The lower beam of the main tower in the project of Kunyang Road Bridge has been completed! We will make more brilliant achievements in 2019!

2019-02

After 31 hours of continuous placing, the lower beam of the main tower in the project of Kunyang Road Bridge which is invested by Shanghai Highway Investment and Construction Development Company and built by STEC Luqiao Group has been completed. So far, the beam has been constructed in the Huangpu River, which shows that the construction of main tower for the bridge will speed up.

Tower beam connecting with 6 columns to support heavy load
The top height of the finished lower beam is 33.8m, which is not only the key turning point for the "diamond-type" main tower to continue growing high, but also the safety support for the bridge to extend to both sides in the future. To meet best design and construction requirements of the bridge, STEC Luqiao Group uses 6 steel tubes with diameter of 82cm and height of 19m to form the support system in the construction of the lower beam.

Steel tube is equipped with the truss from the top to support the weight of concrete. The weight of lower beam and connected tower column is over 3,000 tons. The whole support system is sustained by 6 steel tube columns and steel corbel. Before construction, the engineer used 3D model and calculation procedure to calculate, simulate, build and optimize the support system repeatedly, so as to achieve the perfect connection of the tower beam.

Building “balance” bracket bridge to extend towards two sides of the bridge

In the whole construction process of the lower beam, constructors bound 230 tons of rebars, installed 150 tons of steel formwork, and laid 55 bundles of prestressed pipes inside the lower beam. In the future, the main girder of the entire bridge deck will be located on the lower beam, take it as a center pivot, and extend towards two sides of the bridge with stretch-draw of the stay cable. Like a balance, the main tower is a “stand column”, and the cable is hanged, the beam body is the “weight”, and the lower beam is a “bracket” to connect with tower column, thus forming a framework and building a well-balanced stress structure.

One-time concrete placing under assistance of “counter-pull prestress” system
To ensure the quality of overall beam structure, one-time concrete placing is used for connection between the lower beam and the tower column. A lot of rebars and structural members have formed “steel forest”,
so it is difficult for operating personnel to conduct pouring construction for bottom layer of the space with length of 44m, width of 5.8m and height of 5m by reserving holes.

STEC Luqiao Group optimizes the construction plan, bring forth new ideas to “counter-pull prestress” system to replace traditional bracket weight, and completes bracket deformation control safely and quickly; meanwhile, sets a concrete mixing station on the construction platform, advances in order based on pouring points, and greatly shortens the connecting time of working procedure.

Working efforts to advance construction of the approach bridge
The pouring of the lower beam is a key turning point in the construction of the main tower, followed by the continuous climbing of the bridge into the main tower and the construction of approach bridge and accessory structure. At present, prefabricated column of the approach bridge and bent cap are under construction. This also means fully prefabricated bridge construction is applied for the first time in a bridge across the Huangpu River, which effectively reduces on-site cast-in-place bracket workload and greatly shorten construction time.