Seismic risk assessment of the selected structural systems with consideration of uncertainties

摘要

A simplified method for the probabilistic seismic performance assessment of buildings withudconsideration of the effects of physical and modelling uncertainties, taking into account the ageingudprocesses of structural materials, was developed. The proposed method utilizes a general analyticaludmethod for estimating the seismic risk, whereas the seismic response parameters are determined byudusing the N2 method, which is applied to the stochastic structural model. This method was used toudstudy the effects of uncertainties on the seismic performance of reinforced concrete (RC) frames andudframes with infills. The first part of the results relates to the sensitivity of the seismic responseudparameters. The results show that the seismic response of RC frames is most sensitive to theuduncertainty associated with the model of the rotation capacities of the plastic hinges in the columnsudand beams, whereas in the case of the infilled frames, the mechanical characteristics of the infills areudthe parameters which have the greatest impact on the seismic response of such buildings. The secondudpart of the results refers to the study of the effects of physical and modelling uncertainties on theudseismic response parameters, as applied to three RC frames. The results of the study show that theseuduncertainties affect not only the dispersion, but also the median estimates of the response parameters.udIn almost all cases their influence contributed to a considerable reduction of the median displacementudand the acceleration capacity if the latter are compared to those determined by conventionaluddeterministic analysis. Additional uncertainty arises due to the effects of corrosion. In the case of theudselected RC frame, where corrosion has been modelled with simplified models, it has been shown thatudsuch corrosion can lead to the shear failure of the exposed columns, which may considerably increaseudthe seismic risk. A particular source of uncertainty is represented by simplified nonlinear models. Byudusing the proposed iterative pushover-based procedure it has been shown that the seismic risk may beudsignificantly underestimated if possible shear failures of the columns and the contribution of theudmasonry infill to the shear forces in the columns are not properly simulated in a nonlinear analysis.