(1).Gantry crane produced by ZZHZ accesses to national patent with isosceles triangle honeycomb type main girder, it features light self-weight, high stiffness, low deflection and high wind resistance. The main longitudinal girder keeps load-bearing steel plates at two sides of box girder, removes non-load-bearing steel plates at upper and bottom parts, directly welds two sides steel plates together, replaces U-steel at bottom parts, thus the honeycomb girder structure is designed, it keeps the advantages of box girder and overcomes its shortcoming: too heavy.

Compared with box girder, honeycomb girder features low gravity centre, light weight, high safety and strong wind resistance;

Compared with truss girder, the honeycomb girder has a big welding contact area with uniform stress as loading, while the truss girder bears capacity, load-bearing contact point is U-steel welding point which will deformed as loading objects. So honeycomb girder has a lower deflection, higher stiffness. 6 pins connect two main longitudinal girders, short assembly time and uniform load-bearing.

Because main girder of honeycomb girder gantry crane adopts load-bearing steel plate which is $100 higher per ton than that of truss girder, the cost of honeycomb girder gantry crane in ZZHZ will be 5% or above higher than that of truss girder gantry crane, based on same configuration and same weight. ZZHZ insists on using honeycomb girder gantry crane because it has three advantages comparing with truss girder gantry crane:

1. more durable main girder

2.lower deflection

3. higher safety

(2). type and function

MG series gantry cranes are patent products specially designed for bridge construction. Because bridge constructions are characteristic of little work batch, large weight, short power supply and frequent worksite changing, combined with advantages of existing machines at home and abroad, ZZHZ designs gantry cranes featuring simple structure, convenient installation, easy operation and energy savings. Advantages of the gantry crane are as below:

1)   Unique honeycomb girder first made by ZZHZ features light self weight, large bearing load and high wind resistance

2)     Mature pin connection mechanism, stable and reliable, fast and convenient assembly (it only takes several minutes to put a steel pin)

3)     Pipe support legs can be disassembled as single pieces as transferring sites, quite convenient to transport

4)     Min power solves the problem of electricity supply in the wild.

5)     Travelling mechanism uses frequency converter whose speed is multistage and adjustable, high alignment precision and small impact on the complete machine.

(3) installation

1) Cranes match to assemble main girder, support legs, gear boxes by mark on the ground. After passing examination, install main longitudinal girder on the ground, firstly lift the main longitudinal girder in the certain place (mark and distinguish one side main girder and another side girder)and install walking platform

2) Install the crane gear boxes on the crane rails, alignment with diagonal and fix the gear box. Then lift one side support leg to assemble with wheel box and connect them firmly with pins, then use steel wire rope and chain block to adjust and tighten them and to fix them on the ground anchor. Install the other side support leg with the same way, make two support legs stand vertically on the ground, ensure installation dimension of main girder.

3) Two truck cranes at the same time lift one side main girder to put it on the support legs, adjust it and use bolts to fix the connection plate at the bottom of the main girder with that of support legs trimmers. Then install the other side main girder. Attention: the truck crane is not allowed to loose hook before the main girder is fixed tightly.

4) One truck crane lifts connection frames, fix them tightly with bolts

5) One truck crane lifts trolley and installs it on the rail, adjust it to make its wheel tread contact with rail plane

6) One truck crane lift driver’s cabin, halfpace, walking platform, handrail and other accessories to the certain position.

7) Install electrical facilities, pave the electrical lines, remove mooring rope, ground anchor and other equipments. Then start a test run and make a record according to the demand of the quality inspection department