Terex crawlers erect Asia’s largest radio telescope
By Alex Dahm25 June 2012
Tianjin Launch Specific Hoisting Equipment Engineering Co. Ltd used a pair of Terex crawler cranes to erect Asia's largest radio telescope.
The 1,000 tonne capacity CC 5800 and 600 tonne capacity CC 2800-1 lattice boom crawlers lifted in tandem to install the 320 tonne back frame of the reflector for the antenna. It was the second lift performed by the cranes after lifting and positioning the pitching mechanism on 17 March.
Lifting the 65 metre diameter and 11 m tall frame was a challenge due to its large cross-section and the low wind speed requirement set by Tianjin Launch. Weather in Shanghai meant that the lift had to be made before 10 a.m. because wind speed increases after this time and the lift would have been too dangerous. At 06.30 the cranes began lifting the frame to a height of 39 m before starting to crawl.
The two cranes crawled for 1 hour and 35 minutes to position the load. At 09.10 the back frame was positioned and attached to the supporting structure. It all took less than four hours and was within the specified time frame, Terex said.
"This lift was particularly challenging because the back frame features a large diameter and heavy weight, so a larger operation radius was needed. Additionally, the project is highly sensitive and precise, so we had to work with much smaller tolerance margins. For these reasons we chose the reliable and proven design of the Terex CC 2800-1 and CC 5800," commented Zhang Yongliang, deputy general manager and chief engineer of Tianjin Launch.
The CC 5800 was used in SWSL 54 + 36 m configuration, and the CC 2800-1 in HSWSL 54 + 36 m configuration. A custom spreader with a bias hook position was also used to allow the higher capacity CC 5800 to take more of the load. "In tandem lifts, it is of vital importance to monitor the load of each crane while performing the lift. So, for this sensitive project we relied on the accurate load moment readings of the IC1 load moment indicators, redundancy LMIs was a feature requested by our customer," added Zhang.
The radio telescope is a co-operation between the Chinese Academy of Sciences and the Shanghai Municipality. The main reflector is 65 m in diameter and weighs around 2,600 tonnes. It will be operated by the Shanghai Observatory and will be used for Very Long Baseline Interferometry (VLBI) orbit testing, part of the Phase II Lunar Exploration Project.
Tianjin Launch Specific Hoisting Equipment Engineering Co., Ltd is a heavy lifting contractor headquartered in Tianjin. Projects include using a CC 2800-1 to lift a 370 tonne engine for Beijing Jingfeng Electric Power Plant, lifting the Nanchang Honggutan ferris wheel and lifting work on the Tianjin Fenghua Bridge. In addition to the CC 5800, Tianjin Launch has two each CC 2400, CC 2500, and CC 2800-1 Terex crawlers.