scholarly journals Seismic Strengthening of Unreinforced Masonry Walls using Sprayable Eco-Friendly Ductile Cementitious Composite (EDCC)

2017 ◽  
Vol 210 ◽  
pp. 154-164 ◽  
Author(s):  
Salman Soleimani-Dashtaki ◽  
Carlos E. Ventura ◽  
Nemkumar Banthia
Keyword(s):  
Unreinforced Masonry ◽  
Masonry Walls ◽  
Cementitious Composite ◽  
Seismic Strengthening

Enhancing the out-of-plane behaviour of unreinforced masonry walls under impact loading through the use of partially bonded layers of engineered cementitious composite

2019 ◽  
Vol 11 (2) ◽  
pp. 209-234
Author(s):  
Saeed Pourfalah ◽  
Demetrios M Cotsovos
Keyword(s):  
Impact Loading ◽  
Composite Layer ◽  
Unreinforced Masonry ◽  
Masonry Walls ◽  
Full Potential ◽  
Cementitious Composite ◽  
Premature Failure ◽  
Engineered Cementitious Composite ◽  
Composite Layers ◽  
Out Of Plane

Published experimental work reveals that the out-of-plane behaviour of unreinforced masonry walls under impact loading can be significantly enhanced through the use of engineered cementitious composite layers fully bonded to the surface of the masonry. The disadvantage of this method is associated with the localised cracking exhibited by the engineered cementitious composite layer close to the joints forming between bricks. This cracking is associated with the bond developing between the masonry and the engineered cementitious composite layer and does not allow the latter layer to achieve its full potential, thus resulting in its premature failure. In an attempt to address this problem, a series of drop-weight tests were carried on masonry prismatic specimens strengthened with a layer of engineered cementitious composite partially bonded to the surface of the masonry acting in tension. The latter prismatic specimens consist of a stack of bricks connected with mortar joints. The specimens are considered to provide a simplistic representation of a vertical strip of a masonry wall subjected to out-of-plane actions associated with impact or blast loading. Analysis of the test data reveals that under impact loading, the specimens retrofitted with partially bonded engineered cementitious composite layers can exhibit a more ductile performance compared to that exhibited by the same specimens when strengthened with fully bonded layers of engineered cementitious composite. This is attributed to the fact that along its unbonded length, the engineered cementitious composite layer is subjected to purely uniaxial tension (free from any interaction with the surface of the masonry), allowing for the development of multiple uniformly distributed fine cracks.

Assessing vibration induced damage in unreinforced masonry walls subject to vehicular impact – A numerical study

2021 ◽  
Vol 245 ◽  
pp. 112843
Author(s):  
Mohammad Asad ◽  
Tatheer Zahra ◽  
David P Thambiratnam ◽  
Tommy H.T. Chan ◽  
Yan Zhuge
Keyword(s):  
Numerical Study ◽  
Unreinforced Masonry ◽  
Masonry Walls

Innovative seismic strengthening of historic masonry walls using polymer mortar and steel strips

2021 ◽  
Vol 228 ◽  
pp. 111507
Author(s):  
Xianhua Yao ◽  
Zi-Xiong Guo ◽  
Syed Humayun Basha ◽  
Qunxian Huang
Keyword(s):  
Masonry Walls ◽  
Seismic Strengthening ◽  
Historic Masonry ◽  
Steel Strips ◽  
Polymer Mortar

Full‐scale shake‐table tests on two unreinforced masonry cavity‐wall buildings: effect of an innovative timber retrofit

2021 ◽  
Author(s):  
Marco Miglietta ◽  
Nicolò Damiani ◽  
Gabriele Guerrini ◽  
Francesco Graziotti
Keyword(s):  
Seismic Vulnerability ◽  
Concrete Slab ◽  
Cost Effective ◽  
Unreinforced Masonry ◽  
Full Scale ◽  
Cavity Wall ◽  
Masonry Walls ◽  
Shake Table ◽  
Earthquake Excitation ◽  
Reinforced Concrete Slab

AbstractTwo full-scale building specimens were tested on the shake-table at the EUCENTRE Foundation laboratories in Pavia (Italy), to assess the effectiveness of an innovative timber retrofit solution, within a comprehensive research campaign on the seismic vulnerability of existing Dutch unreinforced masonry structures. The buildings represented the end-unit of a two-storey terraced house typical of the North-Eastern Netherlands, a region affected by induced seismicity over the last few decades. This building typology is particularly vulnerable to earthquake excitation due to lack of seismic details and irregular distribution of large openings in masonry walls. Both specimens were built with the same geometry. Their structural system consisted of cavity walls, with interior load-bearing calcium-silicate leaf and exterior clay veneer, and included a first-floor reinforced concrete slab, a second-floor timber framing, and a roof timber structure supported by masonry gables. A timber retrofit was designed and installed inside the second specimen, providing an innovative sustainable, light-weight, reversible, and cost-effective technique, which could be extensively applied to actual buildings. Timber frames were connected to the interior surface of the masonry walls and completed by oriented strands boards nailed to them. The second-floor timber diaphragm was stiffened and strengthened by a layer of oriented-strand boards, nailed to the existing joists and to additional blocking elements through the existing planks. These interventions resulted also in improved wall-to-diaphragm connections with the inner leaf at both floors, while steel ties were added between the cavity-wall leaves. The application of the retrofit system favored a global response of the building with increased lateral capacities of the masonry walls. This paper describes in detail the bare and retrofitted specimens, compares the experimental results obtained through similar incremental dynamic shake-table test protocols up to near-collapse conditions, and identifies damage states and damage limits associated with displacements and deformations.

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.

Out-of-plane strength reduction of unreinforced masonry walls because of in-plane damages

2015 ◽  
Vol 44 (13) ◽  
pp. 2157-2176 ◽  
Author(s):  
Kiarash M. Dolatshahi ◽  
Mohammad Yekrangnia
Keyword(s):  
Unreinforced Masonry ◽  
Strength Reduction ◽  
Masonry Walls ◽  
Out Of Plane

Experimental testing of unreinforced masonry walls with openings subject to cyclic in-plane shear

2016 ◽  
pp. 1401-1408 ◽  
Author(s):  
C. Allen ◽  
M.J. Masia ◽  
A.W. Page ◽  
M.C. Griffith ◽  
H. Derakhshan ◽  
...  
Keyword(s):  
Experimental Testing ◽  
Unreinforced Masonry ◽  
Masonry Walls ◽  
Plane Shear

scholarly journals Numerical simulation of soft brick unreinforced masonry walls subjected to lateral loads

2018 ◽  
Vol 5 (1) ◽  
pp. 1551503
Author(s):  
Jayaprakash Vemuri ◽  
Syed Ehteshamuddin ◽  
Subramaniam Kolluru ◽  
Massimo Latour
Keyword(s):  
Numerical Simulation ◽  
Unreinforced Masonry ◽  
Masonry Walls ◽  
Lateral Loads
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