scholarly journals Experimental Study on Dynamic Behavior of Unreinforced Masonry Walls

2013 ◽  
Vol 8 (2) ◽  
pp. 305-311 ◽  
Author(s):  
Taiki Saito ◽  
◽  
Luis Moya ◽  
Cesar Fajardo ◽  
Koichi Morita ◽  
...  
Keyword(s):  
Dynamic Behavior ◽  
Failure Mode ◽  
Shear Failure ◽  
Shaking Table Test ◽  
Unreinforced Masonry ◽  
Masonry Wall ◽  
Shaking Table ◽  
Masonry Walls ◽  
Plane Failure ◽  
Out Of Plane

The dynamic behavior of an unreinforced masonry wall is investigated through a shaking table test of two specimens. In order to represent a non-engineering one-story house, the first specimen consists of a Cshaped structure with masonry walls connected only at their ends. The second specimen is built to represent an upper story, so the C wall is connected at the top by a wooden diaphragm floor, and a weight is suspended onto it. The test results show each specimen exhibits different behaviors. In the first specimen, an out-of-plane failure mode governs. In the second specimen, a shear failure mode governs.

scholarly journals Numerical Simulation of Unreinforced Masonry Buildings with Timber Diaphragms

Buildings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 205
Author(s):  
Igor Tomić ◽  
Francesco Vanin ◽  
Ivana Božulić ◽  
Katrin Beyer
Keyword(s):  
Failure Modes ◽  
Unreinforced Masonry ◽  
Masonry Walls ◽  
Masonry Buildings ◽  
Seismic Behaviour ◽  
Plane Failure ◽  
Friction Resistance ◽  
Flexible Diaphragms ◽  
Out Of Plane ◽  
Equivalent Frame

Though flexible diaphragms play a role in the seismic behaviour of unreinforced masonry buildings, the effect of the connections between floors and walls is rarely discussed or explicitly modelled when simulating the response of such buildings. These flexible diaphragms are most commonly timber floors made of planks and beams, which are supported on recesses in the masonry walls and can slide when the friction resistance is reached. Using equivalent frame models, we capture the effects of both the diaphragm stiffness and the finite strength of wall-to-diaphragm connections on the seismic behaviour of unreinforced masonry buildings. To do this, we use a newly developed macro-element able to simulate both in-plane and out-of-plane behaviour of the masonry walls and non-linear springs to simulate wall-to-wall and wall-to-diaphragm connections. As an unretrofitted case study, we model a building on a shake table, which developed large in-plane and out-of-plane displacements. We then simulate three retrofit interventions: Retrofitted diaphragms, connections, and diaphragms and connections. We show that strengthening the diaphragm alone is ineffective when the friction capacity of the wall-to-diaphragm connection is exceeded. This also means that modelling an unstrengthened wall-to-diaphragm connection as having infinite stiffness and strength leads to unrealistic box-type behaviour. This is particularly important if the equivalent frame model should capture both global in-plane and local out-of-plane failure modes.

scholarly journals Experimental Study of Bamboo As A House Retrofitting Material For Developing Countries

2017 ◽  
Vol 14 (2) ◽  
pp. 20-27
Author(s):  
Etri Suhelmidawati ◽  
Rekana Zamzarena ◽  
Fauna Adibroto ◽  
Syofiardi Syofiardi
Keyword(s):  
Developing Countries ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Shaking Table Test ◽  
Large Earthquake ◽  
Masonry Wall ◽  
Shaking Table ◽  
Masonry Walls ◽  
West Sumatra ◽  
Small Cracks

Earthquake is one of the main natural disasters which frequently occur in West Sumatra. Large earthquake September 30, 2009, has caused damage to the structure and caused many casualties. Due to this condition, this research was made to study bamboo as a house retrofitting material for developing countries.  Mechanical and physical properties such as moisture content testing, testing density, testing of compressive strength and tensile strength were conducted. It is obtained from the test results, the highest compressive strength and tensile strength are 94.958 MPa and 183 MPa, showed by Betung bamboo. Shaking table test are also undertaken to investigate the seismic behavior of bamboo masonry wall. Two degree of masonry walls, 60° and 90° are tested in order to check the strength of masonry wall by direction of the coming of an earthquake. From the shaking table test, it was observed that a 60° masonry wall showed a better seismic performance than those of a 90° masonry walls. Small cracks were observed at 90° masonry walls after 20 seconds, while there was no crack at a 60° masonry wall. As a result of these test, using bamboo as a house retrofitting material could be chosen, both of technically and economically.

scholarly journals An Equivalent Truss Model for In-Plane Nonlinear Analysis of Unreinforced Masonry Walls

