Falsework consists of temporary structures used in construction to support spanning or arched structures in order to hold the component in place until its construction is sufficiently advanced to support itself. This usage is specifically called centering. Falsework also includes temporary support structures for formwork used to mould concrete to form a desired shape,scaffolding to give workers access to the structure being constructed and shoring which is temporary structural reinforcement used during repairs.
When a rectangular panel is subject to an eccentric load or a lateral load, it tends to deform into a parallelogram with one diagonal shortening and the other elongating. Theoretically, it is sufficient to brace along one of the diagonals (the one in tension). If one diagonal is only allowed to brace inside the rectangular panel, it should be not braced in the diagonal in compression because under severe lateral loading the diagonal may buckle leading to failure of structure.
However, in actual situation lateral loads may come from both sides of the panel and hence it should be braced in both diagonals.
