Gantry Cranes: As we mentioned before; This type of crane is used outdoors and has a high height. It has a longitudinal movement and moves on the rail. Half gantry crane is a combination of overhead and gantry cranes. Two-bridge gate crane: It is generally used outside the warehouse for lifting and loading items. These types of cranes consist of a bridge, two supporting legs, a trolley, electrical equipment and a lifting winch. The frame conforms to the box-shaped welding mechanism. All mechanisms are controlled from the driver's cabin. Power supply is done by cable or collector cable. The capacity of the double beams is different according to the user. These types of cranes are usually made as two bridges with a high capacity and opening and are used for loading and transferring the load in the open space. The crane movements can be controlled from the operator's cabin, which is in It should be placed under the bridge. Important points in the gantry crane of two bridges: the proper angle of the columns of this type of crane, the correct selection and use of the clevis, the proper distance between the bridges, the design and construction of this type of cranes against any type of stress, the design and construction of this type of structure against earthquakes, observing all Standard tips and use of quality materials in the construction and installation of cranes