Machine control for Mexican graders

A major Mexican highway project has benefited from the use of the latest machine control technology from Trimble

Contractor Construcarr estimates that its work on the Guadalajara – Colima highway project was finished 23% faster due to the use of machine control systems than it would have been using conventional technology. The company used a 2122 Trimble GCS900 grade control package instead of staking and grading methods.

The company is a leader in road construction techniques in Mexico and has invested heavily in new equipment, including the purchase of a Trimble GCS900 3D grade control system that was supplied by local dealer SITECH de Occidente. After its purchase this system was first used by Construcarr on a four-lane expansion project for the Guadalajara –Colima highway.

The expansion of the Guadalajara – Colima highway is seen as crucial for economic development as Guadalajara is Mexico’s second most important city and Manzanillo is a vital port on the west coast of the country. Experts estimate the four-lane expansion will reduce transit time across the city and neighbouring communities by 40 minutes.

With support from dealer SITECH de Occidente, Construcarr installed the Trimble system on two of its motor graders.The package uses a digital terrain model (DTM) produced using Business Center – HCE, a software solution from Trimble for machine control. After converting the data, the Construcarr team transferred the design to the in-cab control box, which was then used to automatically move the grader blade to the correct setting.

The Universal Total Station used a minimum of two surveying control points to determine its position (north, east and elevation). The station then linked to the machine through the radio to provide the position of the target. The CB430 control box in the cab ran the GCS900 software, calculating blade position accurately. This reading is then compared to the design to move the blade automatically to the correct position and grade.

Using the system, Construcarr operators were able to achieve finished grade to millimetre accuracy with fewer passes and less machine run time. And the equipment trimmed costs further for the highway project by reducing the need for two personnel who would have otherwise carried out staking and grading tasks. At the same time, twice the accuracy was obtained from running the machine control system from the design compared with conventional methods. And increased productivity meant the time needed for fine grading was reduced, further cutting fuel and operating costs.

In order to measure the time saved using Trimble on the highway project, SITECH de Occidente analysed the time required for standard grading methods compared with the results achieved using the machine control system. The results were telling as with machine control package, crews save an incredible 40 minutes/100m of laying the cement base, cutting the time from 55 minutes to about 15. Overall, the crew reckoned that the Guadalajara – Colima highway project was finished 23% faster due to the use of the machine control technology, while machine run time was cut by 6%, saving fuel use and machine operating costs.