Recently，WithSTThe 4-segment steel tower was successfully installed in place.，ByThe world's largest tower crane jointly developed by Zoomlion and CCCC Second Harbor Engineering——R20000-720 tower craneThe south main tower of Ma'anshan Yangtze River Rail-cum-Road Bridge on the Chaozhou-Ma'anshan Railway was successfully closed，It marks that the south main tower of the world's largest span three-tower cable-stayed bridge has been transferred to the construction stage of the upper tower column steel tower.。

▲Zoomlion, the world's largest tower craneR20000-720 Helps Closure of Twin Towers of South Main Tower of Maanshan Yangtze River Rail-cum-Road Bridge on Chaozhou-Maanshan Railway

Ma'anshan Yangtze River Railway Bridge is a control project of Chao-Ma Intercity Railway.，The main span is adopted for the main bridge(2×1120)M Three Tower Steel Truss Girder Cable-stayed Bridge，The total length is 3248 meters，It is the first three-tower cable-stayed bridge with double main spans exceeding 1000 meters in the world.，It is also the longest steel truss cable-stayed bridge in the world.。

The south main tower of the bridge is made of steel.-Mixed structure，TransverseAType、The longitudinal direction isIShape structure，Total height 306 m，It is divided into upper, middle and lower parts.。Medium、The lower tower column is a concrete double-leg structure.，High 215.5 meters；The upper pylon is of steel structure.，High 87.5 meters。The steel tower adopts the world's largest lifting moment.R20000-The 720 tower crane is hoisted in 16 sections.，The largest segment weighs about 400 tons.。

▲Zoomlion, the world's largest tower craneR20000-720 is under construction

Under wind load、Influence of sunlight and reaction force of super large tower crane，The deformation of the two tower limbs is complicated.，Closure is more difficult，Pecially the accuracy requirement，The error shall be less than 1 mm.，Equivalent to more than ten hairs.。In ZoomlionR20000-Under the millimeter-level control system operation of 720 tower crane，The steel tower weighing 309 tons was lifted smoothly.，Achieve precise docking and closure at an altitude of 228 meters。

The project team of CCCC Second Harbor Engineering has added matching trusses to the main tower.，Two tower limbs can be locked in advanced。At the same time，Surveyors observed for three consecutive days.，Mastering the sunlight on the tower limb、Deformation Law of Temperature and Tower Crane Attitude，Summarize the displacement change of tower limb，Make full use of the centimeter displacement generated by the rotation of the tower arm of the world's largest tower crane during hoisting operation to assist in matching the truss.，Reuse of Conical Matching Pin of Truss to Overcome Millimeter Deviation Effect，Achieve high-precision closure。

After the completion of Chao-Ma Intercity Railway，A fast passage will be established between the two sides of the Wanjiang River.，To optimize and improve the layout of regional railway network，It is convenient for the people along the line to travel.，Promoting the development of the Yangtze River Economic Zone、The integrated development of the Yangtze River Delta is of great significance.。

Source of material：“CCCC Second Harbor Engineering Co. Ltd”Official account