ABSTRACT
The objective of current seismic design practice for structures is related to providing life safety during severe ground motion primarily, providing safety and functionality of contents secondly and only in the end provide structure survivability. These priorities are often changed, depending on the functional design objectives, investments, maintenance costs and repair capabilities. In the structural design some degrees of damage are allowed to occur depending on the seismic risks and the expected earthquake magnitudes. However, the life safety of inhabitants, the integrity and functionality of buildings’ contents are dependent on the performance and the survivability of entire structural system. Therefore the degree of acceptable damage in the structural systems and its control during and after a seismic event are of foremost importance. The current paper summarizes the state of knowledge related to the definitions of damage states and quantifiable damage indicators, useful for characterizations of degrees of damage of structural members. Links between damage states and damage indices are established and used to develop suitable strength reduction factors which target the control of degrees of damage. Although the state-of-the-art in qualification of degrees of seismic damage is in its beginning stages, the principles developed herein to determine design procedures to control this damage may be valid for future developments.
