Buckling-Restrained Braces are a special type of brace that yields inelastically, both in tension and compression. This is achieved by encasing a steel "yielding" core inside a restraining steel member filled with a solid material (such as mortar-filled hollow tube). A small gap between the yielding core and the restraining material prevents the core from buckling when in compression. The result is a member whose ductility, strength and stiffness is relatively similar whether under compression or tension loading.