A state of the art of flat‐slab frame tests for gravity and lateral loading

Coronelli, Dario; Muttoni, Aurelio; Pascu, Ion Radu; Ramos, Aura; Netti, Teresa

doi:10.1002/suco.202000305

Cited by 7 publications

(2 citation statements)

References 14 publications

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“…A state of the art of flat slab floor and frames studies has been presented by Coronelli et al (2020). The results reveal that ultimate drift ratios ranging between 3 and 6% were reached for gravity shear ratios corresponding to seismic design situations.…”

Section: Introductionmentioning

confidence: 99%

Deformation capacity evaluation for flat slab seismic design

Muttoni

Coronelli

Tornaghi

et al. 2022

Bull Earthquake Eng

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In flat-slab frames, which are typically designed as secondary seismic structures, the shear failure of the slab around the column (punching failure) is typically the governing failure mode which limits the deformation capacity and can potentially lead to a progressive collapse of the structure. Existing rules to predict the capacity of flat slab frames to resist imposed lateral displacements without losing the capability to bear gravity loads have been derived empirically from the results of cyclic tests on thin members. These rules account explicitly only for the ratio between acting gravity loads and resistance against concentric punching shear (so-called Gravity Shear Ratio). Recent rational models to estimate the deformation capacity of flat slabs show that other parameters can play a major role and predict a significant size effect (reduced deformation for thick slabs). In this paper, a closed-form expression to predict the deformation capacity of internal slab-column connections as a function of the main parameters is derived from the same model that has been used to develop the punching shear formulae for the second generation of Eurocode 2 for concrete structures. This expression is compared to an existing database of isolated internal slab-column connections showing fine accuracy and allowing to resolve the shortcomings of existing rules. In addition, the results of a testing programme on a full-scale flat-slab frame with two stories and 12 columns are described. The differences between measured interstorey drifts and local slab rotations influencing their capacity to resist shear forces are presented and discussed. With respect to the observed deformation capacities, similar values are obtained as in the isolated specimens and the predictions are confirmed for the internal columns, but significant differences are observed between internal, edge and corner slab-column connections. The effects of punching shear reinforcement and of integrity reinforcement (required according to Eurocode 2 to prevent progressive collapse after punching) are also discussed.

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Section: Introductionmentioning

confidence: 99%

Deformation capacity evaluation for flat slab seismic design

Muttoni

Coronelli

Tornaghi

et al. 2022

Bull Earthquake Eng

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“…Benavent-Climent et al 2008 [32] and 2009 [33] tested both interior and exterior slab-column connections under lateral loadings, and Benavent-Climent et al 2016 [34] and Benavent-Climent et al 2019 [35] conducted shake table tests of a half-scale, one-bay floor system. Further experimental research was conducted by Coronelli et al (2020) [36], with the results of the ultimate drift ratios being between 3% and 6% for gravity shear ratios corresponding to real seismic design conditions. Coelho et al (2004) [37] tested a full-scale, three-storey slab-column structure with one bay in each direction.…”

Section: Generalmentioning

confidence: 99%

Seismic Damage Assessment of Reinforced Concrete Slab-Column Connections—Review of Test Data, Code Provisions and Analytical Models

Genikomsou

2024

Buildings

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Reinforced concrete slab-column connections are vulnerable to punching shear failure when subjected to combined gravity and lateral loadings during earthquakes. Over the years, many experimental campaigns have been conducted and assessed the seismic performance of flat slabs. The experimental findings were used to derive empirical equations for the design provisions. The paper aims to provide a detailed description of the code development for seismic punching shear. Two current code provisions (ACI 318-19, EC 2 & EC 8-2004) for seismic punching shear are presented and discussed. Relevant and updated experimental data of interior slab-column connections without and with shear reinforcement are selected and assessed against the current design provisions with a focus on key response parameters such as the drift ratio and the gravity shear ratio. The ACI 318-19 limit drift line is considered to assess the lateral deformation demand for the connections with respect to the updated database. The gravity shear ratio is shown to have a considerable impact on the limit drift ratio of slab-column connections without shear reinforcement. The majority of the test specimens with no shear reinforcement experienced punching shear failure, followed by the specimens which showed a combined flexure–punching failure. Punching shear failures occurred for a range of gravity shear ratios of 0.2 to 0.9, while all combined flexure–punching shear failures occurred for gravity shear ratio values below 0.5. The shear-reinforced concrete slab-column connections can achieve much higher drift ratios. Most of the slabs were reinforced with shear studs, particularly in the range of gravity shear ratios of 0.4 to 0.6. Most test specimens failed by flexure for gravity shear ratio values of 0.1 to 0.7, followed by the specimens which failed in combined flexure–punching for gravity shear ratio values that ranged from 0.3 to 0.9. Finally, the available numerical and analytical models for seismic punching shear are presented with the objective of observing their potential strengths and limitations.

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