ONSTRUCTION projects around Australia are reaping the productivity benefits of significant ongoing developments in intelligent earthmoving equipment.

Latest developments include the release by Caterpillar of the AccuGrade Grade Control System which the company says can reduce labour requirements, dramatically reduce survey costs, and increase productivity by up to 40 per cent.

The AccuGrade suite of products includes cross slope, sonic, laser, and GPS, and is designed for use with H and M Series Caterpillar motor graders to suit a diverse range of applications. AccuGrade Cross Slope for example provides automatic control of blade slope while AccuGrade Laser operates via dual or single laser receivers, and a single or dual slope laser transmitter, to provide automatic blade lift and tilt.

Sensing ability

An AccuGrade Compaction GPS mapping and measurement system has also been released by Caterpillar for soil compactors. The system is designed to ensure that soil is compacted to specification, thereby eliminating guesswork and avoiding costly and time consuming rework. Through its sensing ability, AccuGrade Compaction alerts the operator to soft spots, buried objects and moisture problems, documents the information, and logs the exact location with GPS.

The system uses an accelerometer to measure drum movement and converts the measurements into stiffness values that are displayed in colour to the operator as they are measured. Progress of the machine can also be monitored on a site office computer through a two-way wireless radio network, which provides a capacity for the operator and the office engineer to see the same data as it’s transmitted to and from AccuGrade Office software.

AccuGrade technology was recently utilised during construction of an army airfield at Timber Creek in the Northern Territory. The project, which took less than two weeks to complete, involved removing considerable amounts of bedrock from the sub-grade and building a runway, together with turn-around ends, capable of taking a C-17 aircraft.

Tasks included clearing and grubbing of the runway and apron areas, placing and compacting three layers of material, fibre-cement stabilisation of the aprons and taxiways, and installation of an edge drain system.

Monitor compaction

Caterpillar ’s Jean-Jacques Clar says five 563E soil compactors and one D8T bulldozer utilised AccuGrade on the project. “The Caterpillar machines were rented by the US army and used for training the US and Australian troops in Darwin for two weeks before being moved to the Bradshaw Field Training Area at Timber Creek to construct the airfield,” Clar says.

“AccuGrade Office was used to monitor compaction and coverage level of each of the compactors in near real time. The site supervisor was able to see vehicle locations and track progress with cut and fill through the use of Site Vision Office software, and vehicle operators used the automatic mode on AccuGrade to control blade position.

“AccuGrade benefits include the ability to monitor daily progress through the provision of electronic data for computer analysis, which in turn creates historical data for use in planning requirements for future projects.”

Technological innovations for earthmoving equipment have been recently developed by Volvo Construction Equipment, including an Automatic Traction Control (ATC) system that will be fitted as standard to the company’s new E series A25 and A30 articulated haulers that are due for release in Australia in November 2007.

The ATC system has multiple speed sensors that constantly check the speed differences within the drive train and select the correct drive combination to negotiate the terrain. Volvo’s general manager, Paul Torrington, says the system monitors wheel slippage and engages the longitudinal differential lock and 6x6 only when needed, which means easier operation and reduced tyre wear and fuel consumption.

Differential locks

“Selectable drive combinations by the operator are reduced from five to two with ATC, but the three transverse differential locks can still be manually activated via the lock button located on the floor. By monitoring traction, the ATC computer ensures the machine has the right traction for every condition, while protecting the drive train from misuse,” Torrington explains.

“Later this year we will also be launching the Care Track telematics system which provides interactive exchange of information about machine operations over a satellite or GPRS wireless communications network. Information provided by the system includes the amount of machine usage, alarms about service and maintenance requirements, fuel consumption, and productivity data such as tonnage moved each day and work cycles. This is a system that will ensure machines are utilised in the best way and that costs are kept to a minimum.”

Volvo recently released the L350F wheel loader that is the biggest ever produced by the company, and which Torrington says has recorded an 18 per cent increase in productivity and 46 per cent better fuel economy over its predecessor. The L350F features a new Tier 3 Volvo engine, stronger hydraulics, an improved lift arm, and a new transmission.

Source: Construction Contractor