On a recent project, Lockhart Enterprises in Los Angeles California was able to use an ABI Mobilram that they purchased from Hammer and Steel to complete a project 60 days ahead of schedule and $1 million under budget. Lockhart was asked to provide shoring for a washed out road in Tunjunga, CA in Northern LA. The road sits next to a river bed with boulders, gravel and sand underlain by bedrock. Instead of using a traditional down-the-hole hammer (DTH) system with casing, the company went with an ABI MobilRam TM rig with the quick coupling docking system.
"Switching out attachments quickly is the key to saving time and coming in under budget in projects like this one," said Daraius Tata, Territory Manager for Hammer and Steel. "However, oftentimes projects utilize many types of equipment in order to perform similar functions within drilling and pile driving. The Mobilram features many different attachments such as vibratory driver/extractors, vertical boring heads for pre-drilling, soil relieving, auger-cast piles, diesel hammers, double head auger drives for installation of secant piles and silent piling/hydro-press system to press sheet pile, that can all be used with the main rig to complete a variety of tasks. This versatility enables the ABI Mobilram to help companies like Lockhart to save time and money on complicated projects."
The ABI Mobilram features functionality similar to a drilling rig, however is versatile enough to handle many different attachment types, so that one rig can be used for the majority of projects such as this one. The Mobilram is known for its quick set up time. The time required to set up an ABI Mobilram is typically less than 30 minutes and bringing it back to transport configuration does not take much longer. All of the attachments are connected and disconnected quickly and safely by the docking system, or the traditional rapid changing device
For this particular project, the ABI rig pre-drilled the holes with a small 8" DTH hammer with casing, stitch drilling a five hole pattern for a heavy duty, 40ft long I-beam. A MDBA 6000 drill was used with a 150 hex connector and a side entry flushing swivel, that was mounted below a knuckle device, which meant the entire drill string could be mounted on the ground and was easy to install and remove. In addition, a break out tong for the DTH hammer bit was provided to make bit changes easy. Each hole took roughly 15-30 minutes to drill, depending on the amount of bedrock and size of the boulders.
Once the holes were predrilled, the ABI rig vibrated in the 125 beams in approximately 20 feet deep. Each beam took only a few minutes to drive. The beams were finally driven to grade into the predrilled bedrock with a Delmag D30 diesel hammer. At the end of the project, only 2 beams needed to be pulled and re-driven because the computerized, automatic alignment feature of the MobilRam helped facilitate verticality of the beams.
The entire project was completed on an extremely narrow and long jobsite with a temporary road running parallel to the site. And to complicate the project, the jobsite was shut down for 3 weeks due to wildfires, that got as close as 300 feet from the job site.
"Working in a confined space can be a challenge for this type of project. Having to switch equipment types for any project can be expensive, due to the time needed to move equipment in and out of a space. However, when a space is this narrow and long, multiple pieces of equipment complicate this matter even further. With the low set up time for the Mobilram and the ability to use one piece of equipment for many aspects of the job, it helped the project keep moving. The MobilRam by ABI is one of the most sophisticated pile drivers on the market right now and it enabled Lockhart to come in under budget on this complicated project," said Tata.
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