Construction of large span steel pipe truss for International Expo Center

The International Expo Center project consists of five functional areas: conference and exhibition, covered property, roof garden, underground shopping mall, underground garage and computer room. According to the plan, there are nine zones: Zone I for the conference section, Zone II, III, IV and V for the exhibition section, Zone VI, VII and VIII for the overlying property Towers A, B and C, and Zone IX for the sunken plaza. The structure system of the above-ground part is mainly steel structure, among which the column-free exhibition hall on the third floor of Zone V is a 72m span spindle pipe truss with 14 trusses in total. Both ends of the truss are hinged to the column ends.  

The long-span steel pipe truss of column-free exhibition hall on the 3rd floor of Zone V of the International Expo Center project is installed by the scheme of “ground assembly and overall lifting”. The construction technology scheme is to reasonably segment the long-span steel pipe truss on the ground, and then assemble it as a whole, and finally use the hoisting machinery to lift the whole, and install it in place. After the 14 trusses are hoisted, the winding horizontal support and winding tie rod will be installed.  

Due to the large span of the truss, eight lifting points of two cranes are used to lift it simultaneously. In order to reduce the deformation of the truss, improve the stability of the truss hoisting, make the load condition of the truss close to the installation condition, try to ensure that the positive and negative bending moment of the truss is equal or close, try to reduce the flexural deformation of the truss members, so as to determine the position of the lifting point in the truss. In addition, the lifting point should be located at the truss node, and the node should be guaranteed to have enough strength to meet the lifting of the truss. Due to the large span of the pipe trusses, two 1100T walking boom tower cranes are used for overall hoisting. The installation sequence is from north to south and backward.