Gantry crane gantry structure is generally based on the main girders, spreader classified form.

(1) The sub-frame structure (a) the whole gantry crane: the main beam without overhang, the car within the main span. (B) semi-gantry cranes: legs have height difference, can use the site's civil request. (C) double cantilever gantry crane: The most common type of structure, the structure of the force and the effective use of the site size is reasonable. (D) single-cantilever gantry crane: This structure is often limited because of the venue was chosen. 

(2) main beam structure divided by (a) single-girder gantry crane: single girder gantry crane cantilever simple structure, manufacture and installation of convenience, its mass is small, the main beam over the rail box-shaped frame structure. And double-girder gantry crane, compared to weaker overall stiffness. Therefore, when the starting weight Q ≤ 50t, span S ≤ 35m, we can use this form. Single girder crane main door gate legs are L-and C-type in two forms. L-type of manufacture and installation of convenience, good mechanical condition , its mass was smaller, but, lifting cargo space through the legs relatively small number of Department. C-type legs raked or curved shape designed to have more horizontal space to make the goods pass the feet. (b ) double girder overhead double girder overhead crane load capacity, span, overall stability, variety, quality and the same, but from the weight of its own single-girder gantry crane to be bigger than, and higher cost . According to the main beam structure is different, can be divided into box girder and truss forms. now more commonly used box structure.