scholarly journals A two-level macroscale continuum description with embedded discontinuities for nonlinear analysis of brick/block masonry

2022 ◽  
Author(s):  
B. Pantò ◽  
L. Macorini ◽  
B. A. Izzuddin
Keyword(s):  
Local Level ◽  
Model Material ◽  
Internal Layers ◽  
Structural Walls ◽  
Embedded Discontinuities ◽  
Large Structures ◽  
Out Of Plane ◽  
Masonry Material ◽  
Structural Scale ◽  
Bond Characteristics

AbstractA great proportion of the existing architectural heritage, including historical and monumental constructions, is made of brick/block masonry. This material shows a strong anisotropic behaviour resulting from the specific arrangement of units and mortar joints, which renders the accurate simulation of the masonry response a complex task. In general, mesoscale modelling approaches provide realistic predictions due to the explicit representation of the masonry bond characteristics. However, these detailed models are very computationally demanding and mostly unsuitable for practical assessment of large structures. Macroscale models are more efficient, but they require complex calibration procedures to evaluate model material parameters. This paper presents an advanced continuum macroscale model based on a two-scale nonlinear description for masonry material which requires only simple calibration at structural scale. A continuum strain field is considered at the macroscale level, while a 3D distribution of embedded internal layers allows for the anisotropic mesoscale features at the local level. A damage-plasticity constitutive model is employed to mechanically characterise each internal layer using different material properties along the two main directions on the plane of the masonry panel and along its thickness. The accuracy of the proposed macroscale model is assessed considering the response of structural walls previously tested under in-plane and out-of-plane loading and modelled using the more refined mesoscale strategy. The results achieved confirm the significant potential and the ability of the proposed macroscale description for brick/block masonry to provide accurate and efficient response predictions under different monotonic and cyclic loading conditions.

A parametric study on out-of-plane instability of doubly reinforced structural walls. Part II: Experimental investigation

2020 ◽  
Vol 18 (11) ◽  
pp. 5193-5220
Author(s):  
Farhad Dashti ◽  
Mayank Tripathi ◽  
Rajesh P. Dhakal ◽  
Stefano Pampanin
Keyword(s):  
Experimental Investigation ◽  
Parametric Study ◽  
Structural Walls ◽  
Out Of Plane

scholarly journals The ductility of structural walls

1985 ◽  
Vol 18 (3) ◽  
pp. 250-269 ◽  
Author(s):  
T. Paulay ◽  
W. J. Goodsir
Keyword(s):  
Reinforced Concrete ◽  
Energy Dissipation ◽  
Shear Load ◽  
Lateral Shear ◽  
Structural Walls ◽  
Structural Wall ◽  
Full Size ◽  
Out Of Plane ◽  
Good Energy ◽  
Code Provisions

The behaviour of four approximately 1/4 full size reinforced concrete structural wall models, subjected to cyclic
lateral shear load and variable axial compression, is reported. The primary aim of the study was to investigate
the mechanism of out of plane instability and the adequacy of existing code provisions with respect to the confinement
of critical parts of the flexural compression zones of wall sections that may be subjected during an earthquake to
large inelastic displacements. While all units exhibited good energy dissipation properties, failure in the majority of cases occurred suddenly when concrete compression strains resulting from large ductility demands became excessive in the unconfined regions of the wall section. Failure by out of plane buckling was found to occur at a relatively small lateral load, after the buckled region has been subjected in a proceeding cycle to very large inelastic tensile strains. Recommendations are made for improved arrangement of the confining hoop reinforcement in the end regions of wall sections.

scholarly journals Development and Calibration of a 3D Micromodel for Evaluation of Masonry Infilled RC Frame Structural Vulnerability to Earthquakes

Geosciences ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 468
Author(s):  
Filip Anić ◽  
Davorin Penava ◽  
Vasilis Sarhosis ◽  
Lars Abrahamczyk
Keyword(s):  
Material Model ◽  
Masonry Wall ◽  
Reinforced Concrete Frame ◽  
Computational Stability ◽  
Infill Walls ◽  
Physical Test ◽  
Concrete Frame ◽  
Out Of Plane ◽  
Masonry Material ◽  
Damage States

Within the scope of literature, the influence of openings within the infill walls that are bounded by a reinforced concrete frame and excited by seismic drift forces in both in- and out-of-plane direction is still uncharted. Therefore, a 3D micromodel was developed and calibrated thereafter, to gain more insight in the topic. The micromodels were calibrated against their equivalent physical test specimens of in-plane, out-of-plane drift driven tests on frames with and without infill walls and openings, as well as out-of-plane bend test of masonry walls. Micromodels were rectified based on their behavior and damage states. As a result of the calibration process, it was found that micromodels were sensitive and insensitive to various parameters, regarding the model’s behavior and computational stability. It was found that, even within the same material model, some parameters had more effects when attributed to concrete rather than on masonry. Generally, the in-plane behavior of infilled frames was found to be largely governed by the interface material model. The out-of-plane masonry wall simulations were governed by the tensile strength of both the interface and masonry material model. Yet, the out-of-plane drift driven test was governed by the concrete material properties.