2018 ◽  
Vol 4 (4) ◽  
pp. 828 ◽  
Author(s):  
Mohammadamir Najafgholipour
Keyword(s):  
Shear Failure ◽  
Computational Cost ◽  
Failure Criteria ◽  
Unreinforced Masonry ◽  
Masonry Wall ◽  
Seismic Evaluation ◽  
Plane Failure ◽  
Seismic Performance Evaluation ◽  
Truss Model ◽  
Performance Based Seismic Design

According to the importance of seismic evaluation of existing unreinforced masonry (URM) buildings, researchers have been interested in numerical modelling of these types of structures and their components. On the other hand, in seismic performance evaluation and retrofitting codes which are mostly based on Performance Based Seismic Design (PBSD), different analysis methods such as linear and nonlinear, static and dynamic analyses are employed. Therefore, simple equivalent frame models with lower computational cost are very useful for modelling and analysis of unreinforced masonry buildings. In this article, a simple equivalent truss model is proposed for modelling and analysis of an unreinforced masonry wall with sliding shear failure as the governing in-plane failure mode. The model is developed according to an analogy between the internal forces in a triangular truss and the Mohr-Coulomb failure criteria. Then, the proposed model is generalized for modelling and push over analysis of combinations of walls. Finally, the modelling procedure is applied for push over analysis of an unreinforced masonry wall consists of some piers and the push over curve of the wall is determined and discussed.

scholarly journals Out-of-Plane Strengthening of Unreinforced Masonry Walls by Glass Fiber-Reinforced Polyurea

2022 ◽  
Vol 8 (1) ◽  
pp. 145-154
Author(s):  
Hye-Sook Jang ◽  
Jae-Hyoung An ◽  
Jun-Hyeok Song ◽  
Seung-Hwan Son ◽  
Yu-Sik Hong ◽  
...  
Keyword(s):  
Glass Fiber ◽  
Glass Fibers ◽  
Peak Load ◽  
Unreinforced Masonry ◽  
Masonry Wall ◽  
Absorption Capacity ◽  
Masonry Walls ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced ◽  
Out Of Plane

Fiber-reinforced polymer reinforcement or polyurea reinforcement techniques are applied to strengthen unreinforced masonry walls (UMWs). The purpose of this experimental study is to verify the out-of-plane reinforcing effect of sprayed glass fiber-reinforced polyurea (GFRPU), which is a composite elastomer made of polyurea and milled glass fibers on UMW. The out-of-plane strengths and ductile behaviors based on various coating shapes are compared in this study. An empirical formula to describe the degree of reinforcement on the out-of-plane strength of the UMW is derived based on the experimental results. It is observed that the peak load-carrying capacity, ductility, and energy absorption capacity gradually improve with an increase in the strengthening degree or area. Compared with the existing masonry wall reinforcement method, the GFRPU technique is a construction method that can help improve the safety performance along with ease of construction and economic efficiency. Doi: 10.28991/CEJ-2022-08-01-011 Full Text: PDF

Shaking table test of fibre reinforced masonry walls under out-of-plane loading

2016 ◽  
Vol 120 ◽  
pp. 89-103 ◽  
Author(s):  
Razieh Sistani Nezhad ◽  
Mohammad Z. Kabir ◽  
Mehdi Banazadeh
Keyword(s):  
Shaking Table Test ◽  
Shaking Table ◽  
Masonry Walls ◽  
Reinforced Masonry ◽  
Out Of Plane

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.

Study on Dynamic Behavior of Ancient Timber Structures Roof

2013 ◽  
Vol 475-476 ◽  
pp. 1559-1562
Author(s):  
Jun Dai
Keyword(s):  
Dynamic Behavior ◽  
Vibration Isolation ◽  
Shaking Table Test ◽  
Shaking Table ◽  
Maximal Response ◽  
Construction Technology ◽  
Magnification Factor ◽  
Finite Element Software ◽  
Moderate Earthquake ◽  
Dynamic Magnification Factor

The roof model of the palace timber buildings was established according to the construction technology of the Ying-tsao fa-shih. Based on its analysis of dynamic behavior with shaking table test and ANSYS finite element software, the dynamic behavior of structure and its maximal response under different conditions were gotten, and also the dynamic magnification factor of the beams layer and the whole structure were gotten, at last the results got by shaking table test was compared with the numerical simulation. Research shows that the nature frequency of the model is 1.486 Hz which is much bigger than that of the whole structure; the maximal displacement of beam layer gradually increases with the increase of ground motion intensity and the height of structure; the vibration isolation performance of semi-rigid tenon-mortise joints in rare earthquake (400gal) is better than that in moderate earthquake (220gal) and frequent earthquake (110gal); the dynamic magnification factor between layers was about 1, and roof 0.9 or so.

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