Construction of the Bugrinskiy bridge, third automobile bridge in Novosibirsk, Russia is nearly over. The opening of the bridge will allow drivers to noticeably reduce time spent driving from one bank to another.
Construction of the Bugrinskiy bridge, third automobile bridge in Novosibirsk, Russia is nearly over. There are still temporary supports in the Ob riverbed; workers are reinforcing the cables which will support the central span above the water, but the main tasks have already been finished. Laying of the top asphalt layer on the bridge’s main driving surface started in the middle of June 2014
The opening of the third bridge will allow drivers to noticeably reduce time spent driving from one bank to another. Dimitrovsky automobile bridge, the second one, was put into operation 36 years ago, so for Novosibirsk, a city overloaded with traffic, the new bridge is obviously vital. It’s also certain that after the first cars drive over the new bridge, the quality of the road surface will be one of the most popular local discussion topics.
With quite a lot of confidence, we can say that Sibavtoban company, the main contractor responsible for the paving, will not have to make any excuses for bumps and holes in the road. Last year, they signed a contract with SITECH Siberia, for supplying the PCS900 Paving Control System for one of their paving machines. By the beginning of the construction season, the machine was re-equipped, specialists completed a training course and the work began as soon as weather permitted.
“During the first week, there were still doubts as to whether the asphalt was being laid in compliance with the project design,” says Artem Shevtsov, geodetic surveyor of Sibavtoban. “It turned out that in automatic mode, the machine accurately complied with the project design. This year, the Construction Codes and Regulations became more stringent; the permissible variation is no more than 5 millimeters (xx inches) now, but we comply with the norm. The quality of work is easy to check. You can just switch the Trimble system from the paving machine to a range pole with the controller — you set the reflector to any point and it shows if there are any deviations.”
Asphalt paver equipped with Trimble PCS900 Paving Control System
String levelling is one way to automatically control paving machine screed, when a string stretched along the edge of the road sets the level of the highest surface of the road. Besides the fact that the string can easily be knocked down, the process of setting it up is quite time-consuming. Work starts with geodesists setting up support stands at intervals of 15–20 meters (xx feet) and 5–7 meters (xx feet) on curves or corners, and then pulling the string over them. This takes about 1.5 hours, according to Artem Shevtsov’s estimates. Throughout the workers’ shift, the string must be constantly moved from one site to another. After the marker is set, the machine starts moving and the geodesist follows it and checks the quality of paving. All this is now in the past.
The paving machine upgrade has changed work methods. Now the maintenance team’s shift starts with setting the robotic total station to a certain point with known coordinates and uploading the road’s 3D scheme to the machine’s computer. After that, they can begin their task. The automatic control system receives information from the robotic total station and commands the paving machine software by radio to set the screed to the proper level. It will now control the accuracy of the asphalt-layer distribution and its compliance with the target thickness.
The robotic total station independently controls the movement of the paving machine along the construction site. Trimble, producer of the equipment, guarantees that deviations from the planned scheme will not exceed 2–5 millimeters in a radius of 200 meters (xx feet) around the robotic total station. One may take a risk and move a little farther, but the deviation might grow. Meanwhile, the robotic total station provides the maximum possible compliance with the project design.
Was transitioning to the new equipment hard? “There are no significant problems on the construction site,” Artem Shevtsov says. “Learning how to use the program took the most time. You have to be very cautious when preparing and uploading the 3D model. In 2003, when I got a degree, we did not study systems like these. Then dual frequency navigators and automatic control systems began to take root in the road construction industry. Our paving machine is the first machine in the company, which leverages this technology. When the system is installed on a grader or bull dozer, the accuracy of implementing the project design is very close to perfect. Our management is taking an interest in our work almost every day now.”
SITECH Siberia employees have provided us with valuable on site support and training. “The first week we were there as instructors,” says Anton Pimshin, SITECH Siberia’s machine control systems sales representative. “There were many questions, and we handled them. We demonstrated to Sibavtoban’s employees that our system works reliably. Now the team at Sibavtoban work on their own. We would come to them just to ask how it was going. The advantage of automatic machine control technology is that it makes life easier for road construction contractors. There’s no need to take additional measurements; you just set up the total station and turn it on, and then do the main work—laying down asphalt. During the work, all the components of the levelling system are constantly controlled to avoid possible failures or breakdowns. All the information is available on the on-board computer screen; the operator only has to choose the direction of movement.”
Finalization of the project before the inspection of the bridge by top government officials
The asphalt paving helped keep the job on schedule. The major concern for the construction workers was that the dump trucks keep delivering the asphalt on time. “Yes, sometimes the delivery is late,” says Artem Shevtsov. “The machines run according to schedule, but the city is stuck in traffic jams, so the asphalt dump trucks have to sit in traffic with the others. Until the third bridge is opened, the transport problem will not be solved.”
Dmitry Kuznetsov, General Manager of SITECH Siberia
“For Russian companies buying and using machine control systems for road-construction heavy equipment is still new, whereas foreign enterprises have already passed this stage long ago. For contractors in other regions constructing a 3D project design model and automatic control of equipment according this model is an approved and established technology.
In Russia, road construction was the first area to leverage the new technology. In fact, it is reasonable because linear construction sites allow us to see the benefits of purchasing the equipment in the first few months. The contractor can choose whether the machine will operate using the robotic total station or GLONASS/GPS signals. Tests show that a machine with the automatic control system operates 40–70% faster than a machine without it. Some of our customers said that our systems allow them to finish work 2–3 times faster. As you can see, this purchase is an investment that makes a lot of sense.
3D Machine control systems were first introduced in Russia over 10 years ago, although Russian road workers at the time were not yet even considering that possibility. One reason is because the standards and codes of site acquisition at the time were extremely liberal. Deviations in road surface of up to 10 centimetres, plus or minus, were allowed. But life doesn’t stand still; in 2013 the standards and codes got more strict, and today the exactness in observing the planning documentation during site acquisition is 5 times higher than it was then. If clients are going to be ordering work done in accordance with the new standards, many contractors will have serious problems.
One of the main advantages of using our equipment is that the road is built exactly according to the project design and the owner can be confident in the result: the construction site will be handed over without having to go back and re-do anything. This also influences the company’s output growth. Material cost savings is another reason many customers buy our automatic control equipment. According to the most conservative assessments, savings can amount to 2–4% of the total cost. It’s not difficult to evaluate the savings on road asphalt mix: even on one kilometre of road, one can save hundreds of thousands of roubles.”