The Effect of Shear-flexure Interaction in Infilled Walls for Study of Building Pounding: Analytical Comparison and Parametric Sensitivity

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Cyclic response of a reinforced concrete frame: comparison of experimental results with different hysteretic models

Publication . Folhento, Pedro Leonel Pamplona; Braz-César, Manuel; Barros, Rui

An accurate hysteresis model is fundamental to well capture the non-linearity phenomena occurring in structural and non-structural elements in building structures, that are usually made of reinforced concrete or steel materials. In this sense, this paper aims to numerically estimate through simplified non-linear analyses, the cyclic response of a reinforced concrete frame using different hysteretic models present in the literature. A commercial Finite Element Method package is used to carry out most of the simulations using polygonal hysteretic models and a fiber model, and additionally, a MATLAB script is developed to use a smooth hysteresis model. The experimental data is based on the experiments carried out in the Laboratório Nacional de Engenharia Civil, Portugal. The numerical outcomes are further compared with the experimental result to evaluate the accuracy of the simplified analysis based on the lumped plasticity or plastic hinge method for the reinforced concrete bare frame. Results show that the tetralinear Takeda’s model fits closely the experimental hysteresis loops. The fiber model can well capture the hysteresis behavior, though it requires knowledge and expertise on parameter calibration. Sivaselvan and Reinhorn’s smooth hysteresis model was able to satisfactorily reproduce the actual non-linear cyclic behavior of the RC frame structure in a global way.

2021Journal article

Open access

Parametric study on a Bouc-Wen model with degradation features for the study of cyclic behavior of a reinforced concrete frame

Publication . Folhento, Pedro Leonel Pamplona; Barros, Rui; Braz-César, Manuel

Non-linear behavior in building frame structures is inevitable and expected in moderate to severe seismic events. This behavior tends to be concentrated at the ends of beams and columns of moment-resisting frames. These critical regions, where plastic hinges form, are important for the global stability of the structural system. Depending on the available ductility, these mechanisms are responsible for the permanent deformations that the structure undergoes, leaving the remaining parts of the structural elements in the elastic regime, and hence in the safe zone. The importance of these mechanisms led to the search for an adequate model capable of well-capturing the non-linearity phenomena involved. The development of versatile hysteresis models with degradation features has been the aim of different studies. Hence, this paper presents a parametric study based on a smooth hysteresis model, a further modification to the well-known Bouc-Wen model, developed by Sivaselvan and Reinhorn, with a physical interpretation appropriate to the study of the non-linear behavior of civil engineering structures, particularly, building structures. Furthermore, an optimization procedure is implemented to calibrate the mentioned model’s parameters, attempting to replicate the actual cyclic response of a reinforced concrete frame structure. The effect of each parameter in the hysteresis response will help on the understanding and on the possibilities of this kind of model in simulating different types of structural systems or different materials.

2021Journal article

Open access

Effect of earthquake-induced structural pounding on the floor accelerations and floor response spectra of adjacent building structures

Publication . Folhento, Pedro; Barros, Rui; Braz-César, M.T.

The influence of earthquake-induced structural pounding among buildings is paramount in the seismic analysis and design of structures. The recognition of such a phenomenon has been growing in the last decades. The search for ways to understand and mitigate the consequences of these structural collisions in building structures is the primary goal of the investigation of earthquake-induced building pounding. This phenomenon is known for increasing the floor accelerations, mainly where pounding occurs, implying significant local damage. These collisions cause short-duration acceleration pulses that may compromise the building structure and the non-structural elements within the building’s stories. Non-structural elements supported by the structure’s floors under earthquake-induced pounding instances may present a risk to human lives and/or human activity. Hence, the influence of earthquake-induced pounding in the floor response spectra of two adjacent reinforced concrete structures with inelastic behavior is assessed by varying the number of stories and their separation distance. Pounding greatly influenced the floor acceleration spectra, increasing the spread of accelerations over a broader period range, particularly exciting low to moderate periods of vibration.

2024Journal article

Open access