Romain Sousa

The latest earthquakes in Europe exposed some critical problems in the connections of cladding panels in industrial precast reinforced concrete (PRC) structures. These connections did not perform as desired, causing the panels to fall, leading to significant nonstructural damage that resulted in the loss of human life and significant socio-economic impacts due to the interruption of business. Furthermore, in addition to the behavior of the cladding system itself, it is still not clear to what extent it can influence the overall seismic performance of the main structure. Making use of a simplified macroelement, the present study assesses the seismic performance of commonly employed cladding-to-structure connections, as well as the interaction of cladding panels with industrial PRC buildings. The analyses were carried out considering a PRC building representative of a Portuguese industrial park, studied with and without cladding panels. The seismic behavior of the structure was assessed considering both nonlinear static and dynamic procedures.

Past earthquakes have brought attention to the poor performance of precast reinforced concrete structures, especially relating to beam-to-column connections. The evaluation of different methodologies for the analysis of beam-to-column connections in industrial buildings is important. In the present work numerical analyses developed allowed the study of the effect that different story heights and connection properties have on frequencies, drifts, seismic coefficients and connection sliding. The results showed that the friction between concrete elements and the consideration of neoprene have a small impact on the drift demands in the columns and the seismic coefficients of the structures analyzed; on the other hand, the effect of steel dowel on the drift demands and seismic coefficients is significant. The comparison of models with different properties and connections allowed a better understanding of the parameters that affect the seismic behavior of precast reinforced concrete buildings the most and provide indications for building more accurate and efficient numerical models.

The Metropolitan Area of Lisbon (MAL) has the highest population and building density in Portugal, and is exposed to medium to high magnitude earthquakes due to its geographical location. Currently, the MAL housing stock is constituted by approximately 35% of masonry residential buildings with a large variability of materials and construction techniques, as a result of many centuries of history. Most of these buildings were built before the introduction of the first design code for building safety against earthquakes (RSSCS) in 1958 RSCCS. 1958. National standard: Code for building safety against earthquakes (Original title: Regulamento de Segurança das Construções contra os Sismos – RSCCS). [Google Scholar] and therefore were only designed to support gravity loads. Given the presence of these buildings in areas of significant seismicity, a comprehensive research is needed to assess the seismic risk and define mitigation policies for this population of unreinforced masonry buildings. The main purpose of this work is thus to geometrically characterize these typologies, through an exhaustive survey of dozens of masonry buildings collected from original drawings and identify the most important aspects that can influence their seismic behavior. After a compressive historical background, the information collected is statistically analyzed and expressed through probability distributions that can be used for the development of numerical models and derive seismic vulnerability functions, fundamental to conduct seismic risk analyses.

The construction of a vulnerability model requires reliable information on the features of the buildings in the study. The purpose of this work is the characterisation of the precast industrial buildings in Portuguese industrial park, based on the survey of 73 design projects of existing buildings. The collected data are based on a previous study on the features that influence the seismic response of this type of buildings. The parameters collected are associated with the global geometry and specific elements characteristics (e.g., column dimensions, reinforcement ratios, and connections details), to the mechanical properties of the materials and other parameters that can give some important information in the characterisation of the buildings (e.g., construction year and localization). In the end, a comparison with other available databases, namely, from Italy and Turkey, is done in order to conclude about the similarity. This information is important to define representative experimental specimens and numerical simulation to conduce seismic risk analysis.

Distributed plasticity Euler-Bernoulli fiber beams are regularly used by researchers and practitioners to simulate the nonlinear seismic response of reinforced concrete framed structures. This study presents a sensitivity analysis, combining newly proposed and existing goodness-of-fit measures, to identify commonly used engineering modeling options that most critically influence the response accuracy. The dynamic behavior of three distinct structures tested in international blind prediction challenges is considered. Sensitivity parameters include equivalent viscous damping, element formulation, strain penetration effects, and material models. The results are critically discussed in light of theoretical shortcomings of the model assumptions.

SUMMARY: 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. Copyright © 2013 John Wiley & Sons, Ltd.