Eiffel Trading 101: Flat Sheet Pile Setting and Driving Tips in Closed Cells
Sheet pile driving techniques vary from contractor to contractor. Since flat sheet pile (PS27.5 and PS31) are typically driven in a cellular pattern, some of the driving techniques vary from z-sheet pile. Here are some suggestions on how to drive flat sheet pile efficiently on the jobsite:
Handling Flat Sheet Pile
Flat sheet pile has very little section modulus (beam strength) and are highly susceptible to damage during handling. It is recommended for sheet pile longer than 70’ to have two or more lifting points. If you kink the sheet while handling it, it will make driving the sheet pile extremely difficult, if not impossible.
Fabricate an Adequate Template
The diameter of the sheet pile template should be less than the theoretical diameter of the finished cell. This will help ensure the cell closes with ease. Once the sheet pile cell is filled, the cell should theoretically expand to the proper diameter.
When you are driving longer flat sheet pile, around 70’ or longer, you will want to think about a two or three tier template. This will help with ensuring the sheet pile are properly set. As with any type of sheet pile, it is important to ensure each sheet is plumbed and secured when set.
Mark the Template
Layout marks on your driving template for each single or pair of sheet pile. This helps when making adjustments during the setting phase so you can close the cell.
Driving Long Flat Sheet Pile
When driving longer length flat sheet pile, it may help to stiffen the starter sheet full length with a structural shape. This is to help ensure the first sheet is driven as plumb as possible. If the first sheet driven isn’t plumb, the problem will exponentially get worse as you move around the cell.
Drive in Pairs
After the sheet piles have been threaded and set, you will want to drive them down in pairs. It is suggested that driving sheet pile in pairs requires approximately 50% more energy than to drive a single sheet pile.
“Shake Out” Sheets
As noted above, it is extremely critical to make sure all sheet pile are driven plumb. However, when trying to close a sheet pile cell, the last sheet almost never fits perfectly. Picking up and dropping (shaking out) several sheets around the closure point until the sheet interlocks run smoothly helps ensure the sheets stay properly interlocked as they are driven to tip elevation.
Drive Piles in Stages
Once you have all of the flat sheet pile set and interlocked, work your way around the cell alternating sheet pile pairs. On the first pass drive alternating pairs 4 feet, then drive the un-driven pairs 8’. It is also recommended to reverse the direction of driving for each pass around the cell, which helps to keep the cell plumb. Continue this procedure until all of the sheet pile is driven to tip elevation.
Flat sheet pile can be very tricky to install and every contractor has their own best practices. As with any task, if you plan properly and have adequate tools, you should be able to achieve success relatively easily. If you are in the market to buy or sell your used flat sheet pile, please call us at 1-800-541-7998 or email at firstname.lastname@example.org.
Andrew Norman is one of the co-founders of Eiffel Trading. His background is in Heavy-Civil and Marine Construction in Project Management and Procurement. Through his work in Project Management, he worked on several projects driving flat sheet pile with both open and closed cells.