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A new set of partial safety factors is proposed for the seismic safety assessment of existing reinforced concrete buildings. These safety factors are derived using a framework that focuses on the determination of the uncertainty in the limit state capacities. Existing seismic safety assessment standards, such as EN1998-3 or ASCE 41-17, follow a component-based approach that consider limit-state acceptance criteria based on capacity-related parameters to verify the safety of ductile and brittle failure modes. Despite their similar limit-state philosophy, these standards consider different conceptual formats for introducing the effects of uncertainties: the current version of EN1998-3 adopts confidence factors (CF) that factorize the mean values of material strength, while ASCE 41-17 uses a knowledge factor (k) to reduce the capacity of the component. The CF-based approach of EN1998-3 has been seen to lead to unclear levels of safety that may not reflect the impact of all the uncertainties about the different parameters or the sensitivity of different capacity models to these parameters. To address these issues, the proposed framework establishes a set of partial safety factors derived using an approach similar to that of ASCE 41-17, and involves recent capacity models, their uncertainties and a clear uncertainty management strategy. Furthermore, these new partial safety factors can also be seen to be compatible with the safety format proposed by the upcoming second-generation EN1998-3. [ABSTRACT FROM AUTHOR]

The proposed study examines the propagation of uncertainty associated with the angle of seismic incidence of a group of ground motions, as well as to that of the ground motion group size, to the expected seismic loss estimates of reinforced concrete buildings. Six buildings with infilled frame systems are studied, representative of non-seismically designed structures typical of southern European practice. Their monetary losses are computed using a performance-based earthquake engineering framework, which integrates the site-specific seismic hazard, structural response, damage to building components and contents, and the resulting costs (repair, demolition, reconstruction). To estimate monetary losses, an inventory of the structural and non-structural elements is compiled and existing damage and cost data/functions are employed. Seismic loss estimates account for both the probability of collapse and the probability of demolition as a result of excessive residual storey drifts. Multiple stripe analysis is performed for this purpose using numerical models capable of simulating the relevant limit states up to collapse. Results are presented in terms of expected losses conditional on the ground motion intensity and expected annual losses, which are determined by integrating the former with the seismic hazard curve of the site. Results show that the comparative effect of the ground motion group size in the expected annual losses is much more important when compared to that of the angle of seismic incidence, whose influence is shown to be less significant and mostly concentrated on the variability of the results. [ABSTRACT FROM AUTHOR]

As part of the development of a European Seismic Risk Model 2020 (ESRM20), the spatial and temporal evolution of seismic design across Europe has been studied in order to better classify reinforced concrete buildings (which represent more than 30% of the approximately 145 million residential, commercial and industrial buildings in Europe) and map them to vulnerability models based on simulated seismic design. This paper summarises the model that has been developed to assign the years when different seismic design levels (low code, moderate code and high code) were introduced in a number of European countries and the associated lateral forces that were specified spatially within each country for the low and moderate codes for typical reinforced concrete mid-rise buildings. This process has led to an improved understanding of how design regulations evolved across Europe and how this has impacted the vulnerability of the European residential building stock. The model estimates that ~ 60% of the reinforced concrete buildings in Europe have been seismically designed, and of those buildings ~ 60% have been designed to low code, ~ 25% to moderate code and 15% to high code. This seismic design model aims at being a dynamic source of information that will be continuously updated with additional feedback from local experts and datasets. To this end, all of the data has been made openly available as shapefiles on a GitLab repository. [ABSTRACT FROM AUTHOR]

The accurate determination of demand during the seismic analysis of buildings requires that all factors having a significant contribution must be accounted for. The present study examines the effect of the angle of seismic incidence of earthquake ground motions on the inelastic demand of reinforced concrete buildings and defines its significance for different engineering applications, including both deterministic and probabilistic analyses. Three commonly used engineering demand parameters are examined by analysing three statistics obtained from their empirical distributions at several intensity levels. The results show that the influence of the angle of seismic incidence is different for the three statistics, and that this effect depends also on the engineering demand parameter under consideration. Central tendencies of the demand appear to be less affected by the angle of seismic incidence when compared to its variability, thus showing the potentially larger influence of the angle of seismic incidence for probabilistic analyses rather than for standard-based (i.e. deterministic) applications. Finally, recommendations on the minimum number of angles of seismic incidence that should be considered are given as a function of the number of ground motions used in the analysis. [ABSTRACT FROM AUTHOR]

Experimental testing is considered the most realistic approach to obtain a detailed representation of the nonlinear behaviour of masonry-infilled reinforced concrete (RC) structures. Among other applications, these tests can be used to calibrate the properties of numerical models such as simplified macro-models (e.g., strut-type models) representing the masonry infill behaviour. Since the significant cost of experimental tests limits their widespread use, alternative approaches need to be established to obtain adequate data to validate the referred simplified models. The proposed paper introduces a detailed finite element modelling strategy that can be used as an alternative to experimental tests to represent the behaviour of masonry-infilled RC frames under earthquake loading. Several examples of RC infilled frames with different infill configurations and properties subjected to cyclic loading are analysed using the proposed modelling approach. The comparison between numerical and experimental results shows that the numerical models capture the overall nonlinear behaviour of the physical specimens with adequate accuracy, predicting their monotonic stiffness, strength and several failure mechanisms. [ABSTRACT FROM AUTHOR]

New material safety factors (CF mat ) are proposed to characterize material strength in existing buildings. These safety factors are developed in order to be compatible with seismic safety assessment procedures defined by current standards such as Eurocode 8 Part 3. The general theory behind the development of the CF mat safety factors considers the uncertainty associated to the number of surveyed structural elements and the inherent variability of the material strength under analysis. The CF mat safety factors are developed using a finite population approach where the material properties in a building are discretized by considering one value per element. The proposed theory is used to define specific CF mat values and survey plans for the concrete compressive strength and for the reinforcing steel yield strength. [ABSTRACT FROM AUTHOR]