Deterioration Modeling of Steel Components in Support of Collapse Prediction of Steel Moment Frames under Earthquake Loading

Abstract

Reliable collapse assessment of structural systems under earthquake loading requires analytical models that are able to capture component deterioration in strength and stiffness. For calibration and validation of these models a large set of experimental data is needed. This paper discusses the development of a database on experimental data of steel components and the use of this database for quantification of important parameters that affect the cyclic moment-rotation relationship at plastic hinge regions in beams. Based on information deduced from the steel component database, empirical relationships for modeling of pre-capping plastic rotation, post-capping rotation and cyclic deterioration for beams with reduced beam section (RBS) and beams other than RBS are proposed. Quantitative information is also provided for modeling of the effective yield strength, post-yield strength ratio, residual strength, and ductile tearing of steel components subjected to cyclic loading.

Collapse Risk Evaluation of Self-Centering Steel MRFS With Viscous Dampers in Near-Fault Regions

“…T from the OpenSees [35] models is 0.94 s for CP3D and HP20D SC-MRFs and 1.18 s for CP3D and HP20D MRFs.…”

“…Beam local buckling is expected after the end of the reinforcing plates, and so, the unreinforced lengths of the beams are modeled as elastic elements with zero length nonlinear fiber hinges at their ends that exhibit strength and stiffness deterioration [35]. The fiber hinge sections are composed of the Bilin material [33] that simulates the modified Ibarra-Krawinkler [35] deterioration model.…”

“…The fiber hinge sections are composed of the Bilin material [33] that simulates the modified Ibarra-Krawinkler [35] deterioration model. The hinges are calibrated individually in order to exhibit the same behavior as the multi-linear deteriorating concentrated hysteresis model [36].…”

“…The connections of the conventional MRFs are assumed to be rigid and have full strength, while beams are modeled as elastic elements with zero length rotational springs at their ends that exhibit strength and stiffness deterioration [35]. Columns and panel zones are modeled as described above for the SC-MRFs.…”

Simplified Seismic Collapse Assessment of Generic Frame Structures Subjected to Pdelta and Material Deterioration

“…To all springs of a frame the same deterioration parameters Λ K and Λ S are assigned. Lignos, Krawinkler [19,18] compiled a database of experimental cyclic studies on steel components, which allowed to identify the significant parameters affecting the cyclic moment-rotation relationship at plastic hinge regions in beams. Based on this study, in the present publication three different levels of deterioration, representing slow, medium, and rapid deterioration, have been defined.…”