This machine is designed to place concrete box beams of bridge in mountainous tunnels for high speed railways. This machine can also be used 900 ton concrete box beams. Without disassembling machine, and without the help of other auxiliary facilities, the machine can directly placed box beam on the top of the piers at the entrance or exit of tunnels. This machine is consisted of two parts, one is the special carrier, and the other is underbridge machine. The special carrier is in charge of lifting box beams from the casting yard and carrying beams to the jobsite. Then, with the help of the underbridge, the special carrier places concrete box beam on the pier. Underbridge machine plays a role as the supporting beam, and works together with the special carrier. After the erection of the box beam, the underbridge machine will change the position of its legs by itself in order to be ready for next operation in the cycle. The working procedure of special carrier has a remarkable characteristic. It has three functions: beam lifting, beam transporting and beam placing. It is quite different from ordinary launching equipments in structure and working mechanism. And its dimension is much smaller than other kinds of launching gantry. This kind of special launching carrier collects the three functions together and there is no overlap in functions, so it can work efficiently.
1.1 Working conditions
·Placing concrete box beam for same length span of bridge or different length span of bridge, with ballast or without ballast on deck. ·Erecting the concrete box beam on the top of the piers at the entrance or exit of tunnels. · Erecting and transporting box beam in the limit area of height and width ·Surmountable slope 2 % · Min. radius of the bridge 2000m. ·Wind speed: 72km/h with load, 144km/h without load
1.2 Main technical characteristics
·Lifting, transporting, and placing huge box beam are achieved through one machine with lower economic investment of the construction company. ·Besides working for normal erection of bridge, the machine can directly placed box beams on the top of the piers at the entrance or exit of tunnels. ·It is convenient to change jobsite without any auxiliary devices. The special launching carrier can lift the underbridge itself to transfer to other jobsites. It is especially suitable for launching concrete beams between the tunnels. · With small modification, the special launching carrier can easily erect other kinds of bridges. ·The carrier is also an independent lifting machine that can satisfy lifting box beam in the casting yards. · When the distance (between the stacked yard of box beam and the job site of bridge erection) is over 4 km, the erection of two concrete box beams can be completed. If there is a situation with the tunnels in the construction, the working efficiency is of this machine much higher than any other kinds of launching machines. ·The machine is 34m between the front running tyre group and rear running tyre group, and it means the two tyre groups always stand on the different concrete boxes, so the forces on deck and the pier or abutment are less than other kinds of the transporting and launching machines.
