China selects Trimble machine control, paving and compaction control systems to reduce re-work needed on the job site, saving time, money, and materials for the massive nearly $23.1 billion (RMB) $3.6 Billion (USD) international airport construction project
Originally built in 1922, Kunming WUJIABA International Airport is an important regional hub in southwest China. In 2010, the airport handled more than 15 million passengers, far beyond the intended capacity of the facility. This volume of passenger traffic made Kunming Airport the seventh busiest airport in mainland China. On top of that, it's the seventh and eighth busiest airport in terms of cargo traffic and aircraft movements, respectively.
With high-growth expected to continue in the region, China's National Development and Reform Commission approved a feasibility study to examine the need for the construction of a new airport. By 2020, the project will have the ability to handle 38 million passengers annually. The new airport will have one 4,000 meter long and 60 meter wide runway, and another 4,000 meter long and 45 meter wide runway. It will also include a 550,000 square meter terminal building, a 2,800 square meter tower, and other supporting facilities such as air traffic management and a fuel supply system. The project is estimated to require an investment of nearly $23.1 billion (RMB) (USD $3.6 billion).
Contractors working under Kunming New International Airport Construction Commission selected several products from the Trimble® Heavy Civil Construction portfolio, including Trimble Site Positioning Systems and Machine Control Systems. With these systems, the owner is able to set up an "Airport Digital Construction Site."
During the initial phase of the project, the team established four GPS base stations around the airport site. The team selected Trimble GNSS-based Site Positioning Systems because the tools eliminated the need to use additional surveyors. Instead, one person operating the equipment can provide accurate positioning in two seconds anywhere at the site, and work can continue over 24 hour shifts. The four GNSS Base Stations provided complete coverage over the entire site and used a common calibration. This allowed Grade Checkers and Machines to easily move around the entire site. The Trimble SPS930 Universal Total Station was also chosen because the technology's high accuracy and performance capabilities not only for construction site positioning, stakeout, and measurement, but also in regards to machine control.
The Business Center-HCE powered by Trimble application is also being used to control site operations. The application organizes site information, enabling seamless data sharing and the creation and distribution of reports. The team can edit, process, and adjust data from all Trimble instruments efficiently and effectively with Business Center. Early on, the project's design files were transferred from the traditional 2D design blueprint into the 3D design, which can be recognized and executed by the Site Positioning System and machine control systems. By doing this, the project owner has more precise and efficient management of earthmoving volume control, as well as additional project process control.
Setting the foundation for a digital project site, the team is also using machine guidance technology. The earthmoving grade control system uses GNSS and Universal Total Station technology to accurately position equipment to reduce material overages and improve productivity. Essentially, the Trimble GCS900 Grade Control System puts design surfaces, grades, and alignments inside the cab for machine operators, from dozers, graders to pavers.
"On the dozer, the GCS900 can help produce a good surface at an adequate accuracy level, guided by GPS," said Bruce Zhang, technical support engineer with Trimble. "In this case, it can save a lot of rework and it allows operators to reach the base-level requirements much faster. On the grader, the machine control is used in Cement Bound Material (CBM) paving-which needs higher accuracy than the dozer. The grader is guided by the total station to create a very smooth surface and precise slope within 1 centimeter accuracy. In all, the Trimble system helps follow the design work correctly, whatever the requirements, the first time to save time and money."
Constructing the two new 4,000 meter long runways at the airport site is one of the most critical components of the entire project. Confident in the results of Trimble's Site Positioning and Grade Control, the project owners also selected Trimble's Paving Control and Compaction Control Systems.
Today, the Trimble PCS900 Paving Control System is used in CBM paving and also the asphalt paving. Zhang believes the project contractors are satisfied with the significant improvements in paving productivity and overall time savings experienced. Contractors are able to pave the base to design correctly, to accuracy within 5 millimeter, saving on any costly rework or unexpected surface degradation.
Runways require increased durability, stability, and load-bearing capacity. As a result, the compaction process is even more critical. To manage these inherent challenges, the Trimble CCS900 Compaction Control System is installed on 20 compactors at the airport site. They each provide continuous compaction control to ensure the sub-surface materials are compacted to the appropriate and precise target densities. The Trimble on-machine display and collection of pass count data, Compaction Meter Values (CMVs), and cut/fill information allows the team to identify any potential weak areas immediately.
The system also provides guidance on how to make necessary corrections early in the build process, which saves time and money. Inside the cab of the machines the operators can instantly see an accurate map of compaction measurements and they can view compaction results in real time.
"Accurate reporting capabilities are necessary to deliver consistent, quality results when you're talking about grading or compaction on any project-especially on a large-scale airfield project like this," said Zhang. "This level of in-the-field accurate information and documentation gives the project owners a great level of confidence that they are addressing all factors, from time, cost, and safety perspectives."
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