard principles for deep foundations developed by engineers for over 900 years since the Romans were driving piles in Europe. Additionally APE has added patented drive and coupling technology developed by contractors in the Northwest. This technology has been proven over hundreds of thousands of feet of helical pile, that have been load tested, statically and dynamically hundreds of times. APE has purchased this technology and APE engineers added their years of experience to develop the first mainstream equipment to be specifically designed to install helical piles.
Socket Drive Technology
If you have ever used a socket to turn a bolt you can understand why the APE socket drive technology is simple, reliable and the best way to transmit torque into a pile to drive it. APE has patents on external Socket and internal Allen wrench type drives. Any drilling equipment can be easily modified to use the socket drive technology.
Threaded and Coupled Pile Sections
APE has developed material that uses high strength oil field casings that are threaded and coupled with an APE patented coupler. This connection continues the pile shaft sectional strength through the connection in tension, compression and bending. The connection can be made in less than a minute and makes low headroom work simple. This connection also allows for any depth of pile. Very deep drives are not a restriction for this system. Without the socket drive technology you cannot make up threaded connections, the other systems using large pins to drive the pile keep the material connected to the drill and do not allow the operator to put the pin (male thread) into the female coupler without a high percentage of cross threaded connections.
The APE material is produced under the most stringent standards in the world. APE’s supplier is API ISO certified and API certified for threading and welding on the high strength DOM casings used by APE. These casings have yields of 80,000 psi to 110,000 psi and a wall thickness of min .400 on all size ranges. You cannot produce this material without these certifications. APE’s global reach and buying power allows us to bring this material to market at prices competitive to products of far less quality.
High Pressure Grouting
APE is introducing true high pressure grouting at the tip of the pile. This can be accomplished with a push out tip that is currently approved by Caltrans as a micro-pile or using ports located at the pile tip to grout while installing. Grouting pile with helical flights gives dramatic improvements in load capacity even in poor soils.
Excavator Mounted Helical Pile Drivers
APE is pioneering excavator mounted drills that handle the pile from the ground and easily connect threaded sections. These high power systems (up to 400,000 ft lbs of torque) are powerful fast systems that show up to the job ready to work after unloading from the trailer. No more power unit, this is self-contained and these drills can be attached to rental equipment in a couple hours with no intrusion into the electrical or hydraulic systems of the excavator. APE has drills for excavators from 28,000 lb class to the biggest machine you can find.
Large OD Helical Pile
APE has developed large diameter shafts up to 42″ in diameter with 1″ wall 80,000 yield DSAW pipe. These large helical are helping designers overcome the endangered species issues that are crippling steel pile driving in marine environments.
Ground Loop Technology
This technology works with standard ground source heat pumps (GSHP) and allows the Helical Pile Foundation to be the ground loop. By heating and cooling the building with the most efficient green energy technology on the market, the foundation qualifies for a 10% on commercial, and 30% on residential tax credit. The foundation will also pay for itself in energy savings in just a few years.
Remote access with the excavator mounted equipment, high capacities with pressure grouting, unparalleled low overhead access and deep drives with the threaded connections, the first material and equipment made for helical pile, socket drive technology, large OD pile that do not endanger marine life. Engineering that fits into the mainstream of the geophysical engineering world, and foundations that heat and cool the building with technology that the DOE dubbed “The no#1 green technology for the 21st century” APE has changed the face of helical piles and deep foundations.
APE’s 200-6 successfully drove six piles at a time for the 32 meter diameter (104 ft) cofferdams that are being used to extend the Hong Kong airport runway. Prior to the project start, the Chinese government design groups had a tough choice between using either 32m (104 ft) diameter super-large piles, similar to the 22m diameter (72 ft) piles driven for the Hong Kong-Zhuhai-Macao man-made island project, or instead to use sheet piles. Since the project is next to the Hong Kong airport there are many safety regulations for construction ships in the area. To drive 32m (104 ft) super-large diameter piles would require a 4,000 ton boat crane with mast that would exceed the 35m (114 ft) height restriction of the area. The fear was that if the boat crane was too tall it would be a danger to the airplanes trying to land at the airport nearby. Therefore, despite the success of the “APE Octakong Project” that drove 22m (72 ft) super-large diameter piles just 10 months ago, they decided to use sheet piles to create the 32m cofferdams instead.
Driving sheet piles for 32m (104 ft) diameter cofferdams on water is no easy task, but despite all of the challenges the main concern was construction speed. To speed up the project the contractor wanted to drive six sheet piles at a time per hammer, something that again has never been done before on this scale. APE provided four 200-6 hammers with six APE model 150 clamps attached to custom beam. Each hammer has a special manifold that allows independent control of each clamp. After the sheets are put in place the APE 200-6 hammer is placed on a row of six sheets to be driven, however when sheets are first placed in the cofferdam template they are not all sitting at the same height since some sink in the soil farther than others. The contractor needed a way to grab onto several piles and vibrate down while some of the clamps are still open.
APE changed the design of the clamp slightly to withstand the forces of a vibratory hammer even while some the clamps are in the open position while others are in the closed. This week the 200-6 was used for the first time with great success. Currently there are now four working 200-6 hammers on the job site each driving six sheets at a time. To increase the speed of the placing of the sheets the contractor also designed a special boat that could grab 49 sheets at a time and place them in the cofferdam template; effectively placing 25% of the sheets at once. A special barge was created to pre-place sheet piles in a position that the special crane could grab. The project requires 147 cofferdams to be driven with 196 flat sheet piles per dam. Each sheet is 30m long to be driven 20m deep. One cofferdam can be fully driven to grade in 4-5 days, a speed unattainable without modified equipment and unique construction techniques used.
This project demonstrates the cooperation APE has had with the Chinese government to continue to supply pile driving equipment that meets their ever increasing construction speed requirements. For more information on this project please contact our commercial lead Steve Gough (email@example.com) who has worked closely with the project groups leaders, or our technical lead David White (firstname.lastname@example.org). Both Steve Gough and David White speak fluent mandarin Chinese and are well versed in pile driving lingo, feel free to contact them in either language. For more pictures of this project please visit our website at www.apevibro.com. Go APE!