ZZHZ is a professional manufacturer of hoisting machinery such as gantry crane and bridge girder launching gantry which are widely used in highway construction.
Compared with the box girder, the honeycomb girder launching gantry made by ZZHZ features low centre of gravity, light weight, high safety and high wind resistance. Compared with truss girder, it has a large welding surface with uniform stress; when the truss girder bears force, U-steel welding points will be load-bearing contact points which will deform terribly as bearing load. So honeycomb girder has a low deflection, high stiffness. 6 steel pins connect two longitudinal main girders, knock them into two main girders, the installation is finished, featuring short time and uniform force. Usually, the installation of the whole launching gantry can be finished in one week. 
A middle support leg and a round girder are added on the bridge girder launching gantry integrating carrying and installing girder developed by ZZHZ. Steps to install girders:
1. The machine finishes installation on the roadbed, then moves forward from one pier to next pier.
2. Support the front part of the machine, knock out the connection pins at the middle part, disconnect two parts of launcher, the rear part can carry girders to the precast yard.
3. The rear part lifts the precast girder and moves to the abutment
4. Connect it simply with the front part of the bridge girder launcher by rail splints and bolts, two lifting trolleys lift the precast girder moving to the front part and put down the girder slowly
5. When install the boundary beams, put the precast beam in the place of middle beam, using one side single girder to bear load, the hanging gallows and trolley lift the precast girder to move horizontally to the right place. 
Generally with different terrain in different worksites, we choose different construction methods.
Featuring multifunction, high efficiency and low cost, the bridge girder launching gantry integrating carrying and installing girders makes a large contribution to the national road construction.