Analogue modelling of strike-slip tectonics from basin to structural-scale comparing silica sand and new rock-analogue materials

2021 ◽  
Author(s):  
Luigi Massaro ◽  
Jürgen Adam ◽  
Elham Jonade ◽  
Yasuhiro Yamada
Keyword(s):  
Fault Zones ◽  
Strike Slip ◽  
Model Material ◽  
Scaling Factor ◽  
Silica Sand ◽  
Model Resolution ◽  
Geometrical Scaling ◽  
Deformation Processes ◽  
Structural Scale ◽  
Fracture Processes

<p>Strike-slip fault zones commonly display complex 3D geometries, with high structural variability along strike and with depth and their architecture and evolution are difficult to analyse. In this regard, analogue modelling represents a powerful tool to investigate the structural, kinematic and mechanical processes in strike-slip fault systems with variable scales. In detail, dynamically scaled experiments allow the direct comparison between model and nature. The geometrical scale factor defines the model resolution, in terms of model/prototype length equivalence, and depends on the physical properties of prototype and model material. Therefore, the choice of the analogue material is critical in scaled analogue experiments.<br>Granular materials like dry silica sand are ideal for the simulation of upper crustal deformation processes due to similar non-linear strain-dependent deformation behaviour of granular flow and brittle rock deformation. Comparing the geometrical scaling factor of the common analogue materials applied in tectonic models, we identified a model resolution gap for the simulation of fault-fracture processes corresponding to the structural scale (1 m – 100 m) observed in fault zones and damage zones in outcrops, field studies or subsurface well data. We developed a new Granular Rock-Analogue Material (GRAM) for the simulation of fault-fracture processes at the structural scale. GRAM is an ultra-weak sand aggregate composed of silica sand and hemihydrate powder capable to deform by tensile and shear failure under variable stress conditions. Based on dynamical shear tests, the new GRAM is characterised by a similar stress-strain curve as dry silica sand and has a geometrical scaling factor L<sup>*</sup>= L<sub>model</sub>/L<sub>nature</sub> = 10<sup>-3</sup> (1 cm in model = 20 m in nature).<br>We performed strike-slip experiments at two different length scales, applying as model material dry silica sand and the new GRAM. Digital Image Correlation (DIC) time-series stereo images of the experiments surface allowed the comparison of the developed structures at different stages of dextral displacement above a single planar basement fault. The analysis of fractures localisation and growth in the strike-slip zone with displacement and strain components enabled the comparison of the different structural styles characterising dry silica sand and GRAM models. The application of the developed GRAM in scaled experiments can provide new insights to the multi-scale investigation of complex deformation processes with analogue models. </p>

scholarly journals Tests on slender ductile structural walls designed according to New Zealand Standard

2017 ◽  
Vol 50 (4) ◽  
pp. 504-516 ◽  
Author(s):  
Farhad Dashti ◽  
Rajesh P. Dhakal ◽  
Stefano Pampanin
Keyword(s):  
New Zealand ◽  
Failure Modes ◽  
Experimental Program ◽  
Test Results ◽  
Structural Walls ◽  
Lateral Drift ◽  
Failure Patterns ◽  
The Third ◽  
Out Of Plane ◽  
Bar Buckling

This paper presents an experimental study conducted to investigate the seismic performance and out-of-plane response of three rectangular doubly reinforced ductile wall specimens subjected to an in-plane cyclic quasi-static loading. The specimens were half-scale, representing the first story of four story prototype walls designed according to NZS3101:2006. The experimental program including details of the specimens, material properties, test setup, loading protocol and instrumentation is described. Also, the test observations, with focus on the significant stages of wall response as well as the failure patterns of the specimens, are reported considering the correlation between seismic damage and lateral drift. Two of the specimens failed at 2% drift, and their failure modes comprised of bar fracture, bar buckling, concrete crushing and out-of-plane instability. The failure pattern of the third specimen was pure out-of-plane instability which proved to have the potential to cause sudden collapse of slender ductile walls that are designed to resist other failure modes. In light of the test results, the efficacy of wall design provisions in the New Zealand concrete design standard (NZS3101) associated with the observed failure modes is scrutinised.

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