A relatively large database of masonry specimens tested in laboratories across Europe was established and used for the estimation of fragility functions for unreinforced masonry walls built from hollow clay units, which are the most common type of masonry units for the construction of new buildings in Europe. The proposed fragility functions can be used to predict minor, moderate, and near collapse damage states for structural walls with expected predominantly shear or flexural behaviour. The results indicate that in addition to failure mode, the h/l ratio, the normalized compressive load, and the boundary conditions have a significant impact on fragility functions. However, due to small sample size, it was not possible to explicitly incorporate their effect in fragility functions. It is shown that the near collapse damage state of the investigated type of masonry wall is most likely attained at drifts of 0.4% or 0.7%, respectively, in the case of shear or flexural behaviour. Useful additional information is provided by the total dispersions of the structural component drifts corresponding to a designated damage state, these dispersions being large regardless of the damage state. In the case of the near collapse damage state, it was estimated that they amounted to 0.57 and 0.47, respectively, depending upon whether the structural components behaved in a predominantly shear or a predominantly flexural manner. It is also shown how the proposed fragility functions can be used to predict the probability of occurrence of a certain damage state, which can be used for loss estimation of masonry buildings.
COBISS.SI-ID: 8260449
In the presented practice-oriented probabilistic approach for the estimation of the failure probability of building structures, called Pushover-based Risk Assessment (PRA) method, the SAC-FEMA method, developed by Cornell and coauthors, is combined with the pushover-based N2 method. The annual probability of “failure” (i.e. the probability of exceeding the near collapse limit state) of a structure can be estimated by an explicit formula, provided that the basic data on seismic hazard and default values for the dispersion of the capacity at “failure” are available. The median capacity of the structure at the near collapse limit state (performance level) is determined by the N2 method. In the paper, the PRA method is summarized. Its application is demonstrated by a test example of a reinforced concrete frame.
COBISS.SI-ID: 8287841
In this paper the procedure for the determination of target displacement and limit-state spectral acceleration by using non-linear response-history analysis of an equivalent single degree of freedom model is presented. The procedure is foreseen in normative Annex E of the draft of new version of the Eurocode 8 standard and is an upgrade of the method for target displacement estimation in Annex B of the current Eurocode 8 standard. The use of the procedure is demonstrated by means of examples of reinforced concrete frame buildings. The proposed procedure improves the determination of the limit-state spectral acceleration, which represents a basis for the estimation of probability of exceedance of the limit states and expected economic loss.
COBISS.SI-ID: 8273249