The thrust line is the geometric location of the "thrust centers" where the forces pass through the cutting planes in a given structure. This thrust line is actually a way of explaining the balance of a set of structures in contact subjected to a system of loads. In graphic statics it is used in the voussoirs of the arches "Arch (architecture)").[1]​.

One of the first applications of the thrust line is made in the arch theory based on voussoirs. In this case, the joints between segments, or the factory joints, are taken as cutting planes. The first to show this concept was H. Moseley in 1835.[1]​ He demonstrates that the shape depends on the geometry, the load structure and the structure of the joints. The load line must be contained in the thickness of the arch so that it is stable and does not collapse. On this aspect of the thrust line and the collapse of arches, W. H. Barlow wrote a series of essays on the stability of these structures in 1846. There are methods to determine the maximum thrust line such as the Fuller method.[2]​.