Trimble Grade Control System and Business Center-HCE support sizeable manpower savings, increased machine productivity, accurate surveying, and overall increased competitiveness
The Isle of Sheppey is an island off the northern coast of Kent. The land covers an area of approximately 92 square kilometers and is home the Elmley Marshes wildlife reserve, which is managed by a partnership between private landowners and the Royal Society for the Protection of Birds (RSPB).
After the RSPB adopted the area, the organization developed a plan to augment the area to make it more hospitable to native bird populations. The Great Bells Farm Habitat Creation project on the Isle of Sheppey is part of the site selected to provide 145 hectares of freshwater habitat. The area was once farmed and is now characterized by intertidal land, salt marshes, and mudflats.The design called for transforming and enhancing old drainage features surrounding the area to look more like the native landscape. By creating shallow pools or 'scrapes' and ditches the area can hold water and encourage native birds and invertebrates to reach vital water and food supplies. In addition, the design included tackling past flood defense work done in the area, as well as future proofing flood works that may have to be done over the next 100 years.
To accomplish this, the RSPB contacted its longtime partner the Pryor Group. With over 60 years' experience, the Pryor Group specializes in earthworks and civil engineering projects. The company provides earth moving solutions for everything from road building and reservoir construction, to landfill construction and land reclamation projects. Fred Lusted, Engineering Manager for the Pryor Group, was selected as the engineering manager on site. He was responsible for creating a 3D model of the project, performing necessary geo surveys, setting up site calibration of equipment, and validating volumes of earth moved.
The project, which began in 2011, had a number of challenging attributes. One of these is the nesting and breeding habits of the birds; another is the extremely wet winter season. As a result, earthworks could not take place from March to September or during the winter, which left Lusted's team only a short window of work time each year.
"Needless to say, maximizing earthworks done in October, November and December was a necessity on this project," said Lusted. "We regularly use Trimble machine control and site position systems supplied by KOREC so we knew a project like this would be much more lengthy, costly, and virtually impossible, with traditional grading and staking methods."
On this project the team used Trimble®Business Center - HCE for preparing data and tracking progress. For site positioning, Lusted trusted a GNSS based Trimble Site Positioning System with the Trimble SCS900 Site Controller Software on the controller. At the busiest time on the project, Pryor had three dozers and one excavator on site, each equipped with a Trimble GCS900 3D machine control system.
Lusted set up the wildlife reserve site with a Trimble Site Positioning System. He then calibrated the system running SCS900 software. With a semi-permanent pole mount receiver in place, Lusted used the software to organize the job site and optimize productivity during earthworks. He believes the intuitive interface makes it easier to perform grade checking, as well as simplifying the process for setting-out, measuring as-builts, and performing consistent quality control checks. In order to create the shallow ditches and scrapes required, the team was tasked with building a number of hydrological earth dams. These gravity-fed dams can be used to control water levels, keeping water in summer and preventing areas from flooding in the winter.
"The Pryor Group is a long standing KOREC customer and we've been involved with machine control right from its earliest days," said Lusted. "The systems have been useful for all our earthworks jobs, but really came into their own on this particular site. At 145 hectares, it's a vast area and the ditches, ponds, hydrological bunds and natural rolling features would have been highly complex for an engineer to set out using traditional methods."
"The RSPB provided us with a drawing and from this we created a 3D design in Terramodel and the machine files were created from this in Trimble Business Center," said Lusted. "The process has been straightforward from start to finish. The benefits of machine control are well documented; we're more efficient, more cost-effective for clients and achieve our Health and Safety targets. KOREC has provided all the support we need and Trimble doesn't over complicate its technology - it does exactly what it says on the tin!"
Lusted used Business Center - HCE to calculate volumes and review how much earth was left to be moved. He performed precise volume calculations during continuous work (months at a time) as well as prior to the re-start of work periods. With Business Center- HCE, Lusted was able to view project data in multiple ways, whenever needed during the work cycle. He reviewed progress in plan mode and spreadsheet mode, as well as profile, cross-section and 3D modes.
"This project was all about precision, not bulk," said Lusted. "So setting-out this area with conventional methods would have taken a whole gang of surveyors, with pegs scattered all over the terrain being knocked over repeatedly. Trimble 3D machine control on our dozers and excavator was an ideal choice because it gets us grade and finish grading work, even for complex and intricate designs like this."
For excavation, the Trimble GCS900 grade control measured the exact position, cross slope and heading of the blade for early grading on the site. On Pryor's excavator, the system uses two GNSS receivers and solid state angle sensors to measure the precise 3D position of the teeth of the bucket. Operators then have accurate, 3D positioning of the bucket. Following the system guides, operators were able to perform more accurately and quickly shape ditches and dig precise slopes required in the design.
For Pryor's three dozers, the Trimble grade control system displayed design information and live cut/fill indications in the cab. The system's automatic blade control and configurable earthworks progress monitoring greatly improved operator's productivity. It also collected as-built data as the machine cut to the specified grade height. Lusted believes this accurate, real-time information helped him keep tighter control over safety issues and see precisely where dirt was being moved on site for increased efficiency and productivity.
After two calendar years- or six months of onsite grading and construction work- Lusted and his team successfully completed the reserve project. He is confident in the Return on Investment of using Trimble 3D machine control and Business Center-HCE. In fact, purely from a manpower standpoint, he estimates that without Trimble he would have had to hire at least two or three more workers on the site-basically one for each machine- to perform surveying and other support work needed for grading. That's a savings of around £600-£700 per week of work. Today, the Trimble 3D machine control systems are being used on other revenue-generating projects, improving the value and returns realized from Trimble equipment overtime. Looking ahead, Pryor plans to expand its Trimble portfolio by purchasing additional GCS900 grade control kits for its excavator fleet.
"Not only is there a sizable manpower savings with Trimble machine control, the precision and reliability of our work as well as increased machine productivity, asset tracking and accurate surveying, save us more and make us significantly more competitive," said Lusted. "From pre-tender meetings, where we can show customers our plan, through to project completion where we finish projects more quickly and with less materials and less rework, customers appreciate working with us in part because of our Trimble expertise."