Nonlinear Finite Element Analysis of Unreinforced Masonry Walls

2016 ◽  
Vol 857 ◽  
pp. 142-147
Author(s):  
S. Thomas Feba ◽  
Bennet Kuriakose
Keyword(s):  
Numerical Model ◽  
Unreinforced Masonry ◽  
Masonry Wall ◽  
Seismic Retrofitting ◽  
Nonlinear Static Analysis ◽  
Masonry Walls ◽  
Masonry Structures ◽  
Element Analysis ◽  
Historical Masonry ◽  
Nonlinear Static

Most of the monumental structures worldwide and residential structures in developing countries are built in masonry. The studies performed by various researchers prove the vulnerability of masonry structures under various circumstances, especially under earthquakes, so as to necessitate detailed contemplation. In this paper, a numerical model for nonlinear static analysis of unreinforced masonry walls is developed based on a macro-modelling approach. A detailed parametric study is also performed to analyse the effect of wall thickness as well as length on the behaviour of the masonry wall. The present numerical model can be utilized for risk assessment and seismic retrofitting of historical masonry structures.

scholarly journals Effect of Buttress Form on Transverse Seismic Resistance of High Masonry Walls

2021 ◽  
Author(s):  
M. Arif Gürel ◽  
Rabia İzol ◽  
Çağrı Mollamahmutoğlu ◽  
R. Kadir Pekgökgöz ◽  
F. Şebnem Kuloğlu Yüksel ◽  
...  
Keyword(s):  
Calculation Model ◽  
Nonlinear Static Analysis ◽  
Seismic Resistance ◽  
Masonry Walls ◽  
Analysis Method ◽  
Base Shear ◽  
Basic Model ◽  
Historical Masonry ◽  
Nonlinear Static ◽  
Modelling Approach

Abstract In historical masonry structures having vault, dome and high walls, for safety against gravity, wind and earthquake loads, buttresses are crucial elements. This study aims to investigate the effect of buttress form on the transverse seismic resistance of high masonry walls. For this purpose, a real historical masonry structure covered by a barrel vault, and has a simple and regular plan and elevation shape was considered. From a slice of this structure, a calculation model and a basic model were created. For the masonry, macro-modelling approach was used. Nonlinear static analysis method was adopted, and finite element modeling and calculations were carried out using the Abaqus program. Firstly, on the calculation model the effect of buttress depth on transverse seismic resistance was investigated, and it was seen that the resistance is almost linearly related to the buttress depth. Then, two groups of analyses were performed on the models obtained by mounting different buttress forms to the basic model. In the first group, the volumes of the buttresses were kept equal, and in the second group their base depths and thicknesses were taken equally. At the end of these analyses, by comparing the base shear forces obtained for the models, the effectiveness of buttress form on the transverse seismic resistance has been determined and evaluated. The results revealed that the model with curvilinear concave buttresses in the first group analyses and the model with semi-cylindrical buttresses in the second group analyses have the highest seismic resistance.

scholarly journals In-plane retrofitting of masonry structures by using GFRP strips in the Bedjoints

2021 ◽  
Author(s):  
Fathollah Osmanzadeh ◽  
Elshan Ahani ◽  
Behzad Rafezy ◽  
Mir Naghi Mousavi
Keyword(s):  
Ductile Failure ◽  
Unreinforced Masonry ◽  
Masonry Wall ◽  
Masonry Structures ◽  
Clay Bricks ◽  
Historical Structures ◽  
Before And After ◽  
Lateral Strength ◽  
Historical Masonry ◽  
Strength And Stiffness

Abstract Many unreinforced masonry structures were vulnerable in the past earthquakes and required retrofitting. However, the vulnerability of masonry structures could solve by providing numerous retrofitting approaches, scarcity of appropriate methods that may provide a solution for the historical masonry structures with lesser effects on their façade is vehemently sensible. In this study, two one-third scale masonry wall specimens made by clay bricks were tested under constant vertical and cyclic lateral loading. The specimens consist of an unreinforced wall and a wall retrofitted by GFRP strips. This study investigates the seismic behavior of unreinforced masonry walls before and after using GFRP strips on their bedjoints. To this purpose, various patterns of using GFRP strips have been studied by simplified micro-modeling. The consequence indicates that the proposed retrofitting technique could improve the lateral strength and stiffness of the unreinforced masonry wall along with a considerable increase in the energy dissipation and ductility content, which leads to making a change in the behavior of the wall from brittle to ductile failure. The proposed method could apply to the modern historical structures in which cement mortar has been used as an adhesive between the masonry layers.

scholarly journals Numerical Modeling of Unreinforced Masonry Walls Strengthened with Fe-Based Shape Memory Alloy Strips

