French Contractor Fougerolle Ballot Terrassements (Eiffage TP Group) uses Trimble 3D Grade Control System and Business Center-HCE to accelerate grade work on rail embankments and platforms
Fougerolle Ballot Terrassements (Eiffage TP Group) specializes in large-scale excavation work with a focus on the design and execution of civil engineering in the areas of construction, public works, energy and metal. The company is currently completing the grading of the platform and finishing Lot 35, one of the flagship construction sites of the LGV Est Européenne. The LGV Est Européenne is a high-speed railway line between Paris and the regions of Northeastern France, Germany, Switzerland and Luxembourg.
This massive excavation project was focused on Lot 35 of the rail line and required moving eight million cubic meters of earth, as well as nearly 30 kilometers of LGV rail platform and one million metric tons of aggregate for the embankment cover. The precision tolerances allowed on this project were extremely tight at approximately 3 centimeters. In order to meet these production and precision requirements in the tight available two year timeframe, the company looked to SITECH® France, a regional Trimble provider. Fougerolle Ballot Terrassements opted decisively in favor of the Trimble® 3D GPS positioning and guidance for part of its machine fleet.
"The objective was clear: move toward new equipment providing for greater productivity," said Frédéric Bourgault, excavation contractor and director of Fougerolle Ballot Terrassements (Eiffage TP). "In the initial phase of such a project, lots of cubic meters need to be moved, but then in the subsequent phase the square meters needed to be groomed, all while meeting deadlines and precision requirements set by the project owner."
In total, more than 120 machines were used on the project, including a team of D10 scraper and bulldozers plus five scrapers, three 90-ton excavators, four 65-ton excavators, and 70 articulated dump trucks.
In addition to adopting Trimble machine control technologies, Fougerolle Ballot Terrassements also assembled a very experienced topography department that included five experienced teams led by Mickaël Hurlain, head topographer at Fourgerolle Ballot Terrassements.
With this job, the Trimble positioning tools were integrated prior to the start of operations, starting with the design phase, and systematized over the 26 kilometers of the project. A network of five Trimble SPS852 fixed base stations were set up along the line, providing the surveyors and equipment with the elevation corrections needed to achieve centimeter accuracy in GPS positioning, wherever they were in the project. The topography teams had three SPS882 GPS-based Site Positioning Systems with Trimble hand held controllers as well as a Trimble SPS730 Universal Total Station.
Hurlain explains that the 3D digitization work of the project required a year and a half, plus two and a half months for the current section, using AutoCad Covadis software. Once the design files were created in 3D, they were then sent to Trimble Business Center software and converted it to the machine-specific format. Trimble Business Center - HCE software is a data preparation and management tool designed specifically for heavy highway construction projects. Business Center - HCE can be used to review field data, perform precise volume calculations during continuous work, and show project data in multiple ways whenever needed during the work cycle.
On the machine end, all the job site's eight bulldozers, along with five graders and two hydraulic excavators were equipped with the Trimble 3D GCS900 Grade Control System. These 15 machines, each equipped with its own system, work in complete autonomy with the same 3D digital design of the project relayed to the in cab CB460 control box.
"The feedback we have on the use of Trimble solutions is all positive," said Vincent Godon, job site superintendent. "We have been testing them for several years, starting with the A29 in 2003. That's a guarantee of reliability and efficiency. Every operator knows what to do and positions himself easily and quickly on the job site for the best daily productivity."
As the most advanced system of the Trimble machine control portfolio, the GCS900 Grade Control System can be used across a wide range of heavy equipment-bulldozers, graders, and excavators-and allows for centimeter-accurate guidance. Sensors positioned on the machine's equipment as well as help from two GPS antennas which communicate continuously with the nearest GPS base station, act as a guide. On the screen of the CB460 control box, the operator can see the exact position of the blade or bucket and its angle in relation to the dimensions of the job's 3D digital plan.
