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Lauzacco, Italy

Beyer K.,Ecole Polytechnique Federale de Lausanne | Beyer K.,ETH Zurich | Dazio A.,EUCENTRE | Dazio A.,ETH Zurich
Earthquake Spectra | Year: 2012

In modern unreinforced masonry (URM) walls, the vertical piers are connected at the story levels by reinforced concrete (RC) ring beams-also known as bond beams-or RC slabs. Particularly, in the outer walls, the spandrel element also includes a masonry spandrel on top of the RC beam or slab ("composite" spandrel). Numerical simulations have shown that spandrels significantly influence the global behavior of the URM building when subjected to seismic loading. Despite their importance, experimental data on the cyclic behavior of composite spandrels were lacking. This paper presents the results of an experimental campaign on five composite spandrels. Each test unit consisted of an RC beam, a masonry spandrel and the adjacent masonry piers required for applying realistic boundary conditions to the spandrel. The investigated parameters included the type of loading, the brick type and the reinforcement content of the RC beam. © 2012, Earthquake Engineering Research Institute. Source

Beyer K.,Ecole Polytechnique Federale de Lausanne | Beyer K.,ETH Zurich | Dazio A.,EUCENTRE | Dazio A.,ETH Zurich
Earthquake Spectra | Year: 2012

This paper presents the results of an experimental campaign on masonry spandrels. Within this campaign, four masonry spandrels were subjected to quasi-static cyclic loading. Two different spandrel configurations were tested. The first configuration comprised a masonry spandrel with a timber lintel, and the second configuration, a masonry spandrel on a shallow masonry arch. For each configuration, two specimens were tested. The first was tested with a constant axial load in the spandrel, while for the second specimen, the axial load in the spandrel depended on the axial elongation of the spandrel. This paper summarizes the properties of the four test units, the test setup, and the most important results from the experiments, documenting the failure mechanisms that developed and the force-deformation hysteresis of the spandrel elements. The paper also presents a mechanical model for estimating the peak strength of masonry spandrels. © 2012, Earthquake Engineering Research Institute. Source

Pessina V.,Italian National Institute of Geophysics and Volcanology | Fiorini E.,EUCENTRE
Soil Dynamics and Earthquake Engineering | Year: 2014

Morphometric analyses of high resolution digital elevation models (DEM), with the support of Geographic Information Systems (GIS), have been implemented to provide a practical tool for the identification on a large scale of sites where, according to the EC8 prescriptions, a topography amplification is expected. An ad hoc procedure for the hilltop ridge detection was implemented to be used in the morphological characterization, together with the standard GIS sequence of steps. The proposed method allowed the fast classification of more than 800 seismic recording stations located on the Alps and the Apennine, according to the indications of the current European norm and the Italian seismic code. The aim is to improve the characterization of the stations of seismic archives, in the view of a potential cross-checking of observed amplification with the attributed site class category. © 2014 Elsevier Ltd. Source

Silva V.,University of Aveiro | Crowley H.,EUCENTRE | Varum H.,University of Aveiro | Pinho R.,University of Pavia | Sousa R.,ROSE Programme
Earthquake Engineering and Structural Dynamics | Year: 2014

The recognition of fragility and vulnerability functions as a fundamental tool in seismic risk assessment has led to the development of more and more complex and elaborate procedures for their computation. Although these functions have been traditionally produced using observed damage and loss data, more recent studies propose the employment of analytical methodologies as a way to overcome the frequent lack of post-earthquake data. The variation of the structural modelling approach on the estimation of building capacity has been the target of many studies in the past; however, its influence on the resulting vulnerability model for classes of buildings, the impact in loss estimations or propagation of the uncertainty to the seismic risk calculations has so far been the object of limited scrutiny. In this paper, an extensive study of static and dynamic procedures for estimating the nonlinear response of buildings has been carried out to evaluate the impact of the chosen methodology on the resulting capacity, fragility, vulnerability and risk outputs. Moreover, the computational effort and numerical stability provided by each approach have been evaluated and conclusions drawn regarding the optimal balance between accuracy and complexity. © 2013 John Wiley & Sons, Ltd. Source

Silva V.,University of Aveiro | Crowley H.,EUCENTRE | Pinho R.,University of Pavia | Varum H.,University of Aveiro
Engineering Structures | Year: 2013

This paper presents a new procedure to derive fragility functions for populations of buildings that relies on the displacement-based earthquake loss assessment (DBELA) methodology. The recent developments in this methodology are also presented herein, such as the development of new formulae for the calculation of the yield period or the consideration of infilled frame structures. In the fragility method proposed herein, thousands of synthetic buildings have been produced considering probabilistic distributions describing the variability in their geometrical and material properties. Then, their nonlinear capacity has been estimated using the DBELA method and their performance against a large set of ground motion records has been calculated. Global limit states are used to estimate the distribution of buildings in each damage state for different levels of ground motion, and a regression algorithm is applied to derive fragility functions for each limit state. The proposed methodology is demonstrated for the case of ductile and non-ductile Turkish reinforced concrete buildings with and without masonry infill walls, and compared with results obtained using nonlinear dynamic procedures and with the results from previous studies. © 2013 Elsevier Ltd. Source

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