Percorrer por autor "Batalha, Nádia"
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- Assessment of existing rc precast industrial buildings according with eurocode 8 - part 3Publication . Batalha, Nádia; Rodrigues, Hugo; Sousa, Romain; Varum, Humberto; Fernandes, PauloPrecast reinforced concrete (PRC) buildings are common in the Portuguese industrial park, as well as throughout Europe. In past earthquakes, namely in Italy and Turkey, this typology of buildings showed a poor performance, namely at structural level. One of the major concerns at structural level regards the connection between the beams and columns. In recent surveys at the Portuguese industrial buildings, it was observed that the buildings built before 1980 present, most of the times, only friction connections between beam and columns. This type of connection is pointed as one of the weakest structural system in this typology of structures and consequently led to serious local and global damage when subjected to seismic loads. Regarding this issue, it was considered appropriate and necessary the study of existing Portuguese buildings with this type of beam-to-column connection and compare it with the use of mechanical connections (dowels), which is a more common solution in the recent buildings. The seismic behaviour of two PRC buildings built with these two solutions was analysed considering nonlinear static and dynamic analyses addressing both global and local (connections) response parameters. When analysed in view of the seismic regulation for existing buildings (Eurocode 8 –Part 3), the results obtained show that, overall, this typology of buildings present an acceptable structural performance. Nonetheless, unsatisfactory performance was observed at the beam-to-column connection in one of the buildings built without steel dowels. The results presented in this study highlight the need to consider adequate models to simulate these connections in order to accurately represent the seismic behaviour on the structure and identify possible limitations in the use of nonlinear static procedures to assess the seismic performance of this typology of buildings. In general, the buildings in study, located in a region of moderate seismicity, exhibited a satisfactory behaviour. However particular attention should be paid to beam-to-column connections, especially in the case of friction connections. In this regard it is important to accurately represent in the model the mechanisms involved in the connections, particularly in buildings located in moderate to high seismic zones.
- Comportamento Sísmico de um Pavilhão Pré-Fabricado de Betão ArmadoPublication . Batalha, Nádia; Rodrigues, Hugo; Varum, Humberto; A. L. Fernandes, Paulo; Sousa, RomainOs pavilhões pré-fabricados de betão armado são muito comuns no parque industrial em Portugal, tendo mostrado um desempenho por vezes deficiente em sismos recentes tanto ao nível dos elementos estruturais como não-estruturais. Torna-se importante a sua caraterização a fim de conhecer melhor o seu comportamento sísmico. Os pavilhões industriais de um piso, com uma estrutura porticada de vigas e pilares, com ligação encastrada na base e rotulada no topo, sobre a qual vigas de secção variável são posteriormente apoiadas é a solução mais recorrente em Portugal. Nesse sentido, este trabalho aborda o comportamento sísmico de um pórtico de um edifício industrial-tipo existente, com estrutura em betão pré‐fabricado. Essa caracterização é feita através de análises estáticas não lineares (pushover) e análises dinâmicas. Os resultados obtidos são apresentados e discutidos.
- Influence of Beam-to-Column Connections in the Seismic Performance of Precast Concrete Industrial Facilities, Structural Engineering InternationalPublication . Rodrigues, Rodrigo; Vitorino, Hugo; Batalha, Nádia; Sousa, Romain; Fernandes, Paulo; Varum, HumbertoPast 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.
- Numerical simulation of beam-to-column connections in precast reinforced concrete buildings using fibre-based frame modelsPublication . Sousa, Romain; Batalha, Nádia; Rodrigues, HugoRecent earthquakes exposed the poor performance of precast RC structures, imposing damage on both structural and non-structural elements. The concentration of damage at the beam-to-column connections highlights the vulnerability of these systems and the need to understand and improve its seismic performance. The numerical simulation of connection systems in efficient software packages has been addressed in the past by several authors. However, these models fail in describing the different mechanisms independently and, therefore, are difficult to apply to generic connection solutions. Once identified the main lateral load resisting mechanisms involved, a new numerical model is proposed accounting for friction, dowel behaviour and the contribution of the neoprene components. The proposed model was validated against different experimental tests and a parametric study was performed to understand the contribution of the different components, especially in what concerns to the maximum horizontal strength and hysteretic energy dissipation.
- Review of Strategies for Modelling Beam-to-Column Connections in Existing Precast Industrial Rc BuildingsPublication . Sousa, Romain; Batalha, Nádia; Rodrigues, HugoIn recent earthquakes, it has been observed that precast RC structures has shown, in several cases, a poor performance presenting damages on structural and non-structural elements, highlighting the vulnerability of industrial buildings. Beam-to-column connection was pointed as one of the main source of damage. Precast concrete buildings are common in the industrial parks. One-story industrial building constituted by a frame system of beams and columns, with hinged beam-to-column connection are the most common structural configuration. In this way, it is important to characterize this type of buildings to understand its seismic behavior in order to develop new methodologies and solutions for design this type of buildings and improve your performance. The presented work is focused on beam-tocolumn connections that play a determining role on precast structures. The proposed work is the review of the different strategies to model beam-to-column connections in a precast industrial RC building is presented. To perform the analyses, the structural software Opensees was chosen. Nonlinear static analyses were performed. The results are presented and discussed.
- Seismic performance of RC precast industrial buildings—learning with the past earthquakesPublication . Batalha, Nádia; Rodrigues, Hugo; Varum, HumbertoPrecast reinforced concrete (RC) industrial buildings have exposed their vulnerability on recent earthquakes, highlighting structural and non-structural damages most related to deficient transferring of horizontal forces namely in connections between elements. Several studies have been carried out on the evaluation of seismic vulnerability of RC structures, motivated mainly by the need of protecting the existent building stock and human lives. However, the same concern is also relative to the industrial building stock, where precast reinforced concrete building is one of the main structural systems. The collapse of such type of structures can result in important losses of human lives and lead to also large economic impact on society. Severe damages can limit its reparability after earthquake events, which result in its demolition and reconstruction. It was this context of damages that emphasized the need for risk assessment to estimate potential damage for future earthquakes. Thus, the main objective of the present paper is to review and identify the main sources that can increase the vulnerability of this typology of buildings to allow the proper seismic assessment of existing precast industrial buildings and solve the inefficient structural and non-structural problems with innovative techniques for its retrofitting.
- Seismic precast. Seismic performance assessment of existing precast industrial buildingsPublication . Furtado, André; Arêde, António; Rodrigues, Fernanda; Rodrigues, Hugo; Vitorino, Hugo; Varum, Humberto; Ostetto, Liana; Batalha, Nádia; Fernandes, Paulo; Sousa, Romain; Silva, VítorPast seismic events exposed important fragilities in precast reinforced concrete buildings and highlight the need to undertake measures to mitigate future losses.The study presented identify potential structural and nonstructural fragilities of the Portuguese building stock and provide guidance to reduce the associated direct and indirect socio-economic impact