Gantry crane is the development of overhead crane. It is used to load and unload bulk loads in freight yard outdoor and in stock ground in harbor. Metal structure of the gantry crane is just like gantry frame, two supporting legs are installed below main girder and can move along ground track. There are cantilever beams at each end of the main girder. Gantry crane is widely used in the port and freight yard, featuring high site utilization, big work range, wide adaptability and good generality.
(1) According to the type of door frame
It is divided into gantry crane and cantilever gantry crane
(2) According to the type of main girder
1. Single girder gantry crane
2. Double girder gantry crane
(3) According to the structure of main girder


1. Truss girder
  Welded by angle iron and joist steel, it features low cost, light self-weight and good wind resistance. Because of many welding spots and its own deflects, the truss girder has many disadvantages such as high deflection, low stiffness, lower reliability and frequent check of soldered dots, so it is suitable for worksite with lower safety requirements and smaller lifting capacity.
2. Box girder
Box type structure welded by steel plate features high safety and high rigidity. Usually the box girder is used for gantry crane with large tonnage and super large tonnage.
For example: MGhz1200 is the biggest gantry crane with 1200t lifting capacity in domestic market, its main girder adopts box girder. But the box girder at the same time shows some disadvantages such as high cost, large self-weight and low wind resistance. 
3. Honeycomb girder
Usually it means “isosceles triangle honeycomb girder” with triangle end face, honeycomb hole in the steel plate of the main girder and chord member on the upper and lower parts. Honeycomb girder combines the features of truss girder and box girder. Compared with truss girder, it features higher rigidity, lower deflection and higher reliability. Because the honeycomb girder is welded by the steel plate, it has a higher self weight and cost and is suitable for fields or precast yard with large lifting capacity and frequent utilization.