Precision road construction in Romania

Austrian contractor PORR is setting new trends with its work on the Sibiu highway in Romania
Connected Construction / October 27, 2021
The machine operators can work from design information downloaded straight into the cab
The machine operators can work from design information downloaded straight into the cab

The firm is working on the 13.2km Lot 1 stretch of the project, one of five lots for the highway which will stretch 123km when complete and at a total cost of around €1.6 billion.

PORR’s Lot 1 contract does not face some of the geotechnical challenges of other stretches but the company opted to set benchmarks with the work.

Daniel Boehnke is construction coordinator for PORR’s contract, overseeing the site managers handling various aspects of the Lot 1 stretch.

Boehnke said that the alignment was in a comparatively undeveloped area. He commented, “When we started it was a green area of fields and forests.” Boehnke explained that this made working simpler as there was no local traffic to consider, which would have required traffic control systems for materials supplies or the movement of construction machines .

The construction work commenced in March 2021 and the Lot 1 project requires considerable earthmoving, with 1.7 million m3 of cut and 1.4 million m3 of fill. Because of the quantities of material to be moved, Boehnke explained that the decision was made to use the latest 3D machine control technology, so as to optimise working. However, this presented a challenge and he explained that sophisticated 3D systems had not been used in Romania for road building previously, while experience of this technology was also limited within PORR.

The 3D earthmoving package was fitted to three excavators and three dozers that the firm wanted to use on the project. He said, “In total we had six machines onsite with the system and we had to figure out what to do. For us it was a new experience.”

Key benefits according to Boehnke are that there is no need for a surveyor onsite all the time to control the operation. This makes the earthmoving portion of the work faster, while also reducing costs. To ensure that the cut and fill working is to specification PORR has had its surveyors check the results and commented, “If we do measurements, the tolerances are from 3-5%.”

The system means that the site manager gets key information on cut and fill data, which is highly reliable. “We get to see the performance onsite,” he commented

Earthmoving operators are benefiting from the use of machine control systems fitted to the excavators and dozers
Earthmoving operators are benefiting from the use of machine control systems fitted to the excavators and dozers

Design data and as-built data for the project can be transferred easily between the Trimble Works Manager and Trimble Earthworks systems. He said, “The operator can see design changes inside the cab.” This was a learning experience for the machine operators and he commented, “In the beginning it was a challenge for the operators as they were afraid to make mistakes.”

However, Boehnke said that they were able to learn how to use the system quickly, with training from Trimble supplier Sitech having proven highly valuable.

Having opted for the 3D system for its earthmoving equipment, PORR also decided to purchase a package for its paving machines. Boehnke said, “We bought a system for our two new finishers.”

At the time of writing, PORR had carried out tests on stretches using the equipment but was still waiting for approval from the Romanian authorities to go ahead with its use on the highway. Boehnke said, “The model has been done and has been loaded on the finishers and we had training with Sitech so that the operators would know how to use the system.”

The plan is to lay the three layers in four lifts. The 16cm base layer will be laid in two lifts of 8cm each, followed by the 8cm binder layer and finally the 4cm wearing course. However, Boehnke is confident that the system will deliver the quality required and commented, “After laying the base layer it should be very accurate.”

He said that there are also cost benefits from using the 3D system for paving, as with the earthmoving portion of the work. Using the 3D system eliminates many of the complex tasks in the setting out process and also allows for greater accuracy in paving. This last will help to cut materials usage, with a significant benefit for costs.

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