Behavior of Square Infilled Frames

Smith, Bryan Stafford

doi:10.1061/jsdeag.0001387

Cited by 190 publications

(34 citation statements)

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“…It was assumed in Model C that the sectional area of the central strut was the double of that corresponding to the off-diagonal struts. The separation between the struts in Models B and C was adopted as a fraction of the contact length, z, defined by Stafford Smith, 1966, It must be noted that the models shown in Figure 1 are valid for static analysis because the struts are located in order to represent the diagonal compressive field that develops in the panel. When the structure is subjected to cyclic or dynamic loading, the diagonal struts should change according the direction of the loading.…”

Section: Preliminary Studymentioning

confidence: 99%

Proposed macro-model for the analysis of infilled frame structures

Crisafulli

Carr

2007

BNZSEE

156

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Reinforced concrete frames infilled with masonry panels constitute an important part of the high-risk structures in different regions of high seismicity. In some developing countries, they are still used as main structural system for low to medium rise buildings. Consequently, reliable methods to analyse infilled frames are required in order to reduce the loss of life and property associated with a possible structural failure. The equivalent strut model, proposed in the 1960s, is a simple procedure to represent the effect of the masonry panel. Several improvements of the original model have been proposed, as a result of a better understanding of the behaviour of these structures and the development of computer software. This paper presents a new macro-model for the evaluation of the global response of the structure, which is based on a multi-strut formulation,. The model, implemented as 4-node panel element, accounts separately for the compressive and shear behaviour of masonry using a double truss mechanism and a shear spring in each direction. The principal premises in the development of the model are the rational consideration of the particular characteristics of masonry and the adequate representation of the hysteretic response. Furthermore, the model is able to represent different modes of failure in shear observed for masonry infills. The comparison of analytical results with experimental data showed that the proposed model, with a proper calibration, is able to represent adequately the in-plane response of infilled frames.

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Section: Preliminary Studymentioning

confidence: 99%

Proposed macro-model for the analysis of infilled frame structures

Crisafulli

Carr

2007

BNZSEE

156

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“…Mechanic-based macro-modeling approaches are derived based on the observation from experimental test results where the load path within the infill panel mainly follows the diagonal direction [29][30][31]. The idea behind the macro-modeling approach is to replace masonry infills by means of one or more equivalent pin-jointed struts for each panel.…”

Section: Modeling Approaches To Simulate the Presence Of Masonry Infimentioning

confidence: 99%

“…The single-strut model was originally proposed by Polyakov [42] and implemented by Holmes [32], which proposed to calculate the width of the equivalent strut as 1/3 of the diagonal length. Afterwards, several authors [29][30][31]37,[43][44][45][46][47] proposed more detailed formulations mainly based on the relative infill panel to surrounding frame elastic stiffness λh first introduced by Stafford-Smith [29]. The single-strut model was originally proposed by Polyakov [42] and implemented by Holmes [32], which proposed to calculate the width of the equivalent strut as 1/3 of the diagonal length.…”

Section: Single-strut Geometrymentioning

confidence: 99%

Effect of Masonry Infill Constitutive Law on the Global Response of Infilled RC Buildings

2021

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Masonry-infilled reinforced concrete frames represent a very common construction typology across the Mediterranean countries. The presence of infills substantially modifies the global seismic performances of buildings in terms of strength, stiffness, and energy dissipation. Although several research studies focused on the overall performances of infilled reinforced concrete frames, the modeling of infill panels remains an open issue due to the complex interaction between the infill and the frame and the uncertainties involved in the definition of the problem. In the present paper, an existing masonry-infilled RC frame designed according to obsolete seismic codes is chosen as a case study. A refined three-dimensional finite element model is built for performing nonlinear static and time-history analyses in order to investigate some significant aspects related to the modeling of infills. In particular, it is investigated the effect of different infill constitutive models on the seismic performance of infilled RC building expressed in terms of engineering demand parameters such as interstory drift ratios and peak floor accelerations, and on the generation of damage fragility curves.

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“…The parameter λ defines the relative stiffness of the RC frame and the infill panel, according to the formulation developed in [17], in which Ec is the concrete elastic modulus, Jp is the moment of inertia of the columns of the surrounding frame and θ is the inclination angle of the panel with respect to the horizontal. The overstrength ratio, i.e.…”

Section: Masonry Infillsmentioning

confidence: 99%

Fragility Models for Existing Masonry Infilled Rc Frames in the Emilia Area

Salamida¹,

Buratti²

2021

Proceedings of the 8th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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Fragility models are important tools for seismic risk assessment and seismic damage scenarios estimation. Some models are already available in the literature, however, in the case of infilled RC frames, further investigations are necessary, given the high uncertainty about their behaviour. In fact, damage observations following seismic events, suggest that the presence of masonry infills can strongly influence the response of reinforced concrete (RC) frames and affect their collapse mechanisms. The main goal of this work is to contribute to the seismic vulnerability assessment of the existing building stock in the Emilia-Romagna region in northern Italy, developing fragility models for infilled RC frame buildings. On the basis of an analysis of both census data on the existing building stock and on damage survey forms after the 2012 Earthquake, a set of representative structures was defined and modelled with finite elements, adopting a concentrated plasticity approach. Different modelling approaches of the infill walls were considered, using single and multi-strut models, in order to simulate shear failure in columns. Non-linear static (push-over) analyses were then carried out on these models to obtain their capacity curves. Displacement demands were computed using simplified procedures (IN2 method). The definition of damage levels in the models was based on the achievement of local deformation capacity limits of structural and non-structural elements, according to the classification provided by the EMS-98 Macro-seismic scale. Fragility curves were finally obtained by considering uncertainties in material properties, by means of the Response Surface method, as well as ground-motion record-to-record variability.

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Behavior of Square Infilled Frames

Cited by 190 publications

References 0 publications

Proposed macro-model for the analysis of infilled frame structures

Proposed macro-model for the analysis of infilled frame structures

Effect of Masonry Infill Constitutive Law on the Global Response of Infilled RC Buildings

Fragility Models for Existing Masonry Infilled Rc Frames in the Emilia Area

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