"All job phases, including clearing, embankment work, grading, and finishing, are now completed using Trimble machine control. And the results are there-impressive," said Hurlain.
The machines were guided starting with the stripping stage, making it possible to work according to the right dimensions right from the very start and to avoid touch-up work.
"The integration of these technologies leads to greater efficiency of about 10 percent, which is a production gain of 50 to 60 cubic meters per hour," said Gordon. "In the clearing areas, generally down to a depth of four to five meters, we were able to ensure the compliance of our work by guiding the large production excavators, while keeping the excavated quantities down to the bare minimum; under other circumstances, exceeding dimensions by 50 centimeters or even one meter is a typical problem. With the GCS900, we had the assurance we would not go below the design dimensions. With the screen of the CB460 control box, even if the bucket is under water, the operator knows exactly at what level to stop without any outside help. This is also a plus in terms of safety."
When working on embankments, Godon was impressed that with the Trimble the GCS900 system, his team could achieve high accuracy grading the first time, which led to a much higher overall productivity rate. Not only was this important for maximizing efficiency and safety, Bourgault believes the Trimble system helped to eliminate material volume errors. For example, because this project contract is based on fixed price compensation, even a minor error of three centimeters would impact external supply volumes, taking a once profitable project into the red.
"In terms of surface area, we easily achieve a grading rate of 350 square meters per hour with a dozer and 200 meters squared per hour with a finishing excavator," said Godon. "We realized that with guidance-equipped bulldozers, we can double the graded surfaces on embankments. This is a 100% productivity gain! No more stakes, which means time savings, efficiency, and safety. The bulldozers grade all surfaces progressively to the right dimension, the very first time."
In addition, Godon was extremely pleased with the results achieve from using Trimble machine guidance technology for grading the platform for the rail line.
"Grading the platform generally occurs toward the end of the planning and therefore requires that maximum yields be reached, if the deadlines are to be met," said Godon. "We made every effort to ensure that, before winter, there would be a platform consolidated with a hydraulic binder treatment at a pace of 10,000 square meters / per day. With a bone level and no guidance system, we were lucky if we could do 6000 meters squared per/day."
The platform complies with a four percent slope for granular materials. With a precision tolerance between 18 and 21 centimeters thick for the sub-ballast, the excavation contractor cannot afford a margin of error. Bourgault believes that the Trimble GSC900 delivered exceptional productivity gains on the excavation work completed for the LGV Est Européenne Lot 35 section of the rail line.
"With the operation having been launched in early 2010, we have completed two full seasons of earthwork over two six-month periods-including spring and summer 2010 and 2011-which was greatly accelerated," said Bourgault. "In short, two high-speed job sites."
The regional Trimble dealer SITECH France also installed its first "ecological" power supply on one of the five fixed Trimble SPS852 bases using a solar panel. The solar panel takes the place of the batteries generally used and allows the surveying teams to do away with the daily task of replacing and recharging the batteries. Bourgault and Olivier Schmitt, SITECH France's sales engineer, believes that the ability to use solar power reliably with Trimble systems- even in cloud-stricken eastern France- is another added benefit.
"This is a savings in time and it also helps us meet our environmental compliance commitments and could be replicated in other major projects and in other locations," said Bourgault.
Looking ahead, the company plans to continue using Trimble grade control technology for its work with Eiffage, who has been hired to perform ramp up work on additional sections, including LGV Brittany-Pays de Loire section which spans over 200 kilometers. The team also has plans to streamline the delivery of monthly quantity reports and follow-ups using Trimble Business Center - HCE. They will also use the software to create quick and accurate production reports, data transmission between machines and the job site base, etc.
"This project has allowed us to confirm our choice of work methods, technologies, and equipment that we need to move toward," said Bourgault. "With its 30 kilometers of platform, LGV Est Lot 35 is a significant test bench before addressing the 210 kilometers of Brittany - Pays de la Loire LGV project."