ABI Mobilram Rig Pre-Drills and Installs PZC 18 Sheet Pile in Tough Driving Conditions
The ABI Mobilram TM 13/16 SL was recently used to drive steel sheet pile for the construction of a new train station project in Fairfield, CA. C.C. Myers, Inc. had to drive PZC 18, 32 ft. to 43 ft. in length, near railroad tracks in very dense material, in some places up to 200 blows/ft.
To overcome these difficult driving conditions, pre-drilling was required using an ABI MDBA 3500 rotary attaching drilling 14 in. continuous flight auger and reversing it when extracting. This method leaves a loose column of soil, and creates an area that the adjacent denser soil can vacate to when the sheeting attempts to penetrate it.
C.C. Myers pre-drilled immediately around the interlocks of each pile. Once this was completed, the ABI Mobilram system was able to disconnect from the rotary attachment to the vibratory hammer within 5 minutes. This was accomplished using the Mobilram docking system, which allows for the swapping of various tools without reconnecting hoses or attaching pins. This allows pre-drilling and vibrating with the same rig far less costly and time-consuming.
C.C. Myers also encountered various other issues that limited production levels on this jobsite. In addition to the difficult driving conditions, the crew had to pause for all trains passing through the area, and also had to deal with limited access from close proximity to the railroad jobsite. With all of these factors C.C. Myers was able to achieve production rates of about 15 sheets per day. However, without an ABI Mobilram on the jobsite, the sheet pile would have been impossible to drive and install quickly. Better yet, it was accomplished with just one machine and with 3 personnel.
For the contractor, pre-drilling accomplished several things:
- Less force was required to drive the sheet pile
- Sheet piles drive straight (as opposed to “fanning out”), and follow the path of least resistance, which are the pre-drill holes
- Less vibration is generated in the surrounding soils, which can damage adjacent structures
- Sheet piles are less likely to be damaged due to rebounding forces from the hard soils, preventing costly sheeting replacements
- Less time is required to drive sheets in pre-drilled ground than trying to force sheet pile in
dense ground conditions, even when the drilling time is included
- Equipment used to drive sheet piles is far less likely to be damaged during installation.