If there is no supporting structure in the form of a building available, gantry cranes are often used. One of the two legs is a pendulum leg to compensate for expansion due to temperature fluctuations, inaccuracies in the crane rail and deflection of the main girder(s) under load.

Most gantry cranes are installed outdoors. They can be either single-girder or double-girder designs, with or without overhang.