Energy-based damage model for MDOF steel structures

Several damage indexes have been developed with the aim of estimating the consequences, in terms of structural damage and deterioration, of severe plastic cycling. Several studies have been devoted to calibrate damage indexes for steel and reinforced concrete members. Currently, there is a challenge to study and calibrate the use of such indexes for the practical structural evaluation of complex structures. This paper introduces an energy-based damage model for Multi-Degree-Of-Freedom (MDOF) steel structures that accounts explicitly for the effects of cumulative plastic deformation demands. The model has been developed from the results obtained in experimental tests of steel members, and from analytical studies regarding the distribution of plastic demands on several steel frames designed according to the Mexico City Building Code. Finally, a simplified approach for evaluating structural damage on MDOF steel frames through equivalent single-degree-of-freedom systems that explicitly consider cumulative damage is discussed.