On the sixth day of the first lunar month, the last day of the Spring Festival holiday, the reporter arrived at the construction site of the Greenland Center·Shufeng 468 project, the tallest building under construction in Western China. Project General Manager Fan Wenjun had already returned to the site from his hometown in Shanghai after the New Year. The Greenland 468 project also became the first commercial project in Jinjiang District to resume construction after the Spring Festival. Before the holiday, the Greenland 468 project had only "grown" to the 8th floor. According to plan, all 101 floors will be completed by October 2018. Is the remaining 600 days or so enough? Fan Wenjun gave a confident answer: "After the Spring Festival, we will construct at a rate of one floor every 5.5 days. There is no problem completing the project on time!"

During the interview, the reporter learned that Fan Wenjun's confidence in the project schedule comes from the tower crane slewing platform, which is used for the first time in domestic super high-rise construction. This platform replaces the traditional externally attached wall-climbing tower crane. During construction, it climbs upward with the building without occupying construction time, greatly improving construction efficiency.

Can move 360 degrees

Can lift giant components up to 80 tons

What new equipment is so impressive? Curious, the reporter followed Fan Wenjun up to a rooftop next to the construction site. On top of the main tower of the Greenland 468 project, which had already reached the 8th floor, there was a huge white structure. "It is an X-shaped steel structure platform that can be equipped with 4 tower cranes, one of which can lift giant components weighing up to 80 tons. It is called a slewing platform because it can move 360 degrees around the circumference, making it easy to hoist large steel components in any direction," Fan Wenjun said.

According to reports, previously in China, traditional externally attached wall-climbing tower cranes were used in super high-rise construction. As the building rose one floor, the tower crane also had to climb one floor. Each climb required a full day of work for disassembly and installation. In constructing the Greenland 468 project, to improve efficiency, Greenland and the contractor—China Construction Third Engineering Bureau—jointly developed a tower crane slewing platform placed on top of the building. It climbs with the help of four hydraulic jacking systems, each with a thrust of 400 tons.

"We began preparations in early 2016, went through twists and turns, and successfully developed it in August," said Zhang Zhenxing, technical director of the Greenland 468 project at China Construction Third Engineering Bureau.

Each floor

Saves one day

It is understood that because the tower crane slewing platform is a "new invention," before it was actually put into use, Greenland and China Construction Third Engineering Bureau conducted experiments together to ensure it would not tilt when lifting heavy components. When the ground construction reached the 3rd floor, the tower crane slewing platform was placed on the roof and put into use.

Fan Wenjun introduced that from the 3rd to the 8th floor, after five floors of adjustment, the tower crane slewing platform has achieved normal operation and greatly improved construction efficiency. "Because it is a super high-rise building, we added steel plate shear walls to each floor. Starting from the steel plate shear walls, tying rebar, erecting formwork, pouring concrete, and then removing formwork—the entire process takes only 5.5 days. After a floor is completed, the tower crane slewing platform is jacked up one floor by the hydraulic system, which does not occupy construction time at all."

During the interview, the reporter saw that on the platform outside the main tower, many workers were already organizing construction materials. Fan Wenjun said that workers are returning to their posts one after another, and by the 15th day of the first lunar month, there will be more than 2,000 workers on site. "In particular, with the use of the tower crane slewing platform, each floor saves one day compared with before. So we are confident that after the Spring Festival, we can maintain the progress of 'one floor every 5.5 days' and complete the 101 floors on time by October 2018."