The difference between gantry and girder is that gantry and girder are both lifting equipment used in engineering construction, but their structures and uses are different. Gantry is a kind of large-scale hoisting machinery, which is composed of columns, beams, legs, wire ropes and motors. Its structure and shape are similar to a gantry, hence its name. Gantry is used to hoist heavy objects, such as large mechanical equipment and building materials. The gantry can be used indoors or outdoors, and its beams can be adjusted as needed to meet the needs of different working occasions. Truss is a kind of scaffolding for building structure, which consists of horizontal bars, vertical bars, connectors, casters and other components. The main function of truss is to provide support and safety protection for workers in construction operations inside and outside buildings, and it can also be used to transport and store building materials. The beam structure is relatively simple, and it can be assembled and disassembled as required, which is convenient for transportation and storage. Therefore, there are great differences between portal frame and beam frame in structure and use. The former is mainly used for hoisting, while the latter is mainly used for building construction and construction.