Browsing by Author "Bento, Rita"
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- Calibration of model parameters for the cyclic response of end-plate beam-to-column steel-concrete composite jointsPublication . Nogueiro, Pedro; Silva, Luís Simões; Bento, Rita; Simões, RuiComposite joints, considering the composite action of steel and concrete, exhibit, in general, high strength and high ductility. As a consequence, the use of this type of joint has been increasing in many countries, especially in those that are located in earthquake-prone regions. In this paper, a hysteretic model with pinching is presented that is able to reproduce the cyclic response of steel and composite joints. Secondly, the computer implementation and adaptation of the model in a spring element within the computer code Seismosoft is described. The model is subsequently calibrated using a series of experimental test results for composite joints subjected to cyclic loading. Finally, typical parameters for the various joint configurations are proposed.
- Comportamento sísmico de ligações metálicas: influência na resposta dinâmica de estruturas metálicasPublication . Nogueiro, Pedro; Silva, Luís Simões; Bento, RitaTem-se verificado nas últimas décadas a ocorrência de grande actividade sísmica em diversas zonas do globo, causando inúmeros danos, quer materiais quer humanos. A competitividade da construção metálica e mista, nomeadamente nestas zonas, requer a apresentação e o estudo de soluções que demonstrem claramente o bom desempenho estrutural. Sabendo-se a importância das ligações no comportamento das estruturas metálicas e mistas, avalia-se a resposta sísmica de três estruturas metálicas, duas planas e uma tridimensional, a partir de análises não lineares. As estruturas estudadas consistem num primeiro pórtico bidimensional, mais baixo (2x5), um pórtico bidimensional, mais alto (2x5), e por fim um pórtico tridimensional (4x5x8), considerando sempre o comportamento histerético das ligações. Para dimensionar e avaliar o desempenho sísmico deste tipo de estruturas recorreu-se a dois procedimentos diferentes: análise estática não linear e análise dinâmica não linear. Os resultados obtidos por ambas as análises foram comparados, quer em termos de deslocamentos horizontais, quer em termos de deformações nas ligações.
- Evaluation of the ductility demand in partial strength steel structures in seismic areas using non-linear static analysisPublication . Nogueiro, Pedro; Bento, Rita; Silva, Luís SimõesThe performance of a structural system can be evaluated resorting to non-linear static analysis, also commonly referred to as Pushover Analysis, because of the nature of application of lateral loads while defining the capacity of the structure. This analysis involves the estimation of the structural strength and deformation demands and the comparison with the available capacities at desired performance levels. This paper aims at evaluating the seismic response of three steel structures using non-linear static analyses, based on the N2 method, adopted by Eurocode 8, the European seismic code. The results are compared with the ones evaluated by means of non-linear dynamic analyses. As a conclusion it can be ascertained that the non-linear static procedures are an alternative tool in seismic assessment and design, over just a force-based design. For structures that vibrate mainly in the fundamental mode, the pushover analysis applied in this work will provide good estimates of global, as well as local inelastic deformation demands.
- Experimental behaviour of standardised European end plate beam-to-column stel joints under arbitrary cyclic loadingPublication . Nogueiro, Pedro; Silva, Luís Simões; Bento, Rita; Simões, RuiThis work presents the results of the study of the six experimental tests of standardised end-plate beam-to-column steel joints under arbitrary cyclic loading. The experimental programme is divided into two groups, varying the column section size. Each group has the first monotonic test and two more cyclic tests with arbitrary loading. The results are presented in terms of M-Ø curves, main mechanical joint properties and same relevant illustrations are presented. Finally, some conclusions can be drawn.
- Influence of joint slippage on the seismic response of steel framesPublication . Nogueiro, Pedro; Silva, Luís Simões; Bento, RitaThe present paper presents an evaluation of the influence of joint slippage on the seismic response of steel frames. Using three alternative hysteretic joint models to simulate the connections of a representative low-rise steel frame, and a series of dynamic time-history analyses for a typical seismic record, it is found that slippage affects the response of the structure and should be allowed for in design.
- Numerical implementation and calibration of a hysteretic model with pinching for the cycling response of steel jointsPublication . Nogueiro, Pedro; Silva, Luís Simões; Bento, Rita; Simões, RuiIn this paper, a hysteretic model with pinching is presented that is able to reproduce realistically the cyclic response of generic steel joints. Secondly, the computer implementation and adaptation of the model in a spring element within the computer code SeismoStruct is described. The model is subsequently calibrated using a series of experimental test results for steel joints subjected to cyclic loading. Finally, typical parameters for the various joint configurations are proposed.
- Numerical implementation and calibration of a hysteretic model for cyclic response of end-plate beam-to-column steel joints under arbitrary cyclic loadingPublication . Nogueiro, Pedro; Silva, Luís Simões; Bento, RitaThis work presents the implementation and calibration of Modified Richard-Abbott model for cyclic response of four end-plate beam-to-column steel joints under arbitrary cyclic loading. The joints parameters are found and the comparison between the analytical hysteretic results and the experimental hysteretic results is made, as well as the hysteretic energy dissipated evaluated for each cycle and obtained for both type of analyses.
- Numerical implementation and calibration of a hysteretic model with pinching for the cyclic response of steel and composite jointsPublication . Nogueiro, Pedro; Silva, Luís Simões; Bento, Rita; Simões, RuiIn this paper, a hysteretic model with pinching is presented that is able to reproduce the cyclic response of steel and composite joints. Secondly, the computer implementation and adaptation of the model in a spring element within the computer code Seismosoft is described. The model is subsequently calibrated using a series of experimental test results for steel and composite joints subjected to cyclic loading. Finally, typical parameters for the various joint configurations are proposed.
- Residual strength of a steel-concrete composite structure subjected to a design seismic event by firePublication . Nogueiro, Pedro; Santiago, Aldina; Silva, Luís Simões; Bento, Rita; Vila Real, Paulo M.M.This paper presents a numerical investigation of the residual strength of a typical PR momentresistant multi-storey steel framed structure, subjected to a design seismic event followed by fire. In order to allow a calibration with some real results from fire tests on a natural scale, the architectural and structural definitions of the eight-storey steel Cardington building were chosen as the reference case, adapted to deal with basic seismic requirements. The seismic action was simulated with an artificial accelerogram with PGA of 0.6g, chosen to achieve significant energy dissipation in the joints. The adopted fire event is limited to an isolated compartment and it is defined as the natural fire observed during a full-scale fire test carried out at the BRE. Finally, the results are discussed in terms of robustness requirements for extreme events.