scholarly journals A Discrete Macro Element Method for Modelling Ductile Steel Frames around the Openings of URM Buildings as Low Impact Retrofitting Strategy

2021 ◽  
Vol 13 (17) ◽  
pp. 9787
Author(s):  
Giuseppe Occhipinti ◽  
Francesco Cannizzaro ◽  
Salvatore Caddemi ◽  
Ivo Caliò
Keyword(s):  
Steel Frames ◽  
Numerical Approach ◽  
Masonry Wall ◽  
Seismic Retrofitting ◽  
Masonry Walls ◽  
Additional Energy ◽  
Displacement Capacity ◽  
Ductile Steel ◽  
Macro Element ◽  
Element Method

This paper adopts the use of steel frames around existing openings as a low-impact seismic retrofitting strategy for unreinforced masonry structures (URM). Although elastic steel frames have been commonly adopted for strengthening masonry walls in case of the realization of new openings, the use of elasto-plastic frames has been proposed only recently. This study adopts the application of low-resistance ductile steel frames on the openings of existing masonry buildings as a low-impact retrofitting strategy. The adopted low-invasive solution possesses the advantage of increasing the in-plane resistance of the masonry wall, improving the displacement capacity, introducing additional energy dissipation under dynamic loadings, and providing a confinement effect on the adjacent masonry piers. An original aspect of the present paper is related to the adopted numerical method for modelling the presence of the steel frames around the openings. Namely, a Discrete Macro-Element Method (DMEM), which allows an efficient and reliable simulation of the involved collapse mechanisms of the masonry walls interacting with the frames, has been adopted. After the validation of the numerical approach, through a comparison with experimental results already reported in the literature, the low-impact strategy has been applied on a benchmark known as the “via Martoglio building”. The obtained results suggest that this low-impact retrofitting strategy can be successfully proposed for URM buildings and can be efficiently modelled by means of the DMEM.

In-plane response of unreinforced masonry walls confined by reinforced concrete tie-columns and tie-beams

2017 ◽  
Vol 20 (11) ◽  
pp. 1632-1643 ◽  
Author(s):  
Masoud Amouzadeh Tabrizi ◽  
Masoud Soltani
Keyword(s):  
Numerical Study ◽  
Nonlinear Behavior ◽  
Numerical Approach ◽  
Masonry Wall ◽  
Masonry Walls ◽  
Lateral Loads ◽  
Confined Masonry ◽  
Smeared Crack ◽  
Modeling Strategy ◽  
Reversed Cyclic

This article focuses on the experimental and analytical investigations of masonry walls surrounded by tie-elements under in-plane loads. The experimental results of an unconfined and a confined masonry wall, tested under reversed cyclic lateral loads, are presented. For numerical study, a micro-modeling strategy, using smeared-crack-based approach, is adopted. In order to validate the numerical approach, experimental test results and data obtained from the literature are used, and through a systematic parametric study, the influence of adjoining walls and number of tie-columns on the seismic behavior of confined masonry panels is numerically assessed and a simple but rational method for predicting the nonlinear behavior of these structures is proposed.

scholarly journals Masonry Walls Retrofitted with Vertical FRP Rebars

Buildings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 72
Author(s):  
Simona Coccia ◽  
Fabio Di Carlo ◽  
Stefania Imperatore
Keyword(s):  
Ad Hoc ◽  
Masonry Wall ◽  
Seismic Retrofitting ◽  
Masonry Walls ◽  
Seismic Capacity ◽  
Seismic Behaviour ◽  
Safety Level ◽  
Dynamic Analyses ◽  
Out Of Plane ◽  
Vertical Bars

