Seismic behavior of damaged buildings may be expressed as a function of their REsidual Capacity (RECag), that is a measure of seismic capacity ???reduced??? due to damage and represented in terms of peak ground acceleration ag. RECag may be estimated through pushover analyses. In fact, adopting a lumped plasticity model, the plastic hinges may be suitably modified to account for the damage level of the single elements [1]; as shown in [2] nonlinear static analyses of the modified damaged models yield pushover curves that, depending on the number of elements involved in the damaged mechanism and on their damage level, may differ significantly with respect to original ones. The applicability of Pushover Analyses (PA) has been demonstrated for regular structures [3, 4], with their significance being generally supported by the comparison of the results obtained by these ???simplified??? analyses with Nonlinear dynamic Time-History (NTH) analyses. However, the usability of pushover analysis for the assessment of the behavior of damaged buildings has not been verified yet, and the study presented in this paper aims at contributing in the evaluation of this issue. The results of PA are confronted with those of NTH for Multi Degree Of Freedom (MDOF) systems representative of existing R.C. building typologies in the Mediterranean regions. In particular, the response (and damage) of each one of the original ???intact??? MDOF systems for earthquakes of increasing intensity is studied with either the PA and NTH. Next, applying the methodology described in [2], damage dependent behavior is estimated for varying levels of initial seismic (damaging) intensity. The maximum inter-storey drift and shape along the height, as well as the ???modified??? RECag are compared to the ones that could be obtained with NTH by subsequent application of suitably scaled pairs of accelerograms. The results of this study suggest that degree of approximation that is obtained by PA applied to damaged structures with respect to NTH does not vary with respect to the approximation of standard PA compared to NTH.
Seismic behavior of damaged buildings: a comparison of static and dynamic nonlinear approach / Polese, Maria; GAETANI d'ARAGONA, Marco; Prota, Andrea; Manfredi, Gaetano. - (2013), pp. 608-625. (Intervento presentato al convegno 4th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering tenutosi a Kos Island (Greece) nel 12-14 June 2013).
Seismic behavior of damaged buildings: a comparison of static and dynamic nonlinear approach
POLESE, MARIA;GAETANI d'ARAGONA, MARCO;PROTA, ANDREA;MANFREDI, GAETANO
2013
Abstract
Seismic behavior of damaged buildings may be expressed as a function of their REsidual Capacity (RECag), that is a measure of seismic capacity ???reduced??? due to damage and represented in terms of peak ground acceleration ag. RECag may be estimated through pushover analyses. In fact, adopting a lumped plasticity model, the plastic hinges may be suitably modified to account for the damage level of the single elements [1]; as shown in [2] nonlinear static analyses of the modified damaged models yield pushover curves that, depending on the number of elements involved in the damaged mechanism and on their damage level, may differ significantly with respect to original ones. The applicability of Pushover Analyses (PA) has been demonstrated for regular structures [3, 4], with their significance being generally supported by the comparison of the results obtained by these ???simplified??? analyses with Nonlinear dynamic Time-History (NTH) analyses. However, the usability of pushover analysis for the assessment of the behavior of damaged buildings has not been verified yet, and the study presented in this paper aims at contributing in the evaluation of this issue. The results of PA are confronted with those of NTH for Multi Degree Of Freedom (MDOF) systems representative of existing R.C. building typologies in the Mediterranean regions. In particular, the response (and damage) of each one of the original ???intact??? MDOF systems for earthquakes of increasing intensity is studied with either the PA and NTH. Next, applying the methodology described in [2], damage dependent behavior is estimated for varying levels of initial seismic (damaging) intensity. The maximum inter-storey drift and shape along the height, as well as the ???modified??? RECag are compared to the ones that could be obtained with NTH by subsequent application of suitably scaled pairs of accelerograms. The results of this study suggest that degree of approximation that is obtained by PA applied to damaged structures with respect to NTH does not vary with respect to the approximation of standard PA compared to NTH.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
