AccuGrade™ boosts productivity in Burundi

Two Cat^® 14M motor graders equipped with AccuGrade dual GPS systems with cross-slope capability are part of an extensive fleet of Cat equipment that includes seven track-type tractors, five excavators, two wheeled loaders and six graders being used for road construction and refurbishment in the Republic of Burundi.

Owned by contractor Sogea-Satom and supplied by dealer Tractafric, the graders join an AccuGrade-ready D7R II already on site, allowing the three machines to boost performance and productivity on the road project by sharing the AccuGrade machine control systems according to job progress.

While the initial requirement was to equip both 14M motor grades with AccuGrade dual GPS systems, the ability to also have a track-type tractor with guidance was reckoned to offer significant benefits with earthmoving activity ahead of road formation.

These two are the first AccuGrade systems being used by the contractor to replace traditional surveying and staking methods on its earthmoving projects. And the system is being thoroughly trialled on three road projects in Burundi that are valued at €70m. These include the 35-kilometre RN14 Kirundo-Gaseyni trunk road, the 104-kilometre RN12 Gitega-Muyinga trunk road and 31-kilometre of road and pavement refurbishment in the capital, Bujumbura. It is reckoned that Sogea-Satom will implement this new technology in its processes in Africa, to improve machine performance and productivity on the three road building projects.

The longest section of road is the RN12 which runs through a mountainous region some 1500-1600 metres above sea level and is heavily shadowed by trees and vegetation that could, in some areas mask satellite signals for AccuGrade. Despite this, Sogea-Satom reports that after 12 months of using the systems on-site, AccuGrade has given +/- 1 centimetre accuracy when the road formation is surveyed.

Sogea-Satom reports that the first application for AccuGrade was with the D7R, removing 30 centimetres of poor material to allow foundation and road base materials to be installed. Previously, this requirement was met using an excavator and just one truck, with productivity at just 100 metres a day. And in many instances, up to 50 centimetres of material was being unnecessarily removed. Using the D7R with AccuGrade, 100 metres of road were completed in 30 minutes, vastly improving productivity. And the final passes were performed in auto mode at ± 2 centimetres.

With the 14M motor graders, the quality of work has been dramatically improved too, compared to relying on stakes every 25 metres. On-site surveyors now have more time for data preparation and grade checking, and they have been reporting improved quality and earlier completion at different stages of the road build.

Cat's evolution of graders into the M-series was done to encourage more operators into the cab. From H to M series, the grader line lost none of its functionality, but gained a huge amount of operational simplicity. This new generation no longer uses a traditional control layout, but a pair of joysticks with each offering seven control functions that fall conveniently to thumb, index finger and wrist use.

Collectively, these two sticks reduce hand and wrist movement by as much as 78 percent compared to conventional lever controls says Cat, which has carried out a motion study comparing its two operating systems. In simple terms, the left-hand stick is used for machine driving, while the right-hand stick controls the mouldboard.

Linked with AccuGrade GPS machine control, the 14M has given the contractor the potential to grade much more road distance on a daily basis, compared to traditional methods. Being able to grade faster has needed better management of the truck cycle to ensure there's enough material brought to the graders to prevent excessive idle time.

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