The out-of-plane behaviour of the walls as a consequence of an earthquake is the main vulnerability of existing masonry structures. In the case of rigid in compression not tensile resistant material, incremental dynamic analyses may be employed to evaluate the effective strength of a rocking element. When the seismic capacity of the wall is inadequate, retrofit interventions are required to assure an acceptable safety level. Conventional seismic retrofitting techniques on masonry walls influence the seismic performance of the element, which typically is modified in an out-of-plane bending behaviour. In this paper, analytical investigations are presented to investigate the possibility of a seismic retrofitting intervention able to increase the seismic strength of the wall without modifying its seismic behaviour. The analysed retrofitting technique consists in the application of composite vertical bars either in the middle section of the wall or at its external surfaces. The seismic behaviour of the retrofitted masonry wall is analytically evaluated by means of a parametric incremental dynamic analysis, carried out with an ad hoc in-house software. The effectiveness of the intervention is analysed in terms of level of seismic improvement, defined as the ratio between the seismic capacity of the reinforced and unreinforced walls.

scholarly journals Attaining a Beam-Like Behavior with FRP Strips and CAM Ribbons

2018 ◽  
Vol 2 (3) ◽  
pp. 6-16 ◽  
Author(s):  
Elena Ferretti
Keyword(s):  
Ultimate Load ◽  
Masonry Wall ◽  
Experimental Results ◽  
Seismic Retrofitting ◽  
Masonry Walls ◽  
Less Invasive ◽  
Entire Height ◽  
Out Of Plane ◽  
Seismic Forces ◽  
Frp Strips

Abstract One of the major concerns in the seismic retrofitting of masonry walls is that of increasing the ultimate load for out-of-plane forces. In multi-story buildings, these forces may originate from the hammering actions of floors, when the earthquake direction is orthogonal to the wall. A possibility for counteracting the out-of-plane displacements is retaining the wall by building some buttresses, that is, some beams lean against the wall and disposed vertically. Another possibility is to make the buttress in the thickness of the wall. In this second case, we must cut the wall for its entire height, realize the buttress, and restore the masonry wall around it. In both cases, the interventions are highly invasive. The first intervention also leads to increments of mass that enhance the attraction of seismic forces. The aim of this paper is to find a less invasive and lighter alternative for realizing buttresses. We proposed to use FRP strips and steel ribbons in a combined fashion, so as to realize an ideal vertical I-beam embedded into the wall, without requiring to cut the masonry. We also provided some experimental results for verifying the effectiveness of the model.

scholarly journals Attaining a Beam-Like Behavior with FRP Strips and CAM Ribbons

2018 ◽  
Vol 2 (3) ◽  
pp. 7 ◽  
Author(s):  
Elena Ferretti
Keyword(s):  
Ultimate Load ◽  
Masonry Wall ◽  
Experimental Results ◽  
Seismic Retrofitting ◽  
Masonry Walls ◽  
Less Invasive ◽  
Entire Height ◽  
Out Of Plane ◽  
Seismic Forces ◽  
Frp Strips

One of the major concerns in the seismic retrofitting of masonry walls is that of increasing the ultimate load for out-of-plane forces. In multi-story buildings, these forces may originate from the hammering actions of floors, when the earthquake direction is orthogonal to the wall. A possibility for counteracting the out-of-plane displacements is retaining the wall by building some buttresses, that is, some beams lean against the wall and disposed vertically. Another possibility is to make the buttress in the thickness of the wall. In this second case, we must cut the wall for its entire height, realize the buttress, and restore the masonry wall around it. In both cases, the interventions are highly invasive. The first intervention also leads to increments of mass that enhance the attraction of seismic forces. The aim of this paper is to find a less invasive and lighter alternative for realizing buttresses. We proposed to use FRP strips and steel ribbons in a combined fashion, so as to realize an ideal vertical I-beam embedded into the wall, without requiring to cut the masonry. We also provided some experimental results for verifying the effectiveness of the model.

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 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.

