Looking to save time and stay under budget on your next TBM project? It pays to consider the benefits of Onsite First Time Assembly (OFTA). By initially assembling the machine at the jobsite, rather than in the manufacturing facility, OFTA results in greatly reduced shipping and manpower requirements. In fact, the time saved can add up to five months, while cost savings can be as much as $4 million USD.
Robbins has proven the advantages of OFTA on nearly every machine type and diameter, in dozens of countries. Whether your project is in the urban jungle of Mexico City, or the remote rainforests of Vietnam, our engineers will tailor the OFTA process to fit your project requirements while ensuring individual components meet the most stringent international quality standards. From the first drawing to TBM launch, Robbins is committed to keeping your project on track and on budget.
OFTA was first developed for the Niagara Tunnel Project in 2006 as a way to assemble the world’s largest hard rock TBM (14.4 m / 47.2 ft diameter) under a tight schedule. That assembly, done entirely on location, resulted in a TBM launch less than 12 months from the contract signing.
Using the OFTA process, the machine is assembled at the jobsite in a concrete cradle—starting with “core components” such as the main beam. Assembly progresses from the inside out, ending with components such as the outer cutterhead pieces. The assembly can take place in a launch chamber, shaft, or pit, and can be customized for any TBM type or diameter.
Since its initial use at Niagara, OFTA has been proven effective again and again. From the 18-week assembly of a giant EPB in downtown Mexico City to the 16-week assembly of a Double Shield TBM in India, OFTA has delivered results.
In a typical TBM factory assembly, the machine is completely finished, then disassembled and shipped to the jobsite, where it is re-assembled once again. By choosing OFTA, the time to disassemble the machine is eliminated, shaving at least one month off your schedule as well as saving manpower costs. The shipping process is also simplified because all shipments are sent to one location (the jobsite), saving at minimum two more months. The average OFTA project is delivered three months faster than its factory-assembled counterpart and saves $1 million USD.
When you choose OFTA, you’re never alone. Every OFTA project is custom designed by a team of Robbins engineers and executed by highly trained field service personnel who work with your crew to coordinate the assembly process. During the assembly your crew will also gain valuable knowledge on proper TBM operation and maintenance.
Components themselves are checked at the factory to ensure proper fit up, and are subjected to rigorous quality control standards, including laser tracking and 3D imaging. Critical sub-assemblies, such as the main bearing and seal assembly, are finished in the factory and shipped to the jobsite. The result is a streamlined process that delivers a Robbins TBM of the same high quality as a factory-assembled machine.
Robbins designs an Onsite First Time Assembly plan to fit your specific machine and project, taking into account the tunnel design, project schedule, site logistics, and many other factors. When you contact Robbins, we review your specifications to determine the best plan for your project. No one has more experience in assembling TBMs on location than our team of engineering experts.
Whether you are in the planning phase of tunnel construction or about to bid on a project, our engineers can help you identify the best solution to achieve your objectives. For more information, complete our online inquiry form or contact your nearest Robbins location.
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