Trimble 3D GCS900 Grade Control System Improves Productivity by 50%
Trimble 3D GCS900 Grade Control System Improves Productivity by 50%
The town of Yutz is located in north-eastern France, in the Lorraine region. Town officials decided to upgrade the "Aéroparc" joint development zone, located near the town's old airport. At the junction point between the existing town and the new districts, this new green area will include a lake, a panoramic viewpoint and a garden. The project site covers about 19 hectares in total. Long-term project plans include building about 256 homes, constructing over three kilometers of roadways, pedestrian paths and cycling tracks. The project also involves landscaping and building a retention reservoir and water management system.
The town authority hired the Eurovia agency, a leading contractor and subsidiary of the Vinci Group, to complete the road infrastructure portion of this project. The Eurovia agency in Yutz is one of six agencies working in Lorraine, handling roads, utilities, urban development and drainage systems.
Eurovia is responsible for the construction of roads and utilities and the six hectares section where a considerable amount of surface modeling is required. In addition to the pedestrian paths, cycling tracks, and lawns laid on stabilized soil, the park will also include a three hectare lake. The area includes a panoramic viewpoint with several small domes. The viewpoint is about five meters high, starting on a ground-level surface of 1,500 square meters and finishing with a platform covering 500 square meters. It can be reached by two gently sloping paths - with 5 percent slopes - laid out on the sides. The project's real centerpiece is a unique garden of sounds. The completed garden will be built with a mound five meters high and emptied out in the middle with a spiral progressively going down to ground level.
Faced with the precision land contouring required on this project, Eurovia again turned to Trimble® machine control. For this project, the team adopted Trimble GCS900 machine guidance as well as two Trimble SPS730 Universal Total Stations and a Trimble GNSS site positioning system. The Total Stations were used for both surveying and guidance of the grader equipped with a Trimble GCS900 Grade Control System.
"Given the complexity of the shapes to be built on this project, the Trimble GCS900 system helped us to comply with the exact rendering of the volumes as imagined by the architect, while at the same time keeping to a very tight schedule," said Emmanuel Delacour, head of surveying at the Yutz Eurovia Lorraine agency. "The results are indisputable."
Prior to starting site-work, the Eurovia teams created a 3D digital model based on the architect's models.
"Compared with the cubic volumes of the existing mounds, the project design initially needed 40,000 cubic meters of extra soil to comply with the original model" said Delacour. "We did some more work on the digital project in coordination with the contracting authority to make the volumes of earth available correspond to the shapes required, while following the architect's original idea as closely as possible."
In the end, the shape of the garden of sounds was maintained and the amount used for making the viewpoint was reduced-20,000 cubic meters instead of the 60,000 cubic meters.
"The only way to achieve this assessment and reduction before starting work was by using 3D modeling," said Delacour. "This eliminated any unpleasant surprises after work had begun, as well as all the extra costs and delays they would have caused."
Once the final 3D models were created, they were loaded into the Trimble machine control system. Blanquin earthworks company was hired to perform the extensive initial earthworks. In total, the team excavated 40,000 cubic meters of soil. The dirt removed for the construction of the lake was then re-used by Eurovia for building complex shapes, without any need for externally-sourced materials.
"Blanquin made two mounds of about 20,000 cubic meters each at the points where the viewpoint and the garden were to be made and then it was our task to shape these," said Stéphane Gallorini, works manager at the Eurovia Lorraine Yutz agency.
To create complex shapes and arrange the park's surface, Eurovia utilized a bulldozer fitted with the 3D Trimble GCS900 Grade Control System. This was the first job done by this bulldozer with the Trimble GCS900 3D system. Trimble machine control was acquired for the bulldozer to replace a competitor's obsolete system. With the CB460 control box inside the cabin, the machine can not only be positioned on the site's overall digital model, but, also, its blade can be accurately located and its angle set in relation to theoretical coordinates. This was achieved using two Trimble MS992 GNSS receivers on the blade of the machine.
The system provides real-time information for monitoring avoidance zones and simultaneously collects as-built data as the machine cuts to grade. With these capabilities, the operator was able to see precisely where dirt is being moved on site. The Trimble grade control system for dozers allowed the team to achieve finished grade to millimeter accuracy with fewer passes. This means finished grade materials were placed more accurately and in a shorter period of time. This kept material costs down significantly.
"All the shapes, especially the more complex ones like the reverse spiral in the garden of sounds, the slopes on the viewpoint mound, etc. were handled using the bulldozer" said Christophe Durrmeyer, CDE TP's land surveyor. "This was the first job done by this bulldozer with the Trimble GCS900 system that we had just acquired to replace a competitor's obsolete system. Thanks to SITECH® France's training and assistance, which began the day after we acquired the system, the bulldozer driver and his machine were operational for beginning site-work."
Olivier Schmitt, sales engineer for the Eastern Region of SITECH France in charge of the Nuits-Saint-Georges agency understands the strict budget and time constraints of a project of this size and scope.
"At SITECH, we are well aware that companies do not have any time to lose, site schedules are always very tight and any day lost on a project represents significant losses," said Schmitt. "With the training courses we give when systems are purchased, companies become completely independent."
Agency leaders believe Trimble solutions and support from SITECH have contributed to every stage in the success of this complex project.
"We have been using Trimble technology and equipment since 2005," explains Delacour. "Wherever possible on a site - new roads, platforms and other projects where a grader is needed - we use the 3D guiding system. For us, it is a guarantee that we'll save time and money, improve the quality of our works and our finishing and make us more competitive. We are really happy with the quality of SITECH's services, especially their reactivity to our requests. I know that if I call up in the morning to get a new piece, I'll have it by the next day."
From grading to finish grade work, Durrmeyer believes the machine control system from Trimble is extremely effective because the information provided by the Trimble CB460 control box shows the machine operator exactly where he is and highlights where the machine should be working. Delacour asserts the benefits of using Trimble 3D technology are evident and estimates a 50 percent gain in productivity.
"The initial survey only required one person and lasted just one day," said Delacour. "It would have taken twice as long using traditional methods. On a site like this, at least half a day would be needed every day for staking out. Thanks to the GPS, I I only need to be at the site for the start in the morning. After that I am free for other projects."
Gallorini asserts that machine control from Trimble provides a cost savings because fewer survey personnel are required on the project, as well as improved safety.
"The machines work on the site without any stakes, which represents both savings in personnel, increased safety because there is no-one walking around at the foot of the machine, not to mention significant time savings," said Gallorini.
Because the Trimble GCS900 Grade Control system allows for faster and more accurate grading it also minimizes the amount of rework needed. The end result was 40,000 cubic meters of land was reshaped to the architect's requirements in barely one month. Gallorini believes this is an important point because the greenery planting phase of the project could not be delayed, due to the growing season.
"The machine's movements are optimized because it goes to the right depth more quickly, which saves time and, therefore, money," said Gallorini. "Moreover, we were also able to quickly and easily take account of any modifications required by the contracting authority and the main contractor after site-work had begun. We change the design in the office and put it on a USB key to provide the driver with updated information as quickly as possible. This makes us very reactive and allows us to make appreciable savings in time," said the site manager.
The team realized additional productivity gains when using the Trimble grade control system to build the project's pedestrian pathways. Eurovia utilized a grader fitted with the Trimble GCS900 system working with the Trimble SPS730 Universal Total Station for the last layer. "The total station provides an accuracy of one centimeter, which enables us to grade these winding pathways both quickly and accurately," said Delacour. "It took us a day and a half for executing a kilometer instead of three to four days if we had had used stakes and string."