The vertical load bearing structure of a building under vertical loads is stable in itself only in some special cases. The lateral stiffness is normally provided by a dedicated structural element or a system of structural elements. Such a structural element or system will be referred to as a bracing element (or bracing core in its most general form) or a bracing system consisting of shear walls and/or cores. Two questions are usually raised regarding the bracing system:
- What is the necessary stiffness of the bracing system to provide the building with adequate stability?