Calibrated analytical element for lateral-strength degradation of reinforced concrete columns

LeBorgne, M. R.; Ghannoum, Wassim M.

doi:10.1016/j.engstruct.2014.09.030

Cited by 45 publications

(21 citation statements)

References 12 publications

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“…This is obvious also in similar existing models that exhibit high variation (e.g. R 2 of 0.6 30 ). As expected, the models for QM specimens have lower variation compared with CS and AS in every case; this is because of in-cycle degradation in these specimens is captured via these models, while the slopes of CS specimens are substantially affected by the displacement pattern used for each test, leading to potentially lower or higher cyclic strength degradation, thus producing extra uncertainty.…”

Section: Descending Branchsupporting

confidence: 70%

“…Although a mechanics-based approach would in principle be preferable to obtain such parameters, it is currently not feasible considering the inherent uncertainty of the post-peak cyclic shear response, with a considerable effect of deformation history and experimental setup that usually cannot be accounted for, as well as the randomness of the succession of degradation phenomena taking place at a lower level. This fact is corroborated by the high variability in the results of similar models for the post-peak response of shear-deficient R/C elements 30 and the considerable variability produced (of the order of 30%-50%) even for pre-peak parameters of R/C elements, even when calibrating against very extensive databases. 31 Additionally, it is also corroborated by the adoption of empirical models even for the pre-peak response of existing structures in Eurocode EN1998-3 31,32 and, lastly, by the fact that even when trying to develop a mechanics-based model, shear deformations might need to be accounted for through an empirical correction factor.…”

Section: Calibration Of Hysteretic Shear Model Parameters In the Crmentioning

confidence: 69%

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Modelling of R/C members accounting for shear failure localisation: Hysteretic shear model

Zimos

Mergos

Kappos

2018

Earthq Engng Struct Dyn

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Summary Reinforced concrete (R/C) frame buildings designed according to older seismic codes represent a large part of the existing building stock worldwide. Their structural elements are often vulnerable to shear or flexure‐shear failure, which can eventually lead to loss of axial load resistance of vertical elements and initiate vertical progressive collapse of a building. In this study, a hysteretic model capturing the local shear response of shear‐deficient R/C elements is described in detail, with emphasis on post‐peak behaviour; it differs from existing models in that it considers the localisation of shear strains after the onset of shear failure in a critical length defined by the diagonal failure planes. Additionally, an effort is made to improve the state of the art in post‐peak shear response modelling, by compiling the largest database of experimental results for shear and flexure‐shear critical R/C columns cycled well beyond the onset of shear failure and/or up to the onset of axial failure, and developing empirical relationships for the key parameters defining the local backbone post‐peak shear response of such elements. The implementation of the derived local hysteretic shear model in a computationally efficient beam‐column finite element model with distributed shear flexibility, which accounts for all deformation types, will be presented in a companion paper.

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Section: Descending Branchsupporting

confidence: 70%

Section: Calibration Of Hysteretic Shear Model Parameters In the Crmentioning

confidence: 69%

Modelling of R/C members accounting for shear failure localisation: Hysteretic shear model

Zimos

Mergos

Kappos

2018

Earthq Engng Struct Dyn

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“…Moreover, the shear strength is typically considered zero at the onset of axial failure -although this is not always the case, as will be shown later on, resulting in higher potential deviations. Another model [5] explicitly accounts for the post-peak descending branch, but is not calibrated against experimental results at all, thus being less accurate, as shown through the model verification against experimentally obtained results and noted by the authors; those that consider it directly and are indeed calibrated, are either associated with substantial scatter [6] or they neglect the effect of some critical parameters, such as transverse reinforcement [7]; furthermore, the datasets on which their empirical models were based are quite limited ( [6], [7]), largely due to the scarcity of experimental tests of specimens up to the onset of axial failure until recently. Most of these constitutive models are based on interstorey drift ratio (e.g.…”

Section: Critical Review Of Existing Modelsmentioning

confidence: 97%

“…This model yields an R 2 of 0.82, which is considered quite high, taking into account the high uncertainty inherent in post-peak phenomena (for instance, the effect of experimental set-up and the randomness of the succession of degrading phenomena taking place at a lower level) as well as comparing it with existing models (e.g. R 2 of 0.6 in [6]). The mean experimental-to-predicted value is 1.00 and the median 0.87 ( Figure 9).…”

Section: Descending Branchmentioning

confidence: 99%

“…[3], [4], [7]), although it has been pointed out that a localised drift ratio (at the shear-damaged region) might be more appropriate, since deformations tend to concentrate at that region after shear failure [8]. Another shortcoming of some models is the consideration of a horizontal residual strength branch without solid experimental basis [6], [9], [10].…”

Section: Critical Review Of Existing Modelsmentioning

confidence: 99%

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Shear Hysteresis Model for Reinforced Concrete Elements Including the Post-Peak Range

Zimos¹,

Mergos²,

Kappos³

2015

Proceedings of the 5th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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Reinforced concrete (R/C) buildings designed according to older seismic codes represent a large part of the total building stock; hence, it is important to accurately and efficiently assess their response to actions induced by natural hazards, such as earthquake. Substandard R/C structural elements are prone to shear failure subsequent, or even prior, to yielding of their longitudinal reinforcement. This can potentially lead to loss of axial load bearing capacity of vertical elements and initiate progressive collapse of the building. So far, there have been efforts to model the full-range behaviour of such elements following a macro-modelling approach, usually based on quite a limited amount of experimental results, especially with respect to the post-peak part of their response, and adopting assumptions that are not entirely appropriate.

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Evaluation of seismic performance of as‐built and retrofitted reinforced concrete frame structures with LAP splice deficiencies

Opabola

Elwood

Liel

2021

Earthq Engng Struct Dyn

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Several studies have looked at the development of hinge models to simulate the hysteretic response of flexure-and shear-critical reinforced concrete (RC) beamcolumn components from damage initiation to onset of gravity collapse. However, few studies have been conducted to develop similar models for older type bond-critical beam-column components. First, using existing experimental data, this paper describes the calibration of simple and efficient hinge models to simulate the inelastic hysteretic response of as-built and retrofitted splice-deficient columns. Subsequently, to demonstrate the applicability of the hinge models, the seismic performance of as-built and fibre-reinforced polymer (FRP) -retrofitted two-and four-story nonductile RC frame buildings with splice-deficient columns are assessed using nonlinear dynamic analysis procedures. The results show that buildings with bond-critical columns may have a lower collapse potential than buildings with shear-critical columns, implying that in certain cases a longer splice length may actually worsen performance. According to the analyses, local retrofitting of the columns can significantly improve the seismic performance of the buildings. Contrary to results presented in this study, a significant U.S. evaluation methodology for RC frame buildings, FEMA P-2018, indicates that buildings with bond-critical columns have similar collapse potential as buildings with shear-critical columns. Modifications are proposed to improve the FEMA P-2018 provisions. The modelling approach presented in this paper are recommended for incorporation into ASCE/SEI 41, engineering practice and future research.

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Calibrated analytical element for lateral-strength degradation of reinforced concrete columns

Cited by 45 publications

References 12 publications

Modelling of R/C members accounting for shear failure localisation: Hysteretic shear model

Modelling of R/C members accounting for shear failure localisation: Hysteretic shear model

Shear Hysteresis Model for Reinforced Concrete Elements Including the Post-Peak Range

Evaluation of seismic performance of as‐built and retrofitted reinforced concrete frame structures with LAP splice deficiencies

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