Influence of Sulphate on the Moisture Movement of Calcium Silicate Brick Masonry Wall

2010 ◽  
Vol 133-134 ◽  
pp. 201-204
Author(s):  
Ibrahim Mohamad H. Wan ◽  
B.H. Abu Bakar ◽  
M.A. Megat Johari ◽  
P.J. Ramadhansyah
Keyword(s):  
Relative Humidity ◽  
Calcium Silicate ◽  
Masonry Wall ◽  
Sodium Sulphate ◽  
Brick Masonry ◽  
Masonry Walls ◽  
Moisture Movement ◽  
Moisture Expansion ◽  
Curing Period ◽  
Wet Condition

This paper presents the behaviour of moisture movement of calcium silicate brick masonry walls exposed to sodium sulphate environment. The walls were exposed to three sodium sulphate conditions with sulphate concentrations of5%, 10% and 15%. For comparison, some walls were also exposed to dry and wet condition which acts as a control conditions. All specimens were prepared and cured under polythene sheet for 14 days in a controlled environmental room and maintained at relative humidity and temperature of 80 ± 5% and 25 ± 2°C, respectively. After the curing period, the specimens were exposed to sodium sulphate as well as drying and water exposures, during which moisture movement was measured and monitored for a period of up to 7 months. As a result, the moisture expansion was observed and recorded for all masonry wall specimens after exposed to the sulphate condition.

An Effective Numerical Approach for Multiple Void-Crack Interaction

2005 ◽  
Vol 73 (4) ◽  
pp. 525-535 ◽  
Author(s):  
Xiangqiao Yan
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Elastic Plate ◽  
Homogeneous Problem ◽  
Crack Problem ◽  
General System ◽  
Numerical Approach ◽  
Displacement Discontinuity ◽  
Crack Problems ◽  
Element Method

This paper presents a numerical approach to modeling a general system containing multiple interacting cracks and voids in an infinite elastic plate under remote uniform stresses. By extending Bueckner’s principle suited for a crack to a general system containing multiple interacting cracks and voids, the original problem is divided into a homogeneous problem (the one without cracks and voids) subjected to remote loads and a multiple void-crack problem in an unloaded body with applied tractions on the surfaces of cracks and voids. Thus the results in terms of the stress intensity factors (SIFs) can be obtained by considering the latter problem, which is analyzed easily by means of the displacement discontinuity method with crack-tip elements (a boundary element method) proposed recently by the author. Test examples are included to illustrate that the numerical approach is very simple and effective for analyzing multiple crack/void problems in an infinite elastic plate. Specifically, the numerical approach is used to study the microdefect-finite main crack linear elastic interaction. In addition, complex crack problems in infinite/finite plate are examined to test further the accuracy and robustness of the boundary element method.

scholarly journals Macro-element method with water absorption and discharge functions for vertical drains

2015 ◽  
Vol 55 (5) ◽  
pp. 1113-1128 ◽  
Author(s):  
Shotaro Yamada ◽  
Toshihiro Noda ◽  
Mutsumi Tashiro ◽  
Hong-Son Nguyen
Keyword(s):  
Water Absorption ◽  
Vertical Drains ◽  
Macro Element ◽  
Element Method

Mechanical Properties of Various Models of Interlocking Concrete Blocks under In-Plane and Out-of-Plane Loads

2021 ◽  
Vol 881 ◽  
pp. 149-156
Author(s):  
Mochamad Teguh ◽  
Novi Rahmayanti ◽  
Zakki Rizal
Keyword(s):  
Mechanical Properties ◽  
Building Material ◽  
Experimental Tests ◽  
Concrete Block ◽  
Masonry Wall ◽  
Masonry Walls ◽  
Plane Shear ◽  
Out Of Plane ◽  
Concrete Blocks ◽  
Local Materials

Building material innovations in various interlocking concrete block masonry from local materials to withstand lateral earthquake forces is an exciting issue in masonry wall research. The block hook has an advantage in the interlocking system's invention to withstand loads in the in-plane and out-of-plane orientations commonly required by the masonry walls against earthquake forces. Reviews of the investigation of in-plane and out-of-plane masonry walls have rarely been found in previous studies. In this paper, the results of a series of experimental tests with different interlocking models in resisting the simultaneous in-plane shear and out-of-plane bending actions on concrete blocks are presented. This paper presents a research investigation of various interlocking concrete blocks' mechanical properties with different hook thicknesses. Discussion of the trends mentioned above and their implications towards interlocking concrete block mechanical properties is provided.

Sign in / Sign up

Export Citation Format

Share Document