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2961
Author(s):  
Moein Rezapour ◽  
Mehdi Ghassemieh ◽  
Masoud Motavalli ◽  
Moslem Shahverdi
Keyword(s):  
Energy Dissipation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Unreinforced Masonry ◽  
Masonry Wall ◽  
Masonry Walls ◽  
Vertical Strip ◽  
Maximum Resistance ◽  
The Cross ◽  
Post Tensioning

This study presents a new way to improve masonry wall behavior. Masonry structures comprise a significant part of the world’s structures. These structures are very vulnerable to earthquakes, and their performances need to be improved. One way to enhance the performances of such types of structures is the use of post-tensioning reinforcements. In the current study, the effects of shape memory alloy as post-tensioning reinforcements on originally unreinforced masonry walls were investigated using finite element simulations in Abaqus. The developed models were validated based on experimental results in the literature. Iron-based shape memory alloy strips were installed on masonry walls by three different configurations, namely in cross or vertical forms. Seven macroscopic masonry walls were modeled in Abaqus software and were subjected to cyclic loading protocol. Parameters such as stiffness, strength, durability, and energy dissipation of these models were then compared. According to the results, the Fe-based strips increased the strength, stiffness, and energy dissipation capacity. So that in the vertical-strip walls, the stiffness increases by 98.1%, and in the cross-strip model's position, the stiffness increases by 127.9%. In the vertical-strip model, the maximum resistance is equal to 108 kN, while in the end cycle, this number is reduced by almost half and reaches 40 kN, in the cross-strip model, the maximum resistance is equal to 104 kN, and in the final cycle, this number decreases by only 13.5% and reaches 90 kN. The scattering of Fe-based strips plays an important role in energy dissipation. Based on the observed behaviors, the greater the scattering, the higher the energy dissipation. The increase was more visible in the walls with the configuration of the crossed Fe-based strips.

scholarly journals Displacement Demand for Nonlinear Static Analyses of Masonry Structures: Critical Review and Improved Formulations

Buildings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 118
Author(s):  
Gabriele Guerrini ◽  
Stylianos Kallioras ◽  
Stefano Bracchi ◽  
Francesco Graziotti ◽  
Andrea Penna
Keyword(s):  
Time History ◽  
Nonlinear Static Analysis ◽  
Equivalent Linearization ◽  
Eurocode 8 ◽  
Masonry Structures ◽  
Equivalent Viscous Damping ◽  
Inelastic Displacement ◽  
N2 Method ◽  
Nonlinear Static ◽  
Nonlinear Time History

This paper discusses different formulations for calculating earthquake-induced displacement demands to be associated with nonlinear static analysis procedures for the assessment of masonry structures. Focus is placed on systems with fundamental periods between 0.1 and 0.5 s, for which the inelastic displacement amplification is usually more pronounced. The accuracy of the predictive equations is assessed based on the results from nonlinear time-history analyses, carried out on single-degree-of-freedom oscillators with hysteretic force–displacement relationships representative of masonry structures. First, the study demonstrates some limitations of two established approaches based on the equivalent linearization concept: the capacity spectrum method of the Dutch guidelines NPR 9998-18, and its version outlined in FEMA 440, both of which overpredict maximum displacements. Two codified formulations relying on inelastic displacement spectra are also evaluated, namely the N2 method of Eurocode 8 and the displacement coefficient method of ASCE 41-17: the former proves to be significantly unconservative, while the latter is affected by excessive dispersion. A non-iterative procedure, using an equivalent linear system with calibrated optimal stiffness and equivalent viscous damping, is then proposed to overcome some of the problems identified earlier. A recently developed modified N2 formulation is shown to improve accuracy while limiting the dispersion of the predictions.

Nonlinear Finite Element Analysis of Masonry Wall Strengthened with Steel Strips

2013 ◽  
Vol 838-841 ◽  
pp. 284-296
Author(s):  
Yu Hua Wang ◽  
Bei Bei Wang ◽  
Pei Chi ◽  
Jun Dong
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Lateral Displacement ◽  
Unreinforced Masonry ◽  
Masonry Wall ◽  
Shear Capacity ◽  
Computational Formula ◽  
Element Analysis ◽  
Steel Strips ◽  
The Cross

The finite element analysis method was adopted to simulate the masonry wall strengthened with steel strips and was verified by comparing with test results. The influence rules of two factors including the cross sectional area of steel strips and vertical compression were investigated. The results show that, as for unreinforced masonry wall, the relationship of the shear capacity of unreinforced masonry wall and the vertical compressive strain is linear under lateral load; the speed of stiffness degeneration is accelerated after the peak point of the curves, but decrease with the increasing of lateral displacement. As for masonry wall strengthened with steel strips, the shear capacity increases significantly, and shows nonlinear relationship with the cross section area of the steel strips and vertical compression; ductility is improved. Finally, a computational formula of shear capacity based on a lot of parametric analysis is proposed to calculate the sectional dimension of steel strips, and it provides theoretical foundation for establishing thorough design method of masonry wall strengthened with steel strips.

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