Concentrated plasticity modelling of RC frames in time-history analyses

Bruschi, Eleonora; Calvi, Paolo M.; Quaglini, Virginio

doi:10.1016/j.engstruct.2021.112716

Cited by 26 publications

(13 citation statements)

References 44 publications

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“…The case study structures are modelled as 3D buildings in the OpenSees software program version 3.6.0 [47,48], adopting the modelling procedure presented in [49] and validated in [1,5,6,41,43]. Beams and columns are implemented through the forceBeamColumn element object [50], assigning a non-linear behavior to the external sections and a linear elastic behavior to the internal section of the element, as shown in Figure 9.…”

Section: Opensees Numerical Modelmentioning

confidence: 99%

Assessment of Non-Linear Analyses of RC Buildings Retrofitted with Hysteretic Dampers According to the Italian Building Code

Bruschi,

Quaglini

2024

Applied Sciences

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While the use of steel hysteretic dampers has spread in the last decade for both new and retrofitted constructions, the Italian Building Code (IBC), as well as the Eurocode 8, does not provide specific recommendations for the design and verification of structures equipped with this technology. Due to their strong non-linear behavior, the effectiveness of the design with these systems must be verified through non-linear analyses. Non-Linear Time-History analyses (NLTHAs) are the most reliable method, but they are computationally expensive. The aim of the study is to investigate the reliability of non-linear static procedures, allowed by the IBC as an alternative to NLTHAs, for the analysis of buildings equipped with hysteretic devices provided with high damping capability. A parametric study is conducted on two reinforced concrete residential buildings, typical of the Italian residential heritage, retrofitted with hysteretic braces characterized by different stiffness and ductility values. The retrofit design is verified using non-linear analyses, both static and dynamic, considering either natural or artificial accelerograms, as the IBC deems them as equivalent. Within this work, reference is made only to the IBC; however, given the significant similarity between the IBC and the European code, the outcomes are expected to have a broader impact and to be not limited to the Italian context. Therefore, although this work is a preliminary study, it is believed to offer some initial insights on the topic and serve as the foundation for a more in-depth study that could lead to a regulatory revision on the subject.

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Section: Opensees Numerical Modelmentioning

confidence: 99%

Assessment of Non-Linear Analyses of RC Buildings Retrofitted with Hysteretic Dampers According to the Italian Building Code

Bruschi,

Quaglini

2024

Applied Sciences

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“…Dead and live loads, as provided in the relevant references [9,59], were uniformly applied to the beams according to the warping shown in Figures 8 and 10. Following [62,63], the beams and columns were modeled using the forceBeamColumn element object [64], which is composed of two external sub-elements of length L pl corresponding to the end regions where inelastic behavior can be triggered, and an internal sub-element characterized by a linear elastic behavior. A different L pl length was assumed for either case-study structure, namely, Equation (4) for the RC building and Equation (5) for the steel MRF.…”

Section: Modeling Of the Case-study Frames In Openseesmentioning

confidence: 99%

“…Equation ( 4) is equivalent to the provision of the Eurocode 8 [65], where z is the shear span of the structural element, h is the depth of the section, d b is the diameter of the longitudinal rebar, f y is the yield strength of steel, and f c is the compressive strength of concrete. According to the norm [65], Equation ( 4) is valid when a well-detailed confinement model of concrete is assumed [62]. For this reason, for the concrete model, the uniaxial material Concrete04 [55], which is based on the model proposed by Popovics [66], was implemented.…”

Section: Modeling Of the Case-study Frames In Openseesmentioning

confidence: 99%

Experimental Characterization, Modeling, and Numerical Evaluation of a Novel Friction Damper for the Seismic Upgrade of Existing Buildings

et al. 2023

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The paper presents the experimental characterization, the formulation of a numerical model, and the evaluation, by means of non-linear analyses, of a new friction damper conceived for the seismic upgrade of existing building frames. The damper dissipates seismic energy through the friction force triggered between a steel shaft and a lead core prestressed within a rigid steel chamber. The friction force is adjusted by controlling the prestress of the core, allowing the achievement of high forces with small dimensions, and reducing the architectural invasiveness of the device. The damper has no mechanical parts subjected to cyclic strain above their yield limit, thereby avoiding any risk of low-cycle fatigue. The constitutive behavior of the damper was assessed experimentally, demonstrating a rectangular hysteresis loop with an equivalent damping ratio of more than 55%, a stable behavior over repeated cycles, and a low dependency of the axial force on the rate of displacement. A numerical model of the damper was formulated in the OpenSees software by means of a rheological model comprising an in-parallel system of a non-linear spring element and a Maxwell element, and the model was calibrated on the experimental data. To assess the viability of the damper for the seismic rehabilitation of buildings, a numerical investigation was conducted by performing non-linear dynamic analyses on two case-study structures. The results highlight the benefits of the PS-LED in dissipating the largest part of seismic energy, limiting the lateral deformation of the frames, and controlling the increase in structural accelerations and internal forces at the same time.

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“…From the several existing methods to simulate cyclic response on reinforced concrete buildings through a non-linear analysis, there are two main categories to represent the non-linear material response on a Finite Element simulation: distributed plasticity, which can be represented by fiber models, and concentrated (or lumped) plasticity models [13]. Fiber models can capture cracking behavior and the spread of plasticity throughout the element, and discretize the element crosssection, considering confined and unconfined concrete and different configurations for longitudinal reinforcement steel.…”

Section: Introductionmentioning

confidence: 99%

Seismic fragility assessment of a RC frame considering concentrated and distributed plasticity modelling

Rodrigues

Cavalcante

Pereira

et al. 2024

Rev. IBRACON Estrut. Mater.

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Researchers must decide on how they will model the non-linear material response in a Finite Element simulation to assess seismic vulnerability. This paper aims at giving an insight into these modelling decisions by comparing Fiber and Lumped Plasticity Finite Element Models in static and dynamic non-linear analysis in a RC frame. The methodology is based on the performance-based earthquake engineering to determine the expected damage on structures. The results indicate that both models are in good agreement with the static analysis, and when considering Extensive and Complete Damage Limit States on the dynamic analysis. The choice between them depends on the main goals of the research and resources available, since they have a significant difference in processing time.

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Concentrated plasticity modelling of RC frames in time-history analyses

Cited by 26 publications

References 44 publications

Assessment of Non-Linear Analyses of RC Buildings Retrofitted with Hysteretic Dampers According to the Italian Building Code

Assessment of Non-Linear Analyses of RC Buildings Retrofitted with Hysteretic Dampers According to the Italian Building Code

Experimental Characterization, Modeling, and Numerical Evaluation of a Novel Friction Damper for the Seismic Upgrade of Existing Buildings

Seismic fragility assessment of a RC frame considering concentrated and distributed plasticity